Rust protection
 

I'm having a 72 914 media blasted and when all the metal work is finished i would like to have the car protected against rust ,what are my best options.The work will be carried out in California so any recommendations would be grateful
Thanks Bond

PPG DP, Epoxy Primer.

the 1st thing you will want to do is pick a product line that you want to use thru out the hole project from start to finish .
that would be all one brand of material of say PPG , glasurit , RM , dupont , what ever .
you do not want to mix and match different product lines .
there are lower , mid and high grades of products to pick from . this you pick for what the job it's self and the rebuild quality your doing for the job . if you were to only want a concourse resto because you are really only going to show the car you would want the top of the line coatings for a project like that . if you are building a daily driver that your taking to the rack from time to time a lower grade product line is fine for that .

for bare metals you can use a Etch or a Epoxy primer .
picking one out of the two has allot to do with how your going to do the job it's self .
many Etch primers you do not want to do your plastic work over the top of them . plastic work is body filler (it's not called bondo as that is a brand and not the product ) the product is called body filler .
A Etch primer kind of does just what it states it etches the bare metal giving very good rust hold out .
the down side is body fillers and spray filler do not like too stick to many of the Etch primers on the market .
so you would do your body work over the bare metal then use the Etch primer after your body work .

Epoxy primer is good if you want to spray the hole car with a coat of primer 1st then do your body filler work over it .
with most Epoxy primes this is ok to do but like with etch primer not all epoxy primers this can be done .
so always get a TDS on all the products your looking to use as they will tell you the does and don't .

then with the two primers Etch and Epoxy they both offer them with or with out it being chromated .
Chromated is good for bare metals as it does add more protection against rust then a non chromated primers would .
a non chromated primer is more then fine if you were using it over aluminum or galvanized metal as it more for adhesion if your using it over those two substrates .

in my shop we go thru about equal amounts of the two products as one is not any better then the other just used in different ways .
if there is little to no body filler needed on a panel we tend to use the etch primer .
if we have a **** load of body filler work to do on a panel we use the epoxy primer .
1st spraying the bare metal then doing the filler work over it .
after all the filler work is finished we then spray another coat or two of the epoxy over the body filler and then our filler primer over it .
where is it's etch primer we do our body work over the bare metal then spray a coat or two of the etch primer kind of going around the filler areas and then spray our filler primer over the etch primer .

this is where picking all one product line comes into play .
people at times will get into trouble with picking on brand of E-primers (etch or epoxy ) and then another makers filler primer to find out later on down the road they are not compatible .
finding out the primer is delaminating , shrinking in or other nasty things .
it's also a myth that you can not ever go over a etch primer with body fillers or spray fillers .
you can but have to wait until it's at full cure before you do .
the wait time to full cure is about 4 to 6 weeks at 70 plus degrees for two medium coats of etch primer .
by 4 to 6 weeks it has finished all it's out gassing of the solvents .
so we do use it on jobs were the car will be in the metal shop for that amount of time before it's going into body shop for it's filler work .

picking a product line is ez to do you want to find a jobber (automotive paint supply store )in your area that you can run down to and get materials .
any product line is good and will work if you stay with in there perimeters and you go by there TDS ( technical data sheets) .

in CAL. like CT we have the toughest VOC rules out of a 50 states .
so if your looking into replacing the cars finish with single stage if the car came with single stage you could be assed out with some manufacturers as they will not offer it in some states because of the VOC rules of that state .
in CAL like CT we still can get single stage but it's hardener is changed to what other states use .
BASF has done this with there S/S product lines but other paint CO's have not .
so if your area jobber can supply you with every thing but the single stage top coat they may not be the right jobber and paint manufacturer for your needs .

Awesome info 962. Thank you!

What about wash primer? Is that something you ever use?

wash primers are essentially that the E-primers are .
this is why I stated it's better to use one with a chromate .
the term wash primer is used more in marine applications then automotive but that is not to say it's not used on cars .
most products that use the name of wash primer are what is called a reversible product and should not be confused with todays E-type primers .
wash primers use a activator not a catalyst by just using a activator it does not harden the product . do not confuse harden with drying but as it is in a dry state like a lacquer you can take a rag soaked with a solvent and lay it on the panel it will turn the product back to a liquid state . you do not want a product like this under a hardened product ! down the road you can or will end up with a finish that is delaminating ,checking ,cracking and pealing .

so yes we kind of do use a primer like that .
as soon as we take a car out of the blasting booth we roll it right into the prep area and then sand the car with 180 or 220 . the spray one coat of a E-primer over all the bare metal , aluminum or other metals . at that point the car will not flash rust on us as we go thru the repair proses . if the car will not be getting it's body filler work done for 4 to 6 weeks we will use a etch primer if the car is not getting much metal work and in a very short time going into the body sho for it's plastic work we will use a epoxy primer . as you can not do filler work over non cured etch primers .