1969 Chris Craft Roamer 46 Refit: Installing the Exhaust Risers

Last week it was the Throne Room paint job that finally got done. This week, the exhaust risers got installed.

On the way to the boatyard

Hanging by a string

I suspended the showerhead from the CO2 fire extinguisher pipes to take the weight while I put the bolts in.

Starboard showerhead is pointed toward the muffler inlet

New old stock

I’ve had this 6″ exhaust hose for a long time, but it’s been wrapped in plastic and the rubber is still like-new. It’s nice to finally be installing stuff like this that’s been in the way for so long.

Starboard riser is installed

As a precaution, I used stainless safety wire to secure the Inferno Wrap, especially near the flange and the showerhead.

Not elegant, but it works

Exhaust temp sender

Temp sender base is installed in the flange port

Starboard side exhaust is done

Port side riser is ready to install

The flange gasket is hanging from the raw water outlet of the heat exchanger in the picture above. It’s not a metal gasket, which is what came with the engines. Hopefully, this type will seal better than the originals.

The OEM flange gaskets showed signs of leaking

Major blowouts

Port riser showerhead is pointing at the right place

Port riser hose is installed

Port exhaust temp sender is installed

The only thing left to complete the exhaust installation is installing raw water hoses. It’s taken a long time to get to this point, but it sure feels good getting this done.

Next up in our 1969 Chris Craft Roamer 46 Refit: The V-berth Bulkhead

1969 Chris Craft Roamer 46 Refit: More Exhaust Riser Insulation

I wish everyone (myself included) a happy and productive 2017, which for me would entail getting this boat done enough that I can finally splash it and take it around to my home port!

With the exhaust risers welded up and the starboard riser insulated, I bought some high temp epoxy resin with the intention of making a hard shell to cover the insulation. But the more I try to make a hard shell, the less convinced I am that I can pull it off. I welcome any suggestions or comments about how to proceed.

DeAngelo riser I bought by mistake has a nice hard shell

I dissected this riser to see how DeAngelo makes them. It’s just a shiny fiberglass layer over dense blanket insulation. But this riser doesn’t have the sharp mandrel bends that mine does, so wrapping it would have been pretty easy. Then there’s the shiny coating, which appears to be just tinted resin that’s heavily saturated the fiberglass cloth below. The more I think about it, if I wet out fiberglass that much, gravity will take over and it’ll end up dripping onto the floor. All I can come up with is that I’d need to mount the riser in a low speed part rotator that kept moving until the resin set up to get a nice, uniform surface like DeAngelo does. Otherwise, I’d need to use the same approach as we did when we made the cabin top bullet-proof, and do the FRP layer, then top with fairing compound, THEN come back and sand, prime, and paint later. But fairing compound, epoxy primer, and urethane paint aren’t high temp products…that can’t be the right way to do it.

When last we talked about my risers…

The 1″ ceramic blanket I’m using as primary insulation is outstanding to work with, and the Inferno Wrap is much, much easier to use than any fiberglass strip product I’ve seen. But after thinking about this over the last couple of weeks, I decided that if one layer of ceramic blanket is good, two would be even better. So…off came the Inferno Wrap and out came the scissors.

Two full inches of ceramic blanket insulation

The mandrel bends are the tricky part

Where there’s a will–and spray adhesive–there’s a way

Inferno Wrap locks the ceramic in place

I wasn’t going for a nice, uniform wrap because I was still planning on doing a fiberglass hard shell at this point. Even without uniform spacing, the Inferno Wrap looks good and holds everything securely. The Inferno Wrap manufacturer recommends the use of straps to permanently hold their product in place.

Ready for a test fit of the FRP layer

First, cut the 1708 into thin strips

Heavy 1708 biaxial cloth cut into strips wraps very nicely, but only on the straight sections

At the sharp bends, the heavy cloth leaves high ridges at every overlap. At the exhaust flange, I never was able to get it to lay down nicely in full contact with the substrate, even though  I spent two whole days trying. Maybe if I overlayed the 1708 with a lighter fabric…

Overlaying the 1708 with 9oz fabric…epic fail

It turns out that the lighter 9 oz fabric lays down even worse around the tight mandrel bends than the 1708. It looked worse with the added layer. So, then I thought maybe I should use the 9 oz fabric as the base layer, and top that with pre-pregged 1708. So I gave that a couple of dry test fits…total failure.

At the end of a long and frustrating weekend…

I tried every permutation in wrapping the FRP, but none of them worked. Now I have a bunch of strips of fiberglass fabric with tattered edges from being handled too much, especially the lightweight stuff. I realize that when wetted out, fiberglass fabric can become quite pliable. But these mandrel bends are tight, and I don’t know how to keep everything in place and smooth until the resin cures.

It did occur to me that I could try wetting out the Inferno Wrap with resin and applying it. I also suspect that DeAngelo isn’t using straight fiberglass to get that nice, smooth finish. But then another thought occurred to me: why not just forget the hard shell? Granted, it’s prettier than fabric insulation blankets, and the hard shell would tend to reduce the possibility of corrosion under the somewhat permeable insulation. Plain Inferno Wrap would eventually get dirty, but if it does (and it bothered me) I could just put another layer on over the top. And there’s still that question of how to keep the resin dripping off until it cures.

I’m leaning toward abandoning the hard shell and just using the double ceramic blanket topped with Inferno Wrap, secured with stainless straps. Feel free to make suggestions/comments below.

Next up on our 1969 Chris Craft Roamer 46 Refit: Priming the V-berth Head

1969 Chris Craft Roamer 46 Refit: Insulating the Starboard Exhaust Riser

Good news! The truck transmission is rebuilt!

Bad news! My wallet is significantly lighter, and now the catalytic converters are tripping codes! I may have to think about monetizing this blog!

Props to commenter Tom aka Florida Boater for reminding me about this hilarious song from the TV show Hee Haw in response to my last post lamenting my life as an old-school country western song. I hadn’t heard that song in decades, but it’s absolutely perfect for this refit! 🙂

That said, I finally wrapped up the welding on the stainless exhaust risers. Next is insulation on the dry sections. I initially planned to use Inferno Wrap from Heatshield Products, and bought 200′ worth of the 2″ wide version. But when I test wrapped one riser, I decided it just wasn’t thick enough to hold in the heat. A fellow on boatdiesel.com said that with 3/8″ of fiberglass wrap, he was seeing 400°F on the outside of the wrap during a run at high cruise speed. I want these things insulated well enough to be able to touch the exterior shell without getting burned. I considered using dry  fiberglass cloth since I’ve got lots left over and could easily build it up to a 1″ wrap or more. But then I found ceramic fiber blanket material. This  stuff is commonly used in the manufacture and installation of wood and pellet stoves. It’s rated for 2,600°F continuous, which is 2x what it will ever see, can easily be cut with professional-grade scissors, and comes in various thicknesses. I got a 1″ x 24″ x 50′ roll and gave my idea a go. It turned out pretty good, I think.

The mandrel bends are challenging

After doing some rough measuring and cutting, I snipped wedges out of the insulation so it would be able to have 100% contact with the the tubing around the mandrel bends. I used el cheapo spray adhesive to stick the center of the wrap to the tube, then snipped additional bits off of one section at a time to get just the right fit. Then I hit it with more spray adhesive, stuck the section in place, and moved on to the next. The spray adhesive isn’t heat rated. I’m only using it to keep the insulation in place until I do the second layer wrap. The adhesive is going to stink when I first run the engines, but once it cooks off I don’t expect it to be a problem.

Use Inferno Wrap as the second layer

In retrospect, I didn’t need the Inferno Wrap at all. I could have just cut a bunch of fiberglass strips from the rolls of cloth I’ve got leftover. But since I’ve got it, might as well use it.

Also, I found it was easiest to use a separate piece of the insulation blanket on the inside radius of the mandrel bends, then form a second piece on the outside radius and sides of the tubing. Doing it all in one go is unnecessary and much more difficult…just gotta make sure there’s 100% coverage.

That’s much, much easier doing the mandrel bends with two pieces

That’s 1″ of ceramic fiber topped with Inferno Wrap

That should keep the heat in

It looks like this approach will work. Next I’ll slice a bunch of strips off the 54″ rolls of fiberglass cloth I’ve got and wrap the riser again, then apply a final layer wetted out with high temp epoxy for the hard shell. Sounds like a good project for this weekend, but only after I get the catalytic converters swapped out in my truck.

Merry Christmas to you all!

Next up on our 1969 Chris Craft Roamer 46 Refit: The Safety Rail Stanchions (again)

1969 Chris Craft Roamer 46 Refit: My Life Is An Old-School Country Western Song

Bad luck (coupled with bad decisions) has been a running theme over the course of this refit. Of course, there was the paperwork snafu that could have tanked the project (there are times when I wish it had). Then there was the burglary in 2014, and the uninsured damage from the big boat explosion next to mine in 2015. Deaths in the family and, more recently, my painter’s 29 year-old brother passing suddenly have made it difficult, too. My old Ford F150 had been a real trooper, but the muffler falling off driving down the road and some other issues convinced me that nature was trying to take it back (and succeeding).

So I sold the truck and got a replacement–a 2005 Nissan Frontier that needed tires, a front bumper, and an alternator. It was a great truck over the spring and summer. Then the missus misjudged distance while backing up her 2002 Mazda Tribute, folding the quarter panel into an accordion. I’d just dropped the full coverage insurance a month before, since it was old enough that the value didn’t justify it. The cost to replace the quarter panel is roughly equal to the value of the vehicle. So she started driving the Nissan truck to work daily, until the transmission failed completely driving home one night last month…on a bridge….during rush hour.  Turns out the transmission cooler in the radiator fails in certain Nissans, and the coolant that gets into the transmission kills them dead. There’s an extended warranty up to 8 years/80,000 miles, but this truck had 98,000 on it when I bought it. So, we went back to driving the crashed Mazda until the transmission gets rebuilt. With the truck out of commission, I can’t load up my Miller Trailblazer mobile welder and finish installing the main raw water inlets.

It’s always gotta be soooo complicated.

But the refit must go on, and I’m getting closer to having the boat exhaust system ready to install. I needed to weld a bracket on the showerhead so I can install a brace that will be attached to the gear. This will help support the weight of the exhaust rather than having it all hang off the turbo flange. I wanted to weld a pad for the bracket on the showerheads to spread out the load, and was using my bandsaw to cut a piece from some extra 6″ 316 stainless tube that was left over from the showerhead. It perfectly matches the curvature, so it’ll be easy to put on. The Harbor Freight bandsaw I bought earlier this year sliced the first piece while I was prepping the welding table. After I set up the second cut, I went inside the house for something…then got distracted. No biggie…the bandsaw shuts off automatically once it finishes the cut. Ten minutes later, I went back to the garage and smelled burnt electrics. Turns out the stainless tube had slipped out of the clamp, twisted, and caused the blade to lock up. The motors on these el cheapo HF bandsaws don’t have thermal protection, so it just kept grunting away until it shorted the windings and let the smoke out of the internal wiring.

Gad.

Pad clamped to the showerhead and ready to weld

Somebody let the smoke out

I swear, I was only away for a few minutes. Both capacitors melted, and the windings are toast. I found a replacement motor on ebay for a good price. But they’re made in China, so you never know if they’ll be DOA or not after waiting a week for the new one to arrive. Oh, and it turns out that Harbor Freight advertizes their metalcutting bandsaw as having a 1hp motor, but in fact they’re only 1/3 of that. The replacement motor is accurately labeled 1/2hp though it’s got the same size case. So the replacement motor has more grunt than the OE unit, and it also comes with thermal protection.

Gotta see the bright side wherever it presents itself.

Back in business

But not really. After getting the new motor installed, the bandsaw wasn’t cutting straight. Turns out the blade had fallen off the backing guide bearing before the old motor self-destructed, so the blade kept going around and getting pinched a bit between the three upper guide bearings. The effect was similar to what happens when you run metal through an English wheel–it  put a curve into the blade. So now I’m waiting another few days for new blades to arrive. But that didn’t stop me from welding up the one pad and bracket. I ran out of argon just as I finished the last section. Now, if only I had a truck so I could get another bottle of gas…

Ready for insulation

Also, we had two warm days last weekend, and my painter indicated he was coming out to FINALLY paint the v-berth head. His car is in the shop (it needs a transmission, too!), so he was getting a ride from his cousin, who works at the same place. They hit a patch of black ice on the way in, skidded off the road, and smashed the car into a tree. Nobody’s hurt, but they had no way to come to the boatyard. So…that’s stalled again until further notice.

Oh…one more thing…I mentioned previously that some of the panes of glass didn’t fit. It took months for the glass shop to finally get around to fixing their errors even though I was happy to pay for mine. They just contacted me to say that the machine that cuts finger notches for the slider windows broke last month and they have no plans to replace it, so the three sliders I’ll have made in this batch won’t match the others on the boat.

Sheesh. If there isn’t an old-school country western song in all of this…

Next up on our 1969 Chris Craft Roamer 46 Refit: Insulating the Starboard Exhaust Riser

1969 Chris Craft Roamer 46 Refit: Welding the Port Exhaust Riser Showerhead

The port riser showerhead was a bit easier to weld up than the starboard riser since it doesn’t have that sharp mandrel bend just before the showerhead can. Still, it took pretty much a whole day to cut all the holes, fit the water inlet and overflow pipe, purge, and get the welding done.

 

First, cut the raw water inlet tube

Point it just behind the exhaust flange and mark with a sharpie

Cope the raw water inlet tube to match the showerhead pipe

Fire up the Zeny Cut 50 and rough cut the raw water inlet hole

The Zeny plasma cutter is a very useful tool…and only $188!

Next, clean up the hole with a carbide burr

Cutting the hole takes less than ten seconds. Cleaning up the hole takes another minute or two. I don’t need a plasma cutter all the time, but it’s great to have one around! What a time saver!

Looks good!

Mark the hole for the raw water overflow

And fire up the Zeny again

Line up the marks, start the purge, and start welding

Fuse the inside joints after the outside is welded

Ready to weld the showerhead to the exhaust

The top of the showerhead is welded

The nozzle plate gets welded last

Done!

Next I have to take the risers to the boat and do a final test fit. I still need to add a tab to the showerhead so I can attach a support arm; I don’t want all of that weight hanging off the turbo flange without additional support. Then I’ll insulate the riser with a combination of ceramic fiber blanket, which is good for continuous exposure to 2,600°F, then a layer of Inferno Wrap to hold that tightly in place, topped with fiberglass coated with high temp epoxy. I have a bottle of white epoxy colorant, which would look nice when the riser is new. I suspect it will brown a bit on the exhaust flange end once the engines run for a bit. All of the other hardshell risers I’ve seen are black, presumably because it hides any discoloration. Feel free to comment below about black/white preferences.

Next up on our 1969 Chris Craft Roamer 46 Refit: Making the Battery Switch Mount

1969 Chris Craft Roamer 46 Refit: Welding the Starboard Exhaust Riser

With the port exhaust riser joints and showerhead end plate and and spray nozzles welded up, next I repeated the process on the starboard side. I also cut, fitted, and welded the showerhead. These are coming together pretty well.

The port side has some tight curves

I’ve seen videos of guys welding exhaust tubing who use devices to rotate the parts at the perfect speed, so all the welder has to do is keep the arc steady and keep feeding in the filler. With no fancy rotator device and all of these tight curves, I’ll get by as best I can by purging the pipe with argon, then stitch welding around each tube. The flange that attaches to the turbo and the showerhead end plate were very challenging because they’re so close to the tight radius mandrel bends. The Series 17 torch that came with my AlphaTIG isn’t huge, but I had to use some less-than-optimal torch angles to get in those tighter spaces.

Argon purge line goes in the exhaust temp sender port on the flange

After welding the tube joints, I did the showerhead spray nozzle plate

$188 Zeny Cut 50 Plasma Cutter has paid for itself already

Cut the raw water inlet tube at the mark

6″ diameter grinder wheel will make coping the tube a breeze

Should give a perfect fit to the 6″ OD showerhead tube

Next, orient the overflow outlet

Raw water will enter the showerhead at the top, so the full length of the exhaust tubing inside the showerhead will be doused with water even at idle. As RPMs rise, more water will flow into the showerhead until it’s completely full and water is spraying out of all of the showerhead nozzles. The overflow tube is at the top of the showerhead, so once pressure starts building the excess water will flow up the overflow tube and off the boat via a hose to a thru-hull. This allows more water to flow through the heat exchangers without the additional water taking up space in the exhaust system. This is potentially an issue since I’m using 6″ exhaust rather than the optimal 8″.

Mark the overflow hole and fire up the Zeny plasma cutter again

Sloppy freehand hole cut took about 5 seconds with the Zeny

Makita die grinder makes the hole pretty in a minute or two

Ready to weld!

Argon purge line goes in the top

I used clamps to hold sheet aluminum as caps on each end of the showerhead tube, then taped the argon purge line in the water inlet. Argon is heavier than air, so as it fills the cylinder it pushes the air up and out, leaving a nice argon atmosphere to protect the back side of the welded area from sugaring (rapid oxidation and breakdown of the stainless alloy).

Not bad for a noob hobbyist TIG welder

Jody over at weldingtipsandtricks.com would probably say that looks like Fido’s butt, but then he’s a pro whose got that wicked robot welding hand that I never will. Camera flash makes a couple of the starts look like there are gaps in the weld, but it’s continuous and well fused all the way around.

I fused the inside joint, too, but without filler

Next, fit the showerhead and set up the purge

After tacking the showerhead in a few spots, I taped up all of the nozzle holes on the bottom to keep the argon from draining out.

 

Aluminum foil taped to the tube holds argon that spills over

My TIG torch travel speed is inconsistent and frequently too slow, which puts too much heat into the part. I’m also inconsistent when it comes to adding filler, so I don’t get that stack o’ dimes look that professional welders can do. But the welds are robust, and I am getting better at making them look nice as time goes on. I was joking with the missus that by the time I finish this project, I’ll have developed these news skills pretty well…but will hopefully never have to use them again. 😉

Repeat the process on the spray nozzle end

Starboard riser welding is done!

Inferno Wrap is rated at 2000°F continuous

First layer

Second layer

My original plan was to use two layers of Inferno Wrap, then top that with strips of fiberglass cloth I’ve got left over from the Bullet-proof Cabin Top. Then I was going to use hi-temp epoxy to wet out the top layer and make a hard shell. But I’ve been looking into other approaches and found ceramic insulation blanket material that might be even better. Stay tuned.

Next up in our 1969 Chris Craft Roamer 46 Refit: Welding the Port Exhaust Riser Showerhead

1969 Chris Craft Roamer 46 Refit: Welding the Port Exhaust Riser

First, the bad news. One of my Boatamalan fairing crew guys died last Saturday morning. He was 29.  Went out for beers with buddies after work the night before. Had 7~8 over the course of 6 hours…got home around midnight. At 4:30am, he called his buddy to say he wasn’t feeling well and wouldn’t be going to work. He went back to bed, but at 6:30am when his wife nudged him to wake him up…he was gone. Stone cold, but without ever having had any kind of health problems. Gus was the brother of my painter, and when we painted the boat back in 2013, the lead painter was up on the scaffolding to paint the top portions of the hull while Gus was below spraying near the chine at the bow. Gus flowed out the Awlgrip paint really well, and he was friendly, helpful, super hard worker…a good man. It’s too bad he’s gone…the second death of the year that’s affected me. 29-years old…I still can’t believe it.

Gus’s handiwork…RIP

With that said, at long last, I finally started welding my exhaust risers together. I tacked the risers together in July 2016 then learned that I need to purge the air from the inside of the stainless tubing before welding. Failing to purge causes oxygen to react with parts of the stainless alloy, which turns it into a crusty black crystaline form on the inside of the tubes that’s prone to rapid corrosion degradation. To purge the air, I need to have a dual regulator that can attach to my one 80cf tank of argon. They make dual regulators that sell for ~$100 and up, but I figured I’d save a buck or two by just using pipe fittings I’ve already got and adding a second el-cheapo regulator off of ebay.

Turns out that was a stupid idea. I should have just bought the off-the-shelf dual regulator.

Eventually I got it all worked out, though, and got to welding.

My argon regulator needs a tee to another

Pull all the bits off one-by-one

Don’t worry…the valve is off. I don’t have a vice to work with–I broke mine–so the bottle provides a stable base.

To Avoid any HURT…do not unassemble.  oops…too late

All the bits and pieces

The way I’ve laid out the pix, you might think there was a smooth transition from risking “hurt” to myself by “unassembling” the regulator, but you’d be wrong. The argon regulator on the left in the pic above sells for $7 on ebay, and it’s advertised as having 1/4 npt threads. It was coming from China, so I had to wait three weeks. The weekend after it arrived, I tried to assemble the whole thing but failed. Turns out those aren’t NPT threads at all…they’re M14X1.5mm. After an absurd amount of wrangling with the seller, just trying (but failing) to get them to correct the ad, I got a full refund on it for misadvertising. Then I found an M14X1.5mm to 1/4″ NPT adapter in England and ordered it. Another week gone. When I finally assembled it and attached it to the argon bottle, all of the joints were gas-tight except for the 1/4″ NPT side of the damned adapter. The more I looked at the threads, the more they looked to me like flat threads, not tapered NPT. Two months had gone by getting to this point, and the only options I could think of were to buy a dual regulator and be done with it or break out the Marine Tex epoxy and glue the leaking joints together.

Marine Tex did the trick

Ready to go

The gold regulator feeds the AlphaTIG, the chrome one feeds the fish tank bubbler at the end of the clear 1/8″ ID PVC hose. The bubbler will act as a diffuser for the gas inside the pipe, which they say helps smooth out the flow, avoid mixing of argon with the air in the pipe (argon is heavier than air), which helps push all of the O2 in the air out of the exhaust pipe.

It was late on that Sunday when I finally got the regulators installed and ready to go…too late to start welding. So I closed up shop and planned to come back the following weekend and get to welding. I spent the whole week “image training” how I’d do each weld, practicing smooth hand movements in the air with my hands holding pretend filler and TIG torch. When the following weekend arrived, I suited up in coveralls, went to the shop, turned on the lights, but when I went to turn on the argon I found it was already on. I’d forgotten to turn off the bottle valve the week before. Checking the gauge, the brand new bottle I’d just bought a week before was down from 1500psi to 500.

Son of a ….

After the Marine Tex had cured and I’d installed it on the argon bottle, I spritzed all of the pipe fittings with soapy water to make sure they were gas tight. But I hadn’t spritzed the main tank connection. So I spritzed it and, sure enough, a bubble started growing out of one spot. It’d been leaking all week long.

Son of a ….

So I got to purging and welding while hoping the bottle would hold out for at least one riser.

Ready to seal up the exhaust flange and start purging

I’m using the 1/8″ NPT fitting on the flange as the port for the purge line. As the pipe fills with argon, it’ll push air out the far side of the exhaust.

On the far end, I taped up all but the top of the outlet

Argon is heavier than air, so having the purge exhaust near the top of the opening will cause the whole pipe to fill with argon, shoving the air out the slit at the top of the pipe. It’s time to seal up the tape on the flange end and get to TIGging.

Stitch welded around the flange

I’m not even close to being a pro-grade welder, but I’m not the worst of hobbyists, either. For all of that image training and practicing in the air, I still don’t have that smooth hand that the pros use to the a stack ‘o dimes weld. My welds may not be perfect, but I’m sure they’ll hold it together. Given the price I was quoted to have a set of risers built (>$5,000) and the amount of money I’m into the stainless tubing, flanges, and insulation thus far (~$1250, with plenty of leftover tubing), I still figure it’s been well worth it building my own. The experience, skills, and knowledge acquired alone has made it worth it!

Stitching the showerhead

The AlphaTIG has a post-flow function that keeps the argon flowing after I stop welding. The dial goes from 1 to 10, and cranking that up keeps argon flowing over the hot stainless so O2 in the air doesn’t oxidize the weld. Where you see color in the weld is where I got the piece too hot from traveling too slow. The post-flow wasn’t long enough, and air got to the weld while it was still hot enough to be oxidized. That’s what causes the purple and other colors in the weld area. I realized too late that I the post-flow knob goes far past the 10 mark. Cranking it fully open helped keep argon on the weld, but in the spots where I traveled too slowly and got it too hot, it was disappointing watching a beautiful, light gold colored weld turn purple in spots when the gas shut off.

Setting up to weld the showerhead nozzle plate

Showerhead plates welded inside and out

The little pin I welded to the outside of the tube in the pic above is a short length of 3/32″ stainless TIG filler rod. I put those in a bunch of spots around the outside of the tube where I’ll wrap it with insulation. The pins will help keep the insulation from moving around.

Good penetration through to the inside, with no “sugar” oxidation

Showerhead nozzle plate welded on the “wet” side

I decided to weld the showerhead plates on both sides, but in retrospect it might have been fine (better, even) to just weld the outside. I was concerned about crevice corrosion if I didn’t get full penetration in the welds, especially inside the water-cooled portion of the showerhead. But the more I think about it, the exhaust will be hot even after the raw water flow to the showerhead shuts off. Any water remaining in the showerhead will drain into the exhaust hose. If no water remains in potential crevices on the backside of welds because the heat flashes it off, crevice corrosion can’t happen. The only time that corrosion could happen is when the engines are running and the showerheads are full of water. I’m thinking that it would be thousands of hours (maybe tens of thousands) before there was a problem. If I ever have to make another set, maybe I’ll just assemble the showerhead and weld the back plate and nozzle plates on the outside.

Aluminum plate caps off the tube

It was challenging clamping the irregularly shaped riser to my cheapo Harbor Freight welding bench so the outlet at the showerhead was pointed up. Gravity will keep the argon purge in the tube, but the aluminum plate helps with that as well as serving as a heat sink. As I’m staring at this picture now, I’m thinking there was absolutely no reason to weld the outside here. Oh well…what’s done is done.

Showerhead nozzle plate welded on the exhaust outlet side

The gas ran out on the last insulation pin

I’ll have to run to the local welding supply again to get another bottle of argon so I can continue welding the risers together. It’s all good though. And I’ve got to say, even though I can see that my welds aren’t the best, I’m still having a good time doing this part of the job.

Next up in our 1969 Chris Craft Roamer 46 Refit: Welding the Starboard Exhaust Riser

1969 Chris Craft Roamer 46 Refit: Final Exhaust Riser Fit-up

The V-berth head is still stalled while I wait for my painter to show up. But there are so many other things going on that the refit continues to move forward. Most recently, I did the final fit-up on the exhaust riser parts in preparation for welding them all together.

Port riser points at the muffler

New showerhead parts fit well

The showerhead drain hole goes at the bottom

Showerhead test fitted and marked

Starboard riser ready for fit-up

Sharpie marks the spot

Just like that

The raw water hose needs to come down like so…

Heat exchanger outlet needs to be reoriented

I suppose I could also use a formed hose that takes a hard 45° turn with a connector pipe to a flex hose…gonna have to ponder on that for a bit.

Cutting the hole for the raw water inlet proved challenging

I used a cutoff wheel to cut slots in the showerhead water jacket, but the heat from that discolored the stainless. I thought I’d try using some good Bosch metal cutting jigsaw blades to connect the slots, but that 12 gauge 316 stainless burned up blades after about 3/16″. This isn’t going to work. So I went online and started looking for options..and that’s when I discovered that the price for hobby-grade plasma cutters had gone down significantly since the last time I checked.

The Zeny 50 amp plasma cutter…$188 on ebay, delivered

The Zeny plasma cutter comes with almost everything in the box. You have to supply the air hose, air quick disconnect, and plug for the electric cord. I had a ruined air hose from the bastard thieves who stole my small air compressor, among many other things, during the big 2014 break-in. But it was just what I needed to connect the supplied air filter to the plasma cutter.

The supplied eye shield/mask is a bit of a joke, but for $188 it’s amazing they include it

Ground clamp is marginal, but for this price…

The torch isn’t elegant but, again, for $188…

I’d rather have a finger trigger than a thumb switch, but it all works.

I used three Bosch jigsaw blades making that one wedge cut

Five seconds later…

I’m waiting for the 1-1/2″ stainless tubing I’ll use for the raw water inlet to show up, and I didn’t want to cut too far. I’ll do a prettier job for the real deal.

As long as the Zeny 50 holds up for a couple of cuts, it will easily pay for itself

Gotta love the Chinese

They can make a high tech inverter plasma cutter with a digital readout and deliver it to the east coast of North America for $188, with a bunch of people making a bit of profit along the way. But the Chinese interpretation of a phillips drive hose clamp leaves a bit to be desired. There’s the shape of the phillips drive, but there’s no depth to it. Just goes to show that you can steal an idea, but the execution is what really counts. But for the price, I really can’t complain.

I’m going to hold off on welding the risers together until the 1-1/2″ tubing arrives for the raw water inlet. I’ve got to back purge the riser by filling them with argon before welding, and there’s no sense in wasting gas doing that more than once.

Next up in our 1969 Chris Craft Roamer 46 Refit: Dry Fitting the Stainless Bow Safety Rail

1969 Chris Craft Roamer 46 Refit: Exhaust Showerhead Parts

Earlier this year, I started building the exhaust risers for my Cummins 6-CTA turbodiesels. Verocious Motorsports had all of the straight and mandrel bent tubing I needed. I cut the tubing and tacked it all together using some new toys for 2016: my Harbor Freight metal-cutting bandsaw and AlphaTIG welder. Learning to weld aluminum and stainless has been one of many great things about this refit. Whoever said old dogs can’t learn new tricks was full of it!

Computer aided design (CAD) software has also made it a lot easier to go from concept to execution than old school pencils, rulers, and blueprints. I’ve used Sketchup Make, a free CAD program, to design the aft stateroom, galley, and V-berth, but for the last few months I’ve been trying to figure out how to use it to make showerhead parts for the exhaust risers. After reading tons of material online, it didn’t take long to make the 2D model in Sketchup. The problem was getting the free version to output in a file type that can be read by CNC, waterjet, or laser jet machines. The native file outputs in Sketchup are proprietary (.skb and .skp) and aren’t compatible with anything, near as I can tell. I found a Sketchup extension that changes the output to a machine readable .dxf file format, but for the life of me couldn’t make it work. All of my drawings turned into straight lines when viewed in LibreCAD, a free 2D CAD app. Sketchup’s user interface is a lot easier for me to use than LibreCAD, and I really don’t want to spend a bunch of time becoming that proficient in LibreCAD. Sketchup Pro — the professional version of Make — exports in all sorts of CAD file types, but at $695 it’s a pretty big investment. But eventually I came up with a workaround, found a fab shop with a laser jet, and now have all the parts I need to finish the exhaust riser.

Showerhead parts in Sketchup

The exhaust tubing is 4″ OD mill finished stainless. The outer tubing for the showerhead is 6″ polished stainless, with an ID of 5.871″. I’ll run a continuous TIG bead around the showerhead backer and the nozzle end to attach them to the 4″ tubing, then slide the 6″ tube onto the assembly and run a continuous bead around both ends of that, too. I also need to add a water inlet to the showerhead, but that comes later.

Next, export the two components into separate jpg files

This “backer” will seal the gap between the exhaust tube and high end of the showerhead tube. Circles in Sketchup are made up of short sections of straight lines that are all connected. The more segments you specify, the smoother the lines are and the rounder the final part will be. A triangle is the least-round circle you can make using only three straight line segments. A square, with four segments, is a lightly more rounded circle than a triangle. When making the model in Sketchup, I changed the properties of each circle from 26 segments (the default) to 99, which yields nice, smooth circles.

There were a few issues I want to avoid with my showerhead, one of which is that at low RPMs I don’t want to cook the rubber exhaust hose to which it attaches. This can happen with OEM Cummins showerheads because the holes are symmetrical all the way around. If all of the water that’s entering the inlet at low RPMs can exit the showerhead from only the bottom holes, the top of the exhaust pipe and hose don’t get cooled. Retaining more water in the showerhead and having it exit the nozzles higher up will cool more of the pipe and hose at low RPMs.

My showerhead, with a “re-size line” below

The raw water intakes are 2″ ID, while the raw water outlet at the heat exchanger, which feeds the showerhead, measures 1-3/4″. The raw water inlet for the showerhead will also be 1-3/4″ OD, with an area of ~2.2 inches². I’ve got six 1/4″ diameter holes starting at ~80° from the bottom, followed by four 3/8″ diameter holes, and then seven 1/2″ diameter holes, plus a 1/2″ half-hole for a drain at the bottom. The total area of the holes is 2.2 inches². So even at idle the water will be in direct contact with most of the exhaust pipe and water will be exiting from nozzles relatively high around the pipe and cooling the exhaust  and the hose. When the engines are off, all of the water will drain from the showerhead via the bottom hole. This should eliminate the possibility of crevice corrosion.

The resize line is necessary because I imported these jpg files into LibreCAD, then traced the outlines and deleted the jpg layer, leaving the traced outlines ready to be saved in the .dxf format. But LibreCAD’s standard measure for imported jpgs is pixels, and there is no simple way to instruct LibreCAD to convert pixel dimensions to specific linear dimensions. So if I don’t resize it, the LibreCAD file will see that resize line as being 931 units (ie pixels) long, while the laser jet that makes the part would see it as 931 units (ie inches or mm or ???). To re-dimension from pixels to inches after importing the full-size pic to LibreCAD, I trace a straight vector line over the 6.000 inch “resize line” in the jpg. Then I select that vector line and the jpg and use the resize function, entering 6.000/931 as the conversion factor. This shrinks the whole thing to the proper vector dimension in inches. Then I delete the jpg layer and the resize vector line, leaving just the part I want in the proper dimension, to within .001″, ready to be saved in the .dxf format.

Et voila!

After a bit of hunting around, I decided to have Stainless Steel Specialties, Inc. in Raleigh, North Carolina make the parts. Their prices were quite a bit less than what I was quoted from the laser jet fab shops that come up in internet search ads, they didn’t care that it was a small job, turnaround time was reasonably quick, and the parts came out just like I imagined them. I’ll be using Stainless Steel Specialties for some future laser jet work I need to have done.

Stainless showerhead parts

Just about a perfect fit!

The tubing isn’t perfectly round, but this fit is well within tolerance.

Perfect fit on the exhaust tube, too!

Dry fitting the showerhead parts to see how long the 6″ tube should be

Harbor Freight bandsaw does the job, but just barely

The dry-fitted starboard riser

The showerhead backer

The showerhead

I really wanted to fire up my AlphaTIG and start putting the final welds on this thing, but I still have to take all the pieces to the boat and “clock” the parts to make sure everything is oriented properly. When the flanges are mounted on the turbos and the exhaust is pointed at the mufflers, the showerhead drain holes need to be on the bottom. Then I need to mark the places where the raw water inlets need to be attached to the showerhead outer tubes so they’re pointed at the raw water outlet on the heat exchangers.

This all makes perfect sense in my head and when I read it, but I’m not sure it’ll make sense to you readers. All I can say is, stay tuned…the pix will tell the story in a week or so.

Oh, and…update on that .dxf extension for Sketchup that I couldn’t get to work for months…it does work. I always start my Sketchup views like I’m drawing on a wall, with the drawing oriented vertically. But the Sketchup .dxf extension views the object as if the drawing was on a table, laid out horizontally. So my 2D renderings of circles laid out on a virtual wall (when viewed from the Front, which is my default) were rendered into 1D lines when the extension viewed them from above, looking down. I could never understand why all of my converted 2D files changed from the shapes I wanted into single dimension lines. I just assumed it was a poorly designed extension. By rotating each rendering 90° along the X axis, all the sudden it’s a lot easier converting Sketchup renderings to .dxf files. I don’t have to do any of that resizing from pixels to inches anymore. Sure would have been nice if the extension author had put that little tidbit in the instructions! 😉

Next up in our 1969 Chris Craft Roamer 46 Refit: Fitting the Transom Door

1969 Chris Craft Roamer 46 Refit: New Exhaust Risers II

DATELINE: Far side of planet earth (finally getting over jet lag, just in time to return stateside and start over).

While working on the engine wiring, there were several times when the project got stalled because I didn’t have the right hardware to get ‘er done. Since I can only work on the boat on weekends, a week can go by waiting for new parts to show up so I can continue the job. There are plenty of other things to do on the boat, though, and getting the exhaust system finished is a big item on the honey-do list. I’ve got all the tubing I need. I just need to finish preparing the mufflers, then cut, tack, and weld the risers together.

Stainless crush sleeves get bonded to the muffler inlets and outlets

In retrospect, I may have been able to save several hundreds of dollars by buying a 5-foot length of 6″ stainless tubing and cutting it to size rather than buying Centek crush sleeves at $58/ea (wholesale). Ah well…that wouldn’t be the first time I made a noob choice that cost more than it had to.

High temp epoxy thickened with glass bubbles and cabosil bonds sleeve to the muffler

Smooth the epoxy and clamp the sleeve in place

Rubber pads on the bottom to isolate vibrations

I still haven’t decided for sure how much I want to isolate the mufflers so they don’t transmit exhaust vibrations. Since they’re not solidly attached to the engines, vibration may not be a problem at all. Time will tell.

Muffler gets placed on its platform

Starboard muffler loosely positioned

The 180° connector above the muffler allows it to be rotated and also moved in a small arc to line the inlet up with where the riser will be.

Next, figure out how to connect the turbo flange to tubing pointed at the muffler

Cutting somewhere around here ought to do it

And then another one up here should wrap it up

Harbor Freight bandsaw cuts pretty straight when its adjusted right

I had a problem with slightly crooked cuts on the stainless tubing I used for the fuel inlets, which took more work on the disk sander to get the mating surfaces fitting tightly. With the bigger 4-inch tubing I’m using on the exhaust, it was even more of a priority to make sure the cuts were all true. I followed online instructions for truing 4×6 metal-cutting bandsaws, and it cuts nice and straight now.

Square up the cuts on the ShopSmith disk sander

Pretty good fit…just a bit more and it’ll be perfect

Looks about right

Position is marked with a Sharpie…ready to tack

Thick flange and thin tubing are a bit more challenging to tack than similar materials

Mahogany cleats position the tubing perfectly

The muffler inlets are ~6″ in diameter. By clamping two 1″ x 1″ x 24″ mahogany cleats to the inside of the inlets, the distance between the two inner surfaces of the cleats is ~4″. By clamping the 4″ tubing to the other end of the cleats, I can position the mandrel-bent section while being confident that the other end is pointed directly at the center of the muffler inlet. When I weld on the showerhead, which will be made of 6″ tubing, it will be pointed right at the muffler. That’s the theory, anyway.

More tubing cuts

Touch up the cuts for a perfect fit

Bandsaw blade marks on the cut = gaps where the tubing will butt together

After a bit more sanding, no saw marks = no gaps

Nice and flat, with no gaps

Tack this bit to that bit…

Add a bit here across the top

Double-check the angle down to the muffler

Note that the “spillover point” on the dry exhaust side is well above the lowest point of the 180° connector coming out of the muffler. That way, if the exhaust system fills with water it will naturally drain out the side of the hull rather than backing up into the engine. The 6″ exhaust pipe out the hull side would have to be completely full and still overflowing under substantial pressure before water can end up in the turbo. Gravity makes that pretty much impossible.

The final piece of tubing is tacked in place

Ready for final welding!

The dry side of the port exhaust riser is ready to be welded, but I’m still awaiting the delivery of some gear to purge air from inside the tube and replace it with argon. I also have to make the dry section of the starboard riser and have some parts CNC machined for the showerhead.

Next up on our 1969 Chris Craft Roamer 46 Refit: New Exhaust Risers III