Floorpan/Panel Welding Help Needed

[Froggy77]

I am finally to the point of having ripped out all the old crappy metal and have been carefully grinding, cleaning all areas where I will be welding in new panels (drivers floorpan, kickpanel and innerfender, cowl). I have some questions that may be obvious to others, but hey, this is a first for me and I wanna do it right. SO.......

1. I have cleaned and grinded away all the old rust and paint from any areas where I will be welding new metal. I have been putting POR 15 into the floor support channel (great news...it was in perfect shape!!!), the cowl support channel (rusty) and the inner rocker panel. I used the POR Metal Ready to prep these areas and was planning on using weld-through primer on the places where the new metal panels will be welded. I also used the metal ready on these areas to prep them. Is this ok? Should I still spray the weld-through primer over the Metal Prepped areas? Should I grind off the Metal Prep and just primer or just weld to the bare metal? (I have not put POR 15 on any areas where I will be welding)

2. Do I need to grind the opposite side of any areas to bare metal where I am welding (fender lip, etc)?

Thanks in advance. Can't wait to get this side done so I can have more fun on the passenger side!!!

 

[taxx]

1) weld through coating is fine and that is what it is intended for. I used it on many things. The metal ready just etches it so I am sure that is fine.

2) Depends. Are you laying the new metal over and spot welding it in just to the top side? Or will you be welding near the edge of that lip? If you do burn through (and trust me you will atleast once) it might get nasty, but you can worry about cleaning up that one spot then. As much clean metal you can get the better, that way you have a surface ready for paint or whatever and you can also see what you have to work with, but I wouldn't waste much time scrubbing the bottoms of panels. Just make sure where you weld is clean and you'll be set.

 

[Froggy77]

I'd say 99 percent will be plug/spot welds except where there are some small gaps at the corners.

Thanks.

 

[dpmerrill]

Metal-Ready is an acid etch with a zinc wash added as a rust inhibitor (the yellow/green coating). Technically, for a good weld you don't want anything but clean steel. I would grind the zinc off in about a 1 inch radius around the weld.

If you decide to weld through it you'll probably be ok, but remember zinc fumes are toxic so don't let your hood fill up with smoke. I would also do a few test welds on Metal-Ready coated steel. If the welds are porous, they'll be brittle so you'll have to clean if off first anyway.

Since etched steel rusts faster than anything, make sure you paint EVERYTHING with weld-through at the weld areas or primer/sealer everywhere else. I don't think the zinc wash is meant for long term protection.