Old Town Restoration Woes

[John Janicek]

I'd like to post a problem that has just cropped up with my recent completion of a '49 Old Town HW model restoration (See 1949 Old Town HW model Restoration) that I'd like to put out for the community to respond in the hope that there is a consensus as to what might have occurred.
First let me provide some pertinent (I hope) background info which pertains directly to the restoration shown in the link provided above:

• Canvas filler was applied 11/20/21 (used a gallon I bought from Rollin Thurlow)
• Two coats Kirby’s marine primer applied (grey) with final coat on 4/16/22 (So there was plenty of time for the filler to cure/dry completely).
• Four coats of Kirby’s topside alkyd-enamel based marine paint. Final coat applied 4/30/22.
• Hull waxed/polished with a good carnuba wax on 6/1/22.
• Canoe was launched on 6/4/22 and taken for only an initial 15 minute paddle.
• On 6/12/22 the owner stored her inside a canoe cover (total encapsulation cover, zipped, nylon, breathable, not waterproof), stored her upside down on a padded rack in a covered, open-sided shed.
• She stayed that way for 2+ weeks during which time we had some pretty hot, humid days.
• On 6/29/22 owner removed the canoe to use and found the paint had bubbled at the bow and stern. See attached photos of the problem areas

My initial thought is that heat and humidity build up while inside the cover caused the paint to bubble or maybe it was some sort of chemical reaction. I don't know at this point (I am leaning towards the former cause though). I don’t think I’ll be able to feather a repaint into the original (it’s a gloss paint) so it looks like a full hull resanding effort followed by another coat of paint.
But before doing that I'd really like to figure out what went wrong.
I’d be most appreciative if the community could share some thoughts on the issue and whether or not anyone has encountered this type of failure before.
I plan to do a good resanding, followed with a good solvent wash then a repaint. Any other tips for refinishing these problem areas would also be most appreciated.

 

[Gil Cramer]

35 years ago, I used a sandable primer to smooth the filler before painting. The paint bubbled when the canoe was stored upside down outside . An old canoe restorer, who has gone on to his reward, told me that sandable primer has microballoons which can absorb moisture. I don't know if that is your problem, but I have never,ever used a primer again.

 

[John Janicek]

Interesting. I did use some bondo but only over the stems areas to fill in any roughness remaining from the canvas overlap. I really don't think bondo would absorb water plus it wasn't really applied in the areas of concern. The primer I used was Kirby's own and specially formulated for use with their paints (I don't think microballoons are in the formulation but I will ask). I spoke with Geo. Kirby Jr. and he quite frankly had never seen this type of paint failure happen before. I'm definitely open to any/all possible causes but at this point I'm still thinking it was the heat & humidity buildup while inside the cover that caused it. Thank you for sharing your thought on the matter though.

 

[chris pearson]

We overprotect our canoes. The total cover allowed it to fester in heat and humidity. These canoes like to be “exposed”, be it in a garage or something but not totally covered. I’ve always been leary of doing that. Primer could have possibly added to the problem, as Gil suggests. I’ve always used the enamel as a build up primer. Bottom line, it’s not a good idea to not let these boats “breathe”.

 

[Mark Giovannetti]

I had this happen to a canoe last year. I had it at a boat show and it got caught upright in a downpour. When I got to it there was a lot (4") of water in it that had been sitting in it a half hour or so. The next day the whole bottom bubbled up like yours. It was a fresh paint job, not sure if that had anything to do with it. As a side note I did use a primer on it, maybe that is the issue.

 

[John Janicek]

Thanks for that info Mark. I don't think a 15 minute paddle would have introduced enough water/moisture to cause the problem especially since it was at the bow/stern high points. I'm still not convinced it is a primer issue yet either. You did not say what you did to your canoe after the fact. Any info is much appreciated.

 

[Mark Giovannetti]

Sanded the whole boat and redid the paint job, all three colors!

 

[Fitz]

I used to see this on a few of my canoes years ago, and there are likely many posts on the forum if you search for something like "bubbles" or "blisters". I am not sure it was ever resolved. I think it is moisture migrating through the canvas and filler and lifting the paint. If you let the canoe dry right side up, the bubbles go away - so I never really worried about it much. I haven't seen the issue in a long time and I have been using Interlux high build primer, so maybe that has helped.

 

[John Janicek]

Thanks Fitz. The canoe has been sitting, unused since it was discovered and the blisters have all but disappeared. I'm thinking that the the paint adherence properties in those areas has been compromised somewhat and there is no guarantee that it won't happen again. I'm planning on sanding the hull again and applying another coat at some point this Fall but for now she'll be used & enjoyed at every chance.

 

[shelldrake]

I think Fitz's explanation is right on regarding "typical" paint blistering where the canvas absorbed some water from the inside of the boat. The canoe is then turned upside down, water vapor migrates through the canvas and temporarily bubbles the paint. Turning the canoe right side up and allowing the water to evaporate and exit the raw(inner) side of the canvas makes the bubbles go away. I've always felt that it would be nice if we could somehow waterproof the inside of the canvas prior to stretching it on the hull and filling.

Regarding the use of Bondo; I believe that Jerry Stelmock experimented with it as a surfacing putty over filler a number of years ago. I have one of those canoes and have never had blistering problems with it despite using it on a number of canoe trips.