Apply Poly after Tung Oil??

[Bob Hayhurst]

Just a quick question. Can I apply poly over the top of tung oil.....and, if so, how long should I wait before applying the poly? I want to "build up" the finish, but I don't want to wait as long as need be between coats if I just use multiple coats of tung oil. By the way, I have already applied one coat of Hope's Tung Oil to my red cedar project. I hope I haven't made a mistake.

Thanks for any help guys. I always appreciate this forum.....

[Scott Holmes]

Red Cedar...hmmm

Is this an interior or exterior project?

What is it?

Pure tung oil is a very poor finish for wood... Don't beleive all the marketing hype.

Boiled linseed oil will perform as well if not better than tung oil at 1/3 the price.

Homer Formby made a fortune selling an alkyd resin/soya oil VARNISH and calling it tung oil.

[Bob Hayhurst]

J. Scott.... Thanks for the "comeback." The project is an Urn, made from cedar. I have already, I think by mistake, given it one coat of Hope's Tung Oil. It darken it nicely, and really "popped the grain," but now I would like to build up the finish at little more.....with possibly 2-3 coats of poly. It has been drying outside in the nice breeze and warm shade of this wonderful Michigan weather we are having. How long do I have to wait to give it more coats?....of anything? After almost 24 hours, it seems dry, but how will I know? I can't smell any more finish on the wood. But I have read the horror stories of putting additional finish on wood before the piece was adequately dry from using Tung Oil. Thanks for any help you can offer.

[Jim Pletcher]

Now that you have already used Tung oil, all you have to do is wait.
I routinely use a mixture of Tung oil, Linseed oil, mineral spirits and Poly to "bring out the grain".
After waiting a day (or two) for the final coat to dry, I apply the final Poly - ususlly three coats.
So far, I've had no problems.

[Scott Holmes]

As Jim said since you already used tung oil to pop the grain so now the question is how long and what next...

Pure tung oil; 5 days (then shellac to seal it)
polymerized tung oil; 24 hours (then shellac to seal it)
Tung oil varnish; you're good to go..

Did you use Hopes 100% pure tung oil or their Tung oil Varnish? If the pure oil then I would strongely suggest a seal coat of de-waxed shellac. The shellac itself would be an excellent finish for this urn. If the latter (TO varnish) then continue to use it and your project will be fine.

In your PM you mentioned using steelwool my advice is NO!

Here's why...

You can't "sand" with steel wool... AND
3 reasons why I say never use steel wool on bare wood or between coats…
Reason #1 Poly does not stick well to itself or anything else for that matter that is why they tell you to sand between coats. Steel wool abrades the finish; it does not give enough "tooth" for poly to adhere well. 220 sand paper 320 at the finest.
Reason #2 you will leave shards of steel wool behind; then you will top coat it. Now you have steel wool IN your finish when water vapor get to it, and it will, it will RUST - IN YOUR FINISH.

Reason #3 Many steel wool products have oil to keep them from rusting so now you have oil on your surface... bad idea.

[Howard Acheson]

You want to avoid using any type of oil based film finish on the inside surfaces of a cedar enclosure. The oils in cedar inhibit the proper drying and curing of oil based finshes. Use shellac, lacque or a waterborne finish.