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Redbeard
21st February 2019, 10:58 AM
Ok, that looks like a nice deep, controversial rabbit hole to dive down into...

I want to turn a coffee cup, not a travel mug but a cup. I don't want to use an insert or the like. So I need a coating/ finish.

Low maintenance
Heat resistant (good, hot, black coffee temp)
No nut oils (just to be on the safe side)

Any suggestions?

Thanks
Redbeard

BobL
21st February 2019, 11:18 AM
I'd start with some Clay.

Redbeard
21st February 2019, 11:50 AM
I'd start with some Clay.It's right there in the forum name, "Wood..."

[emoji3]

Euge
21st February 2019, 12:07 PM
Ok, that looks like a nice deep, controversial rabbit hole to dive down into...

I want to turn a coffee cup, not a travel mug but a cup. I don't want to use an insert or the like. So I need a coating/ finish.

Low maintenance
Heat resistant (good, hot, black coffee temp)
No nut oils (just to be on the safe side)

Any suggestions?

Thanks
Redbeard


Raises many complex questions Redbeard. Very complex & difficult question (ie a deep rabbit hole)

Heat resistance short term to say 90 C? Would wood like that? Getting wet? getting hot? Without cracking?Non tainting / no taste / non toxic?

Its a difficult ask. Letting my imagination soar… “brainstorming” it was called… these options come to mind:

1. Speciality food wax blends (incl high purity synthetic waxes) as used on some paper / cardboard cups etc throwaway kinds (many are proprietary) may be available from food film manufacturers but they are interested in high volume sales only. Ask for test samples

2. Metal films : compliant think soft stickable , buthow to stick them to wood surface (gold foil is stuck to wood, wont stain but it lacks any abrassion resistance- would look fantastic! ) and seal them? which metal .. Gold? Silver? Aluminium all possibilities. Stick / Glue Alfoil to the inside? Maybe!

One could coat the inside with graphite and electroplate a metal to the inside (eg black nickel) if one protected the outside from plating chemicals. It can be done with plastics as well as organic & plant materials

3. Polymers: but which? Polyethylene (low melting but how to apply) polypropylene good as melts higher temps but adhesion? They are good food plastics but cant be bonded to wood easily .. BUT f you used them as a liner and wood as a holder it would work, but that's what you want to avoid

4. Others: 2 part (eg epoxy .. health issues) acrylic (same) cyano acrylates (maybe as they cure with water)

5. Oils: many air hardening oils available and many that stay soft but waterproofing taste / tainting problems exist

I think making a HOLDER for a liner (paper plastic / metal / ceramic) you can live with is best. But you could explore 1 & 2 further

Euge

Bohdan
21st February 2019, 12:11 PM
Add to the flavour - use wood from a coffee tree.

Redbeard
21st February 2019, 12:16 PM
Add to the flavour - use wood from a coffee tree.Interesting idea...

Coffee Tree 6 x 6 x 3" - WoodTurningz (http://www.woodturningz.com/Coffee_Tree_6_x_6_x_3)

Redbeard
21st February 2019, 12:17 PM
Raises many complex questions Redbeard. Very complex & difficult question (ie a deep rabbit hole)

Heat resistance short term to say 90 C? Would wood like that? Getting wet? getting hot? Without cracking?Non tainting / no taste / non toxic?

Its a difficult ask. Letting my imagination soar… “brainstorming” it was called… these options come to mind:

1. Speciality food wax blends (incl high purity synthetic waxes) as used on some paper / cardboard cups etc throwaway kinds (many are proprietary) may be available from food film manufacturers but they are interested in high volume sales only. Ask for test samples

2. Metal films : compliant think soft stickable , buthow to stick them to wood surface (gold foil is stuck to wood, wont stain but it lacks any abrassion resistance- would look fantastic! ) and seal them? which metal .. Gold? Silver? Aluminium all possibilities. Stick / Glue Alfoil to the inside? Maybe!

One could coat the inside with graphite and electroplate a metal to the inside (eg black nickel) if one protected the outside from plating chemicals. It can be done with plastics as well as organic & plant materials

3. Polymers: but which? Polyethylene (low melting but how to apply) polypropylene good as melts higher temps but adhesion? They are good food plastics but cant be bonded to wood easily .. BUT f you used them as a liner and wood as a holder it would work, but that's what you want to avoid

4. Others: 2 part (eg epoxy .. health issues) acrylic (same) cyano acrylates (maybe as they cure with water)

5. Oils: many air hardening oils available and many that stay soft but waterproofing taste / tainting problems exist

I think making a HOLDER for a liner (paper plastic / metal / ceramic) you can live with is best. But you could explore 1 & 2 further

Euge
Ceramic liner? Now there's a thought...

Redbeard
21st February 2019, 12:19 PM
Euge

Thanks for the brainstorm ("they" call it a brain- DUMP these days, sounds messy to me).

Food for thought.

Euge
21st February 2019, 01:08 PM
Maybe the boss (Neil) could suggest if any of his wood coatings are suitable for hot food / beverage contact?
Why not PM him Redbeard? He would have an informed professional view on wood coatings

BobL
21st February 2019, 01:11 PM
It's right there in the forum name, "Wood..."

[emoji3]

I wasn't being flipant.

Wood has practically zero of lasting at those temperatures and the 100% humidity without a lining.
It is possible to do one or the other but not both.
There's no known wood coating that can handle those sort of conditions for too long.
And well before it dies and within short order it will look extremely ordinary.
A type of coffee cup that would last a bit longer than others would be a small chunky espresso cup.
Ristretto (15mL) shot made in ~20s and knocked back in one go Italian style within a minute of being made.

Redbeard
21st February 2019, 01:47 PM
I wasn't being flipant.

Wood has practically zero of lasting at those temperatures and the 100% humidity without a lining.
It is possible to do one or the other but not both.
There's no known wood coating that can handle those sort of conditions for too long.
And well before it dies and within short order it will look extremely ordinary.
A type of coffee cup that would last a bit longer than others would be a small chunky espresso cup.
Ristretto (15mL) shot made in ~20s and knocked back in one go Italian style within a minute of being made.

Certainly, without a lining wood will most likely fail in the proposed use hence me looking for a coating or lining. If necessary I would use some form of full encapsulation to seal the wood (thinking epoxy or similar).

I have built fresh water tanks on boats with epoxy coated plywood and these are still around 20 years later. If I can keep the moisture out surely less than 100 degrees is not going to hurt the wood. The wooden spoons in my kitchen are still going strong after many years of in and out of boiling pots without the wood failing.

I like a Ristretto as much as the next caffeine junkie but I prefer to linger over a larger cup of the black stuff.

Redbeard
21st February 2019, 02:03 PM
Looking back on that last post I realise I contradict myself. The wooden spoons haven't failed and with a bit off a scrub and some oil they look quite respectable still. The same with my wooden chopping boards which go through the dishwasher on occasion.

Based on that, 70-100 degrees is probably not enough to make wood fail, it's probably lack of maintenance which causes it to fail. I don't want to have to maintain the wood of my cup so I need to isolate it from the world around it. Hence a coating.

There are industrial paints capable of resisting much higher temperatures, used in much more aggressive environments so I was wondering if there was something available for my more pedestrian application. Preferably clear(ish) and definitely cheap (because I am).

I think that last bit may cause a problem.

BobL
21st February 2019, 02:46 PM
Industrial pants work on low uniform expansion materials like steel.
The problem with Wood is it typically expands and shrink about 1/4 that of steel parallel to the grain and 3x that of steel perp to the grain.
This differential expansion will eventually crack any rigid coating like epoxy.
If you have to use a flexible plastic coating you might as well use a liner.

Euge
21st February 2019, 02:48 PM
I recall an IWCS friend and noted turner in Sth Aust (Nev S., now deceased, lived Gawler way) was an excellent turner of goblets and had an excellent collection of them.. Like me, he then used Rustin's 2 part finishes for his goblets and they looked fantastic. Just a point - the wood of the bowl portion was very thin 2-3 mm which may give it more flexibility with temp changes. Maybe some were used for red wine, I don't know.

I believe there are now more good coating options and many would pass the the temperature test, but do they pass a taste (tainting) test?

Euge

edit: there are two causes of expansion in wood, thermal and moisture induced changes . Which can be avoided? Not the former with these coffee cups.

Tony ray
21st February 2019, 03:50 PM
I made the wife a Blackwood Kuksa for her birthday last October and finished the outside with Tung oil. She seasoned the inside with strong black coffee and vodka for a few days and it has come up a treat after 5 months of use.

Euge
21st February 2019, 04:06 PM
Interesting treatment Tony ray ... but if it works with hot coffee its simple and worth using. :2tsup:

Just don't use any Taxus sp eg Yew for a cup, especially if uncoated

Redbeard
21st February 2019, 04:07 PM
But, but, but...

The wastage!

Tony ray
21st February 2019, 04:17 PM
Just don't use any Taxus sp eg Yew for a cup, especially if uncoated[/QUOTE]
Thought about making the mother in law a Yew Kuksa:D

Old Croc
21st February 2019, 08:58 PM
Maybe you could try making one out of American White Oak as an experiment. They use it for boiling hides in during the tanning process.
Rgds,
Crocy.

Redbeard
21st February 2019, 09:57 PM
Thanks Tony but while I'm regularly annoyed by my mother-in-law I don't think I'll give that a go...

I don't think...

And Croc, what are you saying about my coffee? That it would tan leather? I know I like strong coffee but it's not that strong.

But seriously...

I'm going to have to do some experimentation.

Thanks fellers.

Old Croc
21st February 2019, 10:08 PM
And Croc, what are you saying about my coffee? That it would tan leather? I know I like strong coffee but it's not that strong.

But seriously...

I'm going to have to do some experimentation.

Thanks fellers.
Cast your mind back to medieval England before pottery took off, they used to eat and drink off wooden plates and mugs. I'd give it a go.
Rgds,
Crocy.

Redbeard
21st February 2019, 10:13 PM
Cast your mind back to medieval England before pottery took off, they used to eat and drink off wooden plates and mugs. I'd give it a go.
Rgds,
Crocy.That's what I'm thinking. Need to find a nice stick of plain, non-resinous wood and give it a go. What can I lose?

Colin62
22nd February 2019, 12:10 AM
That's what I'm thinking. Need to find a nice stick of plain, non-resinous wood and give it a go. What can I lose?
I’d guess that the choice of timber and even the selection of the right piece of wood will be as important as the finish used.

tonzeyd
22nd February 2019, 12:16 PM
The only wood mugs I've ever seen are ones that have had commercially made metal/glass sleeves inserted into them.

This instantly tell me that many have tried and failed and it's not hard to fathom why.

The issue with coatings that will work in this kind of application are not flexible enough to withstand the expansion/contraction the mug will experience over its life and will end up either separating itself from the wood or crack.

orraloon
22nd February 2019, 01:37 PM
Wood was used for plates and cups in olden times as Old Croc mentioned. That said I think your best bet would be no coating at all like wooden spoons. It would take on a weathered look. Would have to be hand washed as the dishwasher makes our wooden spoons come out furry. Does not take long to turn a cup so worth a try.
Regards
John

PS Bit of useless info on historic wooden cups. When Francis Drake went round cape horn the ships carpenter made beer mugs from the wood of an old Spanish gallows. After they buried the skeletons of course. No mention of what finish was used.

Redbeard
22nd February 2019, 01:42 PM
Wood was used for plates and cups in olden times as Old Croc mentioned. That said I think your best bet would be no coating at all like wooden spoons. It would take on a weathered look. Would have to be hand washed as the dishwasher makes our wooden spoons come out furry. Does not take long to turn a cup so worth a try.
Regards
JohnIndeed, care to suggest a wood?

orraloon
22nd February 2019, 02:22 PM
This guy still makes bowls, cups and plates the old way in the UK. May be some help. Good watching and reading anyhow.
Q&A with Robin Wood woodturner | Merchant & Makers (http://www.merchantandmakers.com/pole-lathe-wood-turner-robin-wood/)
Actually he uses some veg oils.
Regards
John

Pagie
22nd February 2019, 04:07 PM
I just made a dozen coffee mugs from clay. A lot of the cups in the old England were clay.

Redbeard
22nd February 2019, 04:14 PM
I just made a dozen coffee mugs from clay. A lot of the cups in the old England were clay.I do understand the benefits of clay but I am not set up for turning clay, one new craft at a time, please...

[emoji2]

Lyle
22nd February 2019, 05:40 PM
Coopers use wood for alcohol. Made from staves and hoops I know but still hold liquid.
Maybe try a cup and seal outside with your choice and "season " the inside with a strong coffee and let sit for a day. See how it goes.
Maybe mango as it is lives in water.?????
Lyle.

Redbeard
22nd February 2019, 06:22 PM
Coopers use wood for alcohol. Made from staves and hoops I know but still hold liquid.
Maybe try a cup and seal outside with your choice and "season " the inside with a strong coffee and let sit for a day. See how it goes.
Maybe mango as it is lives in water.?????
Lyle.Do you mean mangrove? Otherwise, perfectly logical thinking. This will be one of my experiments.

Lyle
22nd February 2019, 06:37 PM
Yep. Just a "seniors moment" .
Mangrove.
Lyle

artful bodger
22nd February 2019, 08:32 PM
You could just use a normal cup like everyone else and wrap it up in this https://www.ebay.com/itm/Wood-Grain-Vinyl-Tape-choose-your-Pattern-and-Size-/222590701905

(https://www.ebay.com/itm/Wood-Grain-Vinyl-Tape-choose-your-Pattern-and-Size-/222590701905)

Redbeard
22nd February 2019, 08:34 PM
You could just use a normal cup like everyone else and wrap it up in this https://www.ebay.com/itm/Wood-Grain-Vinyl-Tape-choose-your-Pattern-and-Size-/222590701905

(https://www.ebay.com/itm/Wood-Grain-Vinyl-Tape-choose-your-Pattern-and-Size-/222590701905)Yeah...
Nah.

NeilS
23rd February 2019, 10:23 AM
This guy still makes bowls, cups and plates the old way in the UK.

Q&A with Robin Wood woodturner | Merchant & Makers (http://www.merchantandmakers.com/pole-lathe-wood-turner-robin-wood/)
Actually he uses some veg oils.
Regards
John

I have one of Robin's bowls, as does Richard Raffan, who told me he uses Robin's as his breakfast cereal bowl. Robin uses palm oil for the finish. An ethical source is one factor to keep in mind with that finish.

I periodically apply mineral oil (as in pharmaceutical paraffin, not kerosene) to all of my food contact bowls. They keep surprisingly well, although none of them get filled with near boiling water.

If you can make tea in it you should be able to drink coffee from it...


449775

Skew ChiDAMN!!
23rd February 2019, 01:27 PM
PS Bit of useless info on historic wooden cups. When Francis Drake went round cape horn the ships carpenter made beer mugs from the wood of an old Spanish gallows. After they buried the skeletons of course. No mention of what finish was used.

Wonder if the wood was Dead Finish?

:scareboo:

Old Croc
23rd February 2019, 08:10 PM
Wonder if the wood was Dead Finish?

:scareboo:
:doh::doh::doh::doh:
Rgds,
Crocy.

Redbeard
24th February 2019, 08:14 PM
So I figured after all this talk I'd better walk the walk. I've turned a branch of acacia (I think) to make an end grain cup, finished the outside with some of our lord and master's Shellawax and am now soaking the inside with a strong pot of coffee.

The coffee was originally to the brim so the wood has absorbed a bit of the black gold. You can see the wood is certainly taking on a lot of the colour.

I'm thinking I should have left the tenon on so I can put it back on the lathe to polish the inside smooth, the grain has come up a fair bit (unsurprisingly). I can probably arrange something like a glue chuck if needs.

We'll see how it goes. https://uploads.tapatalk-cdn.com/20190224/c8423b71d443a2ecf1eb2186b4018b17.jpg

Colin62
25th February 2019, 08:07 AM
That looks pretty good. Is Shellawax not food safe after it’s cured? Might be worth doing the inside with it too.

orraloon
25th February 2019, 08:52 AM
Looking Good. Are you going to try out a few finishes to see what works best?
On the practical side if it is used every day or fairly regular and not allowed to really get too dry then it should likely last. Wood boats and barrels are best kept wet for the same reason.
Regards
John

Redbeard
25th February 2019, 02:37 PM
Shellawax is food safe but it doesn't seem to handle the heat (apparently). Another experiment to come.

I'm going to try a few ideas, see what happens. The stick this cup came from is about two feet long so I can afford to have a few failures.

I'm not sure about keeping it wet. In boats the water has to be salty otherwise rot sets in As for barrels, traditionally they're either holding salty stuff or alcohol.

Cheers

dogcatcher
25th February 2019, 04:45 PM
I used a mixture of 1 oz beeswax to 1 cup mineral oil. Heat the oil and add the beeswax, stir until melted. Wipe the inside of the mug, the oil will soak in with the beeswax. Wipe the inside, let dry. For awhile you will get a little residue, but neither will leave a taste. If you want to get real fancy, get some food grade flax seed oil and sun treat it to remove the fats, and add bees wax to the treated flax seed oil. https://youtu.be/GUyXm2IL4OQ

Redbeard
25th February 2019, 05:04 PM
I used a mixture of 1 oz beeswax to 1 cup mineral oil. Heat the oil and add the beeswax, stir until melted. Wipe the inside of the mug, the oil will soak in with the beeswax. Wipe the inside, let dry. For awhile you will get a little residue, but neither will leave a taste. If you want to get real fancy, get some food grade flax seed oil and sun treat it to remove the fats, and add bees wax to the treated flax seed oil. https://youtu.be/GUyXm2IL4OQWas this for a hot coffee cup?

dogcatcher
25th February 2019, 05:23 PM
Was this for a hot coffee cup?

Yes, used coffee in both, but at first I did the seal with the oil and beeswax, let them dry then poured hot water in them. Some of the mix will come loose, but after that I just poured hot coffee in them. After it has been used for awhile the coffee will stain the inside, but it didn't soak through. Did the same mix for some soup bowls, good how soapy water kept them usable for quite awhile, before I resealed them.

Redbeard
25th February 2019, 05:36 PM
Yes, used coffee in both, but at first I did the seal with the oil and beeswax, let them dry then poured hot water in them. Some of the mix will come loose, but after that I just poured hot coffee in them. After it has been used for awhile the coffee will stain the inside, but it didn't soak through. Did the same mix for some soup bowls, good how soapy water kept them usable for quite awhile, before I resealed them.Ok, you've just added another treatment to my list to try.

What sort of woods are you using?

dogcatcher
25th February 2019, 05:51 PM
I used maple, which was a mistake since it was a light colored wood. The sun treated flax oil and beeswax is also my go to finish for tool handles.