Bob Behnke from Titebond's tech service department gave a very interesting talk at the woodworking club this morning.

 

One thing he talked about was  clamping pressure.  He had a customer call the tech service department and talk about  a jatoba joint  that had failed.  They ran some tests on poplar (a not very dense wood), maple (a medium dense wood), and jatoba (a very dense wood).  There were samples with only a 5 lb weight (0.6 psi), a medium pressure, and a high pressure (1000 psi).  He was shocked at the results contrary to stuff that had been recommended for a long time.  The light clamping force was the strongest, the middle clamping force was less and  the denser the wood, the more it was reduced, and the high clamping force almost 100% of the strength of the Jatoba joint was reduced.

I guess I'm going to have to back off the clamps a bit.   His recommendation was just enough force to get the joints to come together.

 

He also recommended if you are gluing end grain to do one of two things:
* use Quick & Thick glue

* put on the glue, rub it into the end grain and then put immediately together.

I've always thought the Quick Grip clamps were enough as long as the joints were good to begin with.  Can't say I've ever had a joint fail.  Just lucky I guess.

8 minutes ago, HandyDan said:

I've always thought the Quick Grip clamps were enough as long as the joints were good to begin with.  Can't say I've ever had a joint fail.  Just lucky I guess.

Yes, I always went by the old guidelines and clamped until the joints sweated out a bit of glue beads.  Never had a failure, either.  But he said there needed to be a slight film of glue between the joint.

We are trained to clamp till no more comes out..

Another thing he talked about was "open time" meaning the time between applying the glue to a surface and closing the joint.  Titebond 3 has one of the longer open times.  If a glue reaches "putty phase" where a significant part of the water has soaked into the wood or evaporated away, the joint strength will be compromised.  This was one of the downsides of gluing both sides is the time it takes to apply and spread.  Though he didn't discourage two-sided gluing.

 

Also, they said that for the smaller packages of glue, the packaging cost was more than their manufacturing cost of the glue.   I guess I'm going to have to start buying 5 gal. cans of glue?

 

Titebond provided some merch for attendees.  One thing was their glue spreader that looked a lot like Rockler's except for the color.  I got mine into the glue box today and  noticed this:

 

 

 

 

Edited March 9, 20251 yr by kmealy

I always bought my glue by the gallon. True, I've had to throw some out but not much. The glue can last longer than most people think if it's kept refrigerated and buying it by the gallon is so much cheaper than the quarts that even if you throw a little out it's still a savings. But I'd probably have to draw the line at buying 5 gallons buckets of it.

Edited March 9, 20251 yr by Fred W. Hargis Jr

2 minutes ago, Fred W. Hargis Jr said:

I always bought my glue by the gallon. True, I've had to throw some out but not much. The glue can last longer than most people think if it's kept refrigerated and buying it by the gallon is so much cheaper than the quarts that even if you throw a little out it's still a savings. But I'd probably have to draw the line at buying 5 gallons buckets of it.

Yes, I was just kidding.  He said properly stored, TB original can last up to 10 years.  Cooler temps help.

I have my glues for many years even when the water separates, I just mix it back up.Glue isn’t that expensive in the  1 gallon. When in doubt, throw it out..

Edited March 9, 20251 yr by BillyJack

The strength of a glue joint has always impressed me.  Today's glues and adhesives do work well.

If mine gallon jug gets more than 2 years old, I replace it with new. 

 

Then take the old and use it for sealing end grain of logs/turning blanks. If the glue is really thick, I thin it with a little water.

Working with Jatoba is interesting at best. Years ago I built a set of outdoor furniture with it. Tough stuff to work with. One of the reasons it doesn’t glue well is the very high density and also the high oil content. Very much like working with ebony. I was always taught to wipe the gluing surfaces with acetone right before gluing to increase the glue penetration. So I’m not sure the clamping pressure is the most important factor. With those woods I always use epoxy instead of a water based glue. 
Paul

You know manufactures will tell you products have a short shelf life. I bought my daughter many cases of mobile one synthetic for a VolkwagonnJetta. I have several cases and is at least 15 years old. I put several quarts in my a Nissan. Still running..

 

They tell you the same thing with brake fluid..

 

Some change their oil at 3k, some 5k, and 10k.. I’ve  been changing mine at 10k since the 90’s. I have 341k on my 1995 Nissan truck..

Edited March 10, 20251 yr by BillyJack

Clamping glued joints test.  I need to dig in once I have some more time.

glue test.pdf

Thanks! That's a lot of information!!!

22 hours ago, BillyJack said:

They tell you the same thing with brake fluid..

 

 

SUPPPOSEDLY brake fluid that is in use should be changed at least every 5 years. It absorbs water in use. IDK if SEALED fluid absorbs water .

 

22 hours ago, BillyJack said:

Some change their oil at 3k, some 5k, and 10k.. I’ve  been changing mine at 10k since the 90’s. I have 341k on my 1995 Nissan truck..

On an older vehicle/engine you may be able to get away with that, but with newer engines, the tolerances and the design of various systems/components, pretty much requires that the oil be changed more frequently. Not b/c of the lubricity but b/c of the additives that inhibit deposit build up.

 

Also the type of mileage that you put on the vehicle dictates the frequency of maintenance. 

They are saying you can’t store the brake fluid as it will draw moisture..

 

Mileage will alway be determined by use of the vehicle,. On a gravel/dirt road, more often..

 

My wife’s car has an oil indicator, I follow it , but it’s generally after 6000..

Edited March 11, 20251 yr by BillyJack