When I first got the M37, it was a mishmash of faded volunteer fire department red with blotches of fire department applied primer and some of the original Marine green showing through in places.  It also had some rust and a some really bent body panels...   I didn't plan on converting it back to green until I located the original hood markings when I was doing some sanding prior to fixing one of the rust spots...

Painting a MV is not very hard, remember that for the military, paint is a metal protector and a way to help conceal the vehicle. I looked at Bill Wincapaw's truck and the one that David Ahl did for his magazine one weekend at the Thomson rally at Cedar Rock Farm in Thomson, Georgia. Bill's truck was absolutely stunning, but you (and he) would not want to take it where it might get scratched. The truck that was done for the magazine is also pretty. The techniques and paint they used are great. I, on the other hand, used the same paint and general techniques, but went for a "motor pool" truck that can be taken off road.

I've also painted a few Mercedes when I used to restore them, but M37s are a lot less stressful, more fun, and you can do a lot of things differently since your goals are not the same...

Prep and paint for the solid metal areas:

Sand off the existing paint on the hood sides, tailgate center bottom and top corners, rear bumperettes, front bumper, around the tank filler neck, and the dash. Do this in order to read the original unit markings that have most likely been covered by subsequent layers of paint. It is the only way you will ever be able to possibly learn the history of your truck, one day you may want to know this, and if you sandblast, it's gone....    Also be aware that you may have stars or logos on the doors, and various cautions on the dash, so sand them lightly as well.

Sandblast, power wash, or sand the rest of the paint off until you get done to either bare metal or solid paint. Fix rust (see the bit further along on this page).

Blow the area you are going to paint with high pressure air and wipe it down with a tack cloth to remove dust that will cause problems with paint adhesion. 

For the inexpensive, military correct style paint job put three or four coats of good primer on such as Insul-X from Agri-Supply or your local farm supply place, or Home Depot or Lowes (synthetic enamel metal primer). This may be thinned with Xylene or Naphtha at rates of 4:1 or 5:1, rate of thinning and thinner depend on temperature, air pressure, etc. I used 4:1 and about 40psi for my "cheap" gun.

Don't skip on the primer when all your metal prep work is done. The synthetic enamels, and the older lacquer based paints, need five coats to protect the steel against moisture (read rust) so you need at least three of primer and two of color. Alternate your pattern when spraying, horizontal passes on one coat followed by vertical or diagonal on the next so that you are sure to get even coverage everywhere. Go especially heavy on exposed edges like those on the fender lips that will get more contact and that are harder to get good paint coverage on.

Put two or three coats of color on top of the primer. I used Gillespie available from RAPCO in Texas. It takes about three gallons to do a M37 if you partially disassemble it (take fenders off, etc.). Go ahead and order a case since it is your best value. If you are like me and disassemble and paint both sides of everything, you will need a case.   Bill used five gallons, but he did a frame off restoration. He also added hardener and a flatterer (since the hardener will add gloss), but you really don't need the hardener, especially if you are likely to run into tree branches where you are going to scrape the paint off anyway... Plan on giving it a coat every five years or so instead to freshen things up... You can open some big debates on what the exact color the truck should be and who has a perfect OD match, but mine was a Korean War era USMC rig, so it got Lusterless Forest Green, Vietnam era trucks got Semi-Gloss Forest Green. Army trucks get lusterless or semi-gloss Olive Drab with real early examples getting WWII Olive Drab. Any of these colors look good on the trucks. If you want to go local, use a color from the same folks that made your primer in whatever color you like. My rig was Massey Harris red for several years before I returned it to its original USMC livery. Mix just like the primer, 4:1 or 5:1 with Xylene or Naphtha (available at Lowes, Home Depot, Agri-Supply, etc.). Gillespie is very forgiving paint to shoot, lusterless is easier than semi or gloss paint since it doesn't reflect body or painting imperfections as much. Gillespie touchup paint in the spray cans is a perfect color match with the gallons, and it doesn't fade on a truck parked outside like the Aervoe reportedly does...

Clean everything, wipe down with a tack cloth before spraying a coat of paint, lightly sand between paint coats with a 120 or finer grit sandpaper. Clean the sprayer after each batch of paint.

Get a copy of Military Vehicles November December 1998 Issue Number 70.  The issue was devoted to then editor and publisher David Ahl's painting of his M37 project truck that I referred to at the top of this page.

In my opinion, the idea is to get a good coating of paint onto the metal so that it doesn't rust. You also want to look reasonable good without having every ding and dent show too much. Remember to relax when you paint.

Repairing Rust:

For general rust that is not through the metal (surface pitting or flaking). You need to get the metal to what is known as its "gray" state. This is where all you have is bare, relatively shiny metal. It isn't exactly gray, nor is it as shiny as stainless steel cooking pans, but you will know the condition when you see it, no paint or rust, just bare metal. The best way to get there is to sandblast. A cheap siphon job can get you through small amounts of rust or parts (Sears or Northern sell them. You stick the pickup tube in a bucket of sand, hook up to dry air and away you go) but the better way to go (especially if you like tools and think long term) is to get a pressure blaster. The pressure blaster works the same way except that the sand is in a tank that is pressurized. I got a ten gallon job from Northern that works well. You need a good air supply.  A higher capacity compressor with good dryer is needed, but I get along fine with a 5 hp, single stage compressor with a vertical sixty gallon tank with three cheap water separators. I also use "play sand" from Lowes as a blasting medium as it is cheap, removes the paint and rust well, and comes in easy to handle bags. Another acceptable rust and paint removal method is to wire brush.  Although it is not quite as good a solution as you have a greater tendency to leave rust in the pits in the steel. Use a die grinder attached to your compressor, or a wheel in your drill, or a right angle grinder with a cup wire brush in it. Get the metal clean.

Then you skin coat it with Bondo (I know it has a bad name, but it is ok as long as you keep the thickness down, you can't build 1/4" thick sections with it and expect anything good), wait for it to cure, smooth it out with your sander, apply another skin coat and repeat until the area is really smooth and you can't tell where the repair material starts and stops. For smoothing, I start with coarse paper in my DA sander (love my air tools) and work my way to a finer grit paper in the sander and finish by block sanding by hand. Low areas appear as non sanded areas. You fill them in with subsequent thin applications of material and sand some more. When you think it is really smooth, hit it with some primer. Lightly sand it to reveal low spots. Lacquer putty applied with a very flexible (read thin) putty knife on the low spots and bug holes, sanded and followed by more primer and sanding until it is smooth to the eye and hand. If you are doing a trailer queen or a Porsche, do this step for a couple of weeks... Otherwise, do it until you get good and bored... Remember that Military Vehicles (especially ones driven and taken off road) don't need to be super perfect, but have some pride in what you are doing.

Repairing holes:

The best method is to cut a piece of scrap steel of the same alloy and thickness and weld it in, grind the weld, and repair the grind area as above.  Another method is to fiberglass over the hole. Get a fiberglass repair kit. Cut same pieces of the glass cloth just a little bigger than the hole, and some strips that are shorter and thinner than the hole. Mix up the resin and apply to the area around the hole with a cheap paint brush (cheaper the better, you will be throwing it away when you finish you hole repair...). Put a piece of fiberglass over the hole and paint some resin on it until it becomes transparent. Repeat with the other pieces of glass and the strips. Get five or six layers over the hole and mix up the direction of the strips, alternate strips and larger pieces ending up with a larger piece that covers the who area. Paint some more resin on the area, don't worry too much about runs, drips, or errors, or if it sags. Once it all cures and is no longer tacky to the touch, either add more resin and glass to fill in the sagging depression, or sand off the high spots. Sand everything until is is really smooth, add more fiberglass if you cut a hole through your patch. Once you get it relatively smooth, go to the skin coat of Bondo (they make a version expressly for going over fiberglass, but both types work, and the kind for going over fiberglass works well by itself, so you don't need to stock up on too many different products, you can mix manufactures, but I like to stick with one brand...) and finish as above for generally rough areas.

REMEMBER to allow the fiberglass or Bondo (body putty) or lacquer putty to cure before you put another material on top (like Bondo over the fiberglass or primer over the Bondo) as you need to let the gasses escape before you seal them into the layer that you placed. You will get bubbly paint and localized failure if you don't. A day's rest between operations to admire your work is the best way to achieve this. Lacquer putty is an exception as it is basically super thick paint in a tube.

Be fearless. The worst that can happen is that you will have to grind or sand off your repair and do it over again.  At the worst case you will just spend a little more time, money, and sweat to learn how to do better the next time. 

BTW: All the above advice I've been giving you is assuming that you want a respectable truck using off the shelf, inexpensive materials and are planning to use synthetic enamel paint like the primers and the Gillespie (or Aervoe). If you are going for a
high dollar paint job using epoxy based paints then you need to be very careful about mixing brands and materials as the chemistry of the various products will not always be compatible. 

Which brings to mind: WEAR a RESPIRATOR when sand blasting, wire brushing, grinding, sanding, or painting on these trucks. You can do damage to your lungs even with the "safe" products. And don't forget to wear eye protection.

A page listing the marking scheme that I uncovered on my truck is located on USMC markings page.

Color information:

USMC Lusterless Forest Green - 34052

USMC Semi-Gloss Forest Green - 24052
The numbers from Federal Standard 595B catalog for USMC yellow are:
Yellow Matt Finish - 33538 (use with Korean era Lusterless Forest Green)
Yellow Semi-gloss - 23538 (use with Vietnam era Semi-Gloss Forest Green)
Old Caterpillar Yellow is the nearest known civvy colour to USMC yellow, being only a few parts-per-million different.

I used three gallons of Gillespie USMC Lusterless Forest Green (34052) from RAPCO to paint my truck.  I didn't do a frame off restoration, but I did remove just about every part from the fame with the exception of the axles and cab at some point durring the renovation and I put paint on all sides of the pieces that got removed.

For folks with US Army trucks, some scans from TB 43-0209/Color, Markings, and Camouflage Painting of Military Vehicles, Construction Equipment and Materials Handling Equipment/October 1976 might be helpfull.  The illustrations are for a M715 and a M38A1, but the inforation was adapted for use on M37's in inventory at the time the TB was printed.

Tonakadoctor in Fayetteville, NC posted this bit on metalwork in the Powewagon Advertiser Forum in December 2004:

Bondo is Great when used properly

The correct way to do bodywork is to get the metal right first.

If you are repairing a rust hole you need to cut the metal back to good clean solid metal (you won't be able to weld to thin rusty metal).

Shape the patch as best as you can until it matches the contours of the hole NOTE: you want the patch to be larger than the hole, leave about 1/4" excess.

Now slightly recess the metal around the hole with a SMALL hammer so the patch will be flush with the surface of the body.

Now grind all the paint and surface rust away in the area and also on the patch ( if your using rusty metal to patch with shame on you).

TACK weld the new patch into place. DO NOT try to weld a solid bead on the sheet metal unless you are using a TIG welder. Try to use a MIG welder with solid core wire and argon gas, not flux cor wire if possible(110v MIG welders from sears or century work well on sheet metal) or braze the patch on as SMAW(commonly called STICK) welding is worthless for welding thin sheet metal (you'll blow alot of holes in your work or get really frustrated with stuck welding rods)

Now grind down the welds and rough up the surface of the patch and about 3 to 4 inches around the patch down to bare metal ( Fiberglass and Plastic Body fillers will not stick to paint for very long).

Now check that there are no high surfaces on the patched hole.that will protrude from the filler when complete if there are just "adjust' them with a small hammer.

NOW Time for Fillers.
_______Use a fiberglass product for the first layer (BONDO is NOT waterproof and will bubble in less than 6 months due to moisture trapped behind it, FIBERGLASS IS), I preffer to use Tiger Hair or a similar prodict as it has the fiberglass strand already mixed into the putty like resin. Spead a thin SMOOTH layer and allow it to set then rough it up with a grinder or high speed sander and make sure that it is at least flush with or slightly below the finished surface you are repairing (you don't want high spots as it is much harder to sand than the plastic fillers and will result in low spots.
________Now it's time for the "Bondo", spread as smooth a layer as you can (once it starts to harden stop working it or you will have a hard to sand mess). once it is hard you can sand it to shape. repeat as necessary.

One trick I use to "feel" if it smooth is to close my eyes and feel for imperfections.

Now admire your work. and spray some undercoating on the backside of the patch to seal it from moisture

If you are just pulling a dent don't drill a half million holes for a slide hammer like the amature books tell you to. If you have a cheap slide hammer that is used with a screw in it remove the screw and install a hook. now you can tack weld (more tack than weld here please, it's OK if they break off you can tack them back on) 3/8" washers on the dent and use the hook to pull on them like a professional shop will do. The shop I used to work at actually had a spot welder that was made for this purpose. When you have the dent pulled to where you want it simply break off the washers and grind the welds smooth (that's why I said more tack than weld)

For filling a dent (that you didn't drill a half million holes in) get the metal as smooth as you can first and you can simply spread a thin smooth layer of bondo and work it to perfection

Now if you drilled all those holes, buy a new panel and weld or bolt it on as required as it will become a cancer project. or you will be really good at welding holes in sheetmetal.

Good Luck

This page is provided as a resource for other military and civilian power wagon owners, it should not be considered as an endorsement of any particular manufacturer, brand, or dealer.  Information is believed to be accurate at the time it was added to this page, but is not guaranteed in any shape or fashion.   Always read and follow manufacturers' use and safety cautions.