primer and after market parts?

ok so basicly were ever im going to apply bondo i grind that spot to bare metal correct?

body filler w/plastic resins such as "Bondo" which is a brand name will not adhere properly to any primers, sealers, or topcoats except epoxy. Body filler can be applied directly to bare metal if scuff sanded w/at least 80 grit. Remember the coarser the better for adhesion however, you may remove or take out more of the metal w/a coarser material. You can also apply epoxy primer to bare metal which has etching capabilities and will also accept filler w/plastic resins directly over it. Laquer primers are a thing of the past in most shops today. Laquer has a tendency to pull solvents to the top which can increase solvent popping and/or bullseyes even on properly prepped repair areas. 2k is the way to go over repaired areas. Very durable primer. Personally if you plan on stripping the vehicle, I would at that time do as much sheet metal straightening as possible and either apply your filler directly to the metal or epoxy over the bare metal do your body work and then 2k the repair areas. Epoxy is very tough to sand properly but is one of the most versatile primers out there. Lots of hot rod/resto shops use epoxy regularly because of it's versatility. Sorry for the long post but I hope this helps some. If you have any more questions I might help you with you can pm me. I may not reply right away but I will reply eventually.

Late

body filler should be applied directly to bare metal..nothing should be between the body filler and bare metal..so says ASE..check out the link....http://www.ase.com/AMTemplate.cfm?Section=Test_Catalogs&Template=/ContentManagement/ContentDisplay.cfm&ContentFileID=498..........page 16 problem 3

Edited: 5/11/2007 8:41:59 PM by Car Toys

you are partially correct Dusty. ASE tests are tricky for a reason. They are intended to get you to actually think about the situation at hand. The key word in tech B's statement is "paint". you cannot apply body filler w/plastic resins directly to paint. It will not adhere. You can however apply filler w/plastic resins not only to bare metal but also over scuffed epoxy primer. It is a characteristic unique to this primer. you may also apply fillers w/polyester resins over scuffed, cured painted or primed surfaces also known as glazing putty. This is a characteristic unique to this filler. I actually teach auto body at the local community college so I would not steer you wrong. I have 15 years experience in auto body and have learned not only from my mistakes but the industry's mistakes as well. Do a lil research on epoxy primer and you will find that I am steering you in the right direction which ever way you decide to take.

One last bit of info on epoxy primers for those of you interested. It is the only recommended primer to spray over bare fiberglass parts. It is suggested that epoxy is the only primer that will allow the fiberglass to breath. I have personally had success w/spraying fiberglass w/o the use of epoxy in the past and have had no proof that would lead me to believe or disbelieve this theory, but it is the suggested correct method. Hope this helps some.

Late