1969 Chris Craft Roamer 46 Refit: Making a Silicone Gasket for the Laundry Closet Porthole

Things aren’t looking good for splashing in 2022. It got cold all the sudden, and the boatyard manager tells me they got a lot of requests to haul boats starting next week. In September, he said they were keeping the yard relatively empty this year so they could clear out a bunch of Pergatory boats that accumulated in recent years, with non-paying owners, over the winter. Apparently, that plan has changed. Since my tent is at the back of the yard, once boats start getting hauled, I’m basically locked in until April. Stay tuned…who knows how things will turn out?

Back to the refit, since we used our previous boats primarily as liveaboards in The Swamp, the missus insisted on a few things for this Roamer 46: a deep jet bathtub and a washer and dryer.

The bathtub is sitting in the aft head awaiting installation. The washer and dryer are sitting on the aft fuel tanks awaiting me getting the custom laundry closet porthole done. What I needed was an H-shaped gasket with very specific dimensions to go between the new 1/4″ tinted glass that will fill 2/3 of the porthole glass area and a 1/4″ plate with a 4″ hole in it for the dryer exhaust. Needless to say, getting all the portholes installed is a priority, since the boat has to be weather-proof when Tent Model XXX comes down.

Unlike all of the other portholes, the one for the laundry closet has no screen

This is the one porthole on the boat that will pretty much never be opened, so there’s no need for screen to keep out bugs. And a screen would eventually clog up with lint from the dryer exhaust anyway, so it’s best not to have it here.

Brand new tinted glass fills 2/3 of the window space

1/4″ marine plywood with a hole cut for the dryer exhaust fills the rest

I’m considering making that dryer vent section out of aluminum rather than marine plywood. The plywood is fully encapsulated in epoxy and a layer of fiberglass on each side, but the more I think about it, the more convinced I am that aluminum would be a better material to use here. And I have plenty of leftover 5052 plate from the aft deck enclosure build.

1/4″ gap needs to be sealed

I don’t think caulk would be an effective seal here. But I was unable to find an H-shaped gasket that had the dimensions I want. So I decided to make one using the same approach as I did with the silicone porthole seals.

Something like this is what I need

That H-shaped gasket is hiding inside this jointed 2×4

I just have to let it out!

After splitting the 2×4, I cut identical grooves in each half

1/8″ saw blade kerf was the perfect size to make the grooves I needed in four passes

Then I adjusted the saw blade depth and removed an 1/8″ from the middle sections that remained to get my H

Next, I sanded the mold with 120 then 240 grit Mirka Autonet

Ready for varnish

The smooth surface and varnish really help when it comes to pulling the final silicone gasket loose.

It’s Showtime!

After clamping the two mold halves together, I taped the end and edges to keep the silicone from leaking out too much. I made the mold much longer than the final gasket needs to be, in part, because I figured the liquid silicone will end up leaking out to some degree. I just need enough to stay in the mold so I can make my 7″ long gasket.

Ready for the pour

Done with the pour

The tape seems to be holding.

There’s not much getting past the tape on the bottom

There was quite a bit of air in the mixed silicone

It’s good to see the bubbles work their way out of the poured silicone.

Four hours later, the silicone has kicked off

Fortunately, it solidified before the silicone could work its way past the tape. You can see in the picture above that it made it 1/2 to 3/4 of the way past the tape.

I didn’t lose as much silicone as I expected

Tape is removed from the sides and bottom of the mold

Time to split the mold halves

Nice!

The gasket easily came out of the mold once the halves were split

Perfect gasket for a 1/4″ window and dryer outlet plate

So that went well. I just need to finish the dryer outlet plate and I can assemble and install the laundry closet porthole.

I should also maybe mention, as I have before on other articles, that this isn’t a ‘real-time’ posting. I actually made that gasket in 2020. I just never got around to posting about it after I was wrongfully terminated from my job and pretty much stopped working on the boat or posting here.

Over the winter of 2021, a mouse got into our basement. I dealt with the beast as soon as I discovered signs it had taken up residence, one of which was that the bloody thing chewed up a bunch of my H-shaped gasket! Fortunately, I made the mold far longer than the seven inches I need for the gasket. Enough of it remained without nibbles for me to use it on the porthole.

Next up in our 1969 Chris Craft Roamer 46 Refit: Installing the Last of the Portholes

1969 Chris Craft Roamer 46 Refit: Porthole Gaskets II

Getting the boat weatherproof is essential prior to launch. Getting new gaskets in the portholes will leave only a few weatherproofing steps to go.

Ecoflex 00-50 silicone kit and gasket mold are ready to go

The stock gasket profile is 3/8″ x 3/8″, and each gasket requires ~61″ of material. To figure out the volume of silicone to mix up, I converting inches to CCs, which was pretty easy since 3/8″ is roughly equal to 1cm. To fill the mold to the brim should take ~155cc. I want to get the mix exactly right, so instead of relying on my old eyeballs to sight the line on the mixing cup, I’ll use my electronic jewelry scale, which is accurate to 1/10th of a gram. Ecoflex 00-50 has a specific gravity of 1.07 g/cc, and this kit is mixed at a 1:1 ratio. So…I need 83.1 grams of Part A and the same of Part B for each gasket.

Funky looking goop

I transferred equal portions of each component into a mixing cup, then stirred the Ecoflex thoroughly for a solid three minutes before pouring it into the mold. The manufacturer claims no mold release is required so long as you demold the part within a day or so. Pot time is 18 minutes, which is more than enough for this relatively small mold.

Et voilà!

The cure time is four hours, but I poured in the evening and let the material set up overnight. The next morning, I tried to roll the gasket out of the mold but it wasn’t cooperating. I thought of using my utility knife or a putty knife, but I thought the sharp edges might damage the gasket.

Don’t tell the missus about the butterknife!

The butterknife worked great to free it from the mold in the middle. Then, I just pulled it free all the way around.

Nice!

Test fit on the laundry room porthole

That looks pretty good

You can see where a bit of the material flowed over the edge of the mold in the corner. Those pull off easily, leaving a good looking gasket.

Good frame-to-gasket contact

In the picture above, the frame is sitting on the gasket. It’s too light to close any tighter on its own.

Nice seal

Squeezing it tight gives a good seal all the way around

I like it!

The gasket is really soft…like a gummy bear. But I think I can cut down on the volume of silicone and still have plenty of gasket depth for a good seal. With the full-depth gasket, the edges are just a bit ragged from a teensy bit of silicone that flowed onto the surface of the mold. I’ll drop the volume by 10 grams on the next one and see how that works out. It will lose a bit of height for the gasket, but since this porthole stays open by 3″ on the lower edge once the top edge of the gasket contacts the frame, losing a bit of height shouldn’t be a problem. For now, the proof of concept is done.

Now I just need to make 11 more.

Next up in our 1969 Chris Craft Roamer 46 Refit: Aft Stateroom Headliner Prep

1969 Chris Craft Roamer 46 Refit: Porthole Gaskets

Way back in 2013, I disassembled all of the hateful aft stateroom portholes.

OEM gaskets get hard over time

By late 2014 they were back from the paint shop looking very pretty, but it wasn’t until 2016 that I had new glass and screens in them. The last thing I need to wrap up the portholes is gaskets. There are several gasket options that are readily available, and each one has it’s plus and minus points.

WEFCO Square Hollow Rubber Gasket is $1.69 per foot, and I need around 60 feet to do all of the portholes. That’s a relatively  cheap option, but it’s got two downsides: ethylene propylene rubber is a relatively hard material at 65 to 80 durometer on the Shore A hardness scale. This particular gasket is squishy because it’s hollow in the middle, just like the OEM gasket. I suspect it would also get hard over time just like the OEM gasket. The other downside is that there would be four joints in each porthole gasket, and that’s four opportunities to leak.

Then there’s Stop Water Gasket, which offers very nice urethane rubber one-piece gaskets for each style of OEM Chris Craft hatch and porthole. They claim that their urethane is softer than the original gasket material, which is good, but at $41 each it’s a pretty expensive option.

Hardness chart courtesy of Ecoflex

So–and this will come as a total shock, I’m sure–I started looking into making gaskets myself using super soft silicone. I eventually settled on Ecoflex 00-50 platinum-catalyzed silicone. As you can see in the chart above, Shore 00-50 is very soft material. And Silicone retains its its original shape and hardness pretty much forever. So I ordered a 2-gallon kit and set about making the mold while waiting for the silicone to arrive.

2×4 scraps should work for the mold

A few passes over my jointer trued the lumber

Mini Max FS35 jointer leaves a very nice surface on the wood

A super flat surface on the lumber will help ensure the mold is a consistent depth, so the gaskets will have consistent height.

Next I measured the portholes

I sampled several of the portholes. The biggest gap that needs to be filled by the gasket is 5/16″. The stock gasket is 3/8″, which should be fine, but because the silicone is so soft, I’ll add 1/32″ to the mold depth. That should help ensure these things never leak.

3/8″ width will be perfect

Next, I cut all of the lumber to the same width

The first mold cut

Cut 2 makes the width 13/32″

Harbor Freight featherboard was a great buy

If you use a tablesaw, you should have a fingerboard. You can’t buy replacement fingers for $6.99.

Second pass is done

The last pass on the saw

Looks pretty good, but I need to clean up the bottom surface

3/8″ router bit in my ShopSmith cleans up the cuts

Next I varnished the lumber to seal the wood up and then cut the miters at 45°. I used US Composites 635 epoxy to saturate the joint area, then added wood flour to make glue.

Crazy clamps

While I was clamping it all together, it occurred to me that corner clamps would make this a lot easier. Then again, I don’t do this for a living, so I’m not sure I need to buy tools I rarely use. Then again…more tools…mmmmm.

By the time the epoxy cures I expect the silicone will have arrived.

Next up in our 1969 Chris Craft Roamer 46 Refit: Porthole Gaskets II