Glue Failing?? chopping board, too much clamp force?

[jack620]

I did see sand recommended somewhere, but surely the correct answer is proper clamping technique? I've been woodworking for forty years and never had to resort to salt or sand while gluing up.

[Camelot]

"According to Jeff Loflin, glue specialist at Franklin International (maker of Titebond wood glues), salt (and sugar, too, by the way) can react with wood glue and alter its composition, resulting in a weakened joint."

Should I use salt in my glue to prevent slipping? | Wood

I have used this method for years on PVA type glues and I was told the salt just dissolves, also I have not had a joint fail when adding salt, there just needs to be enough salt to cause resistance.

I would say it is most important to have your clamps at 90 degrees to what you are clamping, if you start to see creeping get another glamp and purposely offset it from 90 degrees so that when tightening it pushes the creep back into alignment.

[The Spin Doctor]

What about a few grains of course sand, instead of salt? That would be less likely to react with the glue.

Your planer might find this a bit of an issue.

[derekcohen]

Check that it is not the Merbau. This has much natural oil, and often will bleed tannin. Either first wipe it down with meths, or use epoxy.

Regards from Perth

Derek

[Mountain Ash]

Hi JMcB. A little while ago I had some annoying glue failures when using spotted gum. Doing my research here, most recommended wiping down with acetone just prior to applying glue. I did this recently when gluing up an unknown eucalypt and all worked out fine.

[jpdv]

I was beaten to the punch - Acetone is my preferred pre-treatment for oily/problem hardwoods. Quick wipe with a rag, it'll evaporate within 30 secs and takes the oil out of the wood...

[Chesand]

I was beaten to the punch - Acetone is my preferred pre-treatment for oily/problem hardwoods. Quick wipe with a rag, it'll evaporate within 30 secs and takes the oil out of the wood...

Same here. Have glued up Blackwood, Jarrah, Tasmanian Myrtle and Redgum with no failures.

[rod1949]

Is the failed joint pulling out timber or is it failing clean with no timber breakout? You haven't really described what is happening.

[John Samuel]

If there is no timber tearout and the glue join itself is failing resin in the timber could be the culprit.

Some advocate wiping down the joint with acetone just before glue-up. I prefer to use a PU glue, like Titebond Polyurethane Liquid Glue. Sometimes the colours give away the presence of resins. In NG Rosewood, the red colours also indicate resinous timber.

[rustynail]

One thing that hasn't been mentioned here is the jointer. Some timbers form a very slick surface off a planer. Merbau is one of them. The blunter the blades the more burnished the timber. Add to this the waxy nature of the wood and you have a difficult gluing surface. Acetone will help with the wax but not the burnish. For those types of timber I prefer to glue up off the saw and a wipe down with acetone.

[battlebosun]

Hi Mate,
Did you end up getting positive results at all? If so, what did you change/find that was your issue?