Thread: Primer Questions

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I have my car sanded down to bare metal right now. I'm getting ready to put some filler on in some places. What is the best type of primer to get to put on after the sanding of the filler is done? Also, I need a type that once I have primed it and if additional body filler is required I will be able to respray over that. Are there any sealing primers that I can use? I have read that you can't spray sealing primer over body filler. Any help would be appreciated. Thanks.

Originally Posted by outdoorxtreme1

I have my car sanded down to bare metal right now. I'm getting ready to put some filler on in some places. What is the best type of primer to get to put on after the sanding of the filler is done? Also, I need a type that once I have primed it and if additional body filler is required I will be able to respray over that. Are there any sealing primers that I can use? I have read that you can't spray sealing primer over body filler. Any help would be appreciated. Thanks.

I would suggest an etch primer of some type, forget about a regular expoxy primer since you are down to bare metal. ....Overcoating of filler is just fine, as eventually you will be using some type of sealer over whatever is there just before the paint is laid down.


Bill S.

Can you spray etching primer over body filler? Also, can someone suggest some brands that are good to use for both etching and sealing at a decent price?

Thanks.

I've sprayed self etching primer over body filler many times with no problems. I don't know if it's recommended but I've never seen it cause a problem. I've used dupont varaprime for years along with other brands. Varaprime is the ugly green stuff but it sticks like crazy. You don't have to cover with it....a couple of light coats will do and you'll still be able to see through it. It's very thin and runs easliy....don't ask me how I know I started using it a long time ago Just go over it with a descent two part primer. I've got Sherwin Williams Ultra Fill II on the '35. It's urethane and tintable. Sherwin's new line is called spectraprime. There are a lot of good primers out there though and some have etching built in. Transtar has a primer like that I believe. Dupont's nason primer isn't too bad for the money......there's a lot out there.

Originally Posted by 35chevy

I've sprayed self etching primer over body filler many times with no problems. I don't know if it's recommended but I've never seen it cause a problem. I've used dupont varaprime for years along with other brands. Varaprime is the ugly green stuff but it sticks like crazy. You don't have to cover with it....a couple of light coats will do and you'll still be able to see through it. It's very thin and runs easliy....don't ask me how I know I started using it a long time ago

varaprime is one of the best. we did some test on it. the acme / select/shewin w is good to. i ways let the thinners burn out of it a bit .a lite scuff with a 3m red pad then go to dp 40 them k 200 to k36 with a tint as a sealer i never hammed on the filler with the etch but i did cover the hole part or body this way.it allways work for me

Well here is what I would have done... I would have first gone over the entire bare metal of the car with epoxy primer (I only use SPI Epoxy primer and their clears). Then you can lay your filler over top of the epoxy without even sanding it to adhere (SPI epoxy doesn't need to be sanded in order to put filler over it and priming first is highly recommended). Some people think bare metal is the best way to go and this is what I used to do until I started using SPI epoxy. Anyways after that, you can use a basic high or medium build primer or even the SPI epoxy on top. You can also reduce this primer and use it as a sealer as well.

Originally Posted by FMXhellraiser

Well here is what I would have done... I would have first gone over the entire bare metal of the car with epoxy primer (I only use SPI Epoxy primer and their clears). Then you can lay your filler over top of the epoxy without even sanding it to adhere (SPI epoxy doesn't need to be sanded in order to put filler over it and priming first is highly recommended). Some people think bare metal is the best way to go and this is what I used to do until I started using SPI epoxy. Anyways after that, you can use a basic high or medium build primer or even the SPI epoxy on top. You can also reduce this primer and use it as a sealer as well.

yep they said that about dp just put the filler over it. i never had any rust under filler or loss of hookup. but on the dp your feather the would roll up. sealer or pimer thinner would pull it up so i stop using it that way .on new car with oem finsh with small dent. i sanded the clear off and put the filler right on,it did work good. and for filling more i allways used mar glass on my first coat . i never use spi so it may work just as good as you say. i just saying how i did it every day when i did it and dp for a hold down sealer it suck i do not care for over lapping sealer paint primers .if i am in fresh color if things go wrong it get striped or sanded and more base no sealer or primer if it is a used part like a bumper body part they get striped no new paint on old painted parts less i painted it the first time

I think all the rust under the body filler crap stems from the days when we used to make body panels look like a sifter in an attempt to straighten it. All the holes in the backside allowed moisture to creep in. Also the old lacquer primer was porous and soaked up water like a sponge. we used to wet sand it, then paint over it trapping in the water and we fought blisters and everything else. Boy we have it good now days. With the "new" stuff I've primed before I put on filler, and put filler directly to metal. Either way seems fine as long as there are no holes on the backside. I remember a time when we never put filler over paint, but I stopped grinding off all the paint several years ago. It seems to work fine over good quality paint and I don't have any come backs. If I'm starting from scratch with a clean metal panel, I just do all the filler work first, apply some etching primer and then seal it up with a good urethane or epoxy primer. Seems to be easiest for me. Some of the body filler on my '35 is 15 years old and it looks as good as the day I did it.

if it is a used part like a bumper body part they get striped no new paint on old painted parts less i painted it the first time

Hmmmmm. You had problems with wrinkles or something? I've seen old repaints wrinkle if the base is applied too heavy or using the wrong thinner and the the base lays wet on the surface too long. Usually there is never a problem with old oe paint. If I'm in doubt about the old paint I'll seal it. There's nothing wrong with stripping it I guess but if the paint is in good shape, why? Over the last 20 years I've skipped that step. Personal preferance I guess.

Originally Posted by 35chevy

I think all the rust under the body filler crap stems from the days when we used to make body panels look like a sifter in an attempt to straighten it. All the holes in the backside allowed moisture to creep in. Also the old lacquer primer was porous and soaked up water like a sponge. we used to wet sand it, then paint over it trapping in the water and we fought blisters and everything else. Boy we have it good now days. With the "new" stuff I've primed before I put on filler, and put filler directly to metal. Either way seems fine as long as there are no holes on the backside. I remember a time when we never put filler over paint, but I stopped grinding off all the paint several years ago. It seems to work fine over good quality paint and I don't have any come backs. If I'm starting from scratch with a clean metal panel, I just do all the filler work first, apply some etching primer and then seal it up with a good urethane or epoxy primer. Seems to be easiest for me. Some of the body filler on my '35 is 15 years old and it looks as good as the day I did it.

yes same here the body work on my cars are lead and did some of it back 25+ years ago and ppg DZ lacquer primer on the chevy still holding up good .i stop doing body work sometime ago for a living. i allways put the filler on the steel to if striped clean to