Hi, I service quite a few factories where Hot Dip Galvanizing takes place (Industrial Galvanizers) They do staircases for A/C units on buildings, strret light poles, mining jobs, box & boat trailers, etc., etc. My question - if I had my ol' car's ch***is blasted, would I benefit from having it hot dipped? The process involves a dunking in a dirty big tank of acid, then the job is dunked in a huge tank of molten Zinc. My only doubts about this process is it may warp the frame in the heat? (all brackets, welding, gadgets, etc. all done first before the dip that is) I was only thinking this as it would make the platform of the car last a damn long time. any thoughts?
Why would it warp? I think it would make a hell of a nice foundation, but then I live on the gulf coast where rust is a constant aggravation! The only draw back might be fasteners not wanting to go in holes because of buildup.
Boat trailers yes, cars no, unless you want it to look like a boat trailer! I don't know what kind of extreme conditions and cir***stances you are planning on subjecting this car to, but there's nothing wrong with a sandblasted and properly painted ch***is.
A place i used to work at built boat dock frames and they would come back warped and have some sharp spikes where the galvanizing would run off.
Around here a lot of off road Jeep builders have the frames hot dipped. never heard them talk about any warp issues. I guess it may depend on how stout the frame? Just make sure all your frame mods and welding are done before having it dipped. It looks OK on a Jeep, but in my opinion I would not want it on my roadster.
Galvanizing also increases the size of parts incrementally which may or may not lead to ***embly problems/issues. Threaded holes will need to be chased....
special zinc chromate primer will need to be used, aircraft quality for any painted surfaces. I would hate to be the one scuffing and preping that surface for paint. Bad stuff for your system.
I'm just looking for a solution that will be beneficial to me & my Rod in the long run. I know, I'll need to have all the brackets and welding jobs done first. Re-tapping threaded holes is not a problem at all. I wish that was the least of my problems ahead. All I was worried about was the warping under heat factor. sanding/etching/ painting isn't a big deal for me. I will contact my galvanising customers in the new year, and ask more questions. Thanks guys for the input so far. Will keep you posted as to whether this was a dumb question or not.
I'm an architect and I spec hot-dip galvanizing on fabricated components all the time, even fairly delicate pieces, and haven't had warpage issues - though I've been warned about very long, thin parts. I have had finish issues, though. It's a factor especially on hollow or concave objects where molten zinc takes time to drain and solidifies as lumps or runs or stalac***es. It has to be finished afterwards by sanding, etc. and there's always the chance of taking off too much. Then you "cold-galv" to touch up, and that really isn't as good. Excessive zinc inside hollow sections can also become a weight issue. Done with care it could be a good solution. It depends on the sort of finish you're after, too. What you see on restored Edwardian frames (or, say, steam locomotives) shouldn't be too hard to achieve, but a something you're justified in sticking mirrors underneath at car shows might be a bit harder.
Hey Mudgy...you just gave me an idea of what to coat my set of 5 bent spoke Kelsey Hayes wire with ..... HOT DIPPED GALVANIZE ! Unique!
Instead of HD you should have the frame phosphated and ecoated. This is the process the majority of new vehicles use for the frames and ch***is components. The process is similar to HD, the frames goes through a series of dips and then is baked. An ecoated frame would have a lot more paint opitions then a HD frame. Most new car bodies are phosphated and ecoated.
Hot dipping can warp large pieces of thin material because of the heat. Remember that the vat is in the 500 deg range... Almost as durable, for a car frame, might be cold galv spray or brush. I have had very good success painting over cold spray with little or no prep. It is my favorite base coat on just about everything including blocks, heads, intakes and such. .
My only dealings with galvanized metal was working with galvanized duct work. I had some sheet metal parts made and the guys told me to use "paint lock" instead of the in stock galvanized metal if I wanted to paint the parts. They claimed the paint would not stick well to the galvanizing. This was over 25 years ago. I eliminated it as an alternative after that. I can understand it on swamp buggies but it's not worth the effort for a nice street driven hotrod. IMHO Too many cheaper ways to prevent rust.
Thanks fellas, the car will not be a show pony, rather a daily driver when done. So I'm looking for practical ways to treat components. Mirrors under a car at a show won't be my scene. Rather interested about the subject of paint not sticking to zinc. I wanted to hot dip the ch***is, then whack some black epoxy paint on top, just so you don't see a silvery frame. Surely a scuff - up will alow paint to adhere to a zinc finish? I know there will also be stalac***es after a dip. The guys in the plants I look after grind off the dags before packing/strapping jobs for despatch. long thin jobs don't seem to be a problem either, the plants do a LOT of mining bolts daily, and they seem to turn out fine. As said, I would visit a plant every 4 weeks or so, so I will ask all of them about my idea before rushing ahead. If the heat warpage/paint adhesion isn't an issue, I reckon I'll go ahead. Surely on all the innards this would be a great way of keeping the beast in good nick.
Galvanizing(zinc) itself has good resistance to corrosion. But, at any scratches or breeches in the coating, corrosion of the underlying steel is actually accelerated. Another important down side is that the fatigue properties of the steel are reduced by plated galvanizing, and even more by hot dip galvanizing.
I go back to my original statement: Unless an old car has spent the past 70 years in a creek bed, the paint and ch***is are usually fine. Blast it, epoxy prime it (.e.g. PPG's DP40) and topcoat with a single stage black. That would be 2-pak in Aussie speak. I believe you're way overthinking this.
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