Advice and questions on making and fixing instruments
By bighammer
Inside is mostly hogged out on the lathe, then I use a Foredom flex-shaft with a reciprocating power carver and chisels to do the rest. I also have an angle grinder with a King Arthur chainsaw toothed wheel, but I'm hesitant to try to use it inside a confined space.
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By the kid
I don't see any image of the drum.

To answer Kormans question with my guess would be to paint melted wax on the top of the bowl and the bottom of the drum because trees transport moisture and nutrients vertically through it's vascular system. I presume even when the tree is dead moisture moves easier up and down due to the structure of the cells.

Wax could be put on the horizontal part of the bowl too.

Also whether or not a shell warps or cracks in drying would depend on the initial moisture content plus how you decide to dry the finished shell.
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By the kid
Info on what to use can be found by searching for 'how to seal endgrain'. Also of interest is ' how to dry logs/ planks properly. I see some woodworkers use wood glue to seal the endgrain. Handy-er than wax innit.

Reading up on wood reminds us how much soft wood sucks.
By bighammer
korman wrote:
Tue Jan 02, 2018 3:19 pm
How do you prevent the freshly turned shell from cracking while drying?
I am no expert, this is only my 2nd drum, but I have turned a lot of green wood. Wood splits and cracks because of shrinkage as it dries. The most shrinkage is circumferentially or around the growth rings, and is proportional to the length of the growth rings. A vertical grain (or quarter-sewn) board has very minimal shrinkage when compared to a plain or flat-sewn board. There is some longitudinal shrinkage, but it's only a fraction of the lateral shrinkage.

With that in mind, think of all those growth rings around each other like a bunch of rubber bands stretched to their limit. at the center of the tree, there is really no shrinkage. There is not enough length and as you get to the center, there is a solid core that doesn't change. Cut any green log and give it time, it will crack somewhat radially toward the center. Back to the rubber bands, when one goes, a bunch of others let loose.

If you cut a log and remove the center, and keep the thickness similar around its circumference, you minimize the cracking. It's free to change diameter with no interference or tention buildup. That's what I do when I turn a drum. It gets cuts and mounted on the lathe, outside shape completed and center hollowed out, all in one day.

Also, slowing the drying process can reduce splitting. If I can't complete a piece in a day, I put it in a plastic bag until I can get back to it. A lot of turners will turn blanks an put them in paper grocery bags filled with wood shavings to slow the drying process. (sealed in plastic, they'd get moldy)
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By batadunbata
Wow! What beautiful drums, conrgats. I wonder what happened to the walnut drum, and if we can see pics of the final result?
By wyshout
Well done bighammer. I found this site because of wanting to lathe turn some drum shell. Would love to see any process pictures of lathe setup.