Self Etching Primer

[Lowrider1984]

When spraying on self etching primer from a can do you have to sand it afterwards?

 

[kingcolbert83]

All primers has to be sanded for the best possible finish.

 

[beermonkey9417]

isnt self etching primer just primer ya dont NEED to sand and paint will stick to it?

 

[carmangary]

The data sheets for the paint will tell you exactly if you need to sand, what grit to use, etc. But the general rule of thumb for paint is that after it dries you have to sand before applying another coat. There is usually a window of time between it flashing to around 12 hrs or so where you can apply another coat without sanding.

You don't have to sand between wet coats because the paint chemically bonds together. But after it dries the paint won't chemically bond, it has to physically bond, and sanding takes the slickeness off so that the paint will have something to grab. If you don't sand, you run into the risk of the paint flaking.

But, to be sure, download the data sheets for the paint you are using.

 

[85Supreme]

i have dupli-color self-etching primer and lots of it because im currently doing my body work. on the back the directions say "After spraying final coat, allow etching filler to dry for 30 minutes before sanding with 400 grit sandpaper or topcoating.

 

[Bonnewagon]

I guess manufacturers differ. My marine etch primer states NOT to sand it. When all else fails- read the instructions!

 

[85Supreme]

Exactly, just take the time and read the directions because double checking never hurt anyone

 

[kingcolbert83]

Marine paint and auto paint are different. Marine has different needs because its subject to more environmental damage than auto. Yes you should read the instructions but the correct way to do it is to sand the primer. I dont say this to be rude but for the best possible finish. Rather it be dry(to block it) or wet. The smoother your surface is the better your topcoat and clear will lay down....so the better your finish will be. I have never sprayed primer and then went straight to putting the topcoat on. I always let if fully dry(in my case force dry at 140), block, reprime if necessary, wetsand(unless waterbourne is being used).

 

[Lowrider1984]

i have dupli-color self-etching primer and lots of it because im currently doing my body work. on the back the directions say "After spraying final coat, allow etching filler to dry for 30 minutes before sanding with 400 grit sandpaper or topcoating.

I have another question I stripped my hood and before I sprayed the self etching primer on their I sanded it with 320 grit instead of using 80 grit and when I sprayed the hood and I noticed it does dries quick and I ran my hand across the hood and felt some smooth spots and some rough spots and now it has been sitting their for a couple days most of the hood has more rough spots rather than smooth ones. Why would this happen? Should I remove the primer and start over and after spraying the primer spray the next layer with a different primer? And I saw a video from dupli color tv and they did not sand it and after they sprayed the self etching primer they sprayed filler primer so should I just do that?

 

[Oldsmoletick]

Are you using cheap rattle can stuff, or real self etch primer? If you stripped the hood down to bare steel, that should be done with 80 grit, and left in 80 grit, 320 is for blocking your first coat or two of primer surfacer. Spray your etch prime (I like PPG's DPX, stuff is nasty, never spray it with out a respirator) let it dry, then use a high build primer surfacer to hide the 80 grit. With the dpx as long as you stay with in the stated time frame you do not have to sand it before recoating, or coting with primer.
Side Note: This advise applies to using automotive grade products, not off the shelf rattle can.