Before the boat can splash, I need to make sure all the holes below the waterline are filled or closed off. I dealt with three major holes when I installed the raw water circuits for the air conditioners. Installing the swim platform closed up dozens of bolt holes that were below the waterline. The only holes remaining are the raw water inlets for the Panda genset and the Cummins 6CTA main propulsion engines.
The thru-hull for the Panda will be the re-purposed inlet for the OEM central air conditioner. But the original raw water inlets for the main engines were too small for the Cummins turbodiesels: 1-1/2″ pipe vs 2″ recommended for the diesels.
I cut out the original standpipes in 2016 and had a new set made. I brought the Forespar Marelon valves to a machinist who’d previously done good work for me. I was surprised when he charged $300 to thread one end of each of the 2″ pipes…seemed a bit steep. I put the pipes and valves in a box and left them in my garage until recently, when I tried to thread the Forespar Marelon valves onto the pipes. They’d only turn 2 revolutions, which isn’t right. The more I looked at them, the clearer I saw: the “professional” machinist put National Pipe Tapered threads on them, not National Pipe Straight like the Forespar valves.
I brought the pipes to a different machine shop in Amish country, and $75 later had both standpipes threaded perfectly for my new Forespar valves.
Back at the garage, I cut the pipes to match the angle of the hull bottom
I also did quite a bit of practice welding in the garage
I’m not a pro and these are mission-critical welds. So I spent a few days with the spool gun and TIG torch getting myself comfortable about the job ahead.
My Miller Trailblazer 280NT hasn’t gotten a workout in a while
That’ll do
Everywhere else on the bottom has been freshly coated with Pettit Vivid bottom paint
When I felt I was good and ready, I brought the parts and welder to the boat and installed the standpipes.
I used a stick to push a ground plate up against the bare aluminum hull on the outside
The welding machine’s ground cable is clamped to the ground plate. Inside the boat, I used a clamp to hold the pipe in position.
Then I geared up, fired up the Miller Trailblazer, and got to welding
The missus was on fire watch. So naturally, she focused on taking pictures. None of the resulting fires got too out of hand. lol
Inside the boat…this is gonna be challenging
OK, so I should have welded this standpipe in before I moved the Panda genset from the port side to starboard two months ago. And I mistakenly thought I’d have enough room to maneuver around the pipe, but my spoolgun is too big. And it’s only got a rigid nozzle. There are flexible nozzles, but they start at $400. And even if I had a flexible nozzle to get around the genset supports and have the MIG wire coming out of the nozzle at 45° to the joint, there’s only 2-3 inches from the pipe to the frames and stringers. There’s no MIG nozzle for my Miller Spoolmatic that’s that flexible.
So the standpipes were welded only on the outside. I looked into TIG welding them on the inside, but the torch I had was only rated for 150 amps. This is 1/4″ aluminum, so I’ll have to max out my AHP AlphaTIG’s 200 amp capacity to get good weld penetration. So that’s when I decided to buy a water-cooled torch and make a homemade TIG cooler, which I wrote about recently.
The new TIG torch didn’t come with tungsten collets, collet body, ceramic cups, or anything else, so I foolishly bought an inexpensive stubby gas lens kit on ebay. It had all the stuff I needed. After it arrived, I spent days trying to get that thing welding right, but with no luck. It was like there was no argon coming out, even though I could hear and feel gas flow when I hit the pedal. Somebody on a welding forum suggested the problem was with the cheapo lens kit, so I bought another one manufactured in the US of A by CK Worldwide and waited for it to arrive.
I got the kit at weldmonger.com, whose owner, Jody, hosts a youtube channel where I basically learned how to TIG stainless and aluminum. If you want to learn how to weld, his videos are outstanding. Anyway, when the CK kit finally came, it made a night and day difference.
By the way, all of this was going on in October 2022 and contributed to the boat not splashing as I’d hoped. I didn’t feel too bad about the delay though, because as I’ve been mentioning in recent posts, the painter was finding and fixing all sorts of cracks in the paint.
With all of my welder issues finally resolved, I brought my AlphaTIG to the boat and finished welding in the standpipes.
Getting set up
My settings were: 199 amps AC, no pulse, AC balance set to 35%, frequency was 125Hz, argon was 18CFH with argon post-flow set to 3 seconds, and I was using 2% lanthanated 1/8″ tungsten.
Ground and TIG torch cables both go inside the boat via the standpipe
I welded the standpipe on the opposite side of the one that had the cables run through it, then switched sides.
The stubby lens kit and shorty back cup make the TIG torch <2″ long
That CK Worldwide Series 20 water-cooled torch is so small and light compared to the gas-cooled Series 17 one that came with my AlphaTIG. And even cranked up to 200 amps, it never got even warm. My $50 torch cooler worked great!
Not a stack o’ dimes, but the puddle was good and wet all the way around
I did two TIG laps around each pipe. Even though access for the torch was fine, it was extremely difficult to get a decent line of sight on the weld. I ended up flicking the filler rod (1/8″ 4043) into the tungsten three or four times, and had to stop and regrind the tip. There’s a bit of porosity in spots and some soot, but that’s probably to be expected with 50-year old aluminum that’s been epoxy coated, soaked in oil for decades, and was otherwise less than pristine.
Once the welds were done, I wire brushed inside and outside the pipes
Chris Craft didn’t put any barrier coating inside their standpipes, so they tended to be pitted on the inside to varying degrees. To avoid that problem going forward, I got spiral wound wire brushes to fit every standpipe and thru-hull on the boat. My Makita drill had barely enough power to turn the brushes in these 2″ standpipes, but they roughed up the inside just fine.
I applied Bar Rust 235 epoxy barrier coat to the inside and outside of the pipe and weld areas
I used a small diameter 6″ long, 1/4″ nap paint roller to apply the epoxy inside the pipe from under the boat. I used the same approach with the Panda genset thru-hull, too.
I brushed barrier coat on the flat hull surfaces and welds, then called it a day
Next day, I applied the second coat of Bar Rust 235 once the sun came up
Once the Bar Rust was tack free for an hour or two, I hot-coated with Pettit Vivid bottom paint. Hot-coating is when you apply a coating over a different coating without sanding. Sanding the surface of a cured coating provides a mechanical bond between it and a subsequently applied coating. Hot-coating provides a chemical bond between the coatings, which can be much stronger than a mechanical bond…if you do it right.
The coatings have to be compatible, and you have to apply the second product within the recoat window of the product applied first. Hot-coat too soon, and the second product can cause problems with the curing process of the product you applied first. I know this because I once had a piece of epoxy-coated plywood that I wanted to use as an engine room floorboard that never cured because I hot-coated with a compatible urethane paint product before the base epoxy coat was tack-free.
In this case, Bar Rust 235 is a catalyzed epoxy primer that fully cures in 30 days. The recoat window begins when the product is tack-free. I add a couple of hours just to make sure I won’t have that failed-to-cure problem again. You get the best chemical bond when the Bar Rust is cured enough that the bottom paint won’t affect further curing, but it’s still chemically active enough to lock on tight to the bottom paint as it’s applied.
But the Boatamalans made my heart skip a beat when I went to the place they left the bottom paint can that had the last pint of the Pettit Vivid bottom paint after painting the transom…
The Boatamalans have very bad work habits when it comes to material conservation
Fortunately, it’s been so cold that the pint of bottom paint left in the bottom of the can didn’t get hard even though the Boatamalan bent the lid up so badly it couldn’t seal. One day I plan to post a rant article about materials wasted by the sloppy habits of the professional painters and fairing crew who have worked on this boat. It’s so frustrating…and expensive!
Bottom paint goes not only on the hull, but also up inside the standpipes
I also barrier coated and bottom painted the external strainers for the main engines
I initially planned to weld these strainers to the hull, same approach used by Chris Craft. But the more I thought about it, I finally decided to use machine screws and bedding compound, because I want to be able to remove them for maintenance if necessary.
After waiting the four hours to recoat indicated on the label, I applied one more coat of bottom paint to the thru-hull standpipes, the hull bottom near the thru-hulls, and the exterior strainers. So that’s pretty much a wrap for bottom painting.
Now the standpipe thru-hulls for the mains, the Panda genset, and the air conditioner raw water system are ready to have valves installed to keep the Chesapeake Bay on the right side of the hull when we splash this bad boy.
Next up in our 1969 Chris Craft Roamer 46 Refit: Installing Raw Water Intake Valves and Strainers
1969chriscraftroamer46 