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Brent Cummings
07-09-2005, 05:41 PM
My father in law has a 26' Chestnut canoe with the original canvas. It sat in a garage for several years before we started using it again recently. As soon as it hit the water the paint peeled off in large patches. He has repainted with some marine paint but the same thing happened. We feel there may be mold in/on the canvas. Any ideas on how we should prepare the surface before trying again?

Wild Wassa
07-09-2005, 07:57 PM
The paint sounds good if it is just popping off, that is a good sign it should make preparing the surface easier than not.

One of the real problems with painting and not having used a primer to 'size' or seal the fibres of the canvas, is mould forming under the paint. Which you appear to have identified.

If you have used oil based paints or varnish on unsized canvas, the canvas will/can drag the oil from the paint and the oil will go mouldy affecting the canvas.

If you have used acrylic paint on unsized canvas (or timber/ metal) the paint has a tendency to allow mould to form under it.

With canvas, the canvas should be sized firstly, then a canvas filler applied, then reprimed (primer normally means first but not in this case) which will give tooth to the following coat. That's the theory and if followed, the paint will be on 'good-n-proper' but you will have lost the paint's pop off factor. That's the theory.

Keep popping off the paint, then clean the canvas with a painters anti mould, or use 'old' Chlorox. Chlorox nowadays comes with teflon included in it, so if you have chlorox which is older than about a year this will be OK, otherwise I'd avoid using the ‘new’ chlorox to remove mould when there is a need to paint or repaint the cleaned surface.

Traditional canvas filler formulae can be found at http://www.wcha.org/tidbits/filler.html.

When priming canvas many use marine enamel that has been thinned a little, then two or three coats are applied.

Warren.

[ 07-09-2005, 08:57 PM: Message edited by: Wild Wassa ]

Fitz
07-09-2005, 08:40 PM
Yes, Chestnut Canoe Co. filled their canvas with a "secret formula". The paint goes on over the filler. You might make an inquiry here with your problem and see what they say:

http://www.chestnutcanoecompany.com/

I know of another fella with a Chestnut Oglivy and he is having a similar problem. Does the canoe leak? I was thinking the canvas may be getting wet from the inside of the canoe and the moisture is migrating through the filler and lifting the paint.

You may also try posting the question here. The fella with the Oglivy just asked the question a week or so ago:

http://forums.wcha.org/

Good luck and please report back.

Canoeyawl
07-09-2005, 09:39 PM
26 feet is a big canoe.... whoa!

Cuyahoga Chuck
07-09-2005, 09:47 PM
Until recent times, canoe canvas was "filled" with a coumpound that was basically white lead. Because the content of lead compounds was so high most living things that got under the paint succumed to lead poisoning. There are a lot of new fillers but none can legally be as toxic as white lead.
Charlie

Todd Bradshaw
07-09-2005, 10:53 PM
There are usually four layers of stuff making up the skin: the canvas fabric, the canvas filler, the primer and the paint. The raw canvas was treated with canoe filler, which is usually somewhat similar to flat enamel paint mixed with a lot of powdered flint or a similar mineral. It's quite thick, usually applied in at least two, and more often three coats. It's put on with a stiff brush then rubbed in and smoothed with a canvas mitten or a bare hand. It fills the cloth texture (takes about a month to dry, though my old Chestnut catalogs claim tht they heat-cured their filler) and leaves a smooth, reasonably hard surface most commonly described as being similar to a chalk board. Most canoe companies then applied an oil-based primer (sometimes tinted a bit my mixing in a little bit of the outer enamel) and finally the colored enamel finish coats. It's hard to say without more information whether you're having problems with the paint adhering to the filler, the filler adhering to the canvas or newer coats of paint that don't stay stuck to older paint. What's underneath one of these areas after a spot peels off?

Brent Cummings
07-10-2005, 10:32 AM
The paint peels off to reveal the white colored canvass. The first time it happened the surface was quite chalky - could wipe white off on your hands.
Thanks for the replys guys.

Todd Bradshaw
07-10-2005, 12:13 PM
If you can then rub the white stuff off to the point where you have woven fabric texture that you can feel, then I imagine the filler is breaking down and the only good solution may be to recanvas and re-fill the boat prior to repainting. If, on the other hand, you can get down (by sanding/scraping) to solid, well-attached and smooth, hard white stuff then the filler is probably OK. In that case, removing the paint and re-priming and painting the sanded filler surface is what I'd try. It would certainly be cheaper and a lot less work than stripping off the old canvas and starting over from bare planking, especially on a boat that size which probably needs about three gallons of filler to do the job. If mold or moisture was playing a big part in causing the peeling, I'd think it would be obvious and visible on the surface when a new chunk of paint peeled off.