Glue block

[Faust M. Ruggiero]

I have a piece of Claro that will clean up about 7 1/2" x 3 3/4". I drew up a hollow form that requires I preserve as much of the thickness as possible. I've never used a glue block on green wood and want to tap the experience of someone who uses this method.
After second turning, I will add a pedestal base, something I've not done before. Here are my questions. Should I make the glue block from wood with a similar moisture content and leave it on during the drying process or will that promote cracking? What glue do you find best for this?
How do you prepare the bottom of the hollow form to accept a pedestal? I need to know how much wood I must leave to allow for this process.
Thanks,
faust

[John Keeton]

Faust, how are you going to dry the rough out? DNA will dissolve epoxy, and probably CA glue - not sure of the effect on Titebond, but it would not bond well to the green wood. You could always reglue the block after drying as the rough out will not spin true anyway.

If you are just using a bag, or some other method to slow down the drying, I would suggest a dry block and 5 minute epoxy as I think it will have enough flex to withstand the slight movement in the green wood over a 2" area where the block is glued on.

I leave a short (3/16") tenon on the bottom of the form to insert in a hole in the top of the pedestal that is drilled prior to turning the detailing on the pedestal. You can form that tenon from the glue block, too. I have done that on occasions where I did not have enough thickness on the form.

[Dennis Ford]

CA glue works fine on wet wood, polyurathane glues (like gorrilla glue) also work well on wet wood. Your chances of the glue line remaining intact throughout the drying process are only fair. You may have to replace the glue block after drying, if so, just turn a new tenon between centers (will probably need a jam chuck for one end). I have always used dry wood for glue blocks but wet wood with similiar grain orientation might improve the chances of the block staying put during drying.
A small tenon on the hollow form works well for attachment to a pedestal.

[Faust M. Ruggiero]

Thanks John,
That's exactly what I needed to know. I hadn't thought about removing the glue block after rough turning then truing the bottom and reinstalling it before second turning. That sounds like a good solution. Since the second glue block will be dry wood on a dry form, I can even use a bit if the glue block to form the tenon. I appreciate you sharing your experience. By the way, I hadn't thought about using DNA though I use it often. As long as I remove the tenon, that will short cut the drying. Does Claro react well with DNA?
faust

[Wally Dickerman]

I use glue blocks a lot. I use med CA glue which works well on either wet or dry wood. (Be sure you use a lot of glue) I'm assuming that your blank won't be turned end grain which would change things a bit. Walnut is a fairly stable wood so chances are pretty good that the glue joint will remain intact.

I cut a tenon on the glue block if I'm using a chuck. I often use a screwchuck or even a faceplate instead of a 4-jaw chuck however. I never use DNA. Instead, I apply a heavy coat of Johnson's paste or Anchorseal and set the roughed out piece on a shelf to dry. Right now I have at least 60 roughed out pieces drying in my shop. At least half of them have a glue block attached.

[Marty Eargle]

I'll throw my preference out hot melt glue out on the table. I may be a bit biased because it is the only method I have ever used...but it has also never failed me. It is cheap, fast, and simple.

The hot glue will enough sheer strength, as well as plenty of flex for when the wood is drying. Not sure of how it reacts with DNA, as I never use it. If you do plan on giving it a go...make sure you have a "real" hot glue gun...a small hobby gun will not get glue hot enough to allow for a good bond.