Recently after applying a 3rd coat of danish oil (equal parts of tung oil, poly urethane and mineral spirits) to a walnut rocking chair, I placed it in the covered cargo space of my pickup and drove an hour to a gallery. I had allowed 24 hours between each coat and three days for it to cure. When I took it out of my truck I discovered little droplets of a clear looking substance had wicked up upon its surface. It was probably pretty warm in the cargo space of my truck. The dropletes wiped away easily leaving a good looking finish. In the end the finish still look great but what could I have done differently to avoid having the droplets from coming to the surface?
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Replies
What did the liquid smell like? Was the space it came from before landing in the truck air conditioned? My first thought is condensation from a cool object being put in a warm and humid space without air circulating.
24 hours really isn't long enough for tung oil to cure.
I do not know the technical term but I have had a lot of "bleed back" from "Danish oil" it seems the environmental changes speed this up but it happens over time also. I would allow more time between coats. Lighter coats seem to help this also. I would notice this more from temperature changes more than humidity. Good luck.
The droplets looked clear, felt oily and had very little odor. I had waited 24 hours between coats and it had been 3 days before carrying it to its destination. It had never been in air conditiond space-the dropleets were not condensation. Whenever I apply danish oil I give it 20 minutes or so to soak in and then wipe and wipe and wipe some more to remove any remaining on the surface. I was using my home made recipe for D oil (tung oil). In the past I have used Watco D oil and before that Deftoil (until it was discontinued. The commercially available D oils are made with BLO. I wanted to try D oil made with tung oil.
Bleed-back. Quit mixing products. Don't apply flood coats -- it's a waste of material. More ends up on rags than in the wood. Most of what you've read about using long-oil varnish finishes (Danish oil) is wrong, and what you saw is the end result.
If you apply Watco the way you should, the smallest can they sell will do a couple nice-sized furniture projects. And you won’t have bleed-back or any other problems either. Watco has all the varnish resin in it you need. You neither need to add varnish or thin the product. It's fine as-is. Keep it simple. People vastly overcomplicate finishing with ad hoc home-brews, weird protocols, spray rigs, etc., etc.
Amen brother.
I've been preaching this for years, few ever listen.
Don't get me started on the 1-1-1 ratio finish
Hear you!
I would agree with Charlie on this. First don't mix. Manufactures employ scientists formulating finishes. So why experiment? Secondly oil finishes require a lot more time to fully dry. They also require a lot more elbow grease. I think of it as more of a polish practice in application. Finally, I consider the barometric pressure when I apply oil to begin with. High pressure days followed by low pressure could move undried oil/finish to the surface.
I agree Watco danish oil is a good product. The negative thing about Watco is that it is made with BLO Which will darken in time when used on light woods. It works fine with walnut and dark w00ds but not so well with maple, ash etc..
I agree with everyone who said bleed back. Especially Charlie...
I learned this the hard way..and it took me multiple frustrating lessons.
Super light coats, plenty of time to dry. More is NOT better.
If you want to finish it quickly, you need a different finish.