Wood Turners Finish over Oil?

[Randy Red Bemont]

Anyone ever have issues using Wood Turners Finish over mineral oil? I like the look of mineral oil on cherry and the finish and protection of WTF. I want to use both of them on a cherry turning but was wondering if anyone had issues doing so. Thanks.

Red

[Brian Kent]

The only way I would chance that one is if I could do it in stages. Oil on, wipe off. Allow 2 to 4 weeks until there is no odor. Then I would still use an intermediate coat of de-waxed shellac before starting with the WTF.

[Brian Tymchak]

I don't think mineral oil every truly dries but I could be wrong on that point.

[Ryan Mooney]

I've used it over fully cured walnut oil and blo (wiped on, left sit for 3-4 weeks to cure, lightly sanded back the fuzz). Mineral oil never dries so I'd be concerned that it would cause de-lamination of the top coat eventually.

[John Keeton]

Mineral oil does not cure and I would be afraid to attempt any film finish over it - or, for that matter, any finish including an oil that does polymerize. Why wouldn't you want to use an oil that will cure, such as polymerized tung oil or BLO? They will provide a similar enhancement of the color of cherry - actually better IMO, and you can proceed with shellac and a film finish over that if you wish.

[Brian Kent]

I agree and apologize. I saw "oil" but did not see "mineral oil."

[Randy Red Bemont]

Thanks for the replies. I found this on the General Finishes page about WTF over oil.

Can I use the Wood Turners Finish over oil base
stains? Yes, Enduro-Var can be applied over any dried
stain. For standard oil base stains 24-48 hour wait
time, water base stains and dyes two hours. Not recommended
over long oils such as linseed or danish
oils.

I did up a test piece in cherry and will see how it goes. I can also use BLO. I tried it using mineral oil because that's what I use when I do an oil and wax finish.
Thanks,

Red

[Ryan Mooney]

Not recommended over long oils such as linseed or danish oils.

That's all you need to know right there. Mineral oil is long oil squared. Basically they're saying "if it cures hard, its ok otherwise not so much" as noted mineral oil will never cure.

The problems may not be immediately apparent either, so it may look ok for weeks or months (or possibly years) and then surface coat will peal off, probably in patches.

I haven't seen evidence of a problem on the ~dozen~ pieces I did over walnut oil ~3 years~ in BUT it was also really well cured and I don't have a huge sample size either.

[Randy Red Bemont]

Thanks Ryan. I had never heard the term "long oils" before finding this article.

Red

[Ryan Mooney]

Thanks Ryan. I had never heard the term "long oils" before finding this article.

Red

I'm actually horribly abusing the terms there :rolleyes:

The really short summary version is that "long oil" resins dry softer and more flexible whereas "short oil" resins dry harder and less flexible. The nominal definition is that "short oil" resins have a smaller oil-resin ratio and long have a higher oil-resin ratio, but different oils polymerize differently (harder or softer) so the type of fatty acids in the oil matters as well in determining if its nominally "long or short". Using the terms long/short for just mineral oil is a bit misleading because it doesn't polymerize at all (at least not within any meaningful timeframe).

So when they're saying "not recommended over long oils" what they're really saying is that "not recommended over flexible or soft sub surfaces" or "stains that don't dry really hard".

You may get enough of a mechanical bond that its ok if there is absolutely no surface oil, but if its something for sale I'd be really concerned about the long term survivability of the piece.

I'd agree that WTF by itself generally looks a bit "flat" and a little something something underneath of it helps the wood pop a bit.

[Randy Red Bemont]

I'd agree that WTF by itself generally looks a bit "flat" and a little something something underneath of it helps the wood pop a bit.

And that's why I'm asking about the oil first then the WTF. Just trying to give the wood some pop and amber color that the WTF seems to be lacking. Thanks for the reply.

Red

[John Keeton]

Red, I think you would be pleased with BLO and shellac as a base for the WTF. You can apply the shellac right after the BLO, but you need to then wait 2-3 days before applying the WTF.