metal conditioner/etching primer mistake? [Archive] - Team Camaro Tech

: metal conditioner/etching primer mistake?


keith1365
Jan 1st, 05, 05:17 AM
My local paint supplier recommended using dupont metal conditioner 5717s over the bare metal. He them sold me etching primer dupont 491-17. I have conditioned the entire car and primed the front end only. It now looks like I should have researched more and worked less. Is the etch over metal conditoner going to cause me problems? At least I only have the front end primed. Also, he said filler over conditioner was not a problem. I have started on the body work on the back have and have some filler over conditioner. I think I need some guidance before I waste any more time.

shoddy_F-body
Jan 1st, 05, 06:27 AM
You dont want filler over metal conditioner. You also dont want to etch prime over metal conditioner.

MARTINSR
Jan 1st, 05, 06:50 AM
If the metal is sanded clean there is no reason to use the metal cleaner at all. I believe the 5717 is a "cleaner" and not a "conversion coating" so applying etch primer over it is ok. DuPont 224S would be a No-No but the 5717S is ok as far as I know. But check your tech sheets for BOTH products to be sure.

However, being the 491-17 is NOT a "DuPont" product, it is "NASON" and the 5717S IS a DuPont product the tech sheets of one will not mention the other! So, you have to do some home work and study each one to see what DuPont product is the same technology as the Nason product they are refering to! Whew, that is on problem with mixing "brands".

The other thing you can do would be to sand that primer to bare metal in a little spot with some 120 and see how well it held on to the metal. The slightly too coarse 120 will work better than a finer more appropriate grit like 180 because you can look at each scratch the 120 makes and see if the primer is holding on as it should.
By the way,I couldn't find that 491-17 on the DuPont site, are you sure that is the number?

keith1365
Jan 1st, 05, 08:00 AM
The etching primer can says the number is 491-17. It is a Nason product. Its green and smells bad. I scuffed the primed fender and it appears to be stuck well. How about filler over the cleaner? It appears to be stuck well also.

MARTINSR
Jan 1st, 05, 10:46 AM
What you have done is CLEANED the metal, the filler should be fine.

The one thing that could be a cause of concern in this "Cleaner" (Phosphoric acid) being left in the nooks and crannies of a weld or something like that where it didn't get nuetralized.

shoddy_F-body
Jan 1st, 05, 10:53 AM
5717 is a metal 'conditioner' and usually leaves a chalky looking coating. It is not recommended to apply filler over it.You could have adhesion problems. I was using 5717 followed by epoxy for a while,just because it was cheaper than self etch primer. In one instance i was able to easily scratch the epoxy off with my fingernail.I shy away from 5717 since that episode. If i use it i will sand it before putting anything over it.And that is probably defeating the whole purpose of using it.I just find it easier and less 'what if's' involved if i just use self etch over bare metal. Here is a question from the ASE Coliision and Refinsih Test -
"Painter A says that metal conditioner should be used under plastic filler to assure proper adhesion, Painter B says metal conditioner should be used under plastic filler only if rust is present. Who is right?
The answer is niether A or B. The answer is supplied by ASE in the study guide.

[ 01-01-2005, 02:05 PM: Message edited by: shoddy_F-body ]

HAD1NHS
Jan 1st, 05, 12:01 PM
Shoddy is correct, 5717s is a metal conditioner, the bottle states it is an acid for conditioning bare ferrous metal prior to painting. It will cause you problems under the body filler. I think you might be okay under the primer as even though PPG does not call for metal conditioner under their DP40 epoxy. I know it is fairly common practice to acid condition scrungy rust areas prior to epoxy, unsure if its a benefit but it seems like a good idea.

keith1365
Jan 1st, 05, 02:02 PM
This brings up another question. I emailed Dupont and they said it would be ok to do all the body work then apply the etching primer followed by a urethane primer. They said the etching primer would not hurt the filler as long as it was on top and not underneath. That is my plan as the body work is almost done on the quarters and roof. I don't have a problem stripping the front end as I etched them before the body work. I live in the midwest and rust on bare metal is an immediate problem and the car was stripped in mid summer.

MARTINSR
Jan 1st, 05, 04:34 PM
I stand corrected, the information I have is that it is a "Cleaner" and does not leave a residue. It this is the case, not only would you not want it under filler, you don't want to spray etch primer over it either.

Keith, I feel there is some confusion and I would clairify with DuPont if this is ok, don't listen to some guy behind the counter who may or may not know if his butt is bored or punched.

As far as the etch over the filler, well, other manufactures have a recommendation for it in the tech sheets so it being the same basic technology it should be ok. The thing that is stressed in those other tech sheets is that the plastic filler be "Fully cured" (at least 12 hours).

keith1365
Jan 3rd, 05, 02:40 PM
Good news. At least for me. Acording to Dupont, etching primer is ok over the metal conditioner. Poly filler is also ok over 5717 metal conditioner.

It looks like I got lucky. I was not looking forward to starting all over again. Just thought I would bring everyone up to date.