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Alcohol Drying Green Wood

R

Ron Warman

Joined
Sep 24, 2004
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Dave Smith wrote a article for More Woodturning about alcohol drying of wood in the Nov. issue. I have just taken a bunch of sycamore out of the paper and finished a couple of bowls using this method. I am happy to say I saw no cracks and the wood has taken only 2 weeks to dry. I changed his system only by leaving the big blanks overnight because the 10 percent rule made a 1.8" thickness necessary. I am not that good yet with the McNaughton so the thickness was closer to 2". Anyway add me to the list of people who will use this system.

Ron
 
Thanks for the feedback Ron.

Thanks for the feedback Ron. I think you will find that thinner walls work even better because there is less stress on the wood. Soaking over night for thick pieces is advisable.

I finished some silktree bowls that were part of a standing tree 3 weeks ago. I will be posting some pictures and info on my alcohol soaking blog in my spare time. The bowls were turned to about 5/8" and are around 8" in diameter. They were dry in less than 2 weeks.

Dave Smith

Alcohol saves time and wood in Longview, WA.
 
Dave, I've used the alcohol method a couple of times and I love it. I've done some cherry bowls and turned them to 1/4 inch, and manually sanded them once dried. Looked nice but I hate the hand sanding.


I want to try the above method, turning them thick, air dry, and re-turn to a smaller, more decorative thickness.

The problems I have, with cross-grain bowls, is that the dovetailed hole I turned and used when I originally turned it is oval once it's dried. I use an SN2.

Once I've got a 1.5" thick blank that has air dried and oval-shaped on me, how to I remount it to the lathe? I do not have cole jaws, all I have (and frankly, can afford at the moment) are the standard jaws included with the SN2.
 
Don't know what SN2 is but here is what I do. I use a Vicmarc chuck with jaws big enough to close down on a tenon and put the inside of the wood on the chuck. I bring up the tailstock and center it on the bottom. Because the wood is oval and will need to be returned I use no padding. Tighten the live center on the bottom and turn a dovetail for the jaws. After the dovetail is cut I trim up the outside part way so later I don't have to worry about hitting my gouge on the jaws. Take the tailstock away and mount the wood in the chuck. I turn what I can of the outside to shape, then the inside to thickness, sand and finish the inside. I take the wood out of the chuck and mount a vacuum cylinder, with no vacuum, and use the mark left by the live center earlier to bring up the tailstock to make contact with the cylinder. I then complete the bottom leaving a stub where the live center is which is removed later. I now sand and finish the outside. Take the bowl out, cut the nub away, and sign it. I have used other methods in the past but this seems to work best for me. The cylinder worked so nice on a natural edge I use it all the time now.

Ron
 
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Redfish,
Have you considered building a Longworth chuck? I built mine from some scrap plus about $10 total for a small face plate and some other stuff. It would grip the edges of a rough bowl so you could "true up" the dovetail hole, and then return it to the regular chuck. The centering would be imperfect, but that should not matter in this case.
 
SN2= supernova2.

Thanks for the tips guys.

Texian, I had considered the longworth chuck and promptly forgot it, so thanks for the reminder!
 
Several other things that I've done. Hot-melt the bowl to a waste block on a face plate. Shims are helpful. And use a low speed and take light cuts. If the top is really warped, I'd attach it to the bottom first and clean up the top enough to mount it on a larger face plate. Then I'll reform the dovetail.

Another method, which admittedly isn't always successful is to make the orginal dovetail recess larger, more middle-range on the chuck, so you can still use the recess after it has warped. This has the obvious drawback of a less secure grip for the final turning.

My current preferred method is to use a smaller set of jaws to grip the oval dovetail, true up the top of the bowl, hot melt to a faceplate, form a new dovetail and final turn the outside, then turn the inside with it mounted in the new dovetail. The hot melt glue holds very well in this case and detaching the bowl usually requires multiple applications of a chisel to the joint.
 
Keep It Simple

Seems folks have gone to some lengths to find some complex solutions to a problem that can be solved very simply.

The tenon on a roughed bowl will, of course, go somewhat oval depending on the wood and drying method. Since the tenon is what is there to hold the bowl for retruing the dried rough, that part should be retrued first, so let's do it simply and quickly.

1. Using a jam chuck that will fit inside the bowl (often this is the scroll chuck itself), put fixing pressure on the piece with the tailstock with the bowl in "reversed" orientation. The center of the tenon has not actually moved in the drying, therefore if you position the live center point in the center-point of the tenon and press in against the chuck mounted on the headstock, your rough will be recentered at the same point used to turn it in the first place. If using your scroll chuck is the jam chuck, spread the jaws as wide inside the bowl as you can to give added stability.

2. Now use your bowl gouge to carefully true the face of the tenon using a shear-scraping cut from center to rim (don't worry about the contact point of the tailstock). Ideally you want a tenon thickness that is a bit LESS than the depth of your chuck's jaws from their rim to their bottom as this will allow the chuck's jaws to contact the bottom of the roughed bowl while griping the tenon and provide additional strength and stability.

3. Take your parting tool and recut the circumference of the tenon so that it's round. If you're using dovetail jaws on your chuck, you can cut the bevel at the same time.

4. Retrue the area around the tenon where the chuck jaws' rims will contact the bottom of the bowl, and use your parting tool or a small detail gouge to clean up that inside corner where the tenon meets the bowl.

5. You can now release the tailstock, flip the roughed bowl and insert it into your chuck's jaws, and proceed to re-turn your bowl.

It takes about 1/4 the time to do it this way than it took to write this!

Added tip: When you're first roughing the wet bowl, cut your tenon as big as your chuck jaws will handle. That way, when you recut the dried tenon, it won't be too small to properly mount the bowl for re-turning.
 
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Mark, I think his problem is that he has a recessed dovetail instead of a tenon.

JimQ
 
JimQ said:
Mark, I think his problem is that he has a recessed dovetail instead of a tenon.

JimQ
Click to expand...

Oh.

In that case, he can use the same technique to mount the piece on the jam chuck and then recut the recess round and slightly undercut with the parting tool. It's best to use a short point and cup center. I gave up on expansion-mode mountings years ago; too many broken and/or launched pieces.

M
 
Thanks, Mark for again being clear, concise, and down to earth. I even understand your comments and suggestions 🙂 🙂 Your email was blocked so couldn't send private message, Gretch
 
Forgot The Safety Tag

Should have mentioned that the tailstock should be engaged when re-truing the roughed bowl, regardless of whether we use the tenon or dovetail recess method. In fact, it's especially important to use with expansion mode fixings. The turner can prevent "damage" to the inside of the bowl from the TS point by using a small pressure block between the tailstock and the workpiece. The pressure block is best when used with a piece of double-faced carpet or turner's tape so it won't slip or move but will still be easy to remove from the bottom of the bowl's interior.

M
 
Rough on a pin chuck, leave the pillar when hollowing.

Since the hole is the same length along the grain as it was before drying, it cradles your Forstner in the path of least resistance as it makes the hole circular (and centered) again.

Mount on the pin chuck and turn the outside, same as you did when green.
 
MichaelMouse said:
Rough on a pin chuck, leave the pillar when hollowing.

Since the hole is the same length along the grain as it was before drying, it cradles your Forstner in the path of least resistance as it makes the hole circular (and centered) again.

Mount on the pin chuck and turn the outside, same as you did when green.
Click to expand...

That sounds like the ticket there! I'll use the woodworm screw since I don't have a pin chuck (actually, just remembered, my shopsmith has an arbor that's perfect for use as a pin chuck, it's got a flattened side.... hmmm....)
 
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