I have a question about Sika. I used it at Vistar and I loved it. Lately I have been doing jobs that were on Sika. On several of these it seems like the original thane was stripped down to the correct level and the Sika ran directly on the original skim base. But when I start to restrip these jobs the Sika will almost pull completely off the original urethane. Any ideas what is happening here? All I could think of is that the tech may have primed on top of the base urethane.   HH

Fresh cut urethane is absolutely the best thing for new urethane to bond to. The only way it will peel loose is if there is another layer in between. Black primer is very brittle. When you sandwich a brittle layer between two flexible layers, the brittle layer can fail.

Another possibility could be the use of glass cleaner or release agent to "clean" the bead. This is always a bad idea. We recommend cleaning the dirt and dust off the pinchweld with a brush, compressed air or water before cutting the bead down. This will eliminate any chance of contamination.  Sika Steve

Hey, Steve, what about using the clear glass activator for a quick rub-down of the newly cut urethane. Chrysler recommends this on some products. Have experimented with it some myself, and it seems that it works better than just a simple cleaning as the activator "cleans" some of the remaining "extra" dirt off. It is impossible to get all the old dirt off, of course, but after you cut it, it should be quite clean, and a quick daub of activator seems to be standard on some of the new Chrysler.  Washington

Using Sika Aktivator to clean the bead will not hurt anything, provided you wait 10-15 minutes for it to flash off. However, it doesn't offer any improvement over clean water. Best bet is to clean everything up before you make the final cut of the old urethane. Then you're gunning onto a perfect surface.

Just a thought, we've got this attachment kit for our vacuum at home. It has a bunch of real narrow hoses and brushes for cleaning electronics and hard to reach areas. It hooks to a regular shop-vac. It would probably work real well for vacuuming up the dirt that gets along the edges of the bead. I think we got it out of one of those catalogs of useful stuff that you really don't need that comes in the mail. It was probably about $10.00.  Sika Steve

Also, lubricants (release agent, soapy water, etc.) used to "aid" the cut out process can also be the culprit. Nothing but pure water should ever be used to cool the blade of a cut-out tool.  Glen Moses

One contaminant that is always over looked is the consumer contaminate. I have found that auto owners who use interior cleaning products to excess, such as, armour all , or any other dash and interior products contaminate and sabotage the installation long before an installation is required . There is no work around that I know of for this . Even in the auto body world, armour all on the tires of a vehicle can sabotage a paint job . Most of our job is equal to paint work. If what you do would not allow paint to adhere properly neither will urethane. P.s. why don't the adhesive manufacturers come up with a flexible body primer/adhesion promoter.  RC