BYYB Forums

When I did my skipjack, and was wetting the cloth with epoxy, it seemed like a battle to spread it without dragging, pulling the cloth. On the Stevenson videos, ( which are 100 yrs old) they show spreading epoxy with a paint roller easily. Is there a modern product that spreads like that, or can you thin it in some way?

You shouldn't need to thin the epoxy, though the hardener needs to be in the appropriate temperature range. Some use grooved rollers, but I use plastic putty applicators, like that used for auto body work or a plain rubber squeegee. The cloth will tend to move around, but you can tape or staple along one edge and pull away from it, keeping it in tension, so it doesn't move that much. You also can use spray adhesive, misted very lightly on the area, before the cloth goes on. It'll hold the cloth in place, without affecting the bond, but you have to very lightly dust it, not spray paint it.

Sometimes condisions conspire against you, so warming the epoxy up (not much), so it's viscosity goes down to an acceptable amount is necessary. I just toss it in the microwave for a few seconds and raise the temperature to the mid 80's. If it's a slow hardener, it'll kick off fast at this temperature so spread it out in a large pan and work quickly. Regular cure hardener will also kick off quickly, but not as bad as slow at these temperatures. A slow hardener will not mind too much with low 80's and my super slow is barely in the range it'll setup. In fact, it will not kick off if it's in the low 70's at all. Lastly, chip brushes are commonly seen, but not by the pro's. These apply goo in a pool and you kind of smear around the edges, as you try to spread it around. Rollers (foam or fiber) apply much more uniform coatings, but they also trap a lot of goo in them when you're through, making you feel guilty about the waste.

Check out my epoxy tips page on my site. Also check out some of the videos that Joel made, over at Bateau.com.

I have a bit of left over Marinepoxy that has gone cloudy and thick.  If I warm up the bottle in a bucket of warm water for a while, it will spread out just fine.  I always use fast hardener.  I work in the cold so having the goo cook off isn't so much of a problem, but I still work pretty fast when I have a batch in my cup.  To keep the cloth from moving around too much I always start in the middle of the area and pour as much goo out as I either have in the cup or I think will do the area.  I then work out from the middle so that the cloth gets pulled out in all directions rather than one direction or another.  I have found that once the middle of the area is settled down tight, it won't move very easily.  I also use auto body spreaders to apply epoxy.  They are cheap and can be cleaned off even if the epoxy has cured fully on them.  Buy a bunch of them.  It is always nice to have a fresh one when you have a lot to do and don't want to slow down. 

Al

If the epoxy is cloudy, it's got some crystallization (a really cold weather thing) in it and this is easily fixed, by warming the goo. If your microwave is big enough just nuke the bottles for a while, then stir or shake.

Auto body filler applicators are what I use often too and they are easily conformable and trimmed to fit.

I toss the bottle into a big bucket of hot tap water when I first go into the shop.  By the time I am ready for it, it is nice and runny.  The hardener doesn't seem to need heating, so I leave it cold.  I suspect that when I mix the two, the cold hardener cools off the resin just a bit which is probably a good thing.  I like Marinepoxy. It is all I have used except for a couple gallons of West System, and I see no reason to switch.  I have a pretty good idea of what it will do in various situations, and for different purposes.  It's pretty cheap too.

Al

You're correct, it's usually the resin that's most affected by freezing temperatures (crystallization), though when I do, I heat both. Tap water can work, but sometimes you need more heat, so boiling a pot of water on the stove and dropping the container into it as it cools, with insure all the crystals are broken down.

Marinepoxy works very well and is a reliable brand. It's about the cheapest around too. I think Graham over at B&B yachts has a slightly cheaper epoxy, also a 2:1, but I've never used it.

When I was building Duckie, I had a mishap that caused me to have to peel off a couple square feet of cloth on her starboard bow.  It was early morning and I wasn't sufficiently caffeinated so I lost count of the 5 to1 mix I was making, and in a couple days it was clear that the stuff wasn't going to set up.  That cost me almost a week to fix.  Since then, I have stuck to 2 to 1 mixes. 

This build is going to require a ton of little batches.  I foresee myself mostly mixing up a few ounces at a time.  I have hit on a method that hasn't let me down yet for tiny batches.  I mix little batches with plastic picnic spoons.  I measure out the resin one spoonful at a time, then with the same spoon, I measure out the hardener and mix.  As long as I let the spoon drip out all the way with the resin it works great.  I also use plastic cups for mixing.  Sometimes, I can lift the leftover goo right out of the cup and use the cup again.  I don't like that though because it means that I mixed up too much in the first place. 

One other thing.  I have found a use for any leftover epoxy in my shop.  I  built a couple new benches and left the tops bare plywood.  Where I mix up epoxy, I spread any leftover on the bench top letting it build up.  Eventually, I have to take the belt sander to it to keep it nice and flat, but it takes a while to get to that point.  Now where I mix is impervious to just about anything I might spill on it.

Al

A formica counter top is pretty easy to find and cheap. These make good epoxy mixing station areas.Wax it up and they clean easily.

Doesn't anybody use a kitchen scale?

That is the best and most accurate way to measure I have found. I use epoxy that is mixed 1 to 3 and I tare the scale with a cup or container of sufficient size and the pour in the resin and add the hardener. No need to worry about perfectly emptying your measuring spoon or cup and you can even use a syringe to be exact with the hardener. My batches are between 20 and 200 grams and when in the lower end of the scale the syringe is a good idea, although I have learned to pour pretty accurately straight from the can.

This is where I needed my biggest batch so far: laminating the cloth on my rudder.