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Food Safe Finishes (aka Speaking of Goblets)

This is a major topic in and of itself. Briefly, there are 2 major theories. One being that every common wood finish will EVENTUALLY be safe for food contact given enough time for the solvents and other nasties to evaporate/bind/or otherwise become inert enough to not harm. The other theory is that that is a bunch of BS and you can only use immediately natural foodsafe ingredients to be truely safe.

The proponents of the "everything is foodsafe eventually" idea tend to only concentrate on the solvents used in those finishes. There's more to it than just solvents, you know. They also tend to cite (or, more accurately, cite a common finishing article-writer) the notion that nothing in most of these finishes are listed as a health concern with the American USDA. Of course, lead wasn't listed for many many years before its effects were known either. This is only one example out of thousands.

Personally, I'm in the middle. If I'm making something (like my kitchenware) that I'm going to sell or send to my retailers relatively soon, then I'm going to use natural oils, waxes, etc. because I don't want to have to hold on to them for MYSELF feeling safe. If I have something that I can hold onto for awhile (again, long enough for me to feel like it's safe) then I MIGHT use some other finish IF that finish is the best for the piece given what it's going to be used for, etc.

I also don't take product labeling or advertising at face value either. Many so-called "Salad Bowl Finishes" have solvents and other ingredients in them that I don't consider immediately food-safe. In fact, a couple of these products have changed their labeling recently to reflect their, let's just say creative marketing ideas. They've changed them to read something like "Food Safe after 30 days".

As for your question about applied finish over dyes/stains, as long as your dye/stain doesn't have ingredients that could leech out/under/over/around the finish, then you're safe. Just because you put a finish over something doesn't mean that what is under it stays under it. It depends on many factors.

- Andrew

Reply to
AHilton
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Anyone care to point me in the right direction regarding "food safe" finishes? I've looked into a few, such as walnut, salad bowl, and a few other oils. Can these, or any other finishes, be applied over dies or stains and remain food safe?

Thanks, Antony Sykes WWW (Wannabe Wood Worker)

Reply to
Antony Sykes

To the vast majority of the people in this world who are neither finishing experts nor woodturners, "food safe" means that it doesn't smell like paint, and it doesn't leave an oil slick on the surface of the wine.

Russ Fairfield Post Falls, Idaho

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Reply to
Russ Fairfield

For projects that are going to come in contact with liquids and salads I always use MINERAL OIL. A project with a good sanding and mineral oil will look fine. The disadvantage is having to replenish the oil finish every once in a while depending on useage. It's the one finish that is completely safe. Food dies would be okay but I would be leary about others.

Phil

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Reply to
fipster

Bacteria have cell walls with a hydrophobic (water-hating) exterior, which is why washing with water and a surfactant - detergent, Leif - or soap kills bacteria. Oil protects and shelters them. To get to the bacteria when washing, you have to destroy the oil, too. So why bother?

Now, food safe and safe as food are two very different things. Food safe includes a host of indigestible polymers, safe as food includes things like vegetable oils and resins like shellac, most of which are extracted with _deadly_ solvents in process. Once the solvent's gone, however, different story. Oh yes, mineral oil is as indigestible as polyurethane, it's just that it's also an intestinal irritant, provoking release of water in an effort to break it up. That's why it's used as a laxative.

You might want to avoid "organic" nut oils which are pressed, not solvent extracted, as they can contain the proteins which act as allergens, and can induce severe anaphylaxis in about 1/10th of a percent of the population.

always use MINERAL OIL. A

disadvantage is having to replenish

finish that is completely

Reply to
George

Hi George, I enjoy your commentary; always readable, thought provoking and instructive. You don't argue from dogmatic authority or perpetuate misinformation just because it was printed somewhere. Thanks.

An easily understood, in depth rcw review of the physical chemistry involved as wood dries and cracks and stabilizes (or doesn't) would be a convenient reference printed out or archived. Summed up in one essay, anecdotes aside, what we really know today. What is happening as wood is dried by all the different ways that are revealed to our true believers. You could do it very well. So?

Do you think that adding salt to LDD solution might help transfer the intracellular water by osmosis across a cell membrane made water-loving? Which is the real perp anyway, intra or extra cell water? I doubt that inquiring minds give a damn. :) Arch

Fortiter,

Reply to
Arch

Wood in water is well-preserved, that's for sure, but osmosis is about solute, not just solvent, and I'm not sure that's what we want, given the wood has dissolved salts as well. The problem is that "bound" water, not the casual stuff.

Keeping the surface evaporation equal to the capillary flow from the wood is what we want. If we get a higher rate of evaporation than the interior can replace, we'll get checking as the expanded interior refuses to collapse with the dryer exterior. So anything that either slows the surface loss - high humidity in a bag, in a wax/latex envelope, sitting on a concrete basement floor - is great. The micro and vacuum people use the principle of increased flow, one by pressure from within, one by pulling from without, but they have greater potential for damaging the wood.

Then there are other factors - some woods are more porous than others, some have huge pores with diminished capillary pull, and then there's the closed tyloses in the heart versus the open passages in the sapwood, not to mention orientation and distance between early wood and late wood in trees which experience cycles of heat/cold or wet/dry versus those which don't.

I don't think there's one size to fit all, but I think that easy is the best way to go, even if that means delayed gratification.

Oh yes, then there's the advice I got years ago as I researched the pouring of my first concrete. You can do it so badly as to guarantee failure, but you can't guarantee success. Sometimes it just cracks.

Reply to
George

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