Ok, Newbie Tear builder still confused on epoxy or resin

[Von Pook]

I am building a woody style tear and continue to wonder about the exterior. My confusion is, what to cover it with. I would prefere something that is transparent and allows the beautty of the wood show through. Either fiberglass resin or epoxy resin. Is there a difference or am I losing my mind?

[Juneaudave]

I am building a woody style tear and continue to wonder about the exterior. My confusion is, what to cover it with. I would prefere something that is transparent and allows the beautty of the wood show through. Either fiberglass resin or epoxy resin. Is there a difference or am I losing my mind?

Holy Smoly Mr. Von Pook...you are indeed losing your mind!!! Bottom line is that an epoxy resin such as West, Raka or MAS can be used with or without a fiberglass cloth layer. Coating something with epoxy, in and of itself, doesn't add strength...but it does seal out the weather and build a nice surface for a varnish or poly finish coat. If you lay out a layer of fbergalss cloth...this thread might help...http://www.tnttt.com/viewtopic.php?t=24413&highlight=hatch

[Von Pook]

So Dave, if I ran down to the auto parts store, and got a gallon of fiberglass resin, would that be ok?

[del]

So Dave, if I ran down to the auto parts store, and got a gallon of fiberglass resin, would that be ok?

No, chances are what you would come home with is polyester resin (brittle), and not epoxy resin.

del

[Juneaudave]

So Dave, if I ran down to the auto parts store, and got a gallon of fiberglass resin, would that be ok?

Well maybe, but you would most likely be buying polyester resin that may or may not give you the results that you are looking for. Take a look at the Raka, West, or MAS sites. These are really good and what you want!!!! Raka is probably cheaper...MAS and West are more widely distributed and can be found at marine suppliers and finer hardware stores.

[asianflava]

Resin and epoxy are used interchangably which adds to the confusion. Epoxy is a resin but resin isn't necessarily an epoxy. There are resins like polyester which is to find. It works fine but it is not as strong, and can be tricky to work with because it is dependent on how it is mixed. On the upside, it is cheaper and doesn't need UV protection. An easy way to distinguish wether it is polyester or epoxy resin is by the price, epoxy is usually more expensive.

[leaded]

After what i´ve read of posts, the polyester resin is more brittle. Would this make any trouble with cracks in the "shaking" of the caravan at travel, or is the epoxy resin best because it gives more strength, without making brittles?

[jimqpublic]

A wooden boat magazine I used to read when building my Kayak had a great article on using a light layer of glass cloth with epoxy to stabilize the surface of plywood used in a varnished topsides application. They said that otherwise the surface was much more likely to "check" due to the thermal effects of sun exposure. The thin layer of glass is basically invisible after varnishing.

So if I were to do a varnished or painted exterior it would have epoxy and glass to stabilize it, then varnish or paint for UV stabilization.

[doug hodder]

I've built all of mine using just epoxy over the plywood on the exterior, 2 woodies and 2 painted ones, no cloth. On the woodies I used an automotive clear, on the painted ones, base paint and clear. I also built 2 boats, used cloth on the hull, but not up on the top deck however varnish won't weather like an auto clear will. I've had no problems with any of them checking, but I don't leave them out in the elements year round. My opinion...the epoxy is a lot less of a nuisance to work with over the polyester. I also use it for my main construction adhesive. Doug

[ZendoDeb]

The high-gloss epoxies (even West System) don't contain much in the way of UV protection. In the South, it is recommended to cover with a couple of coats of varnish.

When it degrades, you can have a real mess on your hands.

3. Epoxies yellow, chalk (or more commonly least lose their gloss), in direct sunlight (UV). The yellowing can be a real problem. For pigmented epoxies select colors that are dark or contain a lot of yellow (such as green). Even clear epoxies will yellow and cloud up. Often epoxies are topcoated with latex or urethanes that will retain their color and attractive gloss. This is particularly true if color coding or matching company colors is important.

reference

[Tx River Rat]

Don,t mean to start a war here.
But I have built several kayaks that are used pretty roughly , bouncing of rocks drug up on gravel and sand beaches, and I used polyester with good results, and after several hundred miles on the river they are in good shape.
Epoxy does add strength if you coat both sides , then you have a composite which is 4 times stronger than a raw piece of wood.
Ron

[Von Pook]

I'd like to thank everyone for the responses to my query. Though now maybe I should start a poll and find out which is to be the winning finish on my tear lol. Thank you all again for your help and patience

[Esteban]

I'm fiberglassing my teardrop with epoxy and fiberglass cloth from Raka.com. I'm using fiberglass cloth on the sides and on the top and galley lid.

On the sides I used a light weight tight weave fiberglass cloth. The tight weave made bubbles a little difficult to brush (tip) out. I think the fiberglass cloth helped to level out the epoxy. If I had a do over I'd use a plain weave 4 or 6 oz. cloth.

I have not begun fiberglassing the roof. On it I'll use 4 oz. (6 0z. would be OK too) plain weave cloth that has more of a gap between the criss crosssed strands. It should be easier to brush out bubbles.

On the sleeping cabin floor I'm using epoxy, without cloth, to seal the plywood. The successive coats of epoxy tend to orange peel and require more sanding to level than the sides (with fiberglass cloth) did.

A gotcha I've encountered is that on some real small batches the mix was wrong. They gelled up but never hardened. A PITB to scrape and sand off several days later. There may have been too much hardener in those bad small batches. The Raka hardener bottles said using too much can cause that.

Just some experience from a newbie. Overall I'm pleased with epoxy and fiberglass.

Also the 1/4" sanded plywood, with a grade A face, for the sides was from a local lumber yard. It was very smooth with almost no voids visible between ply layers. For the cabin floor I used 3/8" Orange Box sanded plywood. The local lumber yard plywood cost a little bit more but it seemed easier to epoxy/fiberglass to get a smooth even surface, with less sanding and wasted epoxy, than Orange Box plywood.

edited to add: I'm using a foam roller (from Raka) to spread out the epoxy. I only use a foam brush to very lightly tip off (break) the bubbles that form. Also use a plastic paint edger from HD to help spread epoxy around and to fill in low spots, like nail holes or plywood joints, with epoxy that has begun to thicken.

[doug hodder]

Steve...just an idea, don't use a brush to wet out glass cloth, use a squeege. A body putty squeege works well. Mashes the resin into the cloth and smooths it down. Doug

[starleen2]

Steve...just an idea, don't use a brush to wet out glass cloth, use a squeege. A body putty squeege works well. Mashes the resin into the cloth and smooths it down. Doug

Would have to agree with doug - I learned the hard way with a brush. Sure it works ok, but the many hours of sanding to remove brush marks was tedious and dusty.