old town canoe - wooden

[macdouga]

how many quarts/gallons of spar varnish will I need for the inside of the 18 ft canoe? Four coats is what I should do?

 

[Dave Wermuth]

Two quarts should be plenty. I thin 50/50 for sealer. Then 75/25. then full strength. I sometimes will put clear shellac on first as a sealer.

 

[MGC]

Two quarts should be plenty. I thin 50/50 for sealer. Then 75/25. then full strength. I sometimes will put clear shellac on first as a sealer.

Because he did not strip the hull, I would probably not use shellac in it although I do occasionally do that on my own canoes and specifically Rushton's. His best bet is going to be sticking with spar varnish. Hopefully the old fish was not poly. Time will tell.

 

[macdouga]

thank you - I still have a workout ahead of me before I get to that stage. If the prior finish was polyurethane, what will the symptoms be?

 

[MGC]

When you described the sanding process to be difficult and that the varnish seemed gummy, that suggested the possibility. I am not sure how I can explain the difference to you. I can tell based upon many years of dealing with both. You can most certainly tell when poly fails due to water getting behind it. It tends to bubble and peel in layers. Spar will dry and flake, or alligator.
The uncertainty would keep me from using shellac. Thinned spar......

 

[Michael Grace]

Shellac is often called the universal finish because it can be used on top of or under most other finishes. It certainly can be applied over polyurethane. However, the flexibility of these two finishes is different, so there could be problems in the long term if there is movement caused by sun heating, hull flexing, etc. (both of which are to be expected during use). In any case, as MGC has indicated, polyurethane is a poor finish for wooden boats. It would be best to do whatever possible to get down to bare wood before refinishing, and you seem to be doing a good job at that.

I've been watching your posts from the beginning and given that you're so interested in doing well with this canoe, why not do a full restoration? It was a freebie and there's no family connection for you but even so, you seem to care about and respect this canoe. You might find it great fun to take it down to the bare hull and bring it back to original condition with proper materials. In the end you'll have a canoe that is in much better condition for use, and you'll have the satisfaction of knowing you did it.

 

[macdouga]

When you described the sanding process to be difficult and that the varnish seemed gummy, that suggested the possibility. I am not sure how I can explain the difference to you. I can tell based upon many years of dealing with both. You can most certainly tell when poly fails due to water getting behind it. It tends to bubble and peel in layers. Spar will dry and flake, or alligator.
The uncertainty would keep me from using shellac. Thinned spar......

if it helps, here's what the finish looks like, including where I've scraped it, so you can see the texture of what I've removed.

 

[macdouga]

Shellac is often called the universal finish because it can be used on top of or under most other finishes. It certainly can be applied over polyurethane. However, the flexibility of these two finishes is different, so there could be problems in the long term if there is movement caused by sun heating, hull flexing, etc. (both of which are to be expected during use). In any case, as MGC has indicated, polyurethane is a poor finish for wooden boats. It would be best to do whatever possible to get down to bare wood before refinishing, and you seem to be doing a good job at that.

I've been watching your posts from the beginning and given that you're so interested in doing well with this canoe, why not do a full restoration? It was a freebie and there's no family connection for you but even so, you seem to care about and respect this canoe. You might find it great fun to take it down to the bare hull and bring it back to original condition with proper materials. In the end you'll have a canoe that is in much better condition for use, and you'll have the satisfaction of knowing you did it.

My time with the canoe this summer is limited (hence the 5 a.m. start), but maybe in the future I’ll have the time and energy to strip off the fiberglass and get down to the bare hull. I’m certain there are planks that could benefit from being replaced. I have no idea how to go about canvasing and restoring that part of the canoe to its original condition, but I imagine it would be an interesting challenge.

 

[macdouga]

My plan is to work around the Old Town logo as best I can.