Unwetted cloth problem... Please help!

[WilliamPrince]

Hey all, I have had a small problem with the application of a fiberglass cloth to my hull. I started late in the day and by the tome I was finished it was dark. Much of the glass did not absorb as much epoxy is it wanted, like the attached pic. It is all cured now, it has been 15 hours. What can I do to this glass to make it better? Can I sand and apply another coat? Will the cloth even absorb that next coat?

All advice appreciated, thank you!

 

[upchurchmr]

Grind off the cloth.
Nothing will help you at this point.

Replace the cloth, making sure the surface is smooth with no sharp kinks in shape.

 

[WilliamPrince]

Grind off the entire cloth and start over? Or grind off the parts where it is unwetted and patch it?

 

[TeddyDiver]

Grind off the entire cloth and start over? Or grind off the parts where it is unwetted and patch it?

If it's structural do the first, if merely barrier batching is fine.

 

[WilliamPrince]

It is structural. How bad would it be to leave them? I have poured more epoxy on them and it has taken SOMEWHAT... Not entirely but better than before. The boat only needs to last for 1 month, will it really be a big problem?

 

[PAR]

I'm not sure what portion of the hull this is, but the photo shows 70% - 80% poor contact with the substrate, so it's useless, except as an abrasion resistant sheathing (a poor one at that).

Usually, even in structural applications, you can just cut or grind out the bad spots and lay some more material, but with this much blistering, you're better off just grind it away and doing it again.

If the boat only needs to last a month, then don't bother doing anything.

 

[WilliamPrince]

That picture is of the worst affected area, but you are right, it is not good. I am also taping the chines inside and out, so that will give me some structural integrity. It's not a great job, of course, but I don't need it to last a long time. I have no experience in this matter, so it is hard for me to visualize the consequences of this. If you think my boat will be structuraly alright, at least for the month I need it for, I am inclined to leave it.

 

[PAR]

Well it still depends on where this is (what structural element). From the looks of it, you didn't have enough radius on the wood, for the fabric to lay down neatly.

 

[WilliamPrince]

This is over the outside of the entire hull, a 18 ft long canoe. It's only really bad in that one area, and there is a good piece of tape on either side of that chine.

 

[SukiSolo]

Hard to tell from the picture if a sealing coat of epoxy was put on before the glass was laid on. If it was not, then that is the problem, the wood has absorbed some of the epoxy and it has left some of the glass dry. It is something I come across frequently with epoxy and polyester.

Get a proper orbtal sander and some 60 and 80 grit and take it back to the wood or wood/epoxy saturated surface and redo the coat. Use a gloss paint roller (mini) to really work the epoxy in. It is harder to work epoxy through a woven cloth compared to a woven roving. If it is still a problem use a woven roving as this will saturate better.