[Private_collector]

[QUOTE=Tony Wheeler;177951]what are the relative merits of two-pack vs. enamel with hardener? /QUOTE]

Great differences, with the genuine 2 Pack urethanes beating enamels hands down in durability to UV, abrasion, and impact resistance. Never once in my years of painting have I been asked to paint any vehicle with a 'flattened' urethane. It has always been the preference to use an enamel (often referred to as 'Jam'). In light of its properties, that may sound strange. Prior to recent experience, all efforts were made to achieve the highest gloss, not the least. And there lays the debate. Its all to do with the finish.

Remember when I first started painting my wheels? I had initially trialled a true 2 Pack, which needed a flattening base added to achieve the desired level of reduced gloss. I was told a certain percentage of flat base was required, then added that amount, and found it was still too glossy. Next coat, more base added, and less gloss, but still far too much. At a particular point I gave up trying. Those wheels are still almost high gloss..........on the insides only! I wasnt stupid enough to experiment on outside. Now, flattening base; if you have some, pour a dollop of it onto a surface and let it dry. You will notice it had turned to a white powdery stuff. Thats what is being added to your paint. Thats the cause of grease, oil, dirt, etc... soiling. Flattening base causes a trade off of your desired finish gain VS the loss of durability. This issue exists in all paint types. About now you are probably wondering where you answer is, yeah? Well, its more of a question of choices that decides which paint type is best for you.

Genuine 2 Pack paints.
The 2 Pack paints give a much better durability and long lasting gloss. Gloss obviously NOT desired so a flattening base gets used, thus removing a percentage of the benefit over enamel with hardener. 2 Pack paint is much more difficult to spray, and requires a designated, dust free environment. Though the finish may be almost flat (if you add enough base to the mix) dust nibs and oher contamination will show on the finish. Also the 2 Pack paints are extremely dangerous and the fumes from spraying will damage your lungs, without doubt. Top quality face mask is NOT optional. Much better paint. No question of that, but some of the advantages are lost with trying to achieve low gloss finish, environment it should ideally be applied in, or the ability and experience needed to get a high quality finish.

Enamel paints
Any automotive painter will tell you that enamel paint is inferior to urethanes. In fact, when I say 'urethanes' I refer to several forms of product, each with unique variations that would be difficult to discuss here. Now, the enamels. Much easier to spray, and particularly forgiving when in 'lustreless' or flat form. Still needs a flattening agent or base, regardless of whether its self mix or factory mixed (as mine is). Nowhere near the durability of 2 Pack, but this is much improved with the addition of hardener. An enamel with no hardener is just a sticky mess which takes ages to dry properly, has very bad resiliance to impact or abrasion, can be problematic to recoat in future (especially if using another brand or type of paint), and because it remains tacky for a lot longer.........more contaminants get stuck in th surface. Be warned, you will still need to wear a respirator mask for this paint. It doesnt give off cyanide though, which is airborne with urethanes. In my youthful 'invincible' years I sprayed both types without always botherong to wear a mask, and now suffer accordingly. Let my stupidity then serve as a warning to others. You will not get away unscathed!

My personal choice is the enamel + hardener option. Much easier to use and apply. Its fast drying, and good results can be achieved, even if sprayed outdoors. This has been proven to me on many occasions. I paint everything outside in the open, where the fumes can be dispersed (I still wear a mask though), and parts can be handled gently within a few hours. The 2 Packs really need a heated spray booth for drying correctly. Check through my posts where I have painted something in the morning, then put the parts together later in the day, without damaging the painted surface.

All that is good and well but, as we are painting military vehicles, a finish which is not perfect more accurately reflects how these vehicles would have been done when first built. They would have been full of paint 'runs', surface contaminants, and numerous other flaws. A poor quality paint job would have been the norm. After all, speed of completion was the requirement, not a good finish. The paint they would have used in production would most likely have been a nitrocellulose lacquer or a variation of an enamel produced at the time. The irony is that in production, they would have sprayed a lot of things once the vehicle was almost or fully assembled, resulting in an appaulingly messy finish, with no regard to durability or resistance to damage of any kind. The concerns of succeptability to chemical and physical degradation were not of concern 70 years ago. Having this occur on your vehicle may actually give a more authentic appearance.

One final point. Which ever type of paint you choose, if you use a hardener, there is a fair chance the surface can handle a wipe down with mineral turpentine to get most substances off. You will be wise to test this for yourself, on an unseen area, prior to attempting a full scale clean on outside panels.

My enamel paint (with hardener additive) has served me well, and will actually lose more sheen over time. I also expect it will gain a weathered appearance with use and subsequent cleaning. Thats why I want to spray it as well as I can initially. Time will give me the more authentic aged look.

If you are getting a paint job done professionally, or your vehicle will be getting off-road use (and damage), go for the 2 Pack option. If not, save yourself some trouble and try the enamel. Just dont use enamel without adding the hardener. You'll be sorry in the long run if you do. Well thats my opinion anyway. Others views will vary, no doubt. Paint qualities will vary significantly across brands and types. Protec seems to be universally accepted as one of the more easier/better ones. I can certainly support this from prrsonal experience. I use Barrier type enamel. Its an industrial grade product, more for heavy equipment than, say....a Jaguar.

Hope this helps.

P.S: I cant offer opinion on putting a low sheen clear over solid colors, having never tried it, but I would have thought that a similar surface finish of the clear would sustain staining of contamination also. The clear would definately have to be of same paint brand & type, of course. Just bear in mind that a number of new vehicle manufacturers have moved away from "COB", which stands for Clear over Base, in favor of using the base only without clear top-coat. Base in this case refers to a color, usually metallic, but does not have to be. The down side of this decision is that when machine buffing a metallic finish, the physical abrasion of the cutting compound often leaves swirles visible, and these in turn require further polishing to remove. The same marks are left in a clear coat too, but they are invisible as no pigment is involved in this case. This logic does support the use of clear top-coat to reduce visible marking. I would welcome photos of both methods after a few years, to compare long term results.