I have a 2-year old kevlar/carbon canoe that has developed an odd white-ish blotch in the bilge. I have foam kneeling pads glued in, but I sometimes use a Grade VI kneeling pad to further cushion my 50+ year old knees. The spot is rectangular in shape and appears to be roughly the same size as the Grade VI pad. I paddled the Green R. in Utah back in April and the blotch developed during that trip. The kneeling pad was not used much and spent most of the time laying in front of the glued-in pads. It was not excessively hot and the gear was unloaded every night at camp. I contacted the manufacturer who recommends using acetone to remove the spot, taking care not to let the acetone stay in contact too long. Before I do that, I wanted to pick the brains of some of you folks who are much more knowledgeable than I am about resins and their behavior. Anyone seen a similar phenomenon and have a recommendation? Thanks in advance.
some reaction to or leftover adhesive or something.
I’m thinking if it were amine blush, it would have shown up a long time ago.
I’d go after it with some vinegar at first and see if that does the trick. Use at plastic paint scraper to see it you can get it off.
If not, then acetone. Obviously don’t leave a puddle of it soaking on the spot for hours.
But wetting the area for a 30 seconds to a minute or so shouldn’t hurt it. I’d coat the area, let it soak for a few seconds, then try scrubbing it with like a scotch brite pad. If it is adhesive, the acetone will eventually turn it gummy and you’ll be able to scrape it off.
From what you described, doesn’t sound like you’ll be able to just wipe it off with a soft cloth.
Blush would have washed out the first
few times the boat was used.
Another thing, boat might not even be epoxy…
" Ester" type resins will develop a whitish tinge if they stay wet for prolonged periods of time without drying out … Like under some pads.
Second thing … might be slight delam or break down of laminate from compression … happens easier w/ Kevlar than other materials.
Most builders are thinking compression loading from the outside in … not the other way around and do not compensate for 'point loading ’ from inside out.
We always add some material under bulkheads, seat and foot peg hard points.
Poss. to post a pictue ?
Thanks for the reply. After reading it, I checked the manufacturer’s website. They use vinyl ester resin. There was a very small spot visible as I began the trip…no larger than a quarter. The trip was 5 days long and by the end the spot had grown to it’s present size, roughly a rectangle 24" x 6". My memory is a bit hazy, but I may have left the pad in the boat at night. The Green is quite muddy and there was lots of wet mud in the boat until the end of the trip when I cleaned it out. It’s possible that the area remained wet for the entire 5 days and the blotch is a result of that as you mentioned. Do you think acetone will do the trick? I emailed you a picture since I’m not sure if I can attach one to this post. Hope that’s OK.
…is what the builder recommended too. It’s a fairly aggressive solvent & I was afraid of doing more harm than good. As I mentioned to onnopaddle, the boat was built using vinyl ester resin. I’ll try the vinegar first as you suggested.
Thanks for the reply.