glue blocks on green blanks

[Kevin Jenness]

For those of you who add glue blocks to green bowl blanks, then dry and return them, do you use green wood for the blocks so as to minimize dimensional conflict? If you use dry blocks, do you have any problems with them loosening up or causing cracks in the bowls while drying?

[John Beaver]

You can't glue blocks to green wood. The wood has to be dry to accept a glue block.

[JohnC Lucas]

I have glued blocks to green wood using CA glue but I don't leave the block on after turning. I much prefer to turn the wood between centers without a block and then turn a tenon. Every once in a while however I don't have a large enough piece and need to glue a block on. I have not found any other glue that will work and I doubt CA would stay on for very long because the Woodmovement would break the joint, Also be aware that CA is a brittle joint. A good catch and good by bowl.

[Dennis Ford]

I have used both CA and polyurethane to glue blocks onto green wood. I do NOT expect the block to stay on while the green wood dries and will NOT trust the joint if it does manage to stay on. I have knocked off the original glue block before truing up the dried rough-out and adding a new glue block.

[Michael Mills]

I used glue block with green wood for a while but seldom now. Not because they do not work; I just use other holding methods. The blocks I used are like Lyle's (about 2-2.5" thick) and left on the face plate. You should be able to get about 50 turnings from one block.
I never left the block on green wood when I put it back to dry so I can't help there.
He may have a few more on using them but here is one video.
https://www.youtube.com/watch?v=y8b35iq4LTA

[robert baccus]

I have turned many hundreds of bowls and vases to 125#"s with green wood and dry blocks--very strong blocks such as beech and dogwood. My average piece is an urn, green and 80 #,s and the GB stays on for hollowing and 6-9 months drying. Then returning and finishing on the lathe--I am lazy. The gluejoints are dependable--I check and occasionally find one cracked and simply reglue. GB's are very strong especially compared to any method of grabbing green woods on long pieces especially. Screws simply do not hold well in end grain, especially green end grain. Unless going to many and long screws which ruins a lot of pretty wood. I often use a single screw chuck into the GB which eliminated a faceplate--I can't afford that many. All this on a Nova 2" chuck--tough rascals. I just finished and delivered 6 urns and finished rough turning, waxing, and hollowing 10 urns for curing. GB's must be done correctly--face flattened on GB and blank--then thick CA and wait for 1/2 hour to set. Use fresh CA or test yours on 2 strips of wood for a good hold. Hot weather ruins mine if not refrigerated in the hot months. The CA joint definitely seems to prevent cracks on the bottoms of pieces--the GB seems to hold everything together. Nice extra. Been doing this for 25 years so I trust it. CA is a bit brittle but I defy anyone to knock one off if 3-4" in diameter with any hammer--been there. The brittle thing is academic more than practical me thinks. Just my experience.

[Dave Bunge]

My average piece is an urn, green and 80 #,s and the GB stays on for hollowing and 6-9 months drying. Then returning and finishing on the lathe--I am lazy. The gluejoints are dependable--I check and occasionally find one cracked and simply reglue. GB's are very strong especially compared to any method of grabbing green woods...

The CA joint definitely seems to prevent cracks on the bottoms of pieces--the GB seems to hold everything together. Nice extra.

This is a very interesting approach and result! Have you used it on pieces that include the pith?

[Mark Greenbaum]

I have turned many hundreds of bowls and vases to 125#"s with green wood and dry blocks--very strong blocks such as beech and dogwood. My average piece is an urn, green and 80 #,s and the GB stays on for hollowing and 6-9 months drying. Then returning and finishing on the lathe--I am lazy. The gluejoints are dependable--I check and occasionally find one cracked and simply reglue. GB's are very strong especially compared to any method of grabbing green woods on long pieces especially. Screws simply do not hold well in end grain, especially green end grain. Unless going to many and long screws which ruins a lot of pretty wood. I often use a single screw chuck into the GB which eliminated a faceplate--I can't afford that many. All this on a Nova 2" chuck--tough rascals. I just finished and delivered 6 urns and finished rough turning, waxing, and hollowing 10 urns for curing. GB's must be done correctly--face flattened on GB and blank--then thick CA and wait for 1/2 hour to set. Use fresh CA or test yours on 2 strips of wood for a good hold. Hot weather ruins mine if not refrigerated in the hot months. The CA joint definitely seems to prevent cracks on the bottoms of pieces--the GB seems to hold everything together. Nice extra. Been doing this for 25 years so I trust it. CA is a bit brittle but I defy anyone to knock one off if 3-4" in diameter with any hammer--been there. The brittle thing is academic more than practical me thinks. Just my experience.

Robert - can you please post some pictures of your methods on an urn? I am intrigued lately with the making of urns, and will appreciate learning good reliable techniques. Thanks.

[Kevin Jenness]

Thanks for the responses. If I have plenty of thickness I tenon the blank but in some cases I don't want to lose that material so am looking for a reliable way to mount a block to green wood.

I did a couple of tests this morning on small pieces of green hard maple, with hot melt, and Fastcap 2P10 CA glue, with and without accelerator, put together with hand pressure. They all knocked apart easily with no wood failure, so I was rather discouraged. However I had mounted a 3 1/2" diameter dry cherry block to a 12" hard maple blank with the 2P10 already, so I decided to try hollowing it out with a bowl steady to limit stress on the glue joint and all went well. When finished I tried unsuccessfully to break that joint by driving a chisel in from the perimeter, so I put that blank in a paper sack and will see in a couple of months how the glue joint looks then.

I am not sure what to attribute the success to- the small pieces were faced on the jointer and the bowl and block on the lathe (somewhat rougher), the bowl/block were clamped with the tailstock for a bit longer and the cherry block was dry. Perhaps a combination of the above.

Michael, I looked at that video, but it ends with mounting the glue block to a roughed out, presumably dry blank. Are you able to reuse the glue block so many times because you part off the glueline with the waste on the workpiece? Or do you split it off somehow?

[robert baccus]

Dave & Mark---Probably 95%+ of my pieces include the pith, use plenty of glue and I have no problems. Sorry--I am unable to post pics due to med. problems but will try to get my bride to volunteer.

[Dennis Ford]

Mr Baccus is a friend and neighbor, he makes a lot of very pretty urns. Usually end grain and centered on the pith. He uses fresh CA to attach the glue block and often soaks the pith and surrounding area with CA. I think this stabilizes the wood quite a bit and keeps the glue block on. This method works great for him (it does require slow drying of the rough-out before turning it again).

[John Grace]

I have glued hundreds of 'dried' glue blocks to green wood and only had two failures because I glued them together when it was too cold. I prefer poplar for my glue blocks as it has the right balance...isn't prone to cracking but with just enough give.

[Michael Mills]

Thanks for the responses. If I have plenty of thickness I tenon the blank but in some cases I don't want to lose that material so am looking for a reliable way to mount a block to green wood.

Michael, I looked at that video, but it ends with mounting the glue block to a roughed out, presumably dry blank. Are you able to reuse the glue block so many times because you part off the glueline with the waste on the workpiece? Or do you split it off somehow?

Sorry for my tardiness in respondsing. CRS
I looked but did not find a video of Lyle removing the glue block. It was in his full video.
Use a wide bench chisel (1.5-2"), angle towards the glue block and give a good rap. Sometimes two or three.
I never even considered leaving the glue block on while drying. As other said, it may not stay with warping and you may need a lot of face plates. If left on but having the face plate removed then you have to try and remount in the same screw holes.
I just used a friction drive with the dried blank to re-true and then re-glued and re-turned.
I guess a max loss with re-truing the glue block to be 1/32...just enough to remove the old glue.

[John Beaver]

I know many of you have had success putting glue blocks on green wood, especially with CA glue.

I reached out to Franklin / Titebond and specifically asked about using CA on green wood. Here is their response....

We know customers have glued up wet/green wood with good success. Our recommendations are to only bond wood that has a moisture content of 6-8% no more than 10%. I hope this is helpful.

Mark A. Roberts
Senior Technical Specialist
Franklin International
Construction Products

[robert baccus]

Extensive experience in severe applications vs opinions??