Fiberglass Resin Recommendations?

[Seth and Desiree]

We installed a new awesome fan on the roof but had to build up a 2-inch frame for it (i saw a thread where somebody else did that too, but can't remember which one it was). Now I need to make it pretty so it looks like it came from the factory that way

Can you recommend a fiberglass resin that I can spread over it? I've never used fiberglass resin before. Should I used some sort of mesh tape/paper patch first? Do I fiberglass then sand/paint? Do I fiberglass, then bondo, then sand/paint? Like I said, I'm new to using fiberglass so any pointers are appreciated. Thanks!

-seth

[Jack L]

Resin by itself has very little if any strength . Fiberglass is what provides the strength.

[rick.a]

Hi S&D,

If you have already made your built up frame and only need to "glass it over" to give it shape and color to match, you are on the right track. Your frame is providing all the strength that you need. You only need enough glass in the resin job to give integrity to the resin build up so that it will not crack.

Modern fiberglassing uses epoxy resin and not the old polyester type. You can probably use only one layer of fairly thick FG tape layered in, then a coat of thickened epoxy to hold some shape to the cove curves without running.
Epoxy resin can be thickened with silica or glass micro beads, which gives it sag proof strength and is sandable and shapeable while retaining incredible strength.

Your best source of materials and support is from a company that supports the boat building and repair industry. They live and breath FG and epoxy resin (literally).

I am in the finishing stages of fiberglassing a new floor into a Burro-13 and got my materials and lots of support from a company in FL called RAKA. You can find them on the web. You can read their "how to" fiberglassing manual and or call them. THey are friendly and helpful. They can also help you in gauging the amount of material that you need.

Hint...you can also colorize the epoxy resin so that your last coat is as close as possible to your final coat. The boat builders use "wood flour" which is powder fine sanding dust. This thickens the resin to workable flow strength and colors it like dark wood. I thicked and colored my final coat on the outside edge with white powdered tempra paint, since my Burro is white. It was not white enough for a match but is much better than clear or wood colored, and the cost was minimal. Caution, do not attempt to color with anything other than a powder. Liquid colorants can decrease the strength of the epoxy.

Or you can just sand, prime and paint the finish coat of resin and forget the colorant.

Rick

[David Tilston]

Rick, I must disagree with you. Epoxy will work, but causes more problems then it is worth. What do you see as the advantage? Oh yah, it is also quite expensive in comparison. Polyester resin is still used in trailer manufacturing, and it is probably best to stick with the original material. This is not a high performance application. I have heard that nothing sticks to epoxy, except epoxy. That is enough reason to use polyester resin in my opinion.

Polyester is available at many places, cheep, and same material that the trailer is made of.

[D White]

Originally Posted by David Tilston

Rick, I must disagree with you. Epoxy will work, but causes more problems then it is worth. What do you see as the advantage? Oh yah, it is also quite expensive in comparison. Polyester resin is still used in trailer manufacturing, and it is probably best to stick with the original material. This is not a high performance application. I have heard that nothing sticks to epoxy, except epoxy. That is enough reason to use polyester resin in my opinion.

Polyester is available at many places, cheep, and same material that the trailer is made of.

I totally agree here

[KevinScamps]

If you want to find out all about my problems using epoxy on my Scamp renovation check out my blog.


http://www.fiberglassrv.com/forums/f...ion-49478.html

Use resin, its much much cheaper and it can save you significant hassles.

[kirkman]

I believe most manufactures now use vinyl ester resin. At least that is what my friend who builds fiberglass boats for a living uses. It is stronger and more flexible than the old poly resins.
If you really want to know what resin to use call these guys they are very helpful and have never steered me wrong.
http://www.mertons.com/index.html



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[David Tilston]

I went to Trillium / Outback at lunch. I asked Joe Thoen, the owner, what they use. He told me Aropol:
http://www.ashland.com/Ashland/Stati...2015%20TDS.pdf

Polyester

[D White]

We use vinylester resin (also called tooling resin by some) for many reasons, but as I have stated many times before, everyone should use polyester resin on their trailers. It is what they were built with and what they should be repaired with...PERIOD...this epoxy rage is fueled by marketing and actually causes the do it your selfer more problems than it supposedly solves. There is no problem with polyester, so you shouldn't make one...Fiberglass Dave

[rick.a]

The reason that I reccommended epoxy for this repair/mod is that it is a repair and not a molding job. Manufacturers use poly resins for layups for many reasons, the biggest for them is cost. Poly is cheaper.

Epoxy can use a hardener which allows much slower curing than poly and this has several benefits for the novice doing a repair. Since is cures slowly it soaks into the wood much better. It also allows more time for the user to get the application correct before it hardens in the pot. Epoxy is much stronger than poly which is important for repairs. It also contains a much greater solids content since nothing evaporates out of it as it cures (same weight as liquid or solid). Also epoxy is much more resistant to water (see above about solids content).

Poly sticks very well to poly but epoxy sticks to both poly and much better to wood and any other surface in a mechanical adhesion process which is exactly what this repair is.

So, I agree that poly would be the better choice if the OP is laying up a big piece, but he is covering a wood form and molding it to the gelcoat, for which I would still recommend epoxy.

Also, although the epoxy is more expensive, the left over (unmixed) will store indefinetly. Not so with poly which is continually polymerizing and eventually becomes useless.

Epoxy can be sanded and painted just like gelcoat can.

Regards,
Rick

[Lfoxmont]

Rick.a,

I've got an 82 Burro and I would love to pull out the untracked carpet to put down laminate. Should I put down sub flooring (thin plywood?) and then use laminate? When I pull up the carpet, the fiberglass is in ok shape..........white edges of camper looks bolted down to the FG. Thanks!


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[rick.a]

Hi Linda,
How you proceed depends upon several things. If the floor is sound, not spongy, like old Burro floors can get, then you can proceed with floor covering. If the laminate that you want to put down "floats", meaning it is not adhered to the sub floor, but only to itself, then this is also good . The fiberglass upper surface of the floor often is lifted from the plywood under it so, gluing anything to it is not recommended.

The big issue that you may face with the Burro assembly is that the flanges at the bottom of the lower cabinets which curve out and sit on the subfloor and is screwed to it, are typically raised up by the thickness of the FG mold it is made of. This makes for a raised edge on any flooring that you use. If it is not raised TOO much, you can get away with the stiff style laminate because it will bridge over the gap and still look nice and flat. A softer flooring like vinyl plank will probably show the raised edge.

To eliminate the edge effect you can use a thin underlayment, like you suggest and either but it up against the flange lip depending on thickness match) or go over it right up to the cabinet. Or if the lip is not too thick you might be able to fill in the gap and feather it out to the center to make a smooth transition. If you do this, the typical floor levelers will crack up because of the floor flexing. There are floor levelers which are supposed to be flexible, but I would just use thickened epoxy which will not crack.

So... there is a bit of evaluation required in order to get the best results. But if you use a stiff laminate you might just require a little feathering around the edges underneith and it will be great.

The floor in my 84 Burro-13 was too far gone so I have just replaced it and at that time, I paid special attention to these cabinet flanges, to get them down as flat as possible, because of all the issues that you are facing.

Rick.

[Seth and Desiree]

Hi everybody, sorry I have not responded sooner, but thank you for the info! I ended up using Bondo brand fiberglass resin to which I added the included hardener. I brushed it on, the laid strips of fiberglass cloth over it while it was still wet, then brushed another coat of resin/hardener over the cloth strips once they were in place. I did this twice, then did some sanding to take down sharp edges and high points. Then I used Bondo brand fiberglass filler and used the hardener that came with that to spread around and fill any remaining gaps, pits, low spots, etc. and sanded smooth(ish). Two or three more rounds of that and then it was at a point that I could live with. So I brushed on some primer, followed by a couple coats of white paint and then installed the fan! Fit like a glove and I'm pretty happy with the results! Here are some pics. Enjoy!



-Seth & Desiree




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[deryk]

Looks Great Seth! Good Job!

Rick I agree with you 100% on the use of epoxy over poly. My last sailboat the prior owner used many coats of bottom paint to cover the cracks in the keel. Well a summer of grinding, laying up 8 new layers of cloth and barrier coating solved the problems..... I still have a half gallon of epoxy left...it gets amber coloured with age but 5 years later still good. It does adhere to poly and epoxy and wood better.... but a lot of ppl are afraid to go with the "new" technology...to each their own, but the cost even at my depths of poverty lol is still not that much

After I found this site I stopped buying west system and bought it from them. Marine Epoxy Links - Wooden fiberglass boat repair building

[D White]

Originally Posted by Seth and Desiree

Hi everybody, sorry I have not responded sooner, but thank you for the info! I ended up using Bondo brand fiberglass resin to which I added the included hardener. I brushed it on, the laid strips of fiberglass cloth over it while it was still wet, then brushed another coat of resin/hardener over the cloth strips once they were in place. I did this twice, then did some sanding to take down sharp edges and high points. Then I used Bondo brand fiberglass filler and used the hardener that came with that to spread around and fill any remaining gaps, pits, low spots, etc. and sanded smooth(ish). Two or three more rounds of that and then it was at a point that I could live with. So I brushed on some primer, followed by a couple coats of white paint and then installed the fan! Fit like a glove and I'm pretty happy with the results! Here are some pics. Enjoy!

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-Seth & Desiree




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And that's how it's done....great job....Fiberglass Dave

[David Tilston]

Very nice! That will last for many years.

[MCDenny]

A note to anyone using epoxy (as I would). Epoxy will degrade in UV rays from the sun. It has to be painted to protect it from UV. You would want to paint it anyway for appearances sake.

[David Tilston]

Denny, are you saying that polyester does not degrade, or degrades slower, in the sun?

[MCDenny]

Originally Posted by David Tilston

Denny, are you saying that polyester does not degrade, or degrades slower, in the sun?

I don't know about polyester - never used it. I do know epoxy slowly turns to a chalky white powder in the sun. Doesn't happen overnight but over several years.

[D White]

Originally Posted by MCDenny

A note to anyone using epoxy (as I would). Epoxy will degrade in UV rays from the sun. It has to be painted to protect it from UV. You would want to paint it anyway for appearances sake.

And you must use an epoxy primer because nothing sticks to cured epoxy except epoxy, Not worth the price and not worth the trouble on our fiberglass trailers. The "extra strength of epoxy" in our case is not applicable and gives no benefit. I mean you could cover the entire trailer with 1/4 steel for "extra strength" also. I can't think of one good reason to use epoxy on your fiberglass trailer, and we use it all the time where it really is called for.