Glue block

[transatlantic]

Lets say you're wanting to create a natural edge bowl and you have a blank like below where you don't have quite enough material for a tenon. If it was dry, you could use a glue block. But in the case where it's green, what are your options?

I was looking at the PU glues, and they seem to work up to a moisture content of 25%. Could you perhaps leave it a week or two until just the outer most layer (3-4 mm deep?) is reading 25% or below and then use PU for a glue block?

 

[Lazurus]

I have always used CA and activator without issues as it is moisture activated. Have a look for Lyle Jamieson on You tube he does a great little vide on on the way he uses glue blocks, its the method I now use and seems spot on.

 

[alex robinson]

I use lumberjack 5 minute polyurethane glue. Despite the supposed 25% moisture maximum, I have never had problems, even with freshly cut green timber

 

[sneggysteve]

I've only used hot melt glue for glue blocks but not on green wood - I take it that hot melt is no good therefore?

 

[Tris]

This is an adaptation of a method I used years ago on a pole lathe. Make a scrap disc of ply screwed to a block of wood that fits in your chuck.

Drive short pins through the ply so they will stick into the waste on your half log and tap ply to log.

Mount the block in the chuck, bring up the tailstock and gently turn the inside. Leave a core, that can be held in your smallest chuck jaws, where the tailstock sits.

Reverse the log, gripping the core now, and pry the ply disc off. Bring up the tailstock and turn the outside.

Finish by chiselling off the core and stub.

Apologies if I'm teaching granny to suck eggs but hopefully it'll help

 

[Stormin]

Lets say you're wanting to create a natural edge bowl and you have a blank like below where you don't have quite enough material for a tenon. If it was dry, you could use a glue block. But in the case where it's green, what are your options?

I was looking at the PU glues, and they seem to work up to a moisture content of 25%. Could you perhaps leave it a week or two until just the outer most layer (3-4 mm deep?) is reading 25% or below and then use PU for a glue block?

View attachment 131609

There are adhesives which claim to set under water......saw some in the local builders merchant......might do the job?

 

[Stigmorgan]

Use a mortise instead of a tenon, you lose a tiny amount of depth inside the bowl as opposed to 5-10mm from the outside

 

[Paul Hannaby]

Why not just make a bigger tenon that rather than being removed, is re-turned to form the base/foot of the bowl. That way you don't lose any depth.

 

[transatlantic]

Why not just make a bigger tenon that rather than being removed, is re-turned to form the base/foot of the bowl. That way you don't lose any depth.

The question was regarding the case where you simply don't have enough material for a tenon. Hence the glue block

 

[Stigmorgan]

Why not just make a bigger tenon that rather than being removed, is re-turned to form the base/foot of the bowl. That way you don't lose any depth.

Looking at the photo of the blank I would guess it's only a few inches thick so you wouldn't really get good proportions doing what you suggest and the bowl part would be almost nonexistent

 

[Paul Hannaby]

The question was regarding the case where you simply don't have enough material for a tenon. Hence the glue block

But if you follow my suggestion, you don't need a glue block...

Another option - if you have the right sized spigot and a good set of jaws, the spigot would only need to be 3-4mm deep so even with a "standard" spigot, you wouldn't waste much wood.

Yes there are times when glue blocks are useful but personally, I wouldn't say this scenario was one of those but each to their own!

Looking at the photo of the blank I would guess it's only a few inches thick so you wouldn't really get good proportions doing what you suggest and the bowl part would be almost nonexistent

I'm not sure I follow your logic - my suggestion would allow the full depth of the blank to be used for the bowl with none wasted on a sacrificial spigot. By bigger tenon, I mean larger diameter.

 

[Dalboy]

Like Paul I have turned with a shallow tenon but larger and then used that as a small raiser to the piece lifting it off of the surface it is placed this also gives the appearance of being taller than it actually is.
As long as the tenon is the correct size for the jaws very little or even no sign of the jaws holding the piece will show or require very little clean up.