Ok as many of you builders here are more advanced than I am. ( I keep building prototypes mostly with different hull shapes and woods)

My question is. I fiberglass my hulls and then top coat them with spar outdoor varnish. Which works great.. Problem is if you have to touch up a spot in a couple years. Or as I'm doing now.

I'm refinnishing a canoe we built 12 years ago. That sat out in the elements for a few years. And the spar varnish is like impossible to remove so I can touch up some glass work. Just gums up all my paper when I try to sand it off. And stripper that I've tried so far won't even touch it. :(

I'm wondering if you guys use something different over your resin as a topcoat? Shelac? A different type of varnish that's harder? Any suggestions would be appreciated...

Here's my advice based on many years of building wood canoes.

First, I'm perplexed as to why your sand paper is gumming up. There will be some degree of this happening as you sand but it is not too hard to remove old varnish using sand paper. I'm wondering what was actually on your canoe that is causing this to happen. Old varnish becomes brittle and flakes.

If I had your canoe in my shop, this is what I would do. I would continue to try and remove as much of the old varnish, or whatever it is with a power sander and some 150 grit sand paper. There is a point where you can see that you have sanded it down to the epoxy layer.

I would then give the canoe a light sanding with a power sander using 220 grit paper. Then clean out your shop of every spec of dust. Mop the floor, clean the entire canoe with a damp rag getting all of the dust off. Go over the canoe with a tack cloth, you can buy them at Home depot. It's just a cloth with a sticky solvent and is great at picking up everything.

If you use shellac on your canoe it will all come off when you put it in the water. Shellac is not water resistant. That's why wet glasses leave rings on your coffee table. You really do indeed need to use spar varnish. Spar varnish is softer and flexible compared to your standard polyurethane or "indoor varnish". I DO NOT mean it is actually soft, but it is not brittle and will not chip off when you hit a rock. Your hull is flexible and needs to give when you're in the water. Spar varnish will give too.

Spar varnish also has UV inhibitors in it which is essential in protecting the hull when it's outside. You might have noticed some clouding of the epoxy on your old canoe from sitting outside, this is from the sun. If you're lucky, it's been stored inside.

There is a tremendous variation in the quality of spar varnish. If you buy Helmsman spar varnish at Home Depot you are buying the lowest grade of spar varnish on the market. It works but quickly loses its gloss and UV protection. It's made for a DYI guys. It's applies easily because it's high in solvents so it flows easily and dries fast. Both of which are also an indicator of cheap varnish.

IF this is a canoe you just want to get back in the water then any spar varnish will work. If it's a canoe want to cherish then I would suggest you buy Z Spar Captain's or Flagship Varnish. You can buy it from www.jamestowndistributors.com. Or Google the name.

It's the best spar varnish on the market. All good spar varnish is very expensive but is a great value if you want a good product. You need 2 quarts if you want to do the whole canoe. Three coats per side. The flagship varnish is rahter thick so you need to do it when it's warm and I would also suggest that you buy a pint of the thinner they sell. You need to buy the Z spar thinner, don't just add turpentine, it won't work. About 5% thinner added to the varnish will allow you to coat the canoe in thin layers. THIN layers or else you get runs. It dries very slowly.

I could go on but this is a good start.

Tom

I think it's prolly that I bought a cheaper brand. I ordered it special through the lumber yard. Bout $30 a quart. Spar super varnish is all I remember. But I think the paticular canoe I'm restoring now. Has the hellmans on it. Was build by a good friend of mine. And I remember the can of hellmans. It's just stayed super soft and plyable.(which is good it's heald up well) But yes has clouded a bit.

Definately going to invest in buying better varnish. Thanks for the tip. This stuff just smears when you hit it with a belt or random orbit sander.

Hellman's? Isn't that mayonaise?