# Is the glue the wood or the guy holding the tool????



## flightmedic (May 14, 2013)

I have been attempting a board to bowl project (one I'v done several times before) using a 10×10" piece of 3/4 Bubinga. The first two times I attempted this, I used CA glue to mount a waste block (mdf). The moment the gouge touched the Bubinga, the board separated from the waster block. Several folks reminded me that CA did not have the shear strength for this application and to use a Tightbond product.

So this week, I glued a new waste block on (cedar scrap) using tightbond II. I cut three rings away. As I started the fourth, The Bubinga separated from the cedar waste block.

I had sanded off all the CA residue, prior to gluing with Tightbond II. The Tightbond is only about a month old. I'v frequently used Bubinga in glue ups with segment work so I'm kind of at a loss here. Any thoughts?

Kevin


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## GaryC (Dec 31, 2008)

Just curious, Kevin…how long did you let the glue cure?


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## kdc68 (Mar 2, 2012)

Could it be the natural oils and resins in the Bubinga be the issue here ? If so, prior to glue up wiping the wood with acetone might work here ?


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## GaryC (Dec 31, 2008)

Kevin…....Oh Kevin…...HEY KEVIN…..
How long did you let the glue cure?


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## rrww (Aug 12, 2012)

Like kdc68 said- try wiping down with acetone then titebond over night it should work.


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## Dal300 (Aug 4, 2011)

look at the wood joint, see what broke. The glue is usually stronger than the wood.


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## flightmedic (May 14, 2013)

The glue cured for 18 hours before turning (after the previous week failure I wasn't taking any chances). As far as the joint, both the waste block and the bubinga are intact. The only thing that seemed to have broke was the glue itself. There was glue residue on about 2/3rds of the waste block and about 1/3 of the bubinga (within the spot where glue should be) I had applied the glue to both pieces and used a 10 pound weight to clamp it (all my clamps were elsewhere).

K


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## GaryC (Dec 31, 2008)

You are suppose to wait 24 hours for titebond to cure before putting stress on it. If it had cured, the wood would have given before the glue. It wouldn't hurt to hit it with a little naptha or spirits prior to gluing, then let it set for 24 hours..


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## Dal300 (Aug 4, 2011)

Hmmmm, He said! And repeated, Hmmmm!
A glue joint is stronger than the wood, even with the hardest woods.

I haven't worked with Bubinga, but I believe, (I'm not certain), that it is not that oily. It could be, I only work with domestic woods like the cedar, therefore, the weakest link has to be the Bubinga.

Wipe it down with acetone after sanding it rough. You don't want a slick surface for glue.

Try that and get back to us.


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## flightmedic (May 14, 2013)

@ james, no edits. The tightbond was gluing a cedar scrap wasteblock. 
Originally when I used the CA it was with MDF.

I'll try the acetone and let you know 

K


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## GaryC (Dec 31, 2008)

Kevin, don't forget to wait 24 hrs. I believe even the bottle says that. Watch your clamping pressure too. You don't want to squeeze all the glue out. Doesn't need to be all that tight


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## Wildwood (Jul 22, 2012)

Bubinga an oily wood so wiping down mating surfaces with acetone before applying glue helps. If getting glue failures after wiping down with acetone not sure changing glues will help. Even five-minute epoxy takes 24 hours to fully cure.

I might try scuffing up mating surfaces with sand paper, wipe down with acetone, glue and wait until glue fully cures before attempting to turn.


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## PurpLev (May 30, 2008)

as mentioned, before putting stress on glue joint allow 24 hours to dry.

that said - your comment about both waste and bubinga still in tact sort of suggests that the glue did not penetrate deep enough and cured to allow for these 2 elements to bond together. it may be that the CA or the natural oils in the bubinga are preventing this from happening - use acetone or mineral spirits to wipe off the bubinga real good (with emphasis on the 'real good' part) and reglue. allow 24 hours to dry (I would give it even more if you've experienced some weaknesses already) then try again.

Another thing to try since you notice that the force applied here is large enough to cause glueup issues is take a 2nd 'waste block' and put it at the other end of the bubinga (unglued) - then pin the tailstock with a live center in it against it and apply some pressure. this will create some friction pressure against the bubinga from the tailstock side which will help reduce the amount of the side forces applied by your turning tools which currently only the headstock/glueup are facing and have to stand up to.


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## Bluepine38 (Dec 14, 2009)

I agree with PurLev on the tailstock block, I used that trick when I was making bowls from a blank using 
a cross slide rest for parting the wood and it helped considerably.


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## RussellAP (Feb 21, 2012)

What you need is one of those 6" HF faceplates and some thick double sided tape. You can see it coming apart before it does and perhaps catch it, but mostly if you get a good clean seal it will stay put. That's an awful large piece to turn unchucked though. I'd consider something more conventional.


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## johnstoneb (Jun 14, 2012)

I don't think a 10 lb weight is heavy enough to get a strong glue joint. that is 10 lbs spread over a large area(ie. 3"x3" is 9 square in divided into 10 comes out to 1lb per square in force, not near enough for a good strong glue joint. A larger piece will give even less clamping force.) Try trying gluing both pieces, separate with a piece of paper and clamp for 24 hours. You should get good mechanical strength in the joint and the paper will allow you to separate it without damaging the wood.
I just read your other post. I am not sure western red cedar has the strength needed to handle the centrifugal forces. I would use a doug fir, yellow pine or hardwood for the backing block


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## shawnmasterson (Jan 24, 2013)

I have seen where people are using hot melt glue. It seem to work But I have not tried it yet.


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## papadan (Mar 6, 2009)

I use pine for my waste blocks and turners tape to hold my work. As long as the pieces are dead flat I have never had a failure.


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## CharlieM1958 (Nov 7, 2006)

I'm with Bruce. I think the the whole problem is likely due to insufficient clamping pressure.


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## TheDane (May 15, 2008)

Nix the hot melt glue idea … especially the stuff you get at craft stores.


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## flightmedic (May 14, 2013)

Thanks for all the tips. 
I sanded the surface clean of all residue (80 grit) and then wiped it down with acetone and glued a new waste block on (scrap maple). I then placed it in my bowl press (homemade vertical press I use for segment work). Its going to sit there all week till I return home on Friday.

I will try the tailstock jam block as well. I'll let you all know how it goes. Thanks

Kevin


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## Jim Jakosh (Nov 24, 2009)

Cedar has an oil in it the resists finishes and maybe glue too. Plus it is soft. I would use a good hardwood waste block like maple or oak. I think it will solve you problem. I use tight bond II to put my spigots on with.

...........Jim


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