I have a primered chevelle and I am wondering does the primer paint leave moister in? There is some puddy underneither too. Does puddy and primer leave moister in or does it keep it out? I am having a problem with my drivers side rear quarter panel. I bought replacement panels and welded them on. My drivers side keeps "bubbling out" and when I grind the puddy off, theres a rust spot on the quarter. Passenger side is ok for 2 years. Drivers side quarter panel welds to the curve in the body where the chrome strips are attached for the vinal top. Keep in mine this is a 1968. It always bubbles out there at the weld. Is it a massive stress point on the car, or is it cheap metal?
Passenger side welds above that curve and has given me no problems.
Any comments would be greatly appreciated.

Cews1968,
From what your telling me is the whole car is in primer right? primers are porous and cars should be kept out of rain. I have seen cars primered and when they went to paint they striped primer and it had surface rust now they say the poly primers are alot better.Hope this helps? http://www.chevelles.com/forum/smile.gif

Most plastic body fillers are not waterproof and will let moisture through. Same for non-epoxy primers. If the weld is not water-tight, moisture will seep through it, the filler, and primer from the backside and bubble the paint. You can use resin filler on the weld to seal it and put plastic filler over that. Also, if all the rust is not removed from the weld or metal, it can continue to rust and bubble the paint. If possible, the weld should be coated on the backside. von

Did you use the product called "weld-thru coating" on the bare metal prior to welding? This stuff works great and serves to seal the welded pieces from the inside of the joint...

We've had real good luck with sealing stuff with PPG DP-40 epoxy primer. I know guys who have driven cars over a year primed in this stuff, and no problems when it came time to paint just scuff it up a bit and proceed. (Not that I condone driving a car while doing body work and hoping to have it turn out all that great) I know that some people have no choice.

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Steve

72 Chevelle SS402/4sp

Dude17,
What is weld thru coating stuff? and how can I get some?

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Thanks In Advance!
John Corbin
67' Chevelle Malibu Sleeper(Someday) http://www.chevelles.com/forum/smile.gif
San Antonio, Texas


[This message has been edited by John Corbin (edited 12-01-99).]

[This message has been edited by John Corbin (edited 12-01-99).]

You should lay a coat of primer down right away or the bondo will "suck" up moisture only to come back and haunt you later.

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Lowered '67 Elcamino
ZZ430 eng / 4L60 trans
"Canyon Carver"

No, the whole car is not in primer. More or less the rear quarters are just in primer, execpt for a few places otherwise. The reason I am asking this is because only the drivers side is giving me problems. I used the same puddy for the passenger side and I have NO problems, no bubbling or what so ever. After I finish sanding the drivers side, I lay a couple of coats of primer in a spray can and I lay a couple of coats of black gloss from a spray can. A couple of days later(keep in mind that the weather was great and no rain in sight), the crease that I just finished got lumpy and looked and felt like ****. I have NO choice to leave the old velle out in the rain, although I have a car cover it still lets water through. Has anyone had this problem????
Anymore ideas are welcome...

You might want to start over one more time. Part of the problem may be the material you are using(spray primers), or the weld has not been cleaned, thus not allowing the body filler to adhere. I would get down to the bare metal, clean the weld throughly, use a quality body filler and a good primer such as SSteveL recommended like DP40 (use the DP402 catalyst, not lacquer thinner). As SSteveL stated, DP40 will last a long time without allowing rust to penetrate. Just be sure to scuff lightly before applying more paint/primer.

Make sure when you get it down to bare metal you put on a rust corrision protecting primer befor you put on the regular primer. dupont makes a good product the number is 615s or 625s. PPG also makes the same thing but I don't know the exact number. This should be put over any bare metal that you expose ESPECIALLY on quarters!

Personally, I fed up to the neck with this quarter. So I am taking a winter off and leaving the darn thing rust again. This spring I think I will grind off the puddy AGAIN and start over. One thing I have noticed when I grind it back down, is that the quarter panel is just spot welded on and not a bead going the whole way across. KEEP in mind that my father "the so called professional" welded the panels on for me while I was at college. A couple of months went by and the puddy cracked, so I grinded it down and found the weld didn't stick. So I took my training from college and welded the best bead I could get from a 120v welder. Needless to say the weld didn't break this time. Like you said jnickol, I must have not got all the rust out of it. For the 4th time, this spring I will try using the method you said. I will also go with some good puddy instead of the cheap stuff that is mass produced. THANKS GUYS/GIRLS
If there is anyone else out there that wants to add, feel free