Food-Safe for hot liquids

[martinwildes]

I've only been a member for less than a year, but have already read numerous posts regarding food-safe finishes. Mine is slightly different in that I have a request to turn some tea cups. Does anyone know of a food-safe finish that will withstand boiling liquid? Thanks in advance for your input.

 

[James E Gaydos]

tea cups

Hi Martin, and welcome to the forum.
The Japanese use lacquered wooden bowls for serving rice. I've often wondered if lacquer would be appropriate for a drinking vessel, hot or cold. I've tried drinking vessels with Shellac, and a few plain no finish, they were all turned from Hard Maple.
Sorry, I didn't really answer your question.
Jim

 

[martinwildes]

Hi James,

Thanks for the input. How did the hard maple unfinished vessels hold up? Any leaks from wood movement?

 

[Mark Mandell]

Marty,

Food safe, is one thing (beat-to-death topic IMO), but boiling water is quite another as the heat stress on a coating and the coating/wood interface will be substantial. I anticipate that the only thing that will handle what you propose is epoxy, perhaps even epoxy-stabilized wood which takes special equipment and processes to produce. If, however, you're considering doing the cups via segmenting rather than one-piece , I don't think you're going to have a lot of luck with wood as a material, as the joints and glue won't take the stress.

 

[john lucas]

I'm not sure about epoxy either. I frequently break epoxy joints using heat and it doesn't take as much as you think. I think I would go with the natural wood.

 

[Mark Mandell]

Another Option

Is to learn metal spinning and line the cups with stainless steel, or pure copper.

 

[Mark Mandell]

I'm not sure about epoxy either. I frequently break epoxy joints using heat and it doesn't take as much as you think. I think I would go with the natural wood.

John, If he coats the interior to 1/16th or better with epoxy (or just fills them and then re-hollows) he shouldn't have any epoxy joints to fail.

They'd be hand wash at best though.

 

[James E Gaydos]

The Maple vessels held up well, they were made from solid material, no glue joints. I also kept them about 1/2" thick.
Jim

 

[John Van Domelen]

The best finish on the inside in my opinion is to use nothing.

I made our family 4 sycamore soup bowls a couple years back - they have no finish. They have withstood much use with scalding hot soup. Care is just a wipe out in the sink with a scrub brush or sponge with hot water, allow to air dry. Sometimes simple is better.

 

[Mark Mandell]

Small Note on Woods

Martin,

Since it's not been mentioned, you should keep in mind that a not insignificant portion of the population have allergies to various nuts which, naturally, come from trees. Depending on the wood, using an unsealed wood for a hot liquid drinking vessel can expose the user to some risk. For instance, the Juglone protean in walnut does not disappear when the wood has dried, so, depending upon where in the tree your turning blank came from, there can be a substantial amount present that can leach into a cup's contents. Juglone is poorly soluble in water under normal conditions, but heat the water to boiling and the story will likely change.

As the Old Dude in Petra said, "choose wisely."

 

[Nicholas Tinney]

Make sure the moisture content is very low <8%MC before applying From the specification it is slightly (very little, but will move) flexible.

I use this on coffee mugs (wood) for a local coffee shop. It is a bit hard to work with unless you heat, in a water bath, i used some crocks for cheese/dip each component to 110-130 F then mix. Make sure the object is also warm and use a foam brush. VERY DURABLE!

Call them and get a 2qt sample ~$70 + Shipping

http://www.sscoatings.net/brewcoat-info.htm
Cheers,
Nick
nicholas@nicholastinney.com