Best chassis paint for restoration job

[slihp]

After years I've finally go a house so some where i can work on the truck. Mines is a 2001, My plan is to do a chassis & bulkhead swap 2 years from now but i wanted to see if i could get a couple more years out of the current chassis. After stripping down an welding in what needed replaced im just about ready to paint. Im doing this in 2 half's , back then will turn it around and do front. Everything ive removed will get painted individually but for the chassis what is the best paint to use (primer then paint). Ive been reading a lot about using a paint that docent trap in any moisture currently their and docent crack and let new moisture through. Just wondering if you guys have any advice on what use?

[muzaz]

I'm in your same situation. My plan is to paint the bare metal with a rust converter first, I'm using Wurth. As a top coat still not sure but most probably will use a 2K bedliner type of paint. A friend of mine used "955 Tough Liner" with good results.

I'm all ears to further options and suggestions.

[fmmv]

I normally use Jotun Jotamastic 90 AL as primer, Jotun Hardtop Flex as topcoat, might use Jotun  Barrier on some suspension bits. They are all 2 pack, and produce a tough finish. For a single pack primer I rate Isopon Bondaprimer. The general logic is that marine paints are designed to withstand the sort of conditions Defenders may be in. You can put 2 pack on much heavier than 1, and it hardens rather than dries, with fewer pinholes. However, I think you would need to spray Flex to get a decent finish for bodywork, maybe a roller and brush it out but I haven't tried that, and it would need thinning I would guess. But it works well on the underneath.

[muddy]

If you only need it to last a few years then I wouldn't spend much on fancy paints, A half decent zinc rich primer and some satin black will be ample. Perhaps go crazy and spray some old oil or Dynax S50 around if you so choose.

I like Kramp Paint available from nearly all agricultural suppliers, it brushes on well straight from the tin, the primer dries quickly and the top coats are nice. you can also get a fast drying thinners if you are in a rush.

[fmmv]

To be brutally honest, painting an old chassis with any paint can be a bit of a waste of time; far better if you possibly can  to replace with a new galvanised one, unless originality is important.  The chassis tend to rot from the inside, as well so the damage you can see is probably worse inside.  I know the relative costs, and I also know the feeling of doing nice repairs only for the rust to appear somewhere else. 

[muzaz]

3 hours ago, fmmv said:

To be brutally honest, painting an old chassis with any paint can be a bit of a waste of time; far better if you possibly can  to replace with a new galvanised one, unless originality is important.  The chassis tend to rot from the inside, as well so the damage you can see is probably worse inside.  I know the relative costs, and I also know the feeling of doing nice repairs only for the rust to appear somewhere else. 

But an old chassis is not necessarily a rotten chassis, mine is 36 years old. It has surface rust and required repair to the dumb irons. Treat the rust and repair the damage and it should easly give another 36 years of service. 

The bulkhead is another argument, I went for a galvanised one, but still you have to paint it. 

[fmmv]

You may be right but looking at the picture the rear of the chassis doesn't doesn't look in great shape. If its localised rust, then sure a repair is ok. The OP location is Glasgow so probably a lot of salt on the roads, and I'm guessing the front is better than the rear, but I'm thinking better to be realistic. The OP is planning to put a chassis on in 2 years anyway.

[FridgeFreezer]

Commercial or agricultural zinc-rich chassis paint, cheap, easy, robust, more than good enough.

[Snagger]

18 hours ago, fmmv said:

To be brutally honest, painting an old chassis with any paint can be a bit of a waste of time; far better if you possibly can  to replace with a new galvanised one, unless originality is important.  The chassis tend to rot from the inside, as well so the damage you can see is probably worse inside.  I know the relative costs, and I also know the feeling of doing nice repairs only for the rust to appear somewhere else. 

I agree entirely, and also with your following post about the use of salt on UK, especially the Socialist Republic of Paisley’s roads.  That chassis will be worn out and probably past being worth repairing.

I would just scrape of as much rubbish and loose rust as possible, not bother with wire brushing, and just liberally brush on the rust converter before using Hammerite Underbodyshield - the one that is part bitumen, part waxoil, not the old “underseal” that is almost pure bitumen and causes rust acceleration.  I used that Underbodyshield on my 109; it’s not pretty, but it does a good job and doesn’t chip or flake at all.  It covers well with a roller or brush and has active rust inhibitors (not converters).  Try to wash the inside of the chassis out before drying and using probes with high pressure wax spray to coat the innards.

However, like FMMV said, I suspect this is all a bit of a fool’s errand, along with reassembling the car, just for two years use.  They rot from the inside out, like mine did.  Painting the outside is more cosmetic than structural protection.  If you lived in a non-salted environment like Muzaz (assuming he doesn’t drive on the few beautiful Maltese beaches or dunk the car launching boats), then I’d be less negative, but I honestly think that if you have already decided the chassis needs swapping, then you are peeing into wind with the idea of stretching this one out another two years.