Autobody materials explained

[Sweet Tea Man]

Materials

In this I will cover primers, sealers, adhesion promotors, single stage paints, and base coat/clear coat.

Lets start with primers.

Starting at the bottom. Going over bare metal. A normal primer that is used for simply building over your bodyfiller WILL NOT work here. For bare metal applications, a self-etching primer or an epoxy primer is required. Reason being they are designed specifically for this purpose. By applying one of these two primers, you are eliminating the chance of having rust come through your paint job after all the work you’ve put into it. Do it right the first time.

Next would be primers for going over bodywork or over a vehicle. Now, one common misconception is that you have to prime the entire vehicle for a paint job. NOT TRUE. You only put primer in the areas where body work was done and you block it smooth.

Primers for body work would include Acrylic primers, Urethane primers, and Polyester primers. Generally, your polyester primers are your higher build primers. They are great for bigger areas that you are working on a panel, or for an all over job. Consider primer a “spray on bodyfiller” if you would. It will fill scratches and build the surface. So that when dried, it will be able to be blocked down level with the rest of the vehicle.

Sealers
Sealers are exactly what the name states. They seal the existing finish so that you will get maximum and even coverage when spraying, and do not allow for any bleed through from the substrates.

Sealers are used over primer, tiny bare metal areas, and if doing a color change, the entire vehicle. Don’t worry about having to sand the sealer b/c it lays flat. Once dried, you have a completely uniform canvas to start on. Picture this in your head. You have a dark blue door, and a silver door. Both are being painted a gold. The gold will cover over the silver door quicker and produce a better color match with fewer coats than with the dark blue door. If you were to apply a sealer over both doors, you could get the SAME color on both doors in the SAME amount of coats. Sealers save on material, and time to a painter. Time is money.

Adhesion Promotors
These are generally used on plastics. Bare plastics by themselves, even when sanded, do not like holding on to material that is sprayed on them. The adhesion promoter is sprayed on and helps grab and hold onto the topcoats that you put over them.

When getting ready to spray a bare plastic, sand the entire surface with 600 grit or go over it thoroughly with a red scuff pad, spray two medium wet coats of adhesion promoter on and let it flash for 5-10 minutes. Then seal it and after that sets, apply your topcoats.

Single Stage paints/Acrylic Enamels
single stages and acrylic enamels are the same to a certain extent but couldnt be more different. while your typical single stage is for general use on automobiles, an acrylic enamel is harder than typical paints once dried and is generally used on industrial vehicles. both S.S. and A.E. lay out easily and produce a great finish. A.E. are harder to buff, but can be dry and ready to handle in under an hour(air dry).

S.S. paints do not have "the clear coat mixed in", rather its its own chemical make up that gives it the gloss. If you were to actually mix the base and clear together, say 50%/50%, it would dye back and not give the complete finish desired. it would give off a semi gloss effect. normally good for underhood applications if you need it.

Color Blender
Used on metallic paints when blending a panel. goes on as a clear base coat before the base that helps hold onto the metallics and not let them fall causing shadows in the paint once clearcoated.

Base Coats
All of your colors, pigments, etc. is your base coat. has no shine, and will break down if its not topcoated. solid, metallic, doesnt matter, your base is your color. point blank.

Mid Coats
A mid coat consists of pearls, candies, flip flop colors, etc.

Clear Coats
This is what gives your finish the depth and shine you are going after. protects the substrates(lower coats as in base coat, sealer, etc) from UV rays. sandible and buffable where as the others arent buffable. if you sand through your clear coat, you will have to apply more paint and reclear.

[Bob T]

Hmmm... My body work usually involves duct tape. Didn't see that in your excellent writeup.

[Sweet Tea Man]

[Bagged94Rado]

Thanks this helped quite a bit with my confusion on the different types of paint

[93Sierra]

Originally Posted by Bagged94Rado

Thanks this helped quite a bit with my confusion on the different types of paint

Ditto! Great guide!

[Griff4x4]

some other stuff-

Laquer thinner, a must have for auto body. removes paint if you get it on something not-inteded to be painted.

tar & wax remover, MUST have for paint prep, gets all the oils and grease off the surface- paint only sticks as good as the base surface.

Fast cleaner- same as tar and wax remover, only its wipe on and wipe off, primarily used for paint prep.

Note- the cleaner will also remove the sticky stuff from removing side moldings.

water based cleaner- used on plastic and fiberglass material, only use the fast cleaner on metal.

im sure im missing some stuff... but that is an addon to Sweet Tea Man's great start.