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