Expert: Jamie Yocono - 11/1/2008

Question
QUESTION: Hi Jamie,
I have used an old can of watco exterior oil (my husband had in his collection) to stain my oak table to match some chairs. (which it has perfectly) My intention was to apply a varathane over top to match the sheen of these chairs. However we like the look so much we don't want to put on the varathane. My problem is the can states it is poisonous and we are worried about it being on an eating surface. Do you have any suggestions? Thank you so much in advance... I understand you're the watco guru!
Elaine

ANSWER: Elaine,

A couple of things about your question -

First, I think when you measure the toxicity of something, you're looking at it in it's pure state. So when they say Watco is toxic, I think they're talking about it being poisonous if you drink it straight from the can.

That said, when Watco is applied to wood, it polymerizes to a non toxic state after it cures. That means after a certain time, it actually changes to a non toxic state. I heard one expert say that Watco actually forms a skin on it when it's cured, and can't impart any of it's chemicals into something that is placed upon it. That makes sense to me.

Think about it... say you have a cutting board and you decide to dice some onions on it, or bone a chicken. The time that the food spends on that wood, combined with the fact the Watco has cured, means that very little toxicity is going to transfer onto your food. How much? I am not a chemist, so I can't give you an exact answer. But I know this - I have been using Watco on woods that come into contact with food for many, many years, and I do so without any reservations.

I'm like you, I love the look that wood develops with Watco on it. It's rich, lush, soft and organic. Not plastic-y, like a varnish. And by the way, varnish would also be considered poisonous if you drank it, too. Doesn't sound too enticing.

It's just my professional opinion, but I think you're basically safe using anything that's been finished with Watco, as long as you let the finish cure. I don't think you have anything to worry about putting the exterior Watco on your table and chairs.... just don't lick them.  :)  I'm just kidding. I think you'll be fine.

Jamie Yocono
Wood It Is! Custom Cabinetry
Las Vegas, NV
www.wooditis.com



---------- FOLLOW-UP ----------

QUESTION: Thanks so much for your reply Jamie. A couple follow up questions...How long do you suggest curing for? Since it's an exterior product, are there any differences to consider? Would you suggest a wax on top? If so, do you have a recommended brand? And when would I apply the wax, after complete curing or?
Thanks for your reply :)
Elaine

Answer
Elaine,

The length of time to cure depends on weather/humidity conditions where you live. In a dry climate, maybe 2-3 days. In a humid climate, a week. I would think the exterior version might possible have something added to it to make it a little "harder" of a finish, but I can't see how that would affect toxicity. As I said before, Watco is poisonous if you drink it from the can, which is why they put those warnings on it. But I think a cured surface, combined with the fact that very little of the finish is leeching into any food placed upon it, makes for a relatively food-safe finish. I've been using it for cutting boards since 1976.

I generally apply the wax a day or so after the last coat of oil. The only time you really need to wait for the finish to cure is if you're applying a polyurethane over the oiled surface. Remember that old adage about water and oil not mixing? Well, Watco is an oil, so it has to fully cure, or nothing will be able to dry on top of it.

I like two different kinds of waxes - Watco actually makes a liquid wax, which is really nice to use. It comes in a light and dark version, so depending on the type of wood, buy the right color. I also really like MinWax paste wax and Johnson's paste wax, they come in a one pound tins, and both are a solid wax.

Rub it on, buff it off. I do all my waxing by hand, no power tools. If you let the solid paste wax dry too long, it is sometimes tough to buff off. That's why I like the Watco liquid wax... it's easy to use, and does  nice job.

OK, good luck, write back if you need more help!

Jamie in Vegas