GeorgeRa
2013 Sprinter DIY 144WB, Portland OR
Re: 2010 3500 RV build (formerly painted seat pedestals)
"Use of a primer is an extra step and cost and will depend on substrates and the final
end use. Using primer can improve the corrosion resistance of certain metals as well
as improve the durability of the bond when exposed to high humidity conditions.
For most applications high strength bonds on metal can be achieved without the use
of a primer. Pre-testing for adhesion is suggested to determine if a primer is needed.
The 3M™ Scotch-Weld™ Structural Adhesive Primer EC-1945 B/A works well for
most metals."
Even on a fresh steel surface there is a thin a layer of oxide formed almost immediately so any adhesive bonds to that layer which has good adhesion to steel. Corrosion issue is not critical in your application.
Good luck,
George.
This is from 3M regarding moisture cured polyurethane adhesive. From page 4 http://solutions.3m.com/3MContentRe...assetId=1180609472314&blobAttribute=ImageFileI guess I should have read the data sheet so thanks for the heads up. I think it will be fine since it is on the inside of the van. -and there are 12 screws too. I just checked the bond and I can't peel the adhesive off the metal but I can peel it off the paint pretty easily.
I know a common problem with windshields comes from scratches that are created when the windshield is removed that are not later covered with some primer or the adhesive when the new windshield is installed. - leading to rust.
I'll paint over any remaining bare metal with some white spray paint. I'm glad to have the roof reinforced for the AC unit. The roof is pretty flimsy to begin with.
"Use of a primer is an extra step and cost and will depend on substrates and the final
end use. Using primer can improve the corrosion resistance of certain metals as well
as improve the durability of the bond when exposed to high humidity conditions.
For most applications high strength bonds on metal can be achieved without the use
of a primer. Pre-testing for adhesion is suggested to determine if a primer is needed.
The 3M™ Scotch-Weld™ Structural Adhesive Primer EC-1945 B/A works well for
most metals."
Even on a fresh steel surface there is a thin a layer of oxide formed almost immediately so any adhesive bonds to that layer which has good adhesion to steel. Corrosion issue is not critical in your application.
Good luck,
George.