Troubleshooting Contact Adhesive Bond Failure

Experts say the adhesive itself is rarely the problem. Here are other factors to look into. March 22, 2013

We have been using the Westech Adhesive HCC High Strength Contact Adhesive Low VOC HAP's free Non-Methylene Chloride. The shop is not happy with the adhesion characteristics and when we have tech support they say the panels have been contaminated. We have had some panels come off in the field. Is anyone having similar issues? Do you have any words of wisdom to share to eliminate the questionable bonding of this adhesive?

Forum Responses
(Adhesive Forum)
From contributor P:
The low VOC products will work just fine for you but it's important to understand how they differ from traditional contact cements. They tend to develop their final bond strength slower and I've found that they have a tendency to dive into some substrates leaving little or no glue on the surface. One way to know whether or not you have a glue problem is to look at the entire job that was glued up.

If everything is failing then it could be the glue. If only a few pieces are failing chances are something else is going on. There are a lot of variables to look at in the gluing process - temperature, humidity, application method, amount being applied, substrate, person applying, etc. Generally the adhesive is the first thing people look at for problems and the last thing that actually causes them.

From contributor R:
We have found that the Haps Free Non methylene adhesives (in general) use a faster solvent than the regular solvent contact adhesives. This solvent dries very quickly and it takes a while for the shops to re-configure their methods to allow for the quicker dry time.

From Gene Wengert, forum technical advisor:
I agree with Contributor P Seldom (twice in more than 30 years) is the adhesive the problem (unless frozen or old). Is the surface you are gluing freshly prepared, free of dust, and not burnished by machining? One quick test is to put a water droplet on the surface before gluing. If the surface is active for gluing, the droplet will disperse in a minute or two.