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can I put body filler over primer?

94K views 12 replies 8 participants last post by  deadbodyman 
#1 ·
I’m getting my ’34 ford frame sandblasted and it will be back in a couple of days. The blasting company said I should get primer on it within 24 hours, but I would like to put some plastic filler on the grinding marks and fill any rust pitted areas as the frame is going to be painted in gloss black and i want it to look perfect. I’m wondering if I can put bondo over the primer or could I do the bodywork first. In the past when I’m fixing a dent on my cars I always grind down to the metal and apply the filler, sand and then primer, but in this case they said I should get it primered Quick. It will be in the garage so I don’t think I will see any visual rust for quite some time as I have some other small suspension pieces I sand blasted myself a month ago and haven’t got around to priming yet and they still look fine. So my question is: can I put plastic filler over primer?
 
#5 ·
I looked at a map, Cypress is about 6 miles northeast of Seal Beach?

You get one foggy day, or a day that is cool or cold by LA standards, and then the weather shifts, and you get a warmer moist breeze from the southwest, and your sandblasted steel will turn orange with rust. You could possibly get away with letting it sit a few days in Summer, provided the weather did not shift, but it is not Summer, now

Sandblasting leaves the metal surface stripped of any thing that will protect it. In fact, it stresses the surface of the metal, making it more likely to rust.

Epoxy it. ASAP!
 
#11 ·
filler over primer

lamothe1 said:
I’m getting my ’34 ford frame sandblasted and it will be back in a couple of days. The blasting company said I should get primer on it within 24 hours, but I would like to put some plastic filler on the grinding marks and fill any rust pitted areas as the frame is going to be painted in gloss black and i want it to look perfect. I’m wondering if I can put bondo over the primer or could I do the bodywork first. In the past when I’m fixing a dent on my cars I always grind down to the metal and apply the filler, sand and then primer, but in this case they said I should get it primered Quick. It will be in the garage so I don’t think I will see any visual rust for quite some time as I have some other small suspension pieces I sand blasted myself a month ago and haven’t got around to priming yet and they still look fine. So my question is: can I put plastic filler over primer?
Its best to prime right away because of oxidation it also ok to put plastic filler over primer
 
#12 ·
I didn't see anyone mention phosphoric acid to kill surface rust before coating with epoxy, either that or use an etching primer. The phosphoric acid I refer to is caller rust conversion coating. For metal in an enclosed place the rust conversion coating is good enough to not have to prime for a few months.
 
#13 ·
Thats because most guys dont use it properly and have problems and others think ALL acid products are the same (not true) ..blasting is good but blasting and ospho cant be beat...around here you can almost watch a nice clean body rust before your eyes and Ospho is the only way to stop surface rust effectivly ......I'm sure there are other products that work equally well but when you find something thats works as well as this theres no reason to switch...Ospho REMOVES rust but it'll also convert what little residue (if any)is left ,after its dry it'll protect bare metal for years inside and a couple weeks if left outside...I wont strip a car and NOT use it first...What a difference it makes....As the others say a sandable epoxy is the best foundation to start with....
 
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