What primer to use

[Jacques Reed]

Hi Jason,

In the process of stripping parts of my Ford CMP truck I have seen both red and grey primers used at various locations under the topcoats that were originally applied to the vehicle.

Everyone has their preferences and I fully understand. If you like something stick with it. I prefer single pack alkyd enamels for ease of application and cleanup. Over the years I have used red and grey industrial primers made in Australia by Jotun, Wattyl, and more recently Wagon Paints. They have been top coated with Khaki paint made by Wattyl and Croda.

I have not had any paint failures with those combinations and some of the items were painted 20 years ago.

A lot depends on the level of exposure to the elements of the vehicle. Mine is garaged so I am happy to use single pack primers. In more extreme conditions or locations it may call for more exotic primers. Even basic WW2 primers have held up well for 70 years on those dry outback finds we see in this forum.

Having said that, sometimes it is worth deviating from using only one type of primer depending on the situation. Having read the great testimonials for POR15 I can see where it would be great for inside the split rims to make tyre installation easier. I can also see it being a very good paint around the battery area where acid fumes and droplets can cause havoc to the steelwork.

I may just have to buy a small tin of that!

Cheers,

[chris vickery]

Jacques, agreed.
If regular alkyd enamel primer and paint lasted for the last 70 years they will do so once again...
I suppose today we do get caught up with trying to "re-invent the wheel or improve things", when afterall, original worked just fine.
Perhaps it is the work of going through it all that prompts us into a "might as well" sense of obligation.
One must remember that when these vehicles were made, longevity was the last thing in the manufacturers minds.
I probably have my figures wrong, but I recall reading somewhere for example that most MVs lifespans were quoted in days on the battlefield. Outside of the casualty rate for many MVs, the next estimate was in terms of miles.
I seem to think that Jeeps for example had a mortality rate of less than 2500 miles or one month.
Perhaps someone out there has the correct figures?
At any rate, a MV saved is a piece of history saved no matter what kind of paint you put on it.

[rob love]

I'll have to call hogwash on the myth's of vehicle life during war. Perhaps the life was limited on the front lines, but for every vehicle on the fornt line there would be many many more in the lesser echelons. I cannot say I have seen any signs of lesser quality on a MV due to short life expectancy. Otherwise they would have invented the Iltis 40 years sooner.

[Private_collector]

WW2 paints might very well have had lead in the product, which would assist in protecting the substrate. Remember hearing of primer called 'Red Lead'? It was all the rage in 30s to early 60s, and the name speaks for itself. I'm not sure if that used on military vehicles, but in those days they encouraged the men to smoke too, so workplace health & safety not such a great concern as it is now.

I always use single pack primers, and always start with a light but complete coat of etch primer, for excellent adhesion and protection. Etch is only good on bare metal, so I should say that I always have things sandblasted to begin with. Nothing can hide from the sandblasters gun. Bare metal MUST be sealed as soon as possible, and neither etch nor primer/filler is protected from rain or condensation, so also MUST be kept out of the weather. Be careful using etch or any type. It can contain harmful fumes that damage the lungs. In fact, best avoiding ALL paint fumes, so be sure to wear a mask atall times. I finish coat with Protec Barrier enamel with hardener additive chucked in for good measure. Not actually 2-pack, but does have some of the same properties. My primers on the other hand, are always acrylic. You can paint enamel or Poly paints over acrylic, but not the other way around......ever. If body filler is used, as it invariably will be somewhere, prime once body filler is sanded to completion, then apply several coats of spray putty. Once again, I use acrylics there. If using full-on 2-pack, a combined undercoat/spray putty can be used (2-pack) but in long term restoration process, I would advise against it. If left for weeks or longer, it can get extremely hard, and will then be like sanding granite! Some are worse than others, but I can't say which are the hard ones, so you roll the dice there. In the good ole days we deliberately induced that hardness, by leaving a resto vehicle under primer for a number of weeks, and then did a thorough dry sand with glass paper on a long body file. You sure worked up a sweat, but got rifle straight panels (if sanded correctly). Then the priming would be done again, and painted to completion about a week later. Ah, the good ole days!

Now, how weather-proof are flat paints across the various types........., that's a whole other can of worms!

[Lynn Eades]

Good helpful post Tony. Thanks.

[Stew Robertson]

I find this conversation very interesting about military primers
Of all the vehicles I have worked on and sandblasted over the years I have never seen any primer on the vehicles direct from the factories
Just my conclusion and not saying that I do not use primer on a restoration

[Jacques Reed]

Perhaps sandblasting takes off all the paint before any levels can be exposed.

I have only used sandblasting on the chassis due to its size and preferred using a caustic soda and water bath to remove paint on all the other steel parts of my vehicle. This was then followed up with molasses and water immersion for rust removal. It is a slow process but thorough, and more gentle on sheet metal parts.

I can assure you as the levels of khaki/green/sand whatever paint came off after the caustic bath, the last remaining paint to be water blasted off the bare steel was either red or grey primer.

Cheers,