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Discussion Starter #1
Hi,

I have been working on a 70 Mach 1 for a number of years.
previously I had done some sandblasting to get to bare metal.
I had, on some spots used an automotive sanding primer on the bare metal
to protect it from future surface rust. There are some places or parts that I
left bare metal with no ill effects in 5 to 7 years.

Recently I have begun sandblasting again and have noticed that in a couple of days
there is the start of some spotty surface rust.

I have seen recently in an article in one of the mustang mags that
you should only use self etching primer on bare metal.

My question is what is the proper way to protect the bare metal
prior to applying a good coat of primer for blocking etc?

The primer I had been using says it bonds to bare metal and the
surface after sandblasting, would not appear to need a self etching primer.

Can this protective primer coat be used, then followed up
with a self etching primer?

Any help here would be appreciated.

Thanks.
 

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Self etching primer IS the way to go. Bear in mind, that primer is somewhat porus, so the self etching application should be followed up w/ the primer/surfacer of your choice to afford best protection over a long period before color coats are sprayed.
 

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Get a bottle of Dupont 5717S, metal conditioner and follow directions on the lable. This will put a coating over the metal and protect it from rusting. Primer goes on it at a later date. Once you apply this it will appear to be a bit on the rusty side but it isn't, it is just a reaction of the product and the metal.
It inhibits rust formation and improves the metal for paint ashesion
Don
 
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An acid etch is a better idea. Ospho or other acid etches are available at most paint stores. After an application such as this you can leave it in bare metal and it will be rust protected. This way you can leave it and decide what paint application you want to do later on.
 

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Discussion Starter #7
Thanks for the info. I am starting to see the picture
here. Question, with the dupont 5717s application, is this similar or
much different than the acid etch?. these sound similar, and how long
can this remain before a primer coat is put on for blocking?

How would you go about treating fresh sheet metal, (e.g. with the black
primer/protective coat)?

Sorry for so many questions,
but i fear this whole topic has set me back a bit,
oh well what's another few years on top of the ten already.

thanks
 

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Ed,

Check out an excellent website, Autobodystore.com. That is THE BEST site for the very best information on all questions pertaining to body prep and painting. The host, Len Stuart, is a real pro and so are many of the contributors. They can answer all your questions. Good luck.
 

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Discussion Starter #9
Actually I saw that link in another recent post
and did check it out. Looks like a really good site.
It helped clarify a lot of my questions, in fact there
were very similar questions.

I appreciate being pushed in the right direction,
I think I got the gist here and can proceed.

I will have to do some rework, but as I said it is only
a small setback in the full picture.

Thanks for the help.
 
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