Bobacuda Posted July 23, 2014 Report Posted July 23, 2014 Once again, the more I read on bodywork, the more confused I get. I have been blasting & sanding my fenders, grille, etc down to bare metal. Since I plan on painting pretty much all at the same time (when it is cooler than 95-100 degrees F), I have been painting JASCO Prep & Prime on the bare metal and wiping down the excess. From what I had read, when it came time to prime, the process would be to wash it all of with a grease and oil remover, dry the metal, wipe it all down with denatured alcohol and it would be ready to prime. Since I have started the process, I have found threads that tell me painting over what I have done will work fine, it will all fail miserably, or it will fail around corners and seams. So, have I screwed my project, or is it really just wash it off as described above and don't use an epoxy primer that says it is not compatible with phosphoric acid treatment on the metal? Anyone have experience with this to share? Quote
Plymouthy Adams Posted July 23, 2014 Report Posted July 23, 2014 (edited) If you leave this stuff in areas in heavy film albeit dry..it is not good...I have Jasco here as an experimental and found it not up to par for my outer panels and so will stick with my phosphoric acid in 55% or less as cut by water for my particular need. No matter the acid you use to stop or check micro rust in pits..once the action of the acid has done its job, removal of excess is best...washing and drying will however more than not result in some flash rust coming back on your substrate..this is just normal but you can use a light 10-20% mix of phosphoric to do a light wipe of the surface and remove all flash rust..very light application is the key...allow to air dry very completely and leave alone till you are ready to prime.. I normally will later when ready to prime the completely dry panel go over it with a 3M scruffy pad and wipe all residue from the panel with a good solvent..also allow this solvent to completely dry for if any solvent is left is some small depression or rust pock, it will usually prevent the primer from getting a good bond to the converted substrate surface..unlike new cars and fast turn around body shops..we often dealing with panels that have some light form of corrosion on the panels in many places...you cannot get in a hurry here..do allow your products the time allowed for working many have their favorite rust inhibitors, primers and topcoats...it is all according to what they are accustomed or have found to work best for their body repair techniques and methods and environmental concerns. To say one is better than the other is something I will not get into..but most products do have a label and adherence to those instructions usually do eliminate frustrations in the end.. I have seen where folks use chemical strippers or allow acid to penetrate inside door panels etc and dry in a heavy concentration only to have their paint job fully destroyed once the car is painted and the car gets wet from rain or a subsequent wash job....do watch how and where you apply these products is best I can tell you along with following mfg. instruction on use.. Edited July 23, 2014 by Plymouthy Adams Quote
greg g Posted July 23, 2014 Report Posted July 23, 2014 I stripped fenders, hood, trunk lid and several smaller parts on my car. I used muriatic acid to attack the rust pin holes, neutralized with a plain water rinse, dried with compressed air, then sprayed with ospho, and wiped dry. The pieces stayed pristine in my basement for a little over a year. When the areas that needed filler were done, the whole piece was scuffed, tacked and primed. No problems after 12 years. Quote
HanksB3B Posted July 24, 2014 Report Posted July 24, 2014 I know my shop used a self etching primer that I think had phosphoric acid or something like that if I remember correctly Hank Quote
48Dodger Posted July 24, 2014 Report Posted July 24, 2014 Etching primers are acid based primers.....that's where the term "etching" comes from. They have nothing to do with killing or treating rust. Its merely an old school way of sealing bare metal until you have time to work on it again. Taking the panel down to metal and sealing it with an Epoxy primer is more common. The high content of resins (sticky) keeps moisture out and rust from reforming. The acid in Etching Primers can be problematic for a lot of today's paint systems. Jasco prep and prime is a Phosphoric Acid rust convertor like so many other brands.......plenty of youtube vids to study up on if you haven't done it before. youtube vid on Jasco 48D Quote
HanksB3B Posted July 24, 2014 Report Posted July 24, 2014 (edited) Thanks Tim, I was half expecting the demo guy (working without a respirator) to pass out and be laying on his garage floor overcome by phosphoric acid fumes during the video. Back in the days I first got my truck (used as an old roofing truck) there was a place in Santa Fe Springs that dipped my entire cab and front clip into an acid bath (which was subsequently nutralized) It was rediculously inexpensive like $160 for my entire truck which was returned to me as shiny metal. It was way cool driving my Raw Shiney Metal Cab back home that day. Saved a whole lot of hard work removing coat after coat of paint that had been applied by the P.O. Glad that's over, Hank P.S. EPA put a stop to their business years ago Edited July 24, 2014 by HanksB3B Quote
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