Tung Oil - Food safe?

[Elmojo]

I've made a few bamboo kitchen utensils and plan to "field test" them to see if they hold up well enough to be worth selling cheap to friends, co-workers, etc...
I'd like to put a least some type of finish on them to keep the grain sealed so it doesn't rise when washed.
I have tung oil; is that food-safe once dry or should I look elsewhere?
I'm not interested in anything glossy, and I'd really like it to be a penetrant, like the tung oil.
Any suggestions?
Elmojo

 

[fergy]

Mineral oil is food safe, and usually used for this sort of thing.

 

[Makinsawdust]

Tung Oil is not safe for items in contact with food. Food grade mineral oil and walnut oil are the only oils that should be used.

 

[Mike Davis]

Pure Tung Oil is food safe, but most oils you see marketed as tung oil are only a little tung oil and the rest is boiled linseed oil, metallic driers and solvents.

If allowed to THOROUGHLY dry, like 30 days or more, then it is considered food safe.

I have started using organic cold pressed linseed oil, also known as flax oil. I is a food supplement and totally food safe. But it takes a week to dry. Yet, it does dry whereas mineral oil never will.

 

[Elmojo]

I have started using organic cold pressed linseed oil, also known as flax oil. I is a food supplement and totally food safe. But it takes a week to dry. Yet, it does dry whereas mineral oil never will.

Where do you get the flax/linseed oil?
That sounds like exactly what I want.
Could I thin it with alcohol or ? to make it penetrate more?

 

[CarvedTones]

The tung oil I use is non toxic.

 

[DonnellyJT]

Waterlox is reportedly food safe after 7 days if properly applied. http://www.waterlox.com/site/494/default.aspx

 

[CarvedTones]

I should have added this link to the thread before. Bob Flexner's article on food safe finishes:
http://www.popularwoodworking.com/features/finish3.html

Despite what you've read elsewhere, almost every wood finish should be considered food-safe.

 

[Mike Davis]

Where do you get the flax/linseed oil?
That sounds like exactly what I want.
Could I thin it with alcohol or ? to make it penetrate more?

I'll have to look on the invoice, I have about a dozen natural oil sites book marked and I can't remember which one i ordered from. Some of them are very high priced.

Meanwhile, if you have a good equestrian supply nearby check with them.


Never thin the oil, heat it in a double boiler to make it penetrate and dry faster.

Yes, most finishes are considered food safe since they outlawed the use of lead and most heavy metals in paints and varnishes. But most contain thinners and driers that may or may not completely evaporate and i would rather ingest things that are meant to be eaten.


The 100% pure tung oil is a good finish.

 

[Elmojo]

Thanks so much for the advice, guys!
I'll be looking for the Masters Blend Tung Oil and Flax/Linseed oil.
Any ideas where they might be available locally?
I'm near Greenville, NC.
Any more comments/suggestions are welcome.

Thanks again!
Mike P.

 

[MrAudio815]

Hey Mike,

I agree with Andy (Carved Tones), And Mike (Mike Davis) I also have a book by The Family Handyman with the same topic about the myth of food safe finishes. It's just a way for those to make more money. 30 days is what is it says as well.

Found here: http://www.woodworkersworkshop.com/..._Completely_-_The_Family_Handyman_Series.html

Have a good one!

 

[Mike Davis]

Here's a PDF worth reading.

http://www.wbdg.org/ccb/GREEN/REPORTS/cgrwoodfinish.pdf

 

[CarvedTones]

I do thin the tung oil some times for better penetration (how much is possible is another myth that gets busted by research, but I will avoid that minefield right now; it seems to do a little better thinned) and quicker curing. I use terpentine - the real stuff from the art store. Keep in mind that the wonderful smelling vapor is just as lethal as the modern stuff so proper ventilation is required. But the residue left behind after it has dried is safe to eat (remember the Grape Nuts guy - "Ever eat a pine tree?").

Also note that the pure tung oil will turn amber as clearly illustrated on my bottle.

 

[CarvedTones]

Here's a PDF worth reading.

http://www.wbdg.org/ccb/GREEN/REPORTS/cgrwoodfinish.pdf

Their info on shellac has one glaring omission - you can get dewaxed shellac to avoid the compatibility problem mentioned with some finishes. Zinnser SealCoat is blonde dewaxed shellac (but it does have a few nasty modern chemicals in it to increase shelf life). You can also get it in flake form.
http://www.shellac.net/
Lots of good info there. This is sort of a tangent, since Elmojo doesn't want glossy, though it could be used for a sealer under the oil.

 

[Howard Acheson]

Couple of rules. All finishes are considered non-toxic when fully cured.

Pure, 100% tung oil is a natural product and completely food safe in it's natural state. Flaxseed oil and raw linseed oil are exactly the same thing. Flaxseed is sold in any drug store in the "natural" foods and vitamin section. It's also sold as a laxative.

All that said, the issue is what should be applied to a wood surface that will be used for food preparation? Here is something that may help in that regard.

An excellent treatment for wooden food preparation surfaces like cutting boards and butcher blocks is a mixture of mineral oil and either paraffin or beeswax. This is what is used on many commercial wood surfaces. It will last longer and be more protective than just mineral oil. Mineral oil can be found in most supermarkets in the pharmacy section or in a true pharmacy. Paraffin is found in the canning section of the store or in a hardware store.

Heat the oil in a double boiler and shave in some wax. The exact proportions are not critical--a 5-6 parts of oil to one part of wax will work fine. Stir the mixture until all the wax is liquefied. Apply the mixture heavily and let it set 10-12 hours or overnight. Next day do it again and continue until the wood will no longer absorb the finish. Let it set for 10-12 hours and then lightly scrape off any excess. Then buff it with a rag.

Reapply whenever the wood begins to look dry.

Never put a wood board in the dishwasher and don't soak it in dishwater for long periods.

 

[Makinsawdust]

The reason I say Tung oil is not safe is because of heavy metal contamination. Chemicals that are used in foods are processed in equipment that avoids heavy metal contamination and is tested to insure there is no contamination. Oils meant for wood finishes are not (Technical grade at best). That tung oil could have been (and probably was) processed in some third world country on who knows what equipment. It could contain Lead, Arsenic, or any of a number of other metals. Place a wooden spoon in boiling water and guess what's for dinner. Is it going to kill someone, probably not, but why go there when there's a safer alternative. That why I only use "Food grade" mineral oil on my stuff.

 

[jlwest]

Pure tung oil is safe for food contact. It should say it was tested via a ASTM method. I also have used mineral oil, get it at the drug store, but it needs to be redone periodically based on usage. Avoid tung oil finishes or other blends for food contact. If properly applied and allowed to dry there should be not problem even with heavy metals, unless you eat the wood and then you have to eat it for a long time.

Jeff :icon_thum

 

[CarvedTones]

Hmmm - Master's Blend does not say ASTM and doesn't list country of manufacture. And while it does say it is non toxic, it also says it is not for internal use. I still think it is fine, but Robert (makinsawdust) does have some basis for his opinion. OTOH, my mineral oil from the drug store which has directions for internal use also carries health warnings, though mostly about not taking way more than would be on a spoon. I think the concern is overkill, but not totally unfounded. IMO, it is like worrying where exactly the tree grew that produced the wood, since we have acid rain in the mountains.

 

[Elmojo]

All excellent suggestions and comments.
I really appreciate everyone jumping in to help me sort this out.
I'm looking for some flaxseed or raw linseed oil in my area, but for the interim I got some salad bowl finish from Lowe's and plan to try it out.
I may also use the tung oil finish I have on one or two and give them a good long cure time, then boil them and smell the residue to see if I get a hint of anything but wood and oil. Not very scientific I know, but it's something I can try that will make me feel better!
Thanks again!
Mike P.

 

[CarvedTones]

You can get a small bottle of 100% raw linseed oil in the arts/crafts section of WalMart and you will find larger sizes at "real" art supply stores. If you get flax oil at the drug store, read the label carefully; some oil supplements contain other ingredients (safe and probably good for you, but may slow the already lengthy cure time). I suspect that is why Mike had to shop around.