Im working on replacing the cowl in my 72 comet. What type of products do you guys use in that area? I have an epoxy primer that I will put down as a base, but was thinking that maybe undercoating the entire inside might be a good idea. Has anyone done this? Also when I put the top cowl back on how do you keep any primer from peeling from the heat thats applied when welding the top back on? Im somewhat worried that if it peels away from the edge from welding that it will rust fairly fast and I will have the same problem after a few years.
I would use a product like Eastwood Rust Encapsulator or Rust Bullet before applying a top coat. Not sure undercoating would be a good idea.
Your work fast!! Don't know how many weeks I spent on mine. I'm no expert, but I used OSPHO rust treatment, POR15 and two coats of Eastwood's paintable seam sealer. But NOT between pieces to be welded. Left those areas clean. After welding, I sealed top and bottom of seams with seam sealer. I was having trouble welding unless the metal was really clean. Don't intend to leave the car out in the weather so I expect that will hold it together for a good long time. Would not put undercoating anywhere near where you need to weld. Think it will melt and flow and cause you big problems.
Keep thinking of more things after I post. In the thread I did about my cowl repair I showed how I reinforced the cowl cover on the bottom side to repair damage from spot weld drilling and to give me something solid to weld the apron-to-cowl brace to. But when I welded the brace on I did most of the welding around the periphery of the brace so the reinforcements weren't really necessary. Welding on the periphery let me put down a whole lot more joining welds than just replaceing the spot welds. I wouldn't bother with those reinforceing patches again.
If you think thats fast, I have only had the car for 11 days now. Its just been so much fun to work on, I lose track of time. I start after work then look up at the clock and its already midnight. Sounds like we used about the same process. I used muratic acid to clean, then 3 coats of ospho, then one more coat of ospho and cleaned with laquer thinner. I was thinking about using por-15 but have heard mixed reviews.
Yep, I've seen the comments on POR15 too. Extra steps to clean, pealing, etc. I wouldn't use it under color coat. I'm guessing many of the problems were from inadequate cleaning before application. I also cleaned with laquer thinnner. Anyway, I had aleady bought it before I saw a lot of the negative stuff. Think it'll be OK under the seam sealer.
Ok just got it under epoxy primer. I have been thinking, so I came up with some ideas. One idea is to to put plastic down inside the cowl and hang the edge through the A/C vent before you weld the cowl back on. This way when you paint your car after the cowl is welded on you wont get over spray through the vents which will make the inside look bad for anyone who is going to be looking through your vents. It may seem overboard but you would be surprised how many people look through the vents on these cars especialy if you ever sell it. After painting the car you can simply pull the plastic out through the a/c vent. Second Im going to pre weld the 2 body stiffeners to the cowl, which are the peices that connect the cowl and inner aprons together. Then I will primer the inside of the cowl before installing it. This idea I think will work better than welding the peices on after the cowl is installed because the welding will burn off the back side primer.
Why not just paint it, with car paint? I doubt your car will ever see the kinda weather it's seen in it's lifetime again. It's no longer just an everyday car.
I used weld-through primer along the edges that were going to be welded, then I masked it off and painted everything else with Eastwood Rust Encapsulator and then topcoated it with black semi-gloss acrylic laquer. I also thought of putting something up into the cowl through the vents that I could pull out later, don't know if I will end up messing with it though.
Welding paint will give you a lousey weld and will inject the paint into the weld causing it to corrode/fail.Leave ALL areas where welding will take place naked...NO paint/primer/rust encapsulator/inhibitor etc where you weld.I have had good and bad results with weld thru primers.Take heed....leave em naked and seal em after your done welding.
