Cutting Board finish

[Scoony]

This has been discussed quite a bit, but different angle this time.

Making several end grain cutting boards. My home mix of walnut oil, mineral Oil, and bees wax is about used up. 

I was looking at the MSDS of Watco butcher block finish ($11 a pint) and it is basically Tung Oil and Mineral Spirits. 

Mineral Spirits?  Is that food safe? I guess if Watco is using it, it must be safe once it evaporates.  I have pure tung oil on hand but would like to thin it down just a little. Looked around local stores unsuccessfully for a pure citrus solvent.

I did do a test on a stip of cut-off that is about 3/32" thick and the tung oil did penetrate to the other side so I know that unthinned, it will penetrate at least a little. With the end grain, I am probably over thinking it as the oil will probably soak all the way through. 

What are your thoughts on using MS to thin tung oil for cutting boards?

[Bill Wilson]

Well, I don't know the chemistry behind it all, but if it isn't absolutely necessary, I wouldn't use it.  Then you don't have to worry.  Also, if you warm the oil some, it will help it soak in.

[giradman]

This has been discussed quite a bit, but different angle this time.

Making several end grain cutting boards. My home mix of walnut oil, mineral Oil, and bees wax is about used up. 

I was looking at the MSDS of Watco butcher block finish ($11 a pint) and it is basically Tung Oil and Mineral Spirits. 

Mineral Spirits?  Is that food safe? I guess if Watco is using it, it must be safe once it evaporates.  I have pure tung oil on hand but would like to thin it down just a little. Looked around local stores unsuccessfully for a pure citrus solvent.

I did do a test on a stip of cut-off that is about 3/32" thick and the tung oil did penetrate to the other side so I know that unthinned, it will penetrate at least a little. With the end grain, I am probably over thinking it as the oil will probably soak all the way through. 

What are your thoughts on using MS to thin tung oil for cutting boards?

Hi Scoony - why not just make more of your 'home mix'?  Earlier this year, I put together a rolling kitchen island butcher block kit and added several cutting boards and a stone - for the boards, I bought some commercial products from Amazon (pic below) - basically the ingredients you have used, i.e. a walnut spray & a mineral oil/beeswax combo - has worked fine for me.

As to 'mineral oil', despite being a petroleum product, the oil is perfectly safe for human consumption and has been used for decades as a laxative (particularly in children w/ Hirschsprung's disease).  As to mineral spirits and other oil/varnish mixes, once cured, these finishes should not be harmful if ingested - quoted below are Bob Flexner's comments from just a few years ago (Source); however, I would not use a 'film finish' on a cutting board - would simply get cut up and look flaky and terrible (this would include shellac which is used to coat candies among other options).  Dave

A seemingly never-ending question concerns how to finish cutting boards.
You don’t need any finish on a cutting board. Water won’t hurt it and no finish will keep water out anyway, after a few knife cuts. Nor will the finish continue to look nice after numerous knife cuts. If the cutting board begins to warp due to the water contact on just one side, turn it over and it will slowly flatten out.
If you are selling cutting boards and want them to look nice, apply wax or some type of oil finish. You don’t want a film-building finish because chips of finish will be cut away and get into the food.
Mineral oil will work fine but will leave the wood looking dull. A drying oil such as boiled linseed oil or a blend of oil and varnish (“Danish Oil”) can be made to look shinier and nicer with several coats. But be aware that if you make the cutting boards look too nice people won’t buy them because they won’t want to cut on them and mess them up…I know this from experience. One of my first projects was making cutting boards and selling them at a craft show. Countless people told me the boards looked too nice to cut on so sales were slow.
You don’t need to worry about the safety of any finish for food contact. This is a myth that refuses to die. All finishes are totally safe to eat off of and even to ingest in small amounts once they have totally cured. But if you are selling the cutting boards, the people you sell to might be concerned. So the best policy is probably to finish the boards with wax or mineral oil and promote the finish as food-safe.
 — Bob Flexner

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[Scoony]

I ended up just using the tung oil. The three boards sucked in almost half a pint. 

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[Woodworm!]

I would use the beeswax and mineral oil finish