2 part epoxy

Thanks buddy.

No problem, to be more specific denatured alcohol. Acetone works as well. Both of these will weaken the epoxy somewhat.

The very best method would be heat. It doesn't weaken the bond and it flows like a thin syrup. You could use a heat gun or a double boiler.

Bob Smith Finish - Cure is a 20 min resin that's very thin. It works well for lightweight glass.

I used alcohol thined epoxy on a pair of 1/2A floats . It worked very well , but the drying time is a lot longer then the epoxy without being thined

Be careful heating fast epoxies, the reaction can become quite energetic. Smoking even. Slow epoxies respond better to thinning via heat.

Solvent thinning works well if a some strength loss is OK. There are quite a few solvents that will work well. I have used acetone and denatured alcohol myself. For fast epoxies (less than 15 minute) solvents are the only practical way to thin.

"Instant" epoxies do not thin well, but that is part of the 1 minute or less kick time. These usually have a mixing nozzle with the double tube.

Phil

I have always coated firewalls and other areas that are exposed to raw fuel with epoxy. I use 30 to 45 minute cure times because it gives more work time and I think the longer cure epoxies are less brittle than the 5 minute or instant epoxies. That said, I prefer heat for thinning. After applying to the areas, I use a monokote gun to warm the epoxy to the point it begins to run slightly. This lets me move it over the part and into the crevices and joints where necessary. If it is a plywood firewall, the epoxy will actually begin to soak into the wood and when set, leave a smooth, glass like finish.

andrew wrote:I have always coated firewalls and other areas that are exposed to raw fuel with epoxy.  I use 30 to 45 minute cure times because it gives more work time and I think the longer cure epoxies are less brittle than the 5 minute or instant epoxies.  That said, I prefer heat for thinning.  After applying to the areas, I use a monokote gun to warm the epoxy to the point it begins to run slightly.  This lets me move it over the part and into the crevices and joints where necessary.  If it is a plywood firewall, the epoxy will actually begin to soak into the wood and when set, leave a smooth, glass like finish.

That is what I was going to do with it fuel proof some areas.

Sounds good.

I just use a paint brush and dip it in acetone, then pick up the epoxy with the dripping wet brush and slather it on.

Or, a couple of heavy coats of Minwax polyurethane goes on easier and is pretty super fuelproof too. The pint cans are cheap. For LG holes, screw/bolt holes, etc., I also use a toothpick or a little dental cone brush(meant for flossing between the teeth) dipped in polyurethane too. It really soaks in good inside those bored holes and doesn't foul any threaded inserts or t-nuts as bad as epoxy can.
Rusty

RknRusty wrote:I just use a paint brush and dip it in acetone, then pick up the epoxy with the dripping wet brush and slather it on.

Or, a couple of heavy coats of Minwax polyurethane goes on easier and is pretty super fuelproof too. The pint cans are cheap. For LG holes, screw/bolt holes, etc., I also use a toothpick or a little dental cone brush(meant for flossing between the teeth) dipped in polyurethane too. It really soaks in good inside those bored holes and doesn't foul any threaded inserts or t-nuts as bad as epoxy can.
Rusty

Pipe cleaners work well too for protecting LG and fuel line holes.  Use the ones that do not have wires embedded.  Walmart has them at the tobacco register.  They clean out head, case, and mounting holes too.  Use the tapered wire embeds for this task.

http://www.ebay.com/itm/B-J-LONG-TAPERED-STANDARD-PIPE-CLEANERS-100-BAG-/221791832518?hash=item33a3d2c9c6:g:K38AAOxy0NtTCe0q

http://www.ebay.com/itm/100-Pieces-White-12-Long-Chenille-Pipe-Gun-Cleaner-6mm-Stems-/161583506224?hash=item259f20a330:g:DJMAAOSwYGFUzzKJ

Bob

I build a lot of mostly Profile planes...

I use a hole punch with Blue painter tape to make a round DOT to keep Epoxy, primer, and paint out of the engine bearer and LG holes ---but I do always add thin CA to the hole

Some here may remember my query about a good CA glue that kicks off instantly......slow curing CA in a HOLE is as bad as Epoxy in the hole

Nice, thin, Instant setting CA, is mucho prefered and I am still having trouble getting any that smokes!!!