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Discussion Starter · #1 ·
Hello,

Yesterday I applied the first coat to book shelves I have built with American walnut. My finish was a blend of BLO, mineral spirits and sherwin Williams fast dry oil varnish glossy. It was about 50% BLO 25% varnish and 25% mineral spirits. The varnish was bought and opened for the first time minutes before applying.

The problem is almost 24 hours later the finish is very sticky / gummy in many spots and also streaky when in the light.

Any thoughts on why this is or what I did wrong?

Thank you
 

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It will eventually dry but you would have been better off not mixing linseed oil into it and thin it with naphtha. Personally I think it's best not to play chemist. I've been a furniture refinisher for more than 20 years and if I want a oil/varnish blend I buy a can of Watco Oil Finish or equivalent and leave the brewing to the college boys. I suspect your brew would have been better with a standard varnish rather than polyurethane especially the fast dry version. Polyurethane is a form of plastic rather than a varnish. The resins in varnish are derived from pine sap.
 

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Discussion Starter · #4 ·
I'm starting to agree with playing chemist but it seems like making your own blend is pretty popular and simple. The varnish is actually an alkyd varnish, this is why I used it since p&l 38 and cabots varnish are so hard to find.

Now I don't know if I'm experiencing normal results and it just needs to dry more, it sure doesn't seem right.

Luckily I've only applied finish to the underside so far... Not sure how to proceed...
 

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How did you apply it? I normally wipe it on and then wipe it off (after about 15 minutes), recoat later, maybe the next day. That is more BLO than I would normally use, but doesn't seem to be so much that it would cause your problem. If you didn't wipe it off, you might be able to salvage it by wiping it down with MS and let it sit. I'm willing to bet it's the BLO that's causing the tackiness, especially if you didn't wipe it off after letting the coat sit a few minutes. That much BLO will make the finish much softer than it would be if you reduced it a little....you might experiment with 1/3 each and see how that works, if you find the current formula is a bit soft.
 

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I think the blo is the culprit. If you let it dry and scuff sand it I think you could put a thin coat of the fast dry poly over it alright.
 

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Discussion Starter · #7 ·
On the first piece I applied a generous amount the wiped away the excess about 10 minutes later. On the later pieces I applied a much thinner coat to it as it seemed better. The later pieces are less sticky today but there is still a definite tackiness.

Why do you think the blo may be the problem, just too much of it or something else?

Thanks
 

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Why do you think the blo may be the problem, just too much of it or something else?

Thanks
I agree with Fred. I think the BLO ratio was too high. I wouldn't go over thirds at the most. You could try a sample with 25% and use 50% VM&P Naptha, and 25% varnish resins.

If you eliminated the BLO. you would be using a wiping varnish version. It would dry harder and faster.






.
 

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It would be best to go with the 1/3 mix ratio, IMHO, it's the SW fast dry poly giving you problems. That stuff just does not like to dry. I threw some on a couple of small picture frames, 24hrs before the first coat was sandable, second and last coat, 3 days before it was "touchable". I'll stick with Cabbott or Minwax.
 

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So with the broad range of opinions offered, did you choose a course of action? Results? BTW, I've used SW Fast Dry with that mix and had no problems, my experience is different than dustmagnet's. It's quick to dry to the touch, but seem to take longer to fully cure...I really like it, my favorite behind the P&L and Cabot alkyd varnishes (think the Cabot may have been discontinued, seems non-poly varnishes are becoming extinct).

Edit in: should have mentioned this earlier. If you choose to wait for it to dry, you can speed the process up by letting a fan blow across it.. The BLO and varnish combine with oxygen to cure, and the solvent just evaporates...all these happen faster with moving air.
 

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Did you thoroughly wipe off all the oil/varnish mixture? The technique for applying an oil/varnish mixture it to apply fairly heavily, let set for 15-20 minutes and then wipe as dry as you can. Come back a do it again the next day.

As said by others, mixing equal parts of BLO, varnish and mineral spirits is the time tested ration that seems to work best.
 

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Discussion Starter · #12 ·
So with the broad range of opinions offered, did you choose a course of action? Results? BTW, I've used SW Fast Dry with that mix and had no problems, my experience is different than dustmagnet's. It's quick to dry to the touch, but seem to take longer to fully cure...I really like it, my favorite behind the P&L and Cabot alkyd varnishes (think the Cabot may have been discontinued, seems non-poly varnishes are becoming extinct).

Edit in: should have mentioned this earlier. If you choose to wait for it to dry, you can speed the process up by letting a fan blow across it.. The BLO and varnish combine with oxygen to cure, and the solvent just evaporates...all these happen faster with moving air.
I've been letting the pieces dry and am happy to report they are for the most part dry / not sticky anymore. I will finish the other side with a mix closer to 1/3, maybe a little less on the oil side, and will report back.

I think with some sanding in between coats it should turn out pretty good.

thanks!
 
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