Is Ash too porous to use as a bowl?

[Brian Kent]

My daughter requested four 1-liter bowls made out of kiln-dried ash. After making each bowl I add a liter of mineral oil and mark the level, which I will turn into a, etched marker-line. Of course she knows it won't hold hot soup and should only have wet vegetables for the duration of the meal, with a re-coating of oil as needed.

The mineral oil quickly soaked through the end grain. No dripping, just a soak-through. My plan is to keep on soaking for several rounds.

1. Is this a sign that ash is too porous for this intended usage?

2. Is there ever a time to use a poly / oil / mineral spirits for a wooden bowl - not to form a water-proof surface but to cure thicker than oil inside the grain?

[John Keeton]

I would have used Walnut oil.

[David Gilbert]

Actually, ash bowls will hold soup (or water).

If the bowl is finished everything will be fine. If it's not then there will be problems.

Mineral oil will never harden and seal a bowl. It is manufactured so it will never harden up or cure. Walnut or tung oil can take a very long time to cure. Minwax Antique Oil (my favorite) will seal up a bowl and there may be others penetrating oils that will work fine. I have made numerous ash bowls for salads and such and have never had a problem. All wood finishes are food safe, as long as they are fully cured and dry.

The bowl in your photo may have some problems since it is already saturated with mineral oil. It also has a very interesting grain pattern. Was this glued up to make the bowl blank?

Cheers,
David

[Brian Kent]

Yes, it was glued up from two thicknesses of ash. Good to know about walnut oil for the future.

[Leo Van Der Loo]

My daughter requested four 1-liter bowls made out of kiln-dried ash. After making each bowl I add a liter of mineral oil and mark the level, which I will turn into a, etched marker-line. Of course she knows it won't hold hot soup and should only have wet vegetables for the duration of the meal, with a re-coating of oil as needed.

The mineral oil quickly soaked through the end grain. No dripping, just a soak-through. My plan is to keep on soaking for several rounds.

1. Is this a sign that ash is too porous for this intended usage?

2. Is there ever a time to use a poly / oil / mineral spirits for a wooden bowl - not to form a water-proof surface but to cure thicker than oil inside the grain?

Brian, mineral oil is 357772

or said in another way, 357773

And like motor oil it will never harden, you can take it as a medication where your body will try to get rid of it as fast as it can (maybe good if you have constipation).

An oil like BLO or Tung Oil that will harden in the wood would be a much better product to use IMO.

I have turned all kinds of Ash bowls and never had problems like that with it, but than again I never did pour motor oil or the cleaner type mineral oil in them :D

357774

[Reed Gray]

I had an ash bowl that I used for about 10 years till a ring shake crack opened up on it. I ate every thing that could fit into a bowl out of it, including soup. No problems with leaking till the ring shake opened up. It started out nice and white, and ended up a nice warm amber color.

I quit using mineral oil years ago because it doesn't do anything other than make the wood look wet for a few days, then it is gone. Walnut oil is far better. I use the stuff from 'The Doctor's Woodshop'. It does take a week or so to dry, but it does dry. If you have a more open pored wood, a wet sanding does a good job of filling the pores.

robo hippy

[Brice Rogers]

Hi Brian,
I'm wondering if it might make sense to coat the ash bowl with something like "OB Shine juice". That is, equal parts of de-waxed shellac, DNA, and BLO - - except perhaps substitute regular linseed oil for BLO or get food-safe linseed oil that doesn't have metallic driers in it. Shellac is a natural product and is (IIRC) used as a coating on pharmaceuticals. The shine juice or friction polish (or Tung oil or Danish oil or walnut oil) may tend to close or plug up the pores.

Alternatively, using a finish that hardens is supposedly safe once it has cured and all of the volatile oils/solvents (VOCs) have dissipated.

The most porous wood that I've worked with is our local San Diego jacaranda. I was using an air hose on the inside of a bowl and I saw dust flying off the outside.

[John K Jordan]

The bowl in your photo may have some problems since it is already saturated with mineral oil.

If the pores still contain liquid oil you might be able to remove much of it with compressed air. Set a piece of plywood on the top, seal the with something and hold tight, then force compressed air into a hole in the plywood. I might even follow with mineral spirits and let dry before finishing.

Note that I haven't tried this with mineral oil (I've never used it in wood) but it works to quickly remove excess water in wood with open grain. I learned this from the other J.Jordan who uses compressed air to bubble the free water out of his hollow forms after turning green.

JKJ

[Brian Kent]

I won't try to remove oil from these bowls. But I have some more orders for ash goblets. I will try one of the recommended products on that one.

I am both happy and surprised with these responses.
Happy because I really want a finish that soaks into the wood and hardens.
Surprised because I am used to reading the advise for salad bowls and other wooden kitchen bowls to use mineral oil, soaked in several times until it does not hold any more, and then refreshed as needed after use and hand-washing.

So which of these finishes will soak in and eventually harden?

Walnut Oil
BLO
Waterlox (Tung Oil)
Danish Wood Oil

[John Keeton]

All of them, but with varying degrees of hardness and durability. Danish oil is a varnish oil blend with solvent carriers and of the ones you list it and Waterlox are probably harder and more durable but less easy to replenish if enough coats are applied to form a film. Waterlox is an excellent finish. Danish oil should also cure quicker than the others.

Also, Waterlox is a varnish oil blend - not pure tung oil.

[Frank Drew]

Behlen's Salad Bowl Finish (if they still make it) is food safe and definitely dries hard, and in a finite amount of time.

[John K Jordan]

I won't try to remove oil from these bowls. But I have some more orders for ash goblets. I will try one of the recommended products on that one.

I am both happy and surprised with these responses.
Happy because I really want a finish that soaks into the wood and hardens.
Surprised because I am used to reading the advise for salad bowls and other wooden kitchen bowls to use mineral oil, soaked in several times until it does not hold any more, and then refreshed as needed after use and hand-washing.

So which of these finishes will soak in and eventually harden?

Walnut Oil
BLO
Waterlox (Tung Oil)
Danish Wood Oil

Did you see this thread: http://www.sawmillcreek.org/showthread.php?253701-Food-safe-coating

I believe those four you mentioned will all soak in to some extent and eventually harden. The danish mix might be thinner than the BLO, at least what I have seems to be, so it might soak in better. That's what I usually use. I've known people who would put a turning in a plastic bag and fill it with danish oil so it is actually submersed for a while. Remove and let sit overnight, wipe off everything, let dry for a few days, then see if it will soak up any more oil. If it won't, quit then or it will just build up a layer on the surface. Before using I let it dry (cure) until I can no longer smell the oil.

I use BLO for outdoor farm things, barn doors, shovel handles, etc. I know some people use it for finishes and a lot of people use walnut and pure tung oil.

JKJ

[Reed Gray]

I avoid the finishes that have solvent based penetrating oils. Yes, when they are dry and cured, what is left is 'inert material' but I really don't want anything on my bowls that I can't eat straight out of the can. Some people are hyper sensitive to the solvents, and traces can last for a long time. They are dry to the touch in a day, fairly hard in a week, but only totally cured when you can no longer smell them, and that is a month or so. Walnut oil for me for daily use pieces.

robo hippy

[John Keeton]

Reed is correct as well as the fact that film finishes do not play well with moisture and the various PH situations with foods. As I said initially, Walnut oil is my preferred finish for utility bowls.

[Leo Van Der Loo]

So how safe do we need to go, peanuts or peanut oil, Walnuts and Walnut oil are known to cause problems, never heard that about Boiled Linseed Oil or Tung nut oils.

Dry cured finishes are considered safe according the US FDA, and here is the list, no Mineral oil included BTW.

357828

[John Keeton]

Leo, while I think the solvent concerns are valid, for me it is simply a matter of durability and the probability that heavy use will necessitate replenishment of the "finish." Having had bowls with a film finish taking on a ragged look, I think an oil finish seems much preferable. I use BLO a lot, including using it years ago on the longrifles I built. It fills the bill, but I prefer the way Walnut oil feels on wood for a utility piece. I am sure tung oil works, too. There is disagreement on whether the nut oils trigger an allergic response and I don't know the answer to that.

[Pat Scott]

Minwax Antique Oil, Waterlox, Behlens Salad Bowl and General Finish Salad Bowl Finish are all a Danish Oil blend. GF Salad Bowl Finish has more varnish in it than Antique Oil, so it will build up a film layer faster. Waterlox I think has even more and it's expensive. I used GF Salad Bowl finish for years, with any danish oil just stop applying additional coats as soon as you start to see a shine build. Antique Oil seems to cure faster that Salad Bowl Finish also, meaning when you stick your nose against the piece and sniff, the smell is gone sooner.

I agree with everyone else that Mineral Oil is not a good finish to use for any utility item. You have to reapply more mineral oil every time you wash it.

I've used Mahoneys Walnut Oil but found it took FOREVER to dry. I made a Silver Maple bowl that took 6 months before I could touch it without having an oily residue on my fingers. Lately I've been trying Doctors Woodshop Walnut Oil/Microcrystal Wax blend and really like it. It is applied on the lathe and friction finished. The heat helps drive the oil and wax into the wood, and the heat helps cure the oil and melt the wax. Although as the Doctor says, the wax particles are so small they think they are a liquid. When I need to make and sell a bowl quickly, this is the finish I use. When I have more time, I use Danish Oil.

Doctors Woodshop says:
"The three most common polymerizing oils (oils that will harden to form a solid material without chemical drying agents) are Tung oil, Linseed oil and Walnut oil. Only Walnut oil will harden without darkening, yellowing or clouding. This means a clear vision of the grain and figure in your project."

Danish Oil (DO) is my preferred finish as it's more durable than Walnut Oil. You will not have to reapply Danish Oil as often - or ever - depending on how you use the bowl. Salad Bowls that I made years ago and finished with DO look just as good today as they did when I made them. The only salad bowl that I have had to reapply finish on was a bowl finished with Mahoneys Walnut Oil. A downside to DO is that it can take weeks for the smell to go away. I would not put a bowl in a bag with Danish Oil and soak it. Tried that once and it took forever for the finish to cure (not smell when I stuck my nose against it). A bag might work with a shallow bowl or plate, but anything more enclosed I would wipe on/wipe off. Mike Mahoney and Glenn Lucas both told me that if they had the time they would use Danish Oil. But since they can't wait weeks for the smell to go away, that's why they use Walnut Oil (to be accurate, Glenn uses "Liquid Paraffin, which is Mineral Oil).

The cereal bowls and plates that we use in my home are all finished with DO. These are used and washed every day. I made them 6 years ago and have had to reapply DO a couple of times. That's not bad for a daily use item compared to how many times I would have had to reapply Walnut Oil.