Shaunboy,thanx for clarifying that for me and sorry for the confusion.Let me try to confuse you some more.The sprayable putty is a much better version of the old red putty that shrank like crazy,plus it was lacquer based and urethanes hate lacquer.You can use bondo to scrape into the pinholes in place of the putty,the only drawback being the scum on top of most bondos put on this thin really clogs up the sandpaper.I like to putty all my bodywork (except the real rag jobs) because the putty doesn't soak up the primer like bondo does.Paint and primer shrinkage seems to happen more often priming over bondo vs putty,but there are alot of reasons for shrinkage.The biggest probably is not letting things dry properly and too much material applied at one time.If you're using a urethane base/clear system,you should use a 2part primer surfacer.The drawback is quarts are the smallest you can get it and it is expensive,but lacquer based primers will give you an adhesion problem most of the time.It will chip much easier and usuall you can peel the paint off the primer with little effort.Epoxies are another primer that are usually used for an initial prime over your bare steel (usually after an etch primer).They can be used as sealers depending on the manufacturer's recomendations.I usually only use it on my bare steel before proceding with paint or bodywork.On a cheap job I might use it as sealer,but I prefer not to.As I said earlier I don't coat my bodywork with it.By nature epoxy primer is soft and stays that way for a few days.I use PPG and you can paint or do bodywork over it for up to 3 days without sanding it depending on which hardner you use,so it's soft.If you can wait this long between steps it's fine,but I'd rather not.The way I see it is if you lay down a coat of epoxy and topcoat it with primer or paint after you wait the 30 min or so (and I've gone hours as a test),you're putting a quicker drying substrate on top of a slower one.Now you won't get solvent pop like paint would but it does tend to soak in after a couple days because the epoxy was soft and moving around the whole time.One thing that pisses me off is to see shrinkage in a paint job and I've discovered it's much more likely epoxying my bodywork or using it for a sealer.As a sealer it's usually reduced more so it does dry quicker,but not enough in my opinion.Now other brand epoxies may perform differently,I don't know because I haven't used others,but myself and many others think PPG's DP epoxy is the best.Also remember to stay in the system for products.If you're using say PPG,buy their primer (epoxy,surfacer,sealer),base and clear.Mixing DuPont base and PPG clear for example isn't the kind of chemistry experiment you want to try considering the price of this stuff.You're at a bigger disadvantage because the quantities you have to buy will leave you enough of things like hardner to do another job,so there's a double whammy having $20 of this and $30 of that left over (and hardner goes bad in one to a few weeks after you pop the top and introduce air and humidity to it).It does suck,but a few extra bucks to do it right now is well worth the cost of redoing it later.Good luck and ask away if you need help.
I was ready to give up and buy new fenders and try that. well when I looked at the price of the new fnders I decided to try again. Noticing that when they were doing the fenders on the Jesse James special that they skimmed the whole fenders,
