Fiberglass question - Page 2

RidgeRunner · #11 04-27-2010, 07:51 AM

I have had that happen before. Not a good situation to say the least. I was sure that my surface was clean and prepped (ground with 40 grit on grinder). The glass and resin were new and everything was dry. I believe the substrate(plywood) wicked the resin out of the glass before it had time to kick. Moisture can also cause the glass to fail to properly wet out but if you are sure it was once clear like the surrounding areas the super soaking capacity of the plywood might be to blame. Try to coat the area with resin before laying the glass in. If you were using poly resin I would say to mop on a hot coat first by thinning the resin with acetone and adding a little more hardener to enhance penetration and soak the plywood before proceeding with glassing. I am at a loss with epoxy.
On vertical work I have seen the resin run out of the glass before the resin kicked up it is not for the faint at heart. If you catch it early enough you can recover. (ie get frantic with the bubble popper and resin)
In your case, it is really about sealing the wood and it is structural. There are a couple solid milky areas that need to be redone IMO.
I don't think you will ever get it to be clear and free of air. Prepare to itch. Good luck.

Joker2 · #12 04-27-2010, 02:33 PM

I did put two coats of resin on prior to adding the cloth. The cloth was added a week later. I will post a pic of the outside which came out perfect. Yeh I think it will never be clear, I just want to make sure the bond is good.
http://i648.photobucket.com/albums/u...m/IMG_0045.jpg

RidgeRunner · #13 04-27-2010, 02:57 PM

I am not professing to be a pro. Just observations of what I think I experienced. Since you coated the wood with resin two weeks before the plywood soaking up resin theory is a bust. What produces the beige like color I see on the picture of the outside? Did you thicken it with cabosil or something?

bigshrimpin · #14 04-27-2010, 06:05 PM

When you get to the fairing stage of this project. Systems 3 makes a nice product called Quickfair . . . it's an epoxy fairing compound. It goes on like butter and sands nicely.

Joker2 · #15 04-27-2010, 07:26 PM

No I didn't add any thickeners, this is just the first coat, I still need to recoat a few times to fill in the cloth. The bond is good all around, really happy with how solid the back came out, not sure why the color is like that. More pics
http://i648.photobucket.com/albums/u...m/IMG_0042.jpg

http://i648.photobucket.com/albums/u...m/IMG_0044.jpg

Bonita Dan · #16 04-27-2010, 09:29 PM

Epoxy resin along with roven during the same process should have been solid enough to do your job. Cloth/resin(as a builder) would have been an in-between before the next stage of resin and roven and so on. Not much ya can do now except use a grinder to grind off the bubbles and repair that area. Gelcoat does wonders to repair a mistake,just gotta make sure the repair behind it will last and not come back to haunt ya. Just sayin.

RidgeRunner · #17 04-28-2010, 06:57 AM

My opinion, it looks like you should have used a little more resin. From the pictures of the outside of the transom you look to have some dry edges and once you wet it out it should have had a clear appearance unless I am missing something.
The wood replacement looks tight. You should definitely glass over the top of the transom as resin alone will crack and allow moisture to get to the core. What year is your 20? and how did you remedy the stringer rot?

Joker2 · #18 04-28-2010, 06:39 PM

1975 V20, planning on sistering new resined marine ply thu bolted, then glass over both and also glass to transom. In that pic of the outside I hadn't put any resin on yet except enought to wet it out, needs more coats then fairing. Planning on glassing the top also. Thanks for all your comments, it all helps.

Skools Out · #19 04-30-2010, 07:01 AM

the 2 inch transom is scary most boats with a rating of 200 hp or more has a min of 2 1/2 transom.

RidgeRunner · #20 04-30-2010, 11:43 AM

Quote:

Originally Posted by Skools Out

the 2 inch transom is scary most boats with a rating of 200 hp or more has a min of 2 1/2 transom.

My 20 was rated for 200 or more and it had 1 1/2" core from the factory. It did have an east 1/4" worth of glass on the outside and a courtesy layer on the inside maybe 1/8".