Another sealing question about CPES, RAKA, paint, aluminum!!

[Siouxgirl2]

I am confused and wondering what people suggest. I was looking at Steve Fredrick's use of RAKA systems for epoxy and I see many builders on her use CPES.

It sounds like the consensus is to use CPES first for a sealer (unsure of coats needed), then RAKA systems with fiberglass cloth, followed by several coats of spar varnish, paint, or aluminum. Am I correct on this or am I way off base?

So... CPES and RAKA end up costing a fortune and I'll be completely broke but if I lose my home... I can always live in my tear because I've done it right?

Tell me if I've got it right or if I'm missing something?



Loyal

[afreegreek]

if you are going to use glass cloth you need to use a resin like Raka or West Systems or System 3 and you don't need to do anything except sand the wood first.. no sealer coat at all. CPES and S-1 sealer are thin penetrating epoxies and are only meant to seal wood for paint or skinning with metal etc. Raka is good stuff for glass work and it is water white not amber or green like some others so it doesn't change to look of the wood beneath.

[afreegreek]

BTW!!! make sure you get the right glass cloth. some has a binder in it (acts like starch on fabric) that does not dissolve in epoxy and will not go completely clear. you must ask for epoxy compatible cloth and use a little piece as a sample first to confirm what they sold you is what you got.

[nevadatear]

What afreegeek said. We used just RAKA epoxy for everything. Very happy with the outcome. CPS not needed, epoxy does the same thing. Then several coats spar varnish on top for UV protection.

[synaps3]

I don't see the need to do both CPES and epoxy.

CPES = clear penetrating wood sealer. You'd use CPES + Spar Varnish if you wanted to make your trailer a "woodie." (wood grain finish). Many who go this route fiberglass the edges as well with a high-end epoxy and fiberglass, for a deep, clear finish. Woodies are expensive, and only worth it if you really want that wood look.

An alternative is to coat the exterior of the wood with epoxy, fiberglassing the edges. You then coat the epoxy with an automotive paint, or a similar exterior-grade enamel.

Finally, you can also coat with bedliner -- Durabak seems to be the best option, as it comes in many colors, rough or smooth textures, and can be UV resistive.

After researching for my build extensively (over months), I determined the cheapest epoxy was here: http://www.uscomposites.com/epoxy.html. You don't want to use the cheap epoxy resin at Home Depot -- it's a polyester resin and will eat away at most plastics, and any insulation in your walls.

The route I determined to be optimal between cost and effectiveness is:
1. Light epoxy coat, fiberglassing edges, seams, and window openings. Any epoxy will do -- you're painting over it anyways.
2. Durabak bed liner. It'll be way tougher than automotive paint, is completely UV resistive, and holds up extremely well. I had them send me a sample of it in the mail, and it took me several tries to scratch it.

[S. Heisley]

People here seem to use RAKA if they are using fiberglass and making a woodie (no paint or aluminum). A lot of people use CPES because it is a terrific product. Use one or the other. You don't need to use both.

[planovet]

I don't see the need to do both CPES and epoxy.

Same here. I used CPES as a sealer before I painted my sides and as a sealer before I floated my aluminum roof. If I had used epoxy, I would not have used CPES first.

[Cliffmeister2000]

I used CPES (3 coats), followed by UNIFLEX 255 Aliphatic (3 more coats). Unfortunately, UNIFLEX 255 Aliphatic is no longer available.

[aggie79]

On the roadside of my floor, I used two coats of CPES, one coat of epoxy, and one coat of automotive undercoating. (This is overkill, but I'm still learning about overbuilding my teardrop.)

On my hatch, I have used one coat of epoxy so far, but will probably add a second. Prior to putting the aluminum on the sidewalls, I will apply one or two coats of epoxy, depending upon how much epoxy I have left, as a seal coat. (That is this weekend's project.)

My non-scientific assessment is that CPES is a very good product and it probably does penetrate better than epoxy. Epoxy does build up quicker. Using both CPES and epoxy is probably the most effective, but also the most costly and time consuming.

One thing to consider is that CPES contains a lot of solvents to help it penetrate. If you are using CPES, I would allow at least 1-2 weeks for the solvents to "release" before I covered the CPES-treated wood with epoxy, aluminum, FRP, EPDM, etc.

[Cliffmeister2000]

One thing to consider is that CPES contains a lot of solvents to help it penetrate. If you are using CPES, I would allow at least 1-2 weeks for the solvents to "release" before I covered the CPES-treated wood with epoxy, aluminum, FRP, EPDM, etc.

From Dr. Rot's website on CPES:
Allow approximately 1-3 days for solvents to evaporate before applying paints, urethanes, varnishes, Fill-Itâ„¢ Epoxy Filler or regular epoxy resin (see cure time chart below). (Link to chart provided)

http://www.rotdoctor.com/products/cpes.html

[S. Heisley]

Cliff, FYI: I'm told that the Rot Doctor now has another aliphatic available that is a little safer to use and this one comes in colors too!

Yes, I agree that CPES is a superior product over other epoxies and well worth the money.

[Cliffmeister2000]

Cliff, FYI: I'm told that the Rot Doctor now has another aliphatic available that is a little safer to use and this one comes in colors too!

Hmmm... Single part. I wonder how it compares to the original?

http://www.rotdoctor.com/products/colorcoat.html

[Siouxgirl2]

This helps because I thought I'd read something about using CPES first and then using epoxy and I wondered if that was really beneficial or not or if it was overkill.

Has there been any comparison on the longevity and durability of CPES vs. fiberglassed epoxy?

[aggie79]

CPES is a good product, but you will need to use something to topcoat it.

I found that on baltic birch plywood, two light coats of CPES did not completely fill the pores of the wood. The CPES also slightly raised the grain, so to get a smooth finish, I lightly sanded the material. This, of course, removes some of the protected wood, so sand lightly.

I agree that the RotDoctor said that 1-3 days was sufficient time to allow; however, my experience is that the odors of the solvents were around a long time after 3 days, and this was in 80+ weather.