WTF happened and can I fix it?

[cthippo]

I got my kayak skinned yesterday and once it was finished there were no wrinkles in the skin, pretty much totally smooth. This morning I coated it with sealant and when it dried this was the result!

The material is 10 oz (I think) cotton duck canvas.

What happened and is there any way to fix it? I'd really rather not rip off $40 worth of canvas and start over, especially since I'm not sure how to keep it from happening again.

[gonzo]

Did you shrink it first?

[cthippo]

No, how would I go about that?

[gonzo]

You spray the cotton canvas with water. That makes it shrink and tighten up.

[cthippo]

I owe you a beer, gonzo.

I have it a bath and the wrinkles came right out and it's tightening up smoothly. I think not all of the 1 1/2 quarts of sealant I put on it came out, either. Thanks!

[gonzo]

I'm glad it worked

[Boston]

something tells me if all the wrinkles don't come out you can wet it again and hit it with a blow dryer in the trouble spots

I used to skin model airplanes a lot with velum and it works like a charm

[Petros]

I have built a number of skin on frame kayaks and small boats. I have used cotton canvas, nylon and polyester fabric as skin, and have seen something similar before. IT appears what ever you used relaxed the fabric and made it loose. Usually moisture will do this to nylon and cotton. Polyester is much more moisture stable. Did you leave this out side overnight? Moisture in the air can cause this, and if you can get the moisture out you might save it. Did you use latex paint? That will put a lot of moisture into the fabric.

Try putting it in the house or somewhere warm and dry, and put heat lamps on it overnight. When you shrink the cotton you wet it out and than dry it with heat. This will drive any moisture out and tighten the fabric back up. I have done this and it works. Than I would only use oil based paint or oil based polyurethane paint or clear finish on it (no water soluble stuff). Coat it at least 4 times (allow to dry between coats), and put at least two coats on the inside. This should seal out any moisture and prevent this condition. If you want bright colors you can than paint over the outside with latex paint as a color coat.

Small amounts of moisture will still get through the paint, but not like this. I noticed when I had one hanging in the garage, on damp and foggy days the skin would pucker a bit (not to this extent, but noticeable), and it would go back smooth and tight on warm dry days. It is just the nature of fabrics, like cotton and nylon, that are sensitive moisture, the better you can seal out the moisture, the less it will pucker and change.

btw, there is a guy up there in Bellingham that sells both heavy nylon and polyester fabrics in different weight just for the purpose of covering kayaks. George Dyson Baidarka and company, he is down on Commercial street if I remember correctly, he has the best prices in fabric I have found. For your next one.

Good luck.

[cthippo]

OK, problem not solved, but I think I'm coming to understand it better.

I brought it inside and it wrinkled back up as it dried, instead of soaking it again, I went at it with a spray bottle and lightly dampened it, then rubbed with a damp cloth and the skin tightened back up again. As far as I can tell, it's tightening when it's wet and wrinkling as it dries. I'm thinking maybe I should take it outside when the sun comes up and really soak it with the hose and see if I can rinse the remaining sealant out and what it does from there.

Thanks for your help, everybody.

[gonzo]

New cotton fabric usually shrinks about 2-3% the first time it gets wet.

[wardd]

Originally Posted by Boston

something tells me if all the wrinkles don't come out you can wet it again and hit it with a blow dryer in the trouble spots

I used to skin model airplanes a lot with velum and it works like a charm

were they flying boats?

[cthippo]

I hauled it back outside and let it get rained on and it tightened right back up. I think I'll leave it there for now until I get a better idea.

[Angélique]

Originally Posted by cthippo

... until I get a better idea.

Make it as wet as possible then dry it as hot as possible in a spray booth then seal it again..??

Good luck!
Angel

[cthippo]

Originally Posted by Angélique

Make it as wet as possible then dry it as hot as possible in a spray booth then seal it again..??

Good luck!
Angel

My spray booth is out of order, can I borrow yours?

That's what I'm trying to do now. I let it get rained on for a couple of hours and then I'll go at it with a hair dryer or something. I think I've got most of the old coating out of it now, but I guess I won't know for sure until it dries out again.

[Frosty]

Dont fix it --you might haver accidentally invented a new resistance free surface