I guess techinically it doesn't have to be all that long, but ideally how long would you let your car sit before you would prime out over it??

Thanks,
Steve

After it's sanded and smooth. It takes less than 10 min for the filler to cure. Then sooner you prime, the better. If you leave the filler unprotected, it can asorb moisture and cause the panel to rust.

I don't think a single generic answer is good here. The more modern fillers are better at not shrinking than the older stuff. Here are some questions that may help us to answer your question:
What brand/type filler are you using?
Did you mix any of it 'hot' (too much hardener)?
What air temperature has the car been in?
Any of these factors can cause shrinkage. I've even seen shrinkage happen over a long period of time, say three months after a car has been painted and buffed. Big bummer. It was a slight shrinkage, but on a show finish, it showed. had to re-do it over again. But, the reason it shrunk, in my opinion was that I rushed the body work and immediately put paint over it the next day.
When I showed it to a factory rep (Martin Seneor) he asked the time frame of work done. His opinion was that even though all of the product directions were followed, it was not enough time for the filler, primer and paint to fully cure. It's better to leave some time in between these evolutions.
I'd say a week to be safe. Or, do as you will and when you get everything straight, up to the point where it needs to be blocked out, let it sit for 2 or 3 weeks
until everything cures together and then block it out. Parking the car out in the sun is a good idea if you can do that.
Just my .02 cents worth.

The work I did so far has been with All Metal, most of the work has been to smooth the weld seams where the quarter skins were welded in. The car is kept in a heated garage, I keep it 60 degrees when I'm not working, but it hasen't seen anything past 70 degrees since I did the work.

What problems will come out of using too much hardener?

I have no problem with letting the car sit a little longer if it reduces the chances of future grief.

Thanks,
Steve

One problem when using too much harder is that it will cause the bondo to become brittle and crack easily. The modern fillers dont have the problems like the old fillers did. The use of a quality product like Rage or all metal is a big difference. You can tell when a cheap filler is used because when it goes out in the sun after its been painted the sun can turn the filler into a yellowish color that will stick out on light colors.

I let my filler sit for around 30 to 45 minutes before I sand it. Once its blocked out I go straight for the primer. I believe the shrinkage that people see is in the primer not the bondo. Let the primer sit for two or more weeks the longer the better. Then block out the primer and reprime and let it sit for weeks. If you block it out the next day, you block it smooth only to have it shrink down later, and when it shrinks it changes shape.

If you leave the bondo uncovered it can absorb water out of the air. I wouldnt leave it unprotected for more then a hour or two...Eric

Jimmy, I have to say that the primers and paint are where 99% of the shinking accured.
The plastic filler has so much solids that it shrinks very little. Primer on the other hand has much less solids and is easily applied to heavy (not knocking any work you did, just in general) and solvent gets trapped, this is what causes the "most" shrinkage.

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1965 Buick Gran Sport Convertible
1965 Buick Skylark H/T
"Fan of most anything that moves human beings"

Well, one thing for sure, since I'm new to body work, I have no chance of getting all the work done and primed in no hour or two.

Steve

Steve are you trying to do body work on the entire car at once or in pieces? What I mean is its best to work on one piece then the next piece. For example one night work on one door and get that door in primer. Then the next night work on the other door. Dont try to do it all at once, that is just wasting time and harder to do.

Then by the time you get done priming the body, your doors are ready to block sand. Sand the doors and reprime, keep everything on rotating cycle.

This way you can get it in primer after a hour or two after its been blocked smooth.

Well, this is where I'm at, the body is completely apart, I'm only working on the bare body at the moment. It is stripped down to the steel, I put new quarter skins in and used the all metal to smooth out the seams, as well as a couple other low spots. I know that the preffered method is filler out over primer these days, but I started this before I knew that. I figured on getting the body in primer, and like you said, let it sit and do say the hood, and so on, but if you do like I did, putting the filler on bare steel, I can't see how anyone could get it all done that fast. I'm not saying no one can, but I would sure be impressed to see it. Or do you mean that you would do one quarter, prime just that quarter, and go onto the next spot?

Steve

Steve, since you are using that All metal filler I wouldnt worry much about it absorbing moisture out of the air. If it was a regular filler it might bug me alittle to have it set out. If your filler sat over night I dont believe any danger or future grief will happen. Specially in the dead of winter when the humdity is low, but in the summer when its 90% or more, like it is there in Iowa, I can see the cause for corcern.

If it bothers you that the filler is sitting unprotected what I would and have done, just prime one quarter then move to the next. I would try my best to get the other quarter in primer the following night. And when I say in primer I meen a self etching primer. I dont know what system you are using, I use PPG paint at home and sherwin williams at work. I use the sherwin williams self etching primer, I dont like the stuff from PPG but use all other products from PPG. But the PPG etching primer I would use is DX1791, and sherwin is 980?? I think that is the number and dupont is variprime.

I try to spray the entire body at once but there have been times where I just cant do it. When this happens I just prime one quarter with the etching primer. At a later date when I get around to finishing the work on the other quarter, before I prime that quarter I sand the quarter that is in primer with 320 on a da. If you dont topcoat the etching primer within 24 hours you must scuff it up and recoat.

So yes you can just prime one quarter at a time, but you must sand the prevoius sprayed primer and recoat it. Now once the entire body is in etching primer, spray the whole thing with your primer surfacer or 2K primer. What ever you do dont blend the 2K primer like you did with the etching primer. Once you spray one quarter or the roof spray the entire body. The 2K primer I use is PPG K36 and K38, I like both products. As for the sherwin I believe the number is PH48, sherwin williams paint is a great system and like it alot but I just prefer PPG as that is what I learned and grew up to use.

I hope Ive answered your questions and not got you confused in my ramblings, but if not just write back...Eric

I follow ya, there is alot I don't know and I'm very curious and have alot of questions, lucky for you http://www.chevelles.com/forum/wink.gif

What is the reason you should not blend the 2K primer? I am using DuPont products, thats what my paint supply place carries and they are very helpful when I come in with my 20 questions. I am using the variprime and then the Euro fill (I think thats what it's called) primer, and then BC/CC. That brings me to another quesion, is it standard to use the primer sealer yet before the topcoat? I remember reading someone saying that they felt it was a "waste of orange peel" or something to that effect.

Thanks,
Steve

Steve you have an eamil address I will glady answer any questions?...Eric

Eric, you are right on the money, but I want to point out something. The PPG number you gave PX1791 is for a vinyl wash primer and more similar to S-W E2G973. It is not the same as the E2G980, PPG DPX171 would be much closer and more like Variprime (615S) also. The E2G980 has much more body than the Vinyl wash (it even used to have "filler" on the label). The vinyl wash also has a very short window (S-W is only four hours) and it can't be sanded. It works very well under certain conditions, but a limited use.

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1965 Buick Gran Sport Convertible
1965 Buick Skylark H/T
"Fan of most anything that moves human beings"

myway@paonline.com

Thanks,
Steve