View Single Post
Old 14th Sep 2020, 9:50 am   #45
PsychMan
Octode
 
PsychMan's Avatar
 
Join Date: Jun 2013
Location: Fleet, Hampshire, UK
Posts: 1,764
Default Re: What causes this in polyurethane varnish?

Quote:
Originally Posted by Michael.N. View Post
In my day job I do both spirit and traditional oil based varnishing, mainly brushed on but sometimes French polished in the case of the spirit. I've next to no experience with poly although I once bought a tin to varnish a table. I took an instant dislike to the stuff. They are obviously trying to rid us of the VOC's (understandably). The stuff will obviously work but it's probably a matter of becoming accustomed to it's properties and it's propensity to certain finish problems. All finishes can and do go wrong, perhaps some more than others. There are a lot of alternatives for the home varnisher. Tru oil is a pretty simple product to apply. It's not the hardest finish and is only really suitable for relatively small objects such as table top radios. Some of the boat varnishes such as Epifanes are well established and well regarded, not the cheapest.
I really like the results of a good polyurethane finish, very glossy, very smooth, and hard wearing. But if there are varnishes that can achieve 90% of that, then I will definitely try those out. I'm very new to finishing, and like many things I dive in head first, balls it up a few times, and re do until im happy with the results

Part of the reason for using poly on this project was the grain structure of the veneer, while also being very thin. I tried a few grain filling options but didnt like the results. With poly, the coats are thicker than aerosol lacquers, so its viable to fill the grain by building up coats with it, and that's what I've done. I did of course go wrong with the coats being a tad too thick, and not allowing enough curing time between them.
PsychMan is offline