Montana Riverboats Test Domain Roadkill

Materials Notes

Materials Notes 


I worked with West System Epoxy products for years. They make good stuff and I have no complaints. But in recent years I have experimented with Raka resin. System III makes good resin and there are other sources too. I can't vouch for any of the rest, but those three sources are indeed reliable. Note too, if you do choose to work with West System, don't buy directly from West System. You will get a better price from one of their numerous retail outlets. Use a search engine to shop around.


Plywood is rapidly becoming the do-it-yourself boat builder's biggest problem. I relied on AA Marine fir for years. It was strong and cheap and I didn't care much what it looked like because I paint my hulls anyway (although I do like to leave gunwales, seats and trim bright finished). But good quality Marine Fir plywood is almost extinct now. What is sold as AA marine fire these days is usually lousy three ply stuff you cannot use with confidence. Hydrotek Meranti is the now the cheapest reliably good plywood. I don't have any sources listed here yet. I'll work on it. You can use Okoume and better yet Sepele too. But they're getting harder to find too. And Sepele is not cheap.

Plascore and/or Nidacore Bottoms:

See the Plascore-bottoms link in the Table of Contents. Plastic honeycomb core is what I use now for all bottom panels. 

Weighing resin mixtures instead of measuring

Not too long ago the only practical way to mix two part epoxies was to measure the volumes. You could use marked, different sized containers to measure 2:1 or 5:1 resin to hardener ratios or you could buy pumps. I have a pair of $300 lever handle resin mixture pumps I used (and cleaned and refurbished again and again) for decades.

Now it's a different era. For $20 - $30 USA dollars you can buy an accurate digital postal (or "kitchen") scale. Raka 2:1 resin has a resin to hardener weight ratio of 43:100

I put an empty yogurt container on top of the scale and then press the red button on my postal scale, which then zeros out a digital readout. I pour the needed amount of resin into the container and note the weight. Multiply that by weight by .43 and then put that much hardener into an other container. And then mix.

Sometimes I add the resin weight to the hardener weight and then pour hardener right into the resin cup while watching the scale. I stop pouring hardener when the readout reaches the combined weight. You do have to go slowly if you go that route. It's all too easy to pour too much hardener into the resin. And then you have to start making guesses.

West System hardener has the same density as their resin, which is mixed 5:1 or five parts resin to one part hardener.  So you weigh it that way too. I don't use my pumps at all any more.  

In 2018 I’m closing in on 70 years old. When I was doing subcontract roofing in the late 1970s everybody still used cedar boards for fascia material. I mostly did new construction back then but the few re-roof jobs I got almost always included putting on new cedar fascia boards at the edges of the roof. That was good because I needed work. But it sure is a pain the butt for someone who'd rather not hassle with scaffolding. 

Trex Fascia Board

It was a real leap forward in the '80s when Trex synthetic fascia board started showing up in the lumber yards. It lasts forever. It's heavy and hard to cut but it doesn't soak up moisture.

And it's the best stuff going for edging on boat locker openings, at least if you don't make molded all-fiberglass everything. If you want to cut it on a table saw and glue it to a boat, for finishing off the edges of exposed Plascore or for making raised locker lids, or for making screw-to cleats on the bottom of the boat for semi-removable seats or standing braces--don't use wood. 

The "Encapsulated wood" epoxy/fiberglass idea is in some cases over-rated. It works sort of but moisture ALWAYS finds its way in eventually. But Trex isn't wood. And Trex doesn't soak up moisture. Plastic honeycomb core makes the best bottom panels and Trex (or something like it, perhaps synthetic decking boards) makes the best fastening cleats, locker lid edges and raised opening edges. 

I haven't tried the even newer (last 20 years) synthetic decking boards they sell now. I'll have to buy a few.