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What's a good food grade finish?

John Simmons

John Simmons

Joined
Mar 20, 2019
Messages
126
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Location
Buena Vista, Colorado
I'm wondering what would be a good food grade finish for the small goblets I turned from pine? I used the search function here, but most of the threads were pretty old and I thought perhaps there was something new available.

Since these are Christmas related they may end up with whiskey / egg nog, etc. in them.

Should they be finished inside and out, or just outside?

What about using something like olive oil, is that a bad idea?

Does it make sense to use something like spar urethane on the bases to keep the bark intact?

Thanks in advance!

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For most food grade things I use Mahoney's walnut oil. It has had the alergens removed so it shouldn't bother anyone. That beind said goblets are a whole nother thing. You not only have liquids sitting in them, most of it is alcoholic and even worse than that if it's wine you don't want to put any thing that might change the taste of the wine. Now in my case the wine comes from a box so whatever taste I add might improve it. Jim Rinde did a test making shot glasses and then wine glasses and the finish he came up with is to coat the inside with thin CA glue. Wipe it out and let it dry. The pour melted Carnauba wax in, let is sit for a few seconds and then pour it out. Wipe it down and let it harden. He found that with this finish the wine would not stain the wood and it didn't alter the taste of the wine. I've seen a lot of wine glass questions over the years and tried a lot of finishes myself. Haven't tried this one yet but it's the only one I know of that has gone through the kind of testing that Jim put it through.
 
I make wooden shot glasses from white oak. The only finish I use on the inside is propane :) I use a torch to burn the inside (like a whisky barrel). I do loose a few due to cracking from the heat, so I have started charing the inside before turning the outside so there's more bulk there to take the heat.

Even though barrels and such are made of white oak, and are water-tight, about 50% of my shot barrels do leak a bit. I believe this is because the sides are thin, so some pores go thru. Also mine are one-piece, so the bottoms are end-grain where a real barrel has side-grain lids and bottoms.

The finish I use on the outside has done wonders to fix the leaking problem for me. I make a mixture of pine rosin and boiled linseed oil. I melt the pine rosin In a double-boiler (two nesting tin cans from the recycle bin) on a hot plate. Add just enough BLO to make a honey-like consistency. I apply it warm from the hot plate with the lathe running so it gets melted in.

As the wood pores are not sealed, I only recommend my customers use plain spirits or water or the like. Seems like more sugary/creamy things would just get in the pores and become a health problem in the future.

Works for me.
 
That shape and material chose is not going to do you any favors. I can't imagine the inside is perfectly sanded and smooth all the way to the bottom. I'd suggest you need a finish with a lot of build to fill in the torn grain and sanding scratches. Epoxy would be my suggestion.
 
Richard Coers said:
That shape and material chose is not going to do you any favors. I can't imagine the inside is perfectly sanded and smooth all the way to the bottom. I'd suggest you need a finish with a lot of build to fill in the torn grain and sanding scratches. Epoxy would be my suggestion.
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It was my understanding it was hollowed with a Forster bit so should be reasonably clean surface wise- (edit - spade bit was used so will be a rougher surface.)

Regardless of surface epoxy is an excellent finish for anything holding liquid.
 
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hockenbery said:
It was my understanding it was hollowed with a Forster bit so should be reasonably clean surface wise

Regardless of surface epoxy is an excellent finish for anything holding liquid.
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@hockenbery It was hollowed with a spade bit which seems to me would be unsafe If going deep into end grain.

I would suggest starting by turning to a smooth cylinder between centers and then creating a tenon to hold the wood in a scroll chuck so that it won't rock while drilling. A Forstner bit could be used, but I would prefer a large twist drill. In either case drill slowly and clear the chips frequently or the bit could get hot and jam in the hole.
 
Bill Boehme said:
@hockenbery It was hollowed with a spade bit which seems to me would be unsafe If going deep into end grain.

I would suggest starting by turning to a smooth cylinder between centers and then creating a tenon to hold the wood in a scroll chuck so that it won't rock while drilling. A Forstner bit could be used, but I would prefer a large twist drill. In either case drill slowly and clear the chips frequently or the bit could get hot and jam in the hole.
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I add a little bit of wax when the forstner gets hot...
 
If a finish is "cured", isn't it inert? And wouldn't inert mean food-safe?
About ten years ago I used tung oil on the inside of a piece - I don't think the smell ever left - now all I use for insides is epoxy.
 
Thinwall goblet.jpg Leaking goblet.jpg Sealed Goblet.jpg It happened that I had a student here 2 weeks ago that I showed the difference of surface one gets using a spindle gouge, a scraper and a Termite when hollowing endgrain.

I let the student use the Termite an after that I hollowed the piece to a very thin wall, less than 1/16”.

I decided to make a goblet from it and try sealing it after a member on the Canadian forum asked on what to use, as he had problems trying different things.

I made a couple of pictures to show the outcome of the trial, first one is with a small CFL bulb inside it showing the thin wall.

The next one shows the staining after I poured some red wine in it, it started leaking through the bottom in just a few seconds, I poured the wine out and stained the goblet some more when doing this.

The next one is with red wine in it again, after I had sealed the bottom endgrain only with thin CA, let it sit for better than half an hour, and no leaking at all, even the not sealed wall did not leak or even show any reddening of the wine inside it.
 
Refer to the February 2019 issue of American Woodturner page 52 "Members Gallery", The tankard is entirely made of White Oak and finished with walnut oil only. The first one I tested sat half full of water for a week and never leaked.
I have also for about 25 years made decorative goblets from many species including white pine, but I never felt the need to actually drink from them. The idea of plasticizing a piece of wood with epoxy is something I don't care for I would rather use a glass goblet. The majority of the goblets have the bark edge and are thinner than 1/16". The ones in the photo below are black cherry with the pith.IMG_1624.JPG
 
I make and sell quite a few bowls every year, most are made for food and daily use. I also use Mahoney's Walnut oil on all of them because of what has been already mentioned. Even someone with a severe nut allergy is safe using wood products finished with his walnut oil. The enzymes that react with the allergy are removed in the process he uses. That is a great selling point to many customers. On the other hand I also believe almost all finishes are food safe once they have cured or are completely dried. I don't use the Mahoney's wax because of how water spots and finger prints show up so easily when I used it years ago.
 
Any fully cured finish is food safe. That said, serving liquids in wood containers will eventually wear down the finish, so I don't advise such use. A pure oil finish (like walnut oil) doesn't offer as much protection as other finishes, but the good thing is it can be replenished easily by anyone, whether (s)he's a woodworker or not.
 
I don’t know why people don’t ever use Rubio monocoat here. I’m a flooring guy and use it a lot. It’s totally organic. The accelerator additive could be toxic, but you done need to use that.
 
Sam Beagle said:
I don’t know why people don’t ever use Rubio monocoat here. I’m a flooring guy and use it a lot. It’s totally organic. The accelerator additive could be toxic, but you done need to use that.
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I've never heard of it. Could you tell us what you like about it.
 
Breck Whitworth said:
On the other hand I also believe almost all finishes are food safe once they have cured or are completely dried.
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Back in the 1980's, I tried my hand at making children's wooden toys, and was concerned about using bare Watco Danish Oil on oak for this purpose. I wanted them to be "baby safe" for toddlers who might chew on them. I wrote the company (This is what we did back in the days before most of us had computers! :eek:).....and was assured the product was safe for this purpose, as long as it was fully cured. I probably have that original correspondence somewhere, but haven't any idea where it might be.....:confused:

I am now using DO natural for any salad bowls I produce.....and, apply a lemon oil wax (also food safe) over the top of the DO. I suggest to my customers to wipe clean with a damp rag and apply a coating of mineral oil.

-----odie-----

18 wheeler flat bed.JPG Camper.jpg Hot Rod.jpg Pick-up truck.jpg Veedub.jpg Vette.jpg Z coupe.jpg1606 flame maple salad bowl (18).JPG
 
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Tom Robbins said:
Any fully cured finish is food safe. That said, serving liquids in wood containers will eventually wear down the finish, so I don't advise such use. A pure oil finish (like walnut oil) doesn't offer as much protection as other finishes, but the good thing is it can be replenished easily by anyone, whether (s)he's a woodworker or not.
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Tom is absolutely correct and if you doubt it Google food safe finishes and you should find plenty of information confirming.
 
Rubio is a hard wax oil. It’s a great product. For floors I use the accelerator which I believe is isocynate. But for bowls I use the 1 component. It smells good and all. It’s a plant based finish. U would get a smoother bowl than a Rubio bowl. It is a lower sheen though. 1 coat and done. Hence the monocoat name
 
Sam,

Be careful with the Isocyanate organic compounds can be really bad for your lungs and cause serious problems. I was setting up a machine for Krauss Maffei back in the 1980's and was making a few test shots with the polymer compounds to set the proper mix ratios and timing to inject the proper amount of materials for the injection molds we were setting up and got exposed to some of these fumes which caused some breathing problems for several months. If you get exposed to too much you can become sensitized to the materials.
 
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