VHB Tape: Need a primer?

May 11, 2023
5
Cal 33-2 RKYC
About to replace my cabin windows with new 1/4" acrylic. Frameless. Recesses have no gelcoat but the fiberglass has is smooth and all the low spots have been filled and sanded smooth.

1.) Anyone have experience with VHB on non-gelcoat?
2.) Do I need to use the 3M Primer 94 on either the fiberglass or the acrylic?

Thankw
 
Nov 6, 2006
10,096
Hunter 34 Mandeville Louisiana
I had gel coat on my cabin sides but not on the acrylic. I was advised by the 3 M tech folks to use the 94 primer. Easy on and very quick drying. Two years in , still solid and watertight
 
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Jun 21, 2004
2,916
Beneteau 343 Slidell, LA
When I re-bed my deck fixed skylight with 3M VHB tape & Dow 795 adhesive/sealer, I also used 3M 94 primer. With all of the ordeal involved in replacing the skylight, I wanted to ensure that I was obtaining maximum adhesion. Remains leak free...so far.
 
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