Tung Oil - Food safe?

[Mike Davis]

No, I searched around for the best price.

and I wanted a specific oil.

http://www.botanicoil.com/products/flax_seed_oil.htm

Cold pressed extra-virgin, organic flax seed oil.

Eleven dollars for 8 Oz is fine if you just want to eat a spoonful a day.

But $20 a quart is better is you need to soak bowls in the stuff.

$40 a gallon is even better and no other place I found on line had gallons.

 

[Howard Acheson]

>> 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.

Let me make a couple of points about the oils under discussion. Raw linseed oil (flaxseed oil) and pure tung oil make very poor finishes. Both take more than a week to fully polymerize (cure). They also have little or no resistance to water or water vapor. Both had a distinctive odor that can be picked up in food items that are prepared on treated surfaces. They both will need fairly frequent re-treatment due to being wiped off with water and detergents.

Mineral oil is performs somewhat differently. It NEVER dries. But it has no odor. It is not any more protective than the raw linseed oil or pure tung oil and will also need frequent re-application.

Boiled Linseed oil contains some metallic driers but these driers in the concentration used are considered non-toxic by the FDA when the linseed oil has polymerized.

As to "Salad Bowl Finish" it is nothing more than an oil/varnish mixture. Like any oil/varnish mixture, it contains some metallic driers but again, they are in such small quantities that the government considers the resulting finish non-toxic when fully cured.

 

[CarvedTones]

Let me make a couple of points about the oils under discussion. Raw linseed oil (flaxseed oil) and pure tung oil make very poor finishes. Both take more than a week to fully polymerize (cure). They also have little or no resistance to water or water vapor. Both had a distinctive odor that can be picked up in food items that are prepared on treated surfaces. They both will need fairly frequent re-treatment due to being wiped off with water and detergents.

Not all experts agree. Russ Fairfield says:

Pure Tung Oil provides a hard and tough surface finish that is absolutely waterproof; impervious to dust, alcohol, acetone, fruit and vegetable acids; and it doesn't darken with age like Linseed and other vegetable oils. All of these benefits come at a price - pure Tung Oil takes forever to dry, it doesn't penetrate the wood surface very well, and it is expensive when compared to other drying oils. Tung Oil is a "reactive" finish, commonly called a "drying" oil, in that it will dry and harden when exposed to air.

http://www.woodcentral.com/russ/finish6.shtml

My personal experience is between these extremes, but my opinion is closer to Russ' than Howard's. I have used it on brightwork (wood trim) on a sailboat and it held up fairly well. I have used it on a gameboard that has had spills cleaned up without trouble. Mostly I have used it on instruments and ornamental stuff and I have been pleased with the results.

 

[Elmojo]

My personal experience is between these extremes, but my opinion is closer to Russ' than Howard's. I have used it on brightwork (wood trim) on a sailboat and it held up fairly well. I have used it on a gameboard that has had spills cleaned up without trouble. Mostly I have used it on instruments and ornamental stuff and I have been pleased with the results.

I agree with Andy. I've used tung oil finsh (and pure TO) on other wood projects in the past and have been very happy with the durability and waterproofing qualities of both.
I'm not concerned with the curing time, as these are test runs, so I'm not in any particular hurry.
Reapplication is also a non-issue, since I plan on giving these to friends/family initially with the idea of them being fairly short-life items. I expect them to last 6-10 use/wash cycles before they begin to wear or delaminate.
The point is to find a cheap, easy to make, sustainable utensil that can almost be considered disposable, to avoid filling up the landfills with plastic and metal.

 

[Mike Davis]

The first few spoons I made were treated with mineral oil and looked OK, but they always felt greasy and the oil would float in my tea and coffee. They had to be re-treated constantly and never looked great.

I have a spoon I made twenty four years ago that we use at least once a week to stir soup, beans, rice and other foods. It was coated with very hot organic flax oil (cold pressed pure linseed oil, same thing) that I bought from a health food store. It still looks pretty good except for some darkening at the tip where the heat of the pan has scorched it.

After the first couple times we used it it hasn't imparted any taste to our food (if I had waited a week or two that would not have been an issue), it has not cracked nor dried excessively. We don't put it in the dishwasher but we do scrub it with soap in very hot water in the sink.

I have never re-treated it or done anything to it besides use it and wash it for 24 years.

I am very happy with that treatment and have used it on every spoon and bowl I have made since then except for the last three that had to be done in an extreme hurry. I used spray lacquer on them because I don't believe they will ever be used for food and I had to turn and finish three bowls in one weekend.

I know my experience doesn't count for much compared to the experts and authors who are paid to write about this stuff. However, there it is and I have no reason to lie about it.

 

[Elmojo]

Mike D:
Thanks for the comments.
My experience has been the same as yours, though I have never used raw linseed oil. I used BLO on some wood carvings and it held up really well.
Granted, they weren't for food prep, but the concept is sound.

 

[Mike Davis]

The difference is that raw oil needs to be applied while very hot, almost boiling. That makes it penetrate better and dry faster.

 

[Elmojo]

The difference is that raw oil needs to be applied while very hot, almost boiling. That makes it penetrate better and dry faster.

Good to know, I'll be sure to try that.
I'm happy that it will penetrate without additional solvents.

 

[CarvedTones]

The difference is that raw oil needs to be applied while very hot, almost boiling. That makes it penetrate better and dry faster.

If you heat it enough to make it dry faster, then you are getting partial polymerization, which is what they used to boil it for and now add the driers in the BLO sold in the paint section. But that actually makes it penetrate slightly less because the molecules are bigger. My experience has been that no finish really penetrates all that well in side grain. Finish with just about anything and let it cure, then plane off a very thin shaving and sprinkle water on the wood; it will not bead (no fair using teak ).