Don't RTFI - Titebond cold press veneer glue?

[apreston]

I'm doing a big veneer job and decided to use Titebond Cold Press glue. So far I've used it for laminating two sheets of plywood in my new vacuum bag and it seems to work fine. Next step is to glue the veneer onto some MDF. Then I made the fatal error of reading the instructions...

"press at 100-250psi"

WHAT?

I thought that a vacuum press was the best way of pressing large areas, and atmospheric pressure is... 15psi.

So did they make a mistake of the instructions - or is this glue really not suitable for vacuum pressing? I know I could easily generate 100+psi over small areas using screw clamps, but who's going to apply 100+psi across a large surface when veneering?

Does anybody have any experience and real-world advice when using this glue?

Andrew

 

[custard]

You raise a terrific point.

The instructions are actually buried on Titebond's web site (the bottles are mute on the subject) and are the optimal pressures for maximum bond strength. I've laid hundreds, probably thousands, of square feet of veneer in a vac bag with Cold Press and other PVA's, and I can assure you it works fine. It might not be the very strongest possible bond, but it's plenty strong enough for veneer which isn't terribly demanding of bond strength.

However, all PVA glues have similar guidelines for maximum bond strength, which makes me smile when I hear people fretting about glue starvation and "over cramping". The reality is that in a smaller workshop without industrial hydraulic presses it's virtually impossible to over cramp.

 

[giantbeat]

I make my own plywood using a vac press, I use cold press for the decorative stuff that I want to limit bleed through, never had an issue, never read the instructions, I just use it like I do the cross linked pva's and epoxy. No problems to date.

 

[apreston]

Thanks for the replies. That's just the sort of reassurance I was after. I was trying to work out how to balance a couple of HGVs on one wheel on top of my 8ft x 2ft board, and even that would fall short of 100psi :shock:

Also, I have corrected my original post - the bottle says "100-250psi" not "150-200" as I originally stated - not that it makes any difference to my meaning.