PAINT PREPARATION DO’s AND DON’Ts

   

A good paint job is important for both looks and protection.

By David Doyle

Clearly one of the most visible of any vehicle restoration – if not the most visible aspect – is the paint job. No matter how meticulous the restoration or how careful the selection of the “correct” shade of olive drab, poor preparation can result in a paint job that falls short of the owner’s dreams. In fact, it can ruin an otherwise exacting restoration.

Perhaps the first thing today’s restorationist needs to grasp is that it is completely impractical – and probably undesirable – to apply an “authentic” paint job. In part, this is due to environmental laws, along with efforts to reduce labor costs, and continuing improvements on the part of finish manufacturers the products that were used when our vehicles were being built are simply no longer available. And, if they were, we probably wouldn’t want them, because from the application and performance standpoint yesterday’s finishes were lacking. But beyond that, even the smallest vehicle manufacturer had finishing equipment at their disposal that hobbyists can only dream of owning.

The lack of this finishing equipment however is not a disaster to enthusiasts. The improvements in chemicals allow us to today apply a finish in our back yard that would have been the envy of any painter in Detroit in 1943 or even 1963. In fact, this can lead to a bit of “over restoration” on the part of over-eager buffs.

But, even with today’s most modern paints, the secret to a good looking, long lasting finish is the same as it has been for generations: careful, thorough surface preparation. Unfortunately, many enthusiasts try to cut corners here. Maybe this is done because they are anxious to see the vehicle “finished” or because they feel they can save a few bucks. In either case, this is false economy.

Begin by locating a reliable supplier of finishing products. Not just the final colors sold by vendors found in the pages of this magazine, but a supplier of entire finishing systems. Typically, even moderately sized metropolitan areas have one or more such suppliers listed in the Yellow Pages under “Automobile Body Shop Equipment and Supplies.”  Harder, however will be finding one of these shops who will take time away from their everyday professional customers to help the occasional hobbyist may be a bit more challenging. Harder still will be finding one who understands the nuances of dull military vehicles as opposed to flashy machines with chrome wheels.

I was fortunate enough to enlist the aid of such professionals in the preparation of this article. When Tim Garrett is not on the phone helping long-distance customers, or helping local pros at Auto Paint and Performance in Shepherdsville, Kentucky, he is likely to be found at the wheel of a 1942 GMC CCKW, or working on the M5A1 Stuart housed in his garage. Further information was gleaned from Bill Norvell, veteran tanker, and body shop proprietor of 40+ years, and incidentally the fellow who has painted several MVs for the author.

Their advice, combined with watching and listening as the team at Memphis Equipment prepared my M45 chassis with LeRoi compressor for painting, led to this article. The following step-by-step tips will help you apply a factory-level paint job in your own garage.

Tip 1: Most enthusiasts prefer a “motorpool” type restoration. In such cases the starting point is simply sanding the vehicle after it has been thoroughly washed. Omitting the washing step will lead to deep gouges, clogged paper, and extra work. On a military vehicle particular care must go into the washing step. Large clumps of grease, leaky seals, and oil residue are common. These areas but they must be completely clean for proper adhesion.

Tip 2:  In the case of severe rust, it is usually best to disassemble the vehicle, at least into major components. Then,  sandblast the trouble areas. This can be done either with hobby-grade equipment or by professional contractors.

Tip 3: For those who wish to perform “motorpool” restorations on reasonably well-preserved vehicles, thorough sanding will  suffice. At a minimum, sanding should continue until the original primer is exposed.

For those who wish to perform “motorpool” restorations on
reasonably well-preserved vehicles, thorough sanding will suffice.
At a minimum, sanding should continue until the original primer
is exposed.

Once the surface has been prepared by sanding, stripping or
sandblasting, any flaws in the body should be addressed. These
can range from holes added by civilian owners or rust caused by
mother nature. Depending on the damage severity, repairs can be
affected by installing new panels, welding or using body filler.



If a panel has many imperfections, it is often stripped to bare
steel. Then, a “skim coat” of body filler is applied. The objective
is to fill and smooth any indentations in the panel surface. Be
aware, however, that evidence of spot welded joints were evident
on most wheeled military vehicles when they were new, unlike
their civilian counterparts that had these “flaws” filled at the factory.

Tip 4: An alternative to sandblasting is using a chemical stripper. These are  brutally fast and effective, but follow the safety instructions on the label as well as be alert to environmental and disposal concerns.

Tip 5: Once the surface has been prepared by sanding, stripping or sandblasting, any flaws in the body should be addressed. These can range from holes added by civilian owners or rust caused by mother nature. Depending on the damage severity, repairs can be affected by installing new panels, welding or using body filler.

Tip 6: If a panel has many imperfections, it is often stripped to bare steel. Then, a “skim coat” of body filler is applied. The objective is to fill and smooth any indentations in the panel surface. Be aware, however, that evidence of spot welded joints were evident on most wheeled military vehicles when they were new, unlike their civilian counterparts that had these “flaws” filled at the factory.

Tip 7: After the filler has set, the bulk of it is sanded off. The dual action (“DA”) sander is well-suited for this task.

Tip 8:
A thin coat of glazing putty fills any air pockets in the body putty that sanding may have exposed. It also fills the tiniest imperfections in the steel. Like the body filler, it is applied with a plastic trowel or spatula.

Tip 9: After another sanding, the result is an almost glass-smooth surface. By the time this point is reached, it is apparent why bodywork tends to be expensive. A large amount of material and a huge amount of labor has been consumed to get to this point — especially on a  large vehicle!

Tip 10: If your project is a total restoration, there is no substitute for using an epoxy primer. This product, undreamt of during WWII, completely seals in the metal, protecting it from moisture. This is especially important in the case of WWII-era vehicles, whose matte finishes are porous. The importance of this is increased for vehicles stored outdoors.

Tip 11: One area that many hobbyists skip is the use of a pre-prep wax and grease remover. Having a surface free of skin oils, insures that the primer adheres firmly to the metal. If this bond is not firm, then the primer (and each successive layer of finishing product) will lift off over time. Don’t try to cheat here by blowing off the vehicle rather than washing it. Not only is the process less thorough, but many air compressors expel oil, exactly the situation you want to avoid.

Tip 12:
If the vehicle has not been stripped bare or if there are reservations about using epoxy primer, then a conventional primer-surfacer is in order. In most cases, these products are compatible with the existing, cured finish of the vehicle. Be sure that the primers and finish coatings you use are compatible. The higher the build, the more solids it contains, resulting in a thicker the primer coat.

Tip 13:
A thick primer allows for quick sanding. Many modern primers require an activator, and be sure to mix them in carefully. Splashing the material can distort the ratio, affecting the cure. Ultra high build primers provide an even thicker primer – ideal for a rush job, but perhaps hiding fine details of panel lines. Regardless of the type of primer you select, be prepared to apply more than one coat. Contrasting colors help find troublesome areas. Sand between applications with 180 to 220 grit paper.

Tip 14: For superior results, products like the dry guide coat kit followed by light sanding can find the slightest undulations in the primer. Sanding blocks are available in a variety of shapes and sizes allowing one to reach even the most inaccessible areas to be smoothed. “Blocking is the step that makes the job,” in the words of restoration expert Tim Garret.

CLICK HERE to tell us what you think in the Militaria Message Board

Related Posts:

  • No Related Posts

More Images:

featuredImage
After the filler has set, the bulk of it is sanded off. The dual action ("DA") sanders is well-suited for this task.
featuredImage
A thin coat of glazing putty fills any air pockets in the body putty that sanding may have exposed. It also fills the tiniest imperfections in the steel. Like the body filler, it is applied with a plastic trowel or spatula.
featuredImage
The "primer coat" is actually more than one coat with sanding in between, generally using sanding blocks.

Leave a Reply