Better Bond Problem or Something Else?

[Kevin Jenness]

Not to dissuade you from Unibond, but my understanding is it is not completely free of water. Some of the water typically used in uf glue is replaced by furfuryl alcohol.

Some years back, I was running two vacuum presses off a manifold. Turned one press off to load the other, and neglected to turn the first back on after the second had achieved vacuum. The first one had a 4 piece burl match glued with Unibond, and during the hour or so before I realized my mistake and reapplied vacuum to it the veneer joints opened up at the periphery. Although the pressure was reapplied soon enough that the veneer bonded to the substrate, the moisture in the adhesive caused the joints to open up during the period of low pressure and made the panel unusable for the job (my coworker cut it down and used some filler to make a marginally acceptable coffee table top).The point being that whatever liquid is in Unibond has the ability to expand wood cells.

I have used Unibond numerous times without issues, but some people have had problems with insufficiently mixed batches causing staining in light colored veneers like maple or English sycamore. That is the reason for the instructions calling for mixing, allowing it to rest for several minutes, then mixing again. There is a thread on the topic on the Woodweb forum. I don't know if this is still a potential issue with the newest formulation, but it's something to be aware of.

[John TenEyck]

Thanks for the heads-up Kevin. I used Unibond 800 when I first started vacuum veneering, then switched to Weldwood Plastic Resin Glue because it's cheaper and available locally. I've never had a problem with either with seams opening up. I just figured there would even lower risk if I used Unibond 800, but your post suggests that's not the case.

John

[Jim Matthews]

Anyone with direct comparisons of Unibond ONE to Unibond 800?

I just visited Jamie Robertson, and he's deep into the veneer vernacular.
His shop uses Unibond 800 exclusively.

There are lots of challenges using that stuff, but the results are exemplary.

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[Steve Rozmiarek]

I contacted the supplier I bought the Better Bond Cold Press Veneer Glue from and he told me that it is not suitable for the thick 1/16" shop sawn veneer I used. I saw no reference to this on his extensive website.

For my next panels, I will edge glue the veneers as several have recommended and I will go back to Unibond 800 as it has no water in it.

Thanks for your input. Much appreciated.

John

John, I use Better Bond, and have never had the problem, BUT I sure don't want to either. Did the company have a reason that BB is unsuitable for the thick veneer? From the direction of the thread, I'd assume moisture, but curious what they said.