Boiled linseed oil

[woodcutter]

I made a plywood box to hold a belt sander and painted on boiled linseed oil mix 50/50
I have been waiting at least a week for it to dry and not be sticky.I have used the mix in the past and it worked great.
I left the box out in the sun for two days now and its still sticky on some spots.
Can I put a coat of clear finish on it or do I need to wait till its not sticky.
I think some air got into the mix over time and its not 50/50 any more.
Likely some of the thinners evaporated.

Jim

[Billy in Va]

Jim,

I have had the same problem with the BLO 50/50 mix.  I have noticed that when I use real wood pine, poplar, walnut etc, No problem. It usually drys in a day or less. Have even done two coats in one day.  However when I have used plywood  -  oak plywood 3/16 inch up to 1/2 ply the BLO mix takes forever to dry and cure.  Just my personal observation, but I no longer use the mix on ply wood. I switched to a shellac-denatured alcohol mix at 50/50, followed by a couple of coats of clear lacquer. I am happy with the results. Humidity will affect the drying time of the BLO mix also.

[Al W]

Based on my experience, I would suggest taking a clean cloth and removing as much of the stickiness as you can without using any additional chemicals.  Then give it another day.  If it is STILL wet and sticky, maybe wipe and wait again.  However, since this is a storage box and not a "show piece", I would most like continue with the finish. 

Just an opinion.

Al

[GrayBeard]

Personally I would wipe the 'box' with a rag soaked in mineral spirits to try and remove as much of the 'stickiness' as possible. I would not leave it in the sun to bake the finish since doing so will cause the  the oils to 'leach' out.
Wipe it with the mineral spirits soaked rag, place in a dry, cool place and see what happens.

~~~GB~~~

[Rapid Roger]

I agree, wipe it off as much as you can with mineral spirits and let it dry then, put on a brush (or spray) on finish.
Let's face it, a BLO finish or any other penetrating oil just won't work on plywood. You must remember that the surface ply is only 1/16" or less thick and just below that is a heavy coat of glue so there is no place for oil to penetrate to. Remember the last time you sanded through the top layer of a plywood project? Didn't take long to get into the glue or next layer of wood did it? That is all the wood that the oil has to soak into. 
Penetrating oil of any kind is just what it says it is and needs to penetrate into a thicker piece of wood. I use it a lot to pop the grain on all kinds of solid wood and have good luck with it but with plywood I usually go to shellac cut 50/50 with alcohol to seal the pores of the wood for finishing. 

Rog

[mrsn]

Rodger, your response made me go "well, duh, why didn't I think of that".
I don't use oil much, but when I do it is always been hit and miss. I never thought of the fact that the top surface is so thin and backed with glue. It makes so much sense!
Thanks!!!

[Al W]

Good point on the thickness of the surface layer Rog.  I should have included the use of mineral spirits on my first post. 

Thanks for the continuing education  .

Al

[woodcutter]

Thanks for the reply's
I took the project out of the sun.
I will try wiping off the excess oil with mineral spirits and then let that dry.
Before spraying.
Always something to learn. I didn't clue in about the glue being under the first layer of wood.
I have only used the BLO for solid wood before.

Thanks everyone.

Jim