Espresso Cup Art?

Things You've Made
#1

I like my coffee basically straight. No [Insert Preferrred Coffee Chain Here] cocktails for me.
So I thought…espresso cup!
Fun project. Useful result.

Learned a bit of Blender to create a cup mesh, chop it in 3 and export the stl’s for Estlcam to model.
The carve went well…and I know how to really improve it already so great learning experience. Here’s a glued up piece and 3 carves for a second cup.

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Some sanding.
Finished it with a beeswax and mineral oil blend to waterproof it in a food safe way.
Turned out nice:

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Testing time…
Add some hot water and see what happens.
Well…clearly I don’t know from wood.
Looks kind of neat though.

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Thinking it through…
Non-waterproof glue + hot-water = leaky cup.
Soft Ash middle with insufficient waterproof seal = expansion and warp.
Ah well.

Any thoughts? Is this even possible?

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#2

Epoxy or polyurethane if they’re food safe?

EDIT: A quick search found food-safe varieties of both available.

1 Like
#3

Reading further it looks like shellac would be a better finish for it too.
Food grade epoxy + shellac combo maybe

#4

Shellac could be a problem if Irish coffee’s on the menu.

1 Like
#5

Ha! Too funny.
It would be self defence for the non-drinker though. The cup starts leaking in the presence of alcohol.
Man, the things to think of.

2 Likes
#6

I prefer a mochalattechino, myself. But very good looking cup!

I like to see stuff like this that would traditionally be made on a lathe.

Is the problem with the glue, or with the expansion of the grain? It is hard to fight. Wood only expands one way, so it would be better if the grain was aligned. I am not sure how radical different species are in their expansion either. I wonder if it would work better if the grain was vertical on the cup? I suppose it would still break if they were moving at different rates.

Did it break the glue or the wood?

#7

The glue definitely dissolved.

The ash definitely expanded too as it absorbed the water.
I’ve repeated the process a couple of times. It shrank back down overnight.
Then I dropped it in a large mug with hot water and the ash swelled again.

There’s almost no movement in the walnut.
I suspect unless the ash is completely sealed it’s not useable like this.

2 Likes
#8

I see. It is more open to the water than the walnut.

Is titebond 3 food safe? I didn’t think it would dissolve in water.

People often debate over finishes for cutting boards. Mineral oil is often used, because it can be eaten. It is also a laxative though :slight_smile:. I have also seen people make their own boiled linseed oil without the chemical additives.

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#9

Titebond 3 says it is indirect food safe. Prob ok. Not what I used for sure.
Looking at the way the cup arced it seems like the part that is still glued together has not absorbed much water. Could mean the water is mostly absorbed by the cut edge. Weird though…that’s the face of the board.
It may mean a good glue would fix most of the issue.

#10

Well, it looked good before the failure… keep trying and you’ll find the solution.

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#11

+1 nothing like mineral oil seasoned cutting boards and coffee cups to keep you regular!

2 Likes
#12

Food safe epoxies can be used both for the glue to hold the pieces together and for the finish itself. A lot of the pool cues with their stunning glossy finishes are done with epoxies… Especially since epoxy tends to kill you much slower than CA glues will.

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#13

Afraid the only way your going to be able to use that wood is if its dried and then encased in some kind of expoy resin. Maybe some really dense, oily exotic wood would work in a more natural state but domestic hardwoods aren’t going to work out for you.

Ash is open grained and walnut is closed. You can see it in the end grain. Ash has big pores like oak. Sucks up water like a straw.

2 Likes
#14

So I’ve been looking at the epoxy options.
Any recommendations on a food safe epoxy that would take heat?
Most of them are limited to 50C (122F) or so.
120 is about the lowest you want to go to drink coffee. I like mine hotter. And brewing is up somewhere between 185-205 or so, so it will be hitting the cup much hotter than 120.

#15

What if you found a metal cup and wrapped it with the wood?

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I have no idea if you can find one in the right size.

#16

I was thinking the same thing but with a glass liner.

#17

voila:

1 Like
#18

I know it was common practice among those building composite aircraft using epoxy to prime them (usually a darker color) and then place them in the sun for some time. This post-cure ‘cure’ was said to increase heat tolerance but I don’t think I’ve ever seen actual numbers for what that increase may be. I’ve also seen solar ovens made of foam, glass cloth, and epoxy that must have heated to at least 180F. I know heat degrades epoxy’s strength but the forces on what you’re trying to do must be fairly low?

Might be worth the time to Email some of the larger epoxy suppliers such as West Sytems and request advice. Most manufacturers are happy to supply information and at worst it’ll only take a few minutes to find manufacturers and send an Email.

#19

Double wall, even. Nice.

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#20

80ml is a good size too, my espresso machines pulls 32 grams of espresso (double shot) with 16 grams of grounds, at least when I do a perfect pull… Not that I can ever do anything but sometimes get close. 16 grams of coffee, 30 seconds from the click when the valves close, 32 grams of espresso. You have to get the flow started at about 6 seconds in to come out right.

1 Like