Hi Gang, I have acquired various unfinished projects over the years that I am certain have had a Picklex or Ospho or similar treatment but are now needing some rust removal before epoxy and topcoat. It has been well established that mixing acid etching products is a bad idea, but what, if anything, can be done to mitigate the risk? In other words, can I DA with some 80 grit and then reapply a phosphoric acid rust treatment product without running into paint adhesion problems? Also, is it still a problem if I do more than one application of the same product? For example, treat with Picklex-20, then sand the phosphatized rust off and treat with Picklex-20 again? TIA!
As do I, but that doesn't address the topic: Will you have problems if you use a rust conversion product on metal that has already been treated once, even if you sand the metal first?
Doesn't washing it in a baking powder bath neutralize that stuff??? Haven't tried it but that's what I remember.
Theres a product called DRX.They have a utube video,and they coat a car worse than yours,and pressure wash it clean.I havent used it,but the video is worth looking at.
How long ago was the first conversion done, and what has the car been exposed to since? I'd think the effects of several years between the first conversion and the second would be a lot different then had the time between the two only been a year or two. Also, I believe if you read the directions, (at least any chemical treatments I've used) they tell you that you need to prime and seal the body after the treatment because exposure to weather (sun or water) will break down the chemical treatment. If the 55 Chevy is the car in question, it appears it needs to be completely stripped and redone anyway. Strip it down, then follow the directions completely. Gene
Rust conversion coatings contain tannic acid that turn the rust black. Rust remover's contain phosphoric acid which dissolves the rust and removes it. When you use a conversion coating you should check it by scratching it.. If there's rust under the black film keep treating it until it's gone. Water neutralizes phosphoric acid rust remover's. In your case I would not paint over old conversion coating. Strip it down to bare metal and go from there.Since you decided to go with a epoxy rather than a urethane scrubbing the surface with water is what they want you to do.Give them a call and they will advise you on exactly what they want you to do before using the product
Just checking out the Piclix 20. $92 for a quart.. Now the contents are listed as 85% water, 7% phosphoric acid, and 8% other ingredients unspecified as a trade secret. Now this product contains some solvent to degrease the surface. Years ago I sent a Salt neutralizing Product that was applied to bridges prior to painting. It was analyzed at 95% water 4% soap that was used in electric dishwasher's and 1% die. This gallon container would make 100 gallons of wash solution and 30 years ago was only $30 a gallon. Before you plunk a lot of money out check the MSD sheets on the product your thinking of buying
Baking SODA,, the other one. I use solution of baking soda and water to clean of parts that have been soaking in vinegar. OP's car I would be sanding it down and applying the epoxy primer. Would not take much to clean that body up.
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