110 pound Claro burl

[Paul Atkins]

I thought that might catch a few of you---
( A lurker for awhile - first post.)
I've been turning for 25 years - mostly architectural - (stair parts, rosettes, porch posts, curved mouldings, etc.) but this has got me a bit nervous.
I've got 4 finials to make for a victorian home, but the wood supplied is wet on the inside and dry on the outside. These are about 7" x 12" and of course they want them yesterday. This was a large Claro Walnut burl with graft that was cut 4 years ago. At the "inch a year" formula the 20" burl is obviously not dry. I've roughed out the pieces into 8" cylinders and made the first as a test for design and drying. They are way off balance from inside moisture on one side and dry 'bark side' on the other. My 1st question is about equalizing the moisture. I've microwaved them till they steam and then put them in plastic bags for a few days - rinse and repeat. I'm not sure it's working. How about drilling a 2" hole up from the bottom for quicker drying ? I've boiled a few bowl blanks with no cracks but haven't tried alcohol. (Except after 5:00)
The stuff is beautiful, but is going to shrink, twist and move all over the place till it's at a reasonable moisture. Now what?
I enjoy this forum with all the knowledge, quips, photos and helpfulness. Thanks

[charlie knighton]

i am interested in how this comes out, but you are way out of my league, please keep us posted and any photos you care to take, maybe one day i may do a shallow bowl in a burl, but different moisture levels is really something..... i had the impression that the grain in a burl swirls and it did not matter how green the burl was???? then again someone showed me a 10 lb burl and he said he was drying it and it had been cut 5 years ago..... i guess for a burl to get larger it has to be growing:confused: duh, double duh :rolleyes:

110 lbs :D

[Leo Van Der Loo]

Hi Paul
Quite a graft-burl you got there.
Trying to get it dry without splitting, would mean to stop the outside from drying faster than the inside right, well drilling out as much as you can of the wet inside wood is a good start I think, and then sealing the outside and filling the drilled out hole with silica gel and exchanging it when wet for dry till done would be one way you could get there, but it still does take time, the moisture just doesn't move easily after the initial first layer.
Still I don't think you can guarantee a splitfree outcome, good luck, and yes let us know the how and what of the final outcome of your work when done with it please :-))


Silica gel

[Gary Max]

I would not go the alcohol route with this----the color will bleed and dye itself.
Your uneven weight question may be the wood more so than water.
The best thought I would have is the 2 inch hole and boil them----if you want to yack about this PM me.

[Toney Robertson]

Off topic, but don't any of you sleep?!

Four posts in this thread and they were posted at 1, 2, 3 and 5 AM! Now that is dedication.

I would have to have a gun at my head to be up at that time. :D

Toney

[Tom Keen]

For me walnut is a bugger. It works wonderfully when dry but it partially dry it always seems to crack on me. I think you should consider asking your client to wait. I understand the need to make them happy... but installing your work only to have it crack later would be worse than explaining the situation and asking them for patience. Maybe you could work up some temporary pieces and replace them when your wood is dry.

Couple of suggestions... slather your pieces with anchorseal and let the variations in moisture even out.. or put each piece in a large paper sack and then place them in a room with a stable environment. Then wait. You cant push the natural process much more than you have.

Good luck!

[robert hainstock]

I had a volley ball size nad shaped maple bowl a few years ago, I let it set for four years. No cracking. You friend are in a time pickle and I cannot offer you any solution to your problem. My neighbor, (Steve Schlumpf and I are working a huge cheery burl. Have to let all you forum people know how that turns out. :eek::)
Bob

[Matt Hutchinson]

About alcohol, you shouldn't have to worry about it dying the color to a more even tone. I have never heard of this happening. Of course, I could be wrong, and I think there are others on this forum who could prove/disprove that issue.

Exactly how long can you stretch the time frame? I am concerned that you simply don't have the time to control their moisture loss properly. Depending on how they are getting attached, I like the hollowing idea. The more you can hollow out the better, and a DNA bath at that point might be effective. Also, the DNA could effect your ability to get a perfect finish, since it won't be fully evaporated for a while. Of course, I don't think you will be able to keep the finished product perfectly symmetrical either, although the fact that it's burl may be in your favor.

I wish I had an answer. :confused:

Hutch

[Steve Schlumpf]

Paul - Welcome to the Creek! Hope you can figure something out that actually works and will help with this situation! Once that's taken care of - I hope to be able to see some of your work!

As for a suggestion - is it possible to separate the final into 2 sections, hollow each section down to 3/4" or so, DNA, dry, turn to final shape and then glue back together? That's about the only thing I can think of to minimize the thickness of the wood so that it can dry.

If you did that, then DNA and wrapped in brown paper bag - as warm as it has to be in Chino - I would think your finials would be dry in 3 to 4 weeks.

I wish you luck with your project and look forward to seeing photos of the finished finials!

[Frank Parker]

Hi,
I've dealt with a lot of walnut burl, black, claro, english, and it's going to crack. The question is how much, the best success I've had is to boil it, I than let it cool down with the water, after that I let it drip dry until there is no visible water on the in my case bowl than I drop it in alcohol for about a week. I than wrap the outer half with news paper and put on wire rack until done. By thickness it goes about like this 1/2" thick-2 weeks, 1"-4 weeks, 2"-12 weeks. This brings it down to about 6% to 8%. This also depends on the relative humidity. I've cut blanks and sealed them than go out a week later to check them and they looked like Swiss cheese. If they were cut 4 years ago and haven't cracked yet there's hope. Your best bet is to hollow them out to a inch or two thickness and boil them. The alcohol only changes the color of the first 1/8" or so, easily turned out. It will warp so remember the leave enough material to true it up. One other thing I've found is if it has eyes, most of the time each one will get a tiny split in the center, so if you want a defect free finish be prepared to fill every one, I sand ca glue into the splits.


Frank

[Reed Gray]

For quickest results, I think the micro wave is your best bet, and continue the way you have been doing. Short bursts, 1 minute or so, then let it cool down. You probably should bore out the inside as well. Less mass will help it dry faster, and opening up the inside will let more air circulate. Air drying pieces that big, even where you are is next to impossible, unless you can wait for 20 years or so, and even then, I wouldn't truse it.
robo hippy

[Paul Atkins]

Thanks for all the quick replies and suggestions from all over the country! I'm getting out the big drill first and firing up the canning pot (now that all the tomatoes are in jars) and see what happens. The silica gel sounds good too. I guess the craft shop would have it for drying flowers.
I think the home owner will be willing to wait for a job well done rather than an exploding newel cap down the road.
I have another burl that I cut last winter that has yielded some nice bowl blanks and panels for boxes etc. that I can experiment on too.
This week it's table legs, rosettes and ballusters while the burl stew is brewing. Thanks again. I'll keep you informed.

[Harvey Schneider]

Sounds like lots of good advice. If you don't hollow the piece the wood has nowhere to go when it shrinks.
My experience with DNA is that it doesn't work all that well with large pieces. I have tried it on 12" diameter 1" wall thickness cherry and black walnut. 24 hours in DNA and after three weeks the wood was still at 12-14% water content. That is high enough to cause warping and cracking. By the way, DNA extracted a lot of pigment from the black walnut.
Has anybody tried pulling a vacuum on green wood to accelerate evaporation of the water?

[Paul Atkins]

Update-burl newel caps
Well Thanks for all the suggestions, so here is what I did. I roughed them out about 1/4" larger than I expected them to finally be. I boiled 2 of them for 4 hours and let them 'dry' for a day or so and then microwaved them each for about 20-30 minutes every other day in 3 minute sessions. The third one was just microwaved. All were stored in paper at night. After a couple of weeks I drilled a 1 1/2" hole most the way up the middle. Should have done it first though. More microwaving till the guy called so many times I figured I had to finish them. He said the first one I did (larger) was great and not cracking-it was really damp when he took it and saturated it in oil. I expect in a year it will look a hundred years old. The house is 125 years old so I guess they will fit right in. These three are fairly dry but not where I want. They warped and change a bit more than the 1/4" so they are a bit smaller, but still 12" high. The boiled ones cracked and warped alot less. I should have weighed them to see the water content. Anyway not the way I would have liked to do the whole project, but maybe I can learn to say 'NO, or Wait' a little easier. Now I have 16 acorn finials to turn.

[Jim Becker]

If you don't hollow the piece the wood has nowhere to go when it shrinks.

Bingo! You beat me to it. That's a definite issue with this kind of piece and also why DNA may not be all that useful, too.

[Leo Van Der Loo]

Hi Paul thanks for coming back and filling us in on the answers you got to the questions and what you did do to get there.
The newel caps look quite impressive now, you did a great job on them.
Just as a side note here, in Europe there's some wood drying done under very high vacuum and and microwaving at the same time to help the water boil off and the moisture is than freeze-dried out of the air, all done in some big high pressure container, not something you could do in the home shop I expect :rolleyes: :D