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Old 10-25-2017, 09:56 AM
Chris_Hamilton Chris_Hamilton is offline
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Join Date: Jan 2013
Location: Southisde Virginia
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Quote:
Originally Posted by RockHillWill View Post
I have had quite a bit of experience with using a phosphoric treatment after both glass bead blasting (blow dry) and rock tumbling (rinse and blow dry). It has stood rust free for many months, I was able to weld and grind, then re-apply and wait until painting was done. I do not recall any negatives from using the phosphoric application.
It's is ideal for that type of situation Will. What I am saying is that unless it is properly applied it will leave a acid film that affects the adhesion of epoxy (which is what should be used versus a acid etch primer). Here is a post by the President of SPI over at spiuserforum.com. Maybe it will help get my point across.

""My 2K high build primer cracked, you must have a bad batch"".

OK, the above pretty well sums it up, so I go last week and look at the car.
Now, this is suicide for me as every time I’m honest about something I get it shoved in my face a year later, someone will call and say my primer cracked and I read a year ago you had the same problem.
That is why the majors say nothing about acid film or Soda as they sell product when the guy reads SPI’s warnings, so they instead of researching they just buy another brand and that company could care less as they are not responsible if it comes off, it is your problem.

This is for your education and I think its an important one as there are a lot of cut and pasters out there that promote these different acids and don’t have a clue why or why not.

At least three times a week I hear, my car has been treated with acid, why can’t I use you epoxy.
My answer is always the same, neutralize it or please use one of the major’s epoxy.
You see, if a majors epoxy falls off, it must be something I did, If SPI epoxy falls off it must be the SPI stuff, being a smaller company.

OK for your education, the car was epoxied last winter by a shop and primed and blocked, eight months later cracks are showing up in the 2K primer all over the car as the shop that did the body work went out of business, so car is setting in owner’s garage.

The ex-shop owner is there and I question first the procedure on the epoxy of we used ospho or whatever it is called on the bare metal, I ask about neutralizing and got blank stares. Right away I was cut off at the knees and told the epoxy is sticking like glue but no broken spots to see??

So the owner of new shop is also there to take the car and this guy is good and does great work as known him for years and a rather famous shop so will not mention name.
Well he calls me Friday and says, epoxy at the metal is soft and the body filler at the metal is also not cured and gummy, no doubt its acid for sure as he has seen it many times also.

Yep that is what happens when you apply filler or epoxy over an acid film, outside dries great but part hitting the film does not.

There is a reason we give out these warnings and they are for your protection, not because I want practice writing, yea, I know I need it but!

Edit:
Another thing that should be pointed out here, as this car setting like it did is a rarity, if it had been painted in a normal fashion the the odds would be the primer would not have cracked.
Don't get me wrong, the primer could crack under the paint but the odds would have been better that the first few months out in sun a gassing would take effect with the uncured epoxy and body filler and a large bubble(s) would appear instead.

Maybe this will help someone from making the mistake of using a acid etch, phosphoric etch type product and not neutralizing it properly. Bet most of you didn't know that soda blasting will cause the same sort of problems unless it is properly neutralized. It is always best to blast and immediately put that blasted metal into Epoxy primer.
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Chris (trying to be the best me I can be)

Last edited by Chris_Hamilton; 10-25-2017 at 10:04 AM.
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