First time canoe builder - epoxy question

Hello all!
I'm brand new to the forum and boat building in general. I recently started work on the quick canoe. Haven't done much more than measure and make a few cuts, but it's been a blast so far to be building something that will hopefully float when I'm finished!

Now, to my question. Per the suggestion in the plans, I'm looking at going with West epoxy, but I'm totally new to epoxy. The plans suggest using an epoxy with filler, but there are many kinds of fillers offered by West and I have no idea which one to get. Does anyone have any advice on what I should go with? If I understand correctly, I'll need the epoxy, the hardener, and a filler?

Thanks in advance for the help!

I guess it depends how particular/finnicky you want to be, and how determined you are to keep costs down. Manufacturers would no doubt prefer it if you buy one of each filler and hardener to suit every conceivable purpose. I've never used West before, but according to this guide it looks like you could do everything (except fairing) with say 406 filler (or 405 even), but if you want wood coloured (rather than off white) fillets, you'll want to get some 405 for that. Then you might want or need a lightweight easy-to-sand filler for fairing (410 or 407). Then there are non West brand fillers which might save you some money.

And yes, you need epoxy resin + hardener + fillers. The other decision is which hardener. In this case definitely is preferable to have the right type to suit the job, the ambient working temperature, and whether or not you're doing a clear finish (normal hardener goes yellow with UV exposure, so you need the Special Clear Hardener if you are varnishing). I'd be inclined to avoid the fast hardener unless you really have to work in cold conditions, because a 9-12 minute pot life doesn't leave much time to apply the epoxy.

Hopefully someone experienced with West will chime in. Have fun with the build!

I don't have much experience with the West System epoxy either. I've used Boat Cote and other generic brands. I think the West System filler powders have specific uses. So you probably only want one powder for strengthening bonds. Other fillers can be used to bulk out epoxy for filleting however I doubt this isn't such a concern in a canoe, unless it has a flat bottom. Otherwise a nice fillet between bottom and sides is pleasant to look at.

So you only need filler powder when you use epoxy as glue i.e. for strengthening the joints between ply and wood. I think Storer's OzRacer Mk 2 plans told you when you needed such filler for gluing or the 'peanut butter consistency' type filler for fillets.

When you use epoxy to seal the wood, you wouldn't need any filler. At this point you're just using the properties of the epoxy to seal the top layers of wood fibres to prevent water rotting the wood. For example, once the canoe/boat is constructed you give the whole boat 3 wet-on-wet coats of epoxy.

I trust this helps a little.

Welcome to the forum.

West System epoxy works and is the industry leader, but it's also one of the most costly resin systems out there. Many brands of epoxy exist and quite a few at 1/2 or less of the price for the same amount of West System.

Epoxy use is all about procedure and techniques. Log onto Westsystem.com and Systemthree.com and download their free "user's guides" and "epoxy book" for a good overview on these methods and techniques. My site also has some information about the process.

As to fillers, you'll need two types on your canoe - a structural mix and a cosmedic mix. The filler types and the consistency (viscosity) are dependant on what you're doing with that particular mix. For example, if you're doing some fillets, the viscosity should be fairly stiff, so it doesn't sag. The same would be true with a fairing compound (cosmedic mix) used on a vertical surface or overhead. This all takes a little practice, as you learn about things and you'll "cook" a mixing pot or two in the process, but this is normal and we've all done it. Read up as much as you can on the processes and practices, because (again) success is all about sticking to established techniques.

About fillers; there's three basic categories, fibrous (structural), bulking agents and viscosity modifiers. For viscosity modifiers, there's really only a few things that the backyard guy will use and this is silica. A common brand name is "cabosil", which is just silica. A little of this in a mix will stiffen it up, so you can control viscosity. Bulking agents are light weight materials that add mass to the resin and these are Q-cells, microspheres, 'glass and/or phenol and/or quartz balloons. These are literal microscopic spheres of stuff, that take up space in the resin mix, without being very heavy and they sand easy too. Lastly are the structural materials, which add to the physical attributes of epoxy. There's a whole bunch of these, including things you can find by raiding her kitchen pantry (don't get caught, trust me on this). (> WEST SYSTEM | Filler Selection Guide <) This West System guide will give you an idea of how these fillers apply, though you don't know what's in them.

If you'll just be building this one canoe, then just buy the stuff from West System or System Three (fillers). As for epoxy itself, check out (> Epoxy Resin <) and look at "Marinepoxy" as the low cost alternative. You can also get fillers from DuckWorks for a lot cheaper too.

Wow! Thanks for all the suggestions! Much appreciated. I think I'm going to end up going with the MarineEpoxy from duckworks. My next question is how much will I need? Would a 3 qt kit be sufficient? I'm planning on painting the bottom of the boat. I assume it will still be necessary to put a coat of epoxy on the bottom?

Thanks again!

Wow! Thanks for the suggestions! Much appreciation. I've decided on going with MarineEpoxy. How far will a 3 qt go? I'm planning on paint the hull, will that need a coat of epoxy too?

Hi eggman. I'd really look to encapsulate the whole ship regardless of what bits will be painted or varnished. To my mind the epoxy waterproofs the wood and protects it from physical damage to some degree, then further coatings like paint or varnish protects the epoxy from UV damage in particular.

As for quantity, I think I used about 5L (a touch over 5qt) for my Eureka which is a similar size to the quick canoe but as a beginner I typically made mistakes, laid coats on too thick and basically wasted lots. So 3qt may be enough but I'd go for the next kit size up so you've got some in reserve for finishing it plus for repairs.