Auto Paint: How to Spray Automotive Primer
How to Spray Automotive Primer
I know that I have covered this in the past, it would seem that it’s a popular topic; how to spray automotive primer. Every painter performs this process a bit differently, this is my way of priming a car, this article will cover from first prime to final prime.
My process starts by selecting the primer to use; this is always the painters preference. I use either RM DP 20 urethane primer, or the equivalent in a Dupont primer. As a painter you always have the option of using epoxy primer also.
My opinion is that the urethane primer is easier to use, and the final outcome is comparable. Epoxy is harder to sand, and takes longer to cure. For the best outcome you should always follow the manufactures mixing instructions to the letter.
First Stage: Body Work Primer:
After the body work is completed your should put at least three coats of primer on the body repair areas . Giving at least 15 minutes of flash time between coats, you should never let the primer dry for longer then 25 minutes between coats.
You should then guide coat the primed areas, and sand them with 180 grit paper on a block, or board. If the guide coat is all gone after you sand the primer with the 180 grit paper you are ready for the next step, if not you may need to put some metal glaze in the low areas, and re-prime them.
If you have to re-prime some of the areas just repeat this step in the process.
Second Stage: Full Body Prime:
During the stage you will prime the entire car. Once the entire car is primed you will need to sand it by hand with a block, or a sanding board and 180 grit paper. You will need to put at least three coats of primer on the entire body of the car, and sand it with 180 grit paper on a block or board.
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Make sure that you guide coat the entire car before you begin the sanding process, and as in the above step you should wait at least 15 minutes between coats, and no longer then 25 minutes between coats for the best results.
Third Stage: Final Prime
The two previous steps have been working up to the final prime. This is the last and final stage of the priming process before you put the paint to the car. The last two steps are what create the smooth as glass look on the paint surface, so they are ultra important to follow.
During this step you will be removing the fine scratches left by the 180 grit paper, and creating a smooth perfect surface for the paint to adhere to. During this stage you will be sanding with 320 grit wet paper by hand on a block, or by machine if you prefer.
I prefer that hand sanding process because you are able to get things looking perfect. A machine is designed for one thing, and that is to make the process faster. If your looking for the best outcome you should always sand by hand with wet sand paper.
After you have sanded the entire surface with 320 grit wet sand paper you will be moving to 400 grit wet, or 600 grit wet. I prefer to finish with 600 grit wet paper. When the surface is finished correctly it will have a uniform dull shine over the entire area.
All that is left after this is to clean the residue from the wet sanding process off of the car body, and clean it with paint prep cleaner, and your ready to re-mask and move the car to the paint booth. If you complete these steps you should have a great looking finished product WOOHOO.