Question for epoxy users

[Nitetimes]

I need to know what the difference is between the epoxy resin folks are using to coat their TD's and fiberglass resin or if there is no appreciable difference. Would it serve the same purpose or is it not a suitable substitute. I'm not talking about glueing things together with it but for coating the outside before shooting the clearcoat.
Right now Lowes has 2 gallons of it just sitting there for $13 and change and if it will work I want to go get it before they realize that the HD next door is selling the same thing for $31 a gallon.
Thanks for any input, seems all the sights I've looked at tend to use both names for the same product but I am not certain, it had me a bit confused.

[Arne]

Epoxy is epoxy. There may be subtle differences in quality, but the big difference is between epoxy and polyester.... The big thing is to put it on sparingly.... probably 3 coats to get the job done. Squegees work best.. and a foam brush to tip it, or drag out the air bubbles.....

With epoxy, you have about 36 hours between coats to get a chemical bond, which is best.... beyond that you get a mechanical bond......

Oh, best to wear latex gloves...... and alcohol will clean up unhardened epoxy....

[ceebe]

It depends too on one very important thing. Are you referring to regular fiberglass resin or epoxy resin? Polyester resin never met a water molecule it didn't like. Epoxy is Epoxy and Polyester is.... Its an apples and oranges thing. I do a lot of composite sailplane repair. For structure, i use the resins called out in the manufacturers manuals. Otherwise, i am a big fan of West System products.

[DoWopBox]

I need to know what the difference is between the epoxy resin folks are using to coat their TD's and fiberglass resin or if there is no appreciable difference. Would it serve the same purpose or is it not a suitable substitute. I'm not talking about glueing things together with it but for coating the outside before shooting the clearcoat.
Right now Lowes has 2 gallons of it just sitting there for $13 and change and if it will work I want to go get it before they realize that the HD next door is selling the same thing for $31 a gallon.
Thanks for any input, seems all the sights I've looked at tend to use both names for the same product but I am not certain, it had me a bit confused.

Where did you find it? Both Lowes and HD, here in Albuquerque, only have it in quarts. Its the kind for pouring a tabletop. Did you happen to get any brand names or part numbers? Oh, and I think they have the kind for painting concrete floors but it is all colored and I want clear.

[DestinDave]

If it's the epoxy I've seen in the paint sections at HD it is colored and used for garage floors. If it is the clear resin and of the type for tabletops it is probably only recommended for indoor use.
West System epoxy used with their 207 hardener will give you an almost clear finish; others will turn shades of red or amber. No epoxy is UV protected (or none I know of) so you will need a coat of UV rated varnish or automotive clear over the epoxy.

[Nitetimes]

I'll check the brand and number when I go over tomorrow. I do believe this stuff is clear tho, they had all the others mentioned too but this was next to the body putty. It just said 'fiberglass resin' on the can, I assume to be used with fiberglass cloth, the runny stuff you repair biiig holes with before you put the bondo on.
I plan to use automotive clearcoat on top of it, I just want to be sure this stuff won't do something stupid when I put it on.

[Arne]

More than likely it is crap, i.e., polyester..... It's cheap and sets fast and is worthless on a tear, unless you plan on coating it with something good (expensive).

But, then, what do I know. I only use the stuff....

[AZKick]

I don't know for sure but that stuff you are looking at is not waterproof. I have built a couple of boats and I use epoxy for just about everything. Fiberglass resins needs a gel coat to make them waterproof. If you see a boat with blisters in the gel coat, your almost sure to find water rot in the fiberglass hull.

[mbader]

Here is a link to epoxy information.
http://www.oneoceankayaks.com/Epoxtest.htm

[DestinDave]

Very nicely done and informative test Malcolm. I did a similar test several years ago with several teak finishes (oils, urethanes, varnishes, and epoxy) and came to the conclusion that for the best look and best finish an epoxy base with several coats of varnish couldn't be beat. For my two cents worth I prefer Schooner varnish and Epiphane is a close second. I've always used West System because it's what everyone in the boatyards used however after seeing Steve Frederick's work and your test results I'm going to go with Raka for the tear. Thank you for posting this... It should be a great help to all the woody builders. Dave Speicher

[doug hodder]

Nitetimes....West System has a variety of catalysts for the epoxy system...#206 is used for structural uses...can be thickened with colloidal silica, microballoons for gluing joints....also have thickeners that make it like bondo, will fair and work easily, but not a lot of structural strength...but for top coating, use #207....It has a slight amber cast and a built in UV inhibitor...All top coat epoxies need to be protected with something...whether it is Varnish as Dave mentioned, or clear coat...my preference...I think the advantage to the clear is it is tougher than the varnish and doesn't need the annual maintenance like on a boat....but I think the annual thing is only if you are exposed to the sun a lot...my boats are garage queens or under a cover most of the time...check out www.westsystem.com ... epoxies provide lots of working time and are very forgiving as compared to the older polyester systems...there are a lot of epoxy resins out there...I don't know what HD or Lowes has...I only count on the stuff that I build boats with...it ain't cheap....but it is developed as a system and the results are very repeatable time after time....I know this though....I can pressure wash my tear or boats, and paste wax it or hit it with a commercial polisher just like a car, no wax buildup in the grain, or hazy finish....Yeah....I've got some problems, dust etc......I'm just a yahoo building in a garage, and I do what I can...but I think it is a pretty respectable finish...most of my problems on the tear come from trying to get things done prior to Minden, in a hurry, cutting corners that I shouldn't have cut, my boats aren't like that....next tear will be better......Whatever you decide...I'm sure it'll turn out great.!!!....Just my opinion and experience....Doug

[Nitetimes]

Thanks for all the input and advice guys. The info was appreciated. I think I am going to check and see exactly what the HD stuff is. If it sounds reasonbly useful I'll be the guinea pig and try it out on mine. I am going to top coat with automotive clearcoat so as long as it will harden without any drastic color changes and it's clear when dry it should serve the purpose. The wife has already decided that this one will be the test ride and the next one will have everything she wants just the way she wants it so if I am not totally happy with it I won't be too upset. And if the stuff does turn out to be a good seal coat then it will just be one more option for us to use. And if it isn't the best, well, I'll only be out about $30. Wish me luck, R.

[asianflava]

...I don't know what HD or Lowes has...I only count on the stuff that I build boats with...it ain't cheap....but it is developed as a system and the results are very repeatable time after time

You can say that again. I bought a gallon of 105 epoxy, a quart of 206 hardener (West System), and 2 foam rollers at West Marine. $130 later I was out the door. I'm putting it on as an extra layer of protection under the aluminum. I figure that it will protect the wood from any condensation that forms under the aluminum skin. It will also let me use the tear at Inks Lake even though it is unfinished.

[Arne]

The problem is, it won't serve the purpose. Polyester is brittle. You use it in the wrong place and your seams will tend to crack. Polyester hardens quickly, so it won't soak in.

However, it is your trailer, so go right ahead and use it if you want.

About the weight of your trailer.... seems about 150 pounds too heavy... If it really weighs 400 pounds, I hope that is with the suspension and not just the frame.

And your wheel placement is determined by balance point, not by where you think it looks good.

Just points you might want to consider..... or not.

[asianflava]

OK, I just came in from the garage/driveway. I managed to apply a coat of epoxy on the exterior skins.

My question is, how much should I apply? Should I put on another coat because I am going to use the trailer without aluminum this weekend?

As I said in a previous post, I bought a gallon of West System Epoxy. After applying it with a foam roller, I think I could have done it with a quart. I am not concerned with the looks, because I am going to apply an aluminum skin on top of the epoxy.

I don't mean to hijack this thread but it is relavent. Besides, we already established the differences between epoxy resin and polyester resin.