Epoxy Gurus...help!

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Epoxy Gurus...help!

Postby Eric Adams » Sat Feb 26, 2005 12:00 pm

I was planning on spar varnishing my wood TD then coating it with fiberglass cloth and epoxy. I have absolutely no experience with any fiberglass product other than bondo (on my old jeep) and don't know how much, what epoxy, hardner, and what thickness and how much cloth I will need. :o

Do I sand between coats??

Please help!!!!!!
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Epoxy and fiberglass

Postby An Ol Timer » Sat Feb 26, 2005 12:20 pm

Any good boat material supply house will have any thing that you will require. Just pick one for location near you, price and service. I'd also like to suggest your reading the following manual or a similar one.
http://www.westsystem.com/webpages/userinfo/manual/ Best of luck.
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Postby Guest » Sat Feb 26, 2005 1:05 pm

Eric,
You got it backwards.
Apply the fiberglass cloth and epoxy first. The spar varnish would be applied last to give the epoxy UV protection. Some resin makers recommend applying a seal coat first, some do not.
West's prefered method is to apply the cloth dry because placement and working out wrinkles can present problems, especially on large surfaces if done wet. If your trailer is already built, you may need to employ the wet method for application on vertical surfaces.
How many coats of epoxy depends on how heavy your cloth is and how much epoxy soaks into the wood on your first coat.
Ideally, you want to use how ever many coats of epoxy to "fill" the cloth, plus an additional coat to give you some sandability without risking sanding into the cloth.
There is a great debate about sanding vs. not sanding in between coats.
Whatever brand of resin you go with, just be sure to read their material and have a good understanding of it before you even buy it, because even the temperature and humidity in your working area can have a significant outcome as to how your job turns out.
You will learn things like what "blush" is and how to deal with it.
I think the best advice I can give is, do a test run first on a small piece of same material if you've never laid glass.
Go to the link that Ol' Timer gave you and check it out.
FWIW- I'm going to be using 6 oz. cloth on my teardrop, with 105 resin and 207 hardener. (West)
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Postby asianflava » Sat Feb 26, 2005 2:16 pm

Dean in Eureka, CA wrote:West's prefered method is to apply the cloth dry because placement and working out wrinkles can present problems, especially on large surfaces if done wet. If your trailer is already built, you may need to employ the wet method for application on vertical surfaces.


I've used 3M Super77 spray adhesive to "glue" the cloth so that it doesn't move around when I'm trying to wet it out. It will let you pull it up and put the cloth down so you can place it just right. I've only done this on my small experiments with decent results.

Does anyone have any comments as to wether this will work for a larger application? Like the side of the trailer?
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Postby Guest » Sat Feb 26, 2005 3:32 pm

My concern would be that the spray adhesive would limit the epoxy from penetrating into the wood, or bonding to a previous dry scuffed epoxy seal coat, to end up with a good overall bond of the entire composite sandwich.
Sounds like a slick way to keep the cloth in place though...
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Postby SteveH » Sat Feb 26, 2005 6:20 pm

A model airplane trick we used to use was to put just a few drops of CA glue (super glue) along the edges of the glass cloth to hold it down and then put the resin on. The super glue will prevent the resin from penetrating the wood but to a lesser degree than the spray adhesive.
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Postby doug hodder » Sun Feb 27, 2005 1:08 am

Amen Dean!!....that's why he is a site administrator. While I'm no expert on the use of epoxies, I've done a couple of boats with great results. I lay the cloth down dry, tape it off on the top and the bottoms, with a slight stretch to it. Then lay down the resin using a roller to wet it and squeege. you can squeege the resin into the cloth and watch it dissapear. you can get a bondo squeege for that job. I would not recommend any spray adhesive as if you watch it dry on it's own you can see it. Epoxy will dry clear, so you may have some adhesive visible. Just make sure that all the fibers are wetted out and it will be invisible. If using cloth, I lay down a minimum of 4 layers of clear resin on top of the glass, with sanding inbetween, it comes out super smooth, it just all depends on how much you sand it before the next coat. Epoxy should be laid on cloth or wood, not on top of a previous coat like varnish. Also, don't use an oil based stain. If using cloth, plan on having extra overhang on the top and bottom. After the resin is set up you can sand off the edges and have a sharp edge. Older methods used polyester resin rather than epoxies. they are really hot and set up a lot quicker and don't leave you the working time for the cloth. This method should only be used for a quick repair, not for overall construction. Epoxy is a wonderful adhesive and top coat, check out West Systems site for info. It ain't cheap, but the results are great. Just my 2 cents worth. Doug Hodder :thumbsup:
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Working on vertical surfaces

Postby An Ol Timer » Sun Feb 27, 2005 1:32 am

In the West User Manual they speak of a wet system where you apply a coating of epoxy on the surface, and after it becomes tacky, then placing the cloth onto it. They describe it, but they also don't reccomend the method
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Postby Guest » Sun Feb 27, 2005 1:40 am

If you guys really want to get some good info on glassing go to http://www.bearmountainboats.com/phpbb2/index.php.
It's a forum just like we have here, except it's for canoe, kayak and boat building. We've had some very ineteresting and sometimes heated threads about fiberglass and epoxies. (One guy got all mad and quit a couple of weeks ago during one of the "heated" discussions on this subject)
Recently, a fellow from Germany had to sand his hull clear back down to bare wood and start over, because he didn't take the time to test or learn how to squeegie properly. We've got a fellow right now with quite a messy situation on his hands. He attempted laying two layers of cloth at the same time (A first time glasser) and ended up cutting half of the the second layer off half way through the run. (he panicked because he thought he was taking too long to wet out both layers) He plans to come back and lay the other half of the second layer after everything sets up.
Doug, Thanks for the compliment, but I am no expert on this matter at all, in fact I'm damned near a rookie, but a rookie taking notes big time!
I'll be glassing my 17'-6" Redbird canoe soon and to be quite frank, I'm still a bit imtimidated at this point with the prospect of draping a piece of cloth 5' wide by 20' long over one of the most involved woodworking projects I've undertaken in quite some time.
Believe me... I plan on doing a few test runs to get my feet wet first.
BTW- Eric if you want your wood to show, be sure to use the #207 hardener if you go with West. (It's made just for that... For the natural wood to show through)
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Postby doug hodder » Sun Feb 27, 2005 1:58 am

Dean, again Amen!!.........Not only were you spot on as far as I'm concerned, but you mentioned 207 hardener. I have laid 207 directly on top of the wood and it gives you an incredible deep finish. It also gives you the maximum UV protection. For me.......and I just finished laying up the mohogany sides of my tear today, no cloth, just 207 on top of anilin dye. I don't think that cloth is necessary for the sides of a tear as cloth provides mostly abrasive protection. Tape at joints provides strength. Cloth does provide some strength, mostly it provides abrasion protection, and is necessary in a boat, but I think that most builders of tears have the strength built into their sides without the cloth. If your structure isn't competent, glass cloth on a flat side isn't going to save it. Tape on the joint will though. I would recommend just using the 207 hardener on top of you color and build it up. I live in the west, and if used properly, I've never had a problem with a blush. I do heat the shop with a wood stove however, a dry heat. This is just my experience though and not everyone has the same. PS I applied an epoxy clear coat today in the garage and it was bucketing rain, so humidity was way up, closed the door and fired up the stove, no blush.......... Doug Hodder
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Postby Guest » Sun Feb 27, 2005 2:34 am

Doug,
Well I'll be darned...Did the Gougeon Bros. recently update or improve upon the #207 hardener?
Maybe the stuff I have on hand is outdated? (It's not very old and it still pumps just fine though)
The specs. that I have on the #207 hardener mention that it has an ultraviolet inhibitor in it, but also states that to achieve a long lasting finish, you've also got to use a quality UV-filtering varnish.
A few guys on the boat site have opted for a few different types of sprayed clear coat instead of varnish and the pics sure look awesome, but maybe I've been asleep at the switch and missed the news about that. (Which wouldn't surprise me one bit) :lol:

Hey, that's an excellent point about skipping the cloth on the sides.
I'm sure my exterior composition will be plenty rigid enough.
I plan to lay down a 1/4" ply on my stud wall, then glue the 1/4" x 3/4" bead and cove strips over that, giving me a 1/2" thick outer substrate.
Like I say, I'm pretty new to playing with fiberglass and at this point, glassing up my sides of the teardrop prior to glassing up my canoe sure sounds less intimidating than doing the canoe first.
(I'm definately going to do some tests on that also)
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Postby doug hodder » Sun Feb 27, 2005 2:46 am

Dean... my fault, sorry I didn't mention it, I have in other threads, but I clear coat with automotive urethane on top of the 207, I'm also a big fan of that stuff. You need a compressor, good HVLP gun and some experience with it. It isn't cheap, but you can lay it down, wet sand and polish. Check out the finishes on my boat at www.glen-L.com click on Malahini and find me. I can send/post some photos, but am too stupid to figure it out. Doug Hodder
Last edited by doug hodder on Sun Feb 27, 2005 3:17 am, edited 2 times in total.
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Postby Guest » Sun Feb 27, 2005 2:55 am

...polish it to a mirror like finish, like what you have on that beautiful boat of yours! :thumbsup:
I gotta say... I drooled over your boat pics for quite a while.
That is one awesome finish you have on that!
(I'm sure your pictures really don't do it justice either)
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Postby doug hodder » Sun Feb 27, 2005 3:02 am

Hey Dean, don't sweat it, if doing your canoes, epoxy is very forgiving. After I lay the cloth down and squeege it out, I may spend an hour or 2 walking around it, resqueeging out the cloth that may not be laying down the way that I want it to. This is especially true in a situation where I have the cloth against a splash rail a 90 degree angle. Smooth curves are no problem. Just spend your time at it and you will have no problem. The old type polyester resin sets up in a flash and you are stuck with it, not true with epoxy. Honestly the only thing that matters in the first layer, is making it look clear, the others are the finish coat. PS I'll bet you don't have a blush problem either as you are out here in N. Ca. Also. thanks for the compliments on the boat finish. Doug Hodder
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Postby Guest » Sun Feb 27, 2005 3:19 am

Yeah,
I don't think I'll have any problems with blush, as I live up in the Redwoods, right on the coast. I guess you could say that I'm a "Fog Crawler" of sorts.
Hey, Thanks for reposting your link, I just drooled over those pics again. :lol:
I like the name of your boat, I recently took my first trip to Hawaii and I guess you could say I too was a Malihini and when it was time to pack up and leave, I didn't want to!
Just got one question about your boat... Was it a hard decision to put as much paint on the hull and cover up as much of the wood as you did?
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