Possible to seal over oil finish?

I would ask a real pro like a Charles Neil about it.

The oil on an end grain cutting board tends to go nearly all the way through. I have flooded the surface and you start to see the “wet spots” on the back side.
This would not be true of a face grain design (less issue anyway).
However I would work to remove as much oil as possible first sanding/plane off a bit.

Then i would try to get the oil out using either acetone or lacquer thinner then I would finish (immediately) with shellac.

I think that with the mineral oil – a waterbased poly would be a problem. But the shelac is the best sealer for oils/resins etc. And your piece is for looking at, nobody is setting plates/drinks/ etc on it, so the shelac will be plenty durable.

Good Luck

-- "_If we did all the things we are capable of doing, we would literally astonish ourselves_." Edison

To avoid adhesion problems, I would just coat it with Howards butcher block oil / wax. Mineral oil and waxes were not really meant to be coated with a film forming finish. If it was waxed, the finish will quickly fail.
You can’t go wrong with Howards, and it leaves a nice low luster similar to fine furniture.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

You should be able to apply either shellac or poly over the oil finish with no adhesion problems. I have put shellac ove mineral oil and wax mixture with NO additional prep. I was suprised but it worked fine.

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

If you want to have an oiled look without a visible film, just use
oil and keep oiling it. Tung may form a film, BLO and other light
oils pretty much won’t.

If you want the wet, oiled look with no film you’re talking about
a finish that needs regular maintenance.

I may be overstating. There’s an old technique called hot rubbing
where warm oil is rubbed into the wood. I believe you can get
the wood more saturated faster with this method… because otherwise
fully oiling something may take over a dozen coats spread over weeks.

I also vote shellac. It seems to cover just about anything.

-- Lis - Michigan - http://www.missmooseart.com - https://www.etsy.com/people/lisbokt

Thanks to everyone for the replies!

The piece will be mounted high on the wall, so I don’t think I will go with oil since it would require maintenance.

I’m not familiar with Howard’s, but will check into it for another cutting board. It too is an artisan made piece with turquoise inlays and I was wondering what to use to reseal it.

Shellac, is there a preferred brand? I don’t believe I’ve ever worked with it before.

I’ll try the shellac on the back side first to see how it reacts. If it were to fail, would the failure be noticeable in the first few days?

Shellac will be the best way to go. I have put shellac over BLO that was applied and set for 30 minutes and had no problems with adhesion.

-- Chief Petty Officer USN(RET) 1991-2011

I like dewaxes shellac right from the home center “Bullseye Seal Coat” which is a 2 pound cut.

-- "_If we did all the things we are capable of doing, we would literally astonish ourselves_." Edison

Thank you very much! I’ll get some of that.

Btw: Love all the work I’ve viewed on this forum. Such talent!