Boat varnishes

Tangler

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Sep 5, 2016
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Nanaimo, BC
I am partway through my first boat build (a plywood canoe) and wondering about finishes.
I am going to varnish it but my family is sensitive to off-gassing.
I did notice a Varathane water-based spar varnish and was wondering if that would be appropriate for a watercraft?
Any thoughts on this (or the relative smell retentions of other varnishes) from our more experienced boat builders would be greatly appreciated.
Thank you. Mark.
 

Kayak Jim

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Mar 5, 2016
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Comox Valley BC
If it was me, I'd probably wait for the weather to warm up enough that I could do the finishing with plenty of ventilation (i.e., outdoors covered or similar) rather than use a WB varnish in this total immersion application. No experience with WB spar varnish, just my inclination.
 

JohnAbercrombie

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Dec 7, 2011
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Victoria, BC
I agree with KayakJim.
I haven't used WB spar varnish, but I have come across quite a few 'water cleanup' products that were fairly smelly.
Even latex house paint...
So if you have family members that are sensitive to 'scents', outdoors or in a garage with a good breeze blowing through are probably your best bet. And leaving the boat out in the sun to get hot (once the finish has cured) will help.
Spar varnish is formulated to stay a bit 'soft'; I've found that it has a characteristic (pleasant) smell for quite a while.
Also to keep in mind - some quite hazardous substances aren't very smelly. The converse is also true.
 

OrcaBoats

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May 18, 2007
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Coquitlam, B.C.
I have used the water based varnishes and although they are nice as you can apply several coats in one day and they do not put off as much odor as oil based, I have not been happy with the final finish. So I overcoat with several coats of high gloss oil based. But System 3 does make a water based, two part varnish that has a nice finish and is very hard. https://www.systemthree.com/products/wr-lpu-polyurethane-topcoat Can't comment on the smell as it has been many years since I used it.
 

Tangler

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Sep 5, 2016
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Location
Nanaimo, BC
Thanks for the information guys. :)
The two part looks interesting but I have heard stories about it's application being very humidity dependent...

My main concern with the water based varnish was not the finish but how well it stood up to being immersed for long periods of time.
 
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