Gel Stain and Tung Oil

[Bill Rogers]

I am refinishing an old rifle stock by removing all of the old finish and sanding it with 100, 150, 220 and 320 grit sand paper. I have sealed it with a 50% mixture of dewaxed shellac and denatured alcohol and I did the same with a sample board. On the sample board I have applied four coats of General Finishes Brown Mahogany Gel stain, which according to GF is a wipe on Urethane Formula. My question is, can I use Tung Oil (100% Pure) as the top coat on the finished product? The Tung Oil label states that the surface must be free of all oils, waxes and polishes. I put one coat of Tung Oil on the sample board and it looks good to me!

Bill

[Scott Holmes]

Very astute question, answer is No.

Contrary to popular belief and marketing HYPE... Tung oil is a terrible finish, by itself. Once the wood has been sealed with shellac the TO will do nothing but get sticky and need to be wiped off.

Part of the confusion with TO is that Mr. Formby has been selling an alkyd resin/soya oil varnish thinned 80% with mineral spirits and calling it Formby's Tung Oil Finish for a very long time... THE only Tung Oil is the words printed on the label. The varnish was not even made from TO. Mr Formby has made a fortune and created a "cult" following for TO.

Tung Oil's true claim to fame is: varnish made with TO will be better at waterproofing and will yellow less than varnish made with linseed oil. Period. Mr Formby and th emaketing guys have done the rest.

Dewaxed shellac is desolved in DNA so all you really did is lower the amount of shellac. If you are using the premixed seal coat then it's a 2 pound cut and you dreduced it to a 1 pound cut. 2# cut is great for sealing 1# cut takes more coats.

A quality varnish made from phenolic resin and TO would be the best finish. Waterlox orginal is the most readily available.

Sanding beyond 220 on bare wood will not do much when you apply a film forming finish over it.

[Jim Becker]

No. Pure tung oil must soak into the wood...it's not a "finish" that you can top-coat other work with. If the can says "Tung Oil Finish", it's not tung oil, BTW. For example...if it's Formby's Tung Oil Finish, it's a wiping varnish. If it's Minwax Tung Oil Finish, it's an oil-varnish mixture.

If you wish to top coat over your gel stain, a GF wiping varnish or other brand of the same would be a good choice. And you can make your own by mixing any quality oil based varnish 50/50 with mineral spirits.

[Howard Acheson]

>> can I use Tung Oil (100% Pure) as the top coat on the finished product?

No. Tung oil is a penetrating finish that needs to be applied to a surface that has not been sealed with another finish. Both your shellac and multiple coats of gel stain will have sealed the surface and not penetration will occur. When you wipe off he excess tung oil, you be removing all the oil that remains on the surface.

At this point, you are left with using a film type finish, not a penetrating finish. Something like a wiping varnish made with a non-poly varnish would work well.