Welding floor panels sealed with Por 15?

[Bambikiller240]

Lance: I agree that POR should be applied after welding. I cannot see any benefit to applying it before welding. Sturdy welds are foremost in my mind as well. Does the weld through primer remain after welding or does it burn off in the process leaving just the zinc?

[LanceM]

It is my understanding that in the high temp areas of the weld the zinc remains behind and is bonded to the metal, much like galvanizing which is a zinc coating I believe, which inhibits rust by coating the base metal. The unheated areas are protected by the paint itself. We've probably all have seen it but never recognized it, but heat up a section of metal red hot and then set it outside, the part that was heated rusts first and the most. I don't know why but it does, you can really see the affect at the pick and pull where there are cars that have burned, the closer you are to the hottest point of the fire the rustier the metal is. When you are welding temps probably hit 1200 or more, pretty hot! That is the point of using the weld through primer, it leaves a coating behind a the weld point to inhibit rust, rust that seems to start fastest and be worse at hot points.

[beandip]

Lance I stand corrected here . When you said rattle can paint ,I was thinking you ment zinkcromate or something simular. This would be contrary to the use of rust preventive and the sealing properties of the POR. In this case most likely the cleaning of the pannels welded will rimove the offending paint. The Metal ready has acid in its make-up . When I used POR on my floors I sanblasted prior to welding and after , I preped the metal on both surfaces and applied the POR paint over any and all bare metal . This was over kill , but like you I don't want any problem and I don't want to do it again. Sorry for my misunderstanding . Gary

[LanceM]

No problem Gary,

Weld through primer was new to me before I took the ICAR welding course and reading the word primer and spray can in the same paragraph brings the thought of "don't do it" first to mind!

[yoogener]

Before you read: I am such a newbie. =(

My apologies for interrupting the thread subject, but reading about all this still gives me so many questions. My '71 has a huge rust hole on each side and I'm getting ready to replace with the new Zedd panels that i just got. Only(or many) problem is that i don't know jack about floor panel / body care. My head is so mixed up, maybe because i'm only 19 and not ready to deserve a 240z but im in love with it, regardless. If anyone can write out or link me to step-by-step instructions and care for welding in floor panels. I tried to understand the whole wash/rinse or whatever but the terms like "POR" and "spot weld" and "self tapping screws" and other terms throw me off. Please help meeeeeeeeeeeeeeeeeeeeee.