Gazzar Posted August 3, 2012 Share Posted August 3, 2012 Does anyone have experience with hot zinc spraying? I was talking to a bloke who does it today and he was quoting me about £150 for shot blasting and spraying a chassis. I'm seriously tempted with the Lightweight chassis, it makes sense, especially when doing a second hand chassis, as you can ask the guy to preserve the chassis number and preserve the ID, which is important in some parts of the world. I know I'll have to waxoil the inside, but the sacrificial action of the zinc reduces the chance of rust by a lot anyway. It is also less likely to distort bulkheads and door frames, and the like, and it can be painted straight-away. Looking it up it is used on oil rigs, road and rail bridges and is a good alternative to hot-dip galvanising. Quote Link to comment Share on other sites More sharing options...
oneandtwo Posted August 3, 2012 Share Posted August 3, 2012 I had a load of new defender and a lightweight bulkhead hot zinc sprayed 4 years ago. The lightweight one is used everyday by the sea and there is not a spot of rust anywhere on it, I painted it with red oxide and then Nato green, nothing fancy, and there is no lifting or bubbling of paint either. Quote Link to comment Share on other sites More sharing options...
pinny Posted August 3, 2012 Share Posted August 3, 2012 when i left school i worked for my uncle doing shot/sand blasting and paint spraying we also done hot zinc and aluminium spraying on most jobs as i can remember the spec was 150 microns of zinc followed by a etch primer ,undercoat and then a finish we used to zinc spray many items for military uses i think 150 is a good price ,chris Quote Link to comment Share on other sites More sharing options...
Julian Posted August 3, 2012 Share Posted August 3, 2012 Not that I know what I'm talking about really but I can't help think that on something like a LR chassis, where there's as much metal surface inside the sections than there is on the outside that doing it the way nature intended may be best, ie hot dipped. Is there any reason why you want to avoid doing it this way? Julian. Quote Link to comment Share on other sites More sharing options...
mcc1979ian Posted August 3, 2012 Share Posted August 3, 2012 Not that I know what I'm talking about really but I can't help think that on something like a LR chassis, where there's as much metal surface inside the sections that there is on the outside that doing it the way nature intended may be best, ie hot dipped. Is there any reason why you want to avoid doing it this way? Julian. i'll second that, i would want inside and out done, like the old saying "if a jobs worth doing its worth doing proper" Quote Link to comment Share on other sites More sharing options...
Bingy Posted August 4, 2012 Share Posted August 4, 2012 I would imagine that unless the chassis has been completely sealed, then the galv naturally goes inside as it is lowered down into the tank and after a few miniutes in there, flows back out as it is bieng lifted out, coating inside and out at the same time. If there arent enough holes in the metal, the galvanisers normally put holes in so that the metal doesnt explode whilst it is submerged in the molten tank. I too dont think its a bad price HTH Quote Link to comment Share on other sites More sharing options...
Gazzar Posted August 4, 2012 Author Share Posted August 4, 2012 I know the advantage of dipped over sprayed re box section, I've also seen inside LR chassis and there can be a LOT of paint, crud, sand and stuff inside them after a few years, all of which would prevent the dipped zinc sticking. I've also seen old chassis that have been dipped that carry several kilos of zinc in some forgotten chamber, doing nothing but costing money each time you hit the throttle! Yes, with a new chassis, dipped is the smart choice, but for an old chassis I think that this is a good option, plus it's only 5 miles down the road, saving £50 on diesel and a days travel. I'll hot waxoil the interior when I get it back. I'm going to get it done, I might get the axle casings done while I'm at it! I wonder if he can powdercoat the zinc with black? G. Quote Link to comment Share on other sites More sharing options...
bishbosh Posted August 4, 2012 Share Posted August 4, 2012 Hot zinc (or Ali) spray is used as a base coat in industrial paint coatings. It is not a replacement for galvanising but as said above will give a good level of protection. The main differnece I can foresee is that the sprayed coating will be nowhere near as good as galv when damaged - the galv will "self heal" significantly better than a sprayed coating as the bond between the steel of the chassis and the galv is much much stronger than a sprayed coating. If it was me I would get a pipe cleaning attachment for my pressure washer and stuff it up the chassis rails with a good detergent in the mix and then get it galved. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted August 4, 2012 Author Share Posted August 4, 2012 It won't shift the paint, though. Which bothers me. I think a good zinc spray, followed by a thorough interior waxoil, will be good enough. And powercoat black over the rough zinc. I don't like powercoat in general, but I've seen the finish that the zinc leaves and it will take powercoat very well, I suspect. Anyway, I'll try it, if I ever get the cursed new crossmember fitted - endless flippin' RAIN! Quote Link to comment Share on other sites More sharing options...
bishbosh Posted August 5, 2012 Share Posted August 5, 2012 the pickling process pre galv will shift the paint....... Quote Link to comment Share on other sites More sharing options...
Wingnut Posted August 5, 2012 Share Posted August 5, 2012 In my experience the acid bath at a galvanizing plant will not shift paint. I recently had to put a 'new' chassis under a Discovery 2. I failed to find a newly made, ready galved one so I found a good used one, brought it home, stood it on it's end, washed it out, sand blasted it, repaired it and then took it for galvanizing. The yard foreman agreed to put it into the acid bath on a friday night so that it had a good soak and then dip it first thing Monday morning. The only thing that I have found that will remove paint from the inside of a box section that has been diped in paint is a caustic bath and I failed to find anybody in my area doing this any more. The heat of the zinc bath will probably remove some of the paint from the inside but this is too late in the process to be effective. In the end, when I had finished the swap. I injected 5 litres of Wurth rust preventative into every hole in the chassis while it was still clean - all I could do. Peter. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted August 5, 2012 Author Share Posted August 5, 2012 Yes, that's my main concern with the dipped approach, I don't think it's all that much better than the sprayed. I think I'll stick with the plan, assuming it stops raining when I'm not at work, on holidays, doing wife directed DIY or some other non-landrover task. God, I miss my workshop. Ah, well. Quote Link to comment Share on other sites More sharing options...
Team Idris Posted August 7, 2012 Share Posted August 7, 2012 You could stick with the plan and add to it by seal/weld up all the holes in the chassis so it can hold oil. That way the oil can work into the seems over time. This stems from the fact that rust proofing the top rail inside of the chassis in service is near impossible. I'm part way there with four 3/4" bsp chassis plugs, but water still gets in if it fully submerged. Now I have oily water mix in there. So I conclude it would have been very easy to fix back in the day when it was a bare chassis, and is near impossible now its a complete vehicle. As long as its not filling up with clay, I'm well happy though Quote Link to comment Share on other sites More sharing options...
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