Does BLO go bad, and in how long ?

[Big Bill]

This is probably a dumb question, since I have read some oils last for years. I am pretty much a novice woodworker, and have had a lot of luck with the wipe-on finish of a third BLO, a third poly, and a third Naptha. I have never had a problem with this until now. I have a newer can of GF oil-based poly (opened a month ago and then sealed), the naptha, and about 1 year old BLO - was sealed in its original can sitting in my garage since last use.

I made the mixture and the stuff just wouldn't cure - remains tacky for days outside, and then even inside. Finally I tool mineral spirits and tried to take the excess off, and that has seemed to work. I looked back at the mixture I made in an air-tight jelly jar, and it doesn't look good. The bottom of the jar (just a week after mixing and sitting in this jar) is cloudy like it's try to coagulate, and their are some small chunks floating around. By process of elimination - it can't be the new can of poly (yes I did stir well before pouring into the mix), or the Naptha, right? The BLO has to be the culprit I assume, but have found nothing online that talks about a shorter shelf life. Anyone have any ideas ?

It was sitting in its original BLO sealed can for just over a year, but was air tight. It did not sit open very long at any time.

Thanks for the input.

[PurpLev]

hmm. interesting. I agree with your elimination thought process which makes sense. do you still have any of the BLO - I'd pour it into a glass jar and see what it looks like. although from you posting the question I can only assume you don't have any left.

I just used a year old BLO and it is still just fine on it's own. I used it a year ago when I build my bench, and closed it once I finished the bench, and now used it again on some small shop projects - still as good as new.

would be interesting to hear other inputs though on the matter.

[Gregory Paolini]

This is probably a dumb question, since I have read some oils last for years. I am pretty much a novice woodworker, and have had a lot of luck with the wipe-on finish of a third BLO, a third poly, and a third Naptha. I have never had a problem with this until now. I have a newer can of GF oil-based poly (opened a month ago and then sealed), the naptha, and about 1 year old BLO - was sealed in its original can sitting in my garage since last use.

I made the mixture and the stuff just wouldn't cure - remains tacky for days outside, and then even inside. Finally I tool mineral spirits and tried to take the excess off, and that has seemed to work. I looked back at the mixture I made in an air-tight jelly jar, and it doesn't look good. The bottom of the jar (just a week after mixing and sitting in this jar) is cloudy like it's try to coagulate, and their are some small chunks floating around. By process of elimination - it can't be the new can of poly (yes I did stir well before pouring into the mix), or the Naptha, right? The BLO has to be the culprit I assume, but have found nothing online that talks about a shorter shelf life. Anyone have any ideas ?

It was sitting in its original BLO sealed can for just over a year, but was air tight. It did not sit open very long at any time.

Thanks for the input.

I make a similar type of wipe on finish, and it's pretty normal for me to see it seperate rather quickly - I'll even see it coagulate in a jar within a week or so.

As far as shelf life for BLO - I recently found an old can, that got lost in the shuffle, marked 2003 (I mark all the finishes when I buy them). Just for kicks, I tried some on a few samples, and it worked great.

When you mentioned everything is looking better after wiping with Mineral spirits, the first thing that popped into my head is "too much". The problem I see most of my students have with wipe on finishes is, they often treat them like wipe off finishes too, leaving way too much on the work piece. I tell my students to rub it off, as if they're trying to rub crayon off a wall, after their kids got done playing picasso...

Let me know if changing your technique a little helps eliminate the problem

Best,

Gregory

[Big Bill]

Thanks for the tips. Next time I will do a better job of wiping off any excess and see how that goes. I have not done that in the past, but maybe I am wiping it on too thick now.