Fiberglassing Assistance

[doug hodder]

Doug(et all), I was looking at this site and they have a West Systems product called SB-112, a UV stabilized epoxy...know anything about it????
madjack

I read the info on it and in the technical portion introduction...it says that no epoxy is uv stable and should be top coated for maximum protection...it also sounds like it is pretty "hot" stuff, not giving you a lot of working time especially to coat out the side of a trailer...but hey...it'll probably work...for me, I've got too much $ tied up in left overs of West System to start up with some new stuff....Doug

[doug hodder]

You'll need to use cloth on that one...and the cloth is way expensive, especially when you need a heaver material to protect the foam from punctures...it could be done though...how much dough do you want to spend? If if were me, I'd go ahead and lay down a thin sheet of ply...like 1/8" and then cloth over it with the lighter glass cloth and then epoxy it up....the flat ply will give you a lot better base to work with...less chance of high and low spots like you'll have on direct foam....again..just my opinion...I'm sure others may disagree...and Finn...I laid down all the dye and epoxy before I put the sides on the tear...it's a lot easier to get it to flow the way you want when laying flat...did the final sand and clear coated it after the tear was done.....Doug

PS drop Destin Dave a PM...he does tons of work on boats for a career...I'm just a garage guy...

[Classic Finn]

How bad is the odor or smell from this epoxy before it sets ?



Clasic Finn

[doug hodder]

It's not that bad...you might want to crack a window but I have no problems with it...it's like a liquid plastic, but not high in volatile solvents...just make sure you keep the temps up in the shop for the curing time and don't let all your heat out...being an ex-uranium geologist...and shot a lot of cars...the epoxy is the least of my problems...Doug

[doug hodder]

For me...I operate out of a gallon can of resin and the smaller quart cans of hardener...you need to get the regulating pumps so that you can meter out the hardener to get uniform batches...I get discount coupons at West Marine and buy it when it's on heavy duty sale...better price by the gallon, and you can use it for a lot of other uses around the house...I also use the West System rollers for application...I've used the HD ones and they break down pretty quickly and you are fishing out parts of foam from the surface...cut the rollers in half and use them on the shortie handles...don't work it really fast or you'll whip air into the epoxy and get lots of bubbles...the first couple of coats I just lay down on top of each other...then sand and apply more epoxy with a roller and tip it off using a roller cut in 1/2 lenghtwise held in a spring clamp...backdrag the resin to remove the stipple marks from the roller...that's how you get it smooth...and back to your question...depends on how big your tear is....type of cloth...and you can do it in Kevlar if you have really deep pockets....I bought a new gallon for my tear and still have some left...it's a drag if you are part way through the job and run out though...Doug

[Classic Finn]

Doug

Is it better to epoxy the walls before installation or after completion ?

Classic Finn

[doug hodder]

definately before...like I mentioned...it's a lot easier to get the epoxy to flow out for you if it's laying flat and if it's on too thick in any place you won't have sags or runs that are a real issue to sand out..much easier to work with...do the topcoat after they are all in place...gives you a chance to cover up any scratches..especially if you spray...just my opinion however...Doug

[Juneaudave]

Finn...I've done some fiberglassing on canoes, kayaks and small boats. One of the best places to start investigating clear coats is in the builders forum inBear Mountain Boats. These guys are really good..have members all over the world including Finland (so they know where to get local woods and epoxy). You can ask any question on clear coat fiberglassing and get an answer pronto. Dean in Eureka is an active member, so am I.

I also plan on using glass and epoxy with woody sides. Tentatively, I'm thinking 3 oz cloth on the sides with a clear coat and 6 oz on the top (painted to match the tow vehicle). Epoxy is susceptable to UV, and is traditionally protected with multiple layers of spar varnish. In my case, I intend to put a color coat on the top and shoot the whole trailer with several coats of automotive clear coat.

One consideration is that you might not be able to find 60" cloth in Europe, many overseas builders are forced to use overlapping layers (which works fine, but takes a bit more care in sanding). As far as epoxy...here's some commonly used clear coat brands that you may find by a Google search:

West System 105/207 Special Hardener (very predictable, non blushing)
MAS Slow (my current favorite, predictable, non-blushing, more open time)
RAKA (inexpensive, with a very good product and excellent service)
Citidel (sp?)(a Canadian brand with a good rep)
System Three (people both swear by it and at it)

[Arne]

There is good reason to do it before cutting.. it keeps the edges sharp and eliminates almost all splintering.....

I built my walls. Before I cut out the doors, I went over the area where the cuts would be made with epoxy resin and let it soak in and harden..... That way, when I made the cuts, the plywood did not splinter.

[Classic Finn]

This is really good info....thank you to everyone..

Im going to check with a few folks about the fiberglass since here in Finland they build fiberglass sailboats such as the Finn Swan.. I know a few people there that may provide us with the proper size cloth....In addition to that I,ll also check on other info pertaining to this topic as well..

They could be helpful ... I,ll keep you posted...And I,ll check with the distibutor for West System3 here in Helsinki...


Classic Finn

[Guy]

Dear Finn,

You asked:

How bad is the odor or smell from this epoxy before it sets ?

Doug answered:

It's not that bad...you might want to crack a window but I have no problems with it...

Finn, don't believe him. Just read some of his limericks, and you will see how much it has affected Doug.

Come to think of it Finn, maybe after working in a closed room with some epoxy, you, too, will be thinking in limericks.

[Nitetimes]

OK, another dumb question here. I see the reason for the fiberglass resin on the wood sides, it gives a nice smooth finish and it's waterproof, makes perfect sense. But the question I have is, you are working over at least 1/4" ply, what is the fiberglass cloth doing? Except for the corners I don't see the need for it for added strength. Seems to me that a couple or three coats of resin sanded out with a few coats of automotive clear on top of that would give you a smooth waterproof finish so what does the cloth actually do? 'Cept of course add to the cost of the finished product.

[doug hodder]

I'm with you Nitetimes....I only use it on boat hulls, not top decks....tear sides also don't need it, if you have a wood side to work with....we had this discussion several months ago, somewhere in this forum ..I just don't see the advantage of using cloth, unless you are trying to do something trick....like over a foam side like in Powderburns example...resin on wood works for me....whatever strength you get out of 3oz cloth on a flat side just isn't worth the expense....maybe some abrasion resistance..but then the top coat is going to get screwed up anyway...and a scratch into wood only is going to repair a lot easier than a scratch that has torn through the cloth....Doug

[Arne]

Surface integrity. Same reason you don't use finished plywood for a counter top. You cover it with a laminate. It makes it more durable.

And the only extra cost & weight is the cloth. 2 oz. cloth would hardly be noticeable, weightwise.

[Steve Frederick]

OK, another dumb question here. I see the reason for the fiberglass resin on the wood sides, it gives a nice smooth finish and it's waterproof, makes perfect sense. But the question I have is, you are working over at least 1/4" ply, what is the fiberglass cloth doing? Except for the corners I don't see the need for it for added strength. Seems to me that a couple or three coats of resin sanded out with a few coats of automotive clear on top of that would give you a smooth waterproof finish so what does the cloth actually do? 'Cept of course add to the cost of the finished product.

As you said, the cloth adds strength. I'm using 'glass because I build up the side panels from pieces of ply. The 'glass adds the strength that I want.
As wood moves with temperature, small cracks, or print-through can develope. These cracks can show up in the finish long after it's done.
The next project is going to be a smaller tear. So, I won't build up the side panels. I'll do as Doug has done, and do a few coats of epoxy only, on the sides, covered in clear-coat or spar varnish. I'll still do the roof with 'glass though.
I've never had trouble with epoxy running either! Just work in small batches. in small areas. On bad areas, like where the roof skin curves under the front, as on a 'Diner, use a brush to apply, then squeegee out with an old credit card.