Powder Coat, Galvanize, or Redi-Coat? I think I found a solution to longevity!

[teleskier]

I was investigating how to restore my frame and body and it led me down a path of chemistry and discovery.

I initially was sold on powder coating my frame. A friend of mine owns Austin Speed Shop and they use a great powder coating company here in Austin. As I started to clean the frame I wondered how in the world the crevices and channels will ever get sandblasted and subsequently coated. Its impossible. It looks great, but I just was not totally satisfied.

I then considered galvanizing, but didn't want the look of a galvanized frame. I read some information on painted galvanized surfaces sent to me by Gary at Process | AZZ Basically, you can get paint to stick immediately (<24-48h) or after 1 year, but that requires sanding the surface. This is due to the fact that the zinc in the metal oxidizes and prevents paint bonding. Further, all the holes would need to be tapped and this would lead to exposed bare steel in the most rust-prone areas.

The hot dip process by which the metal is placed in sequential baths of alkali, water, acid, and then zinc is what was the most appealing about galvanization. If the frame was under the fluid, it would go everywhere and coat even impossible to reach areas.

Could I hot dip and then powder coat? Probably not, because the bare steel would flash rust leading to the need to sandblast again anyway.

Then I was on Hot Rod forums and the acid dipping process popped up again. A bunch of bad reviews because the acid would permeate the seams and then leach out somehow later. This was particularly true of seam sealer. If this happened after painting, it would wreck the paint job by bubbling and eating away at the paint. All of these forums concluded at the acid needed to be neutralized or washed to prevent this.

Then I found this place in Detroit called Redi-Coat. These guys take a car, bake off the crud (oven on clean cycle), dip it in alkali, then deionized water to clean, then acid to strip paint and anything else, then a rise, then zinc, then rinse, then a electronically applied primer, rinse , rinse, and bake it on. The parts come out like factory primed body panels. Following this, it would require seam sealing and then topcoat.

This process coats the parts with zinc for corrosion protection and then immediately primes it in a bath of electronically applied primer - same general principal for powder coating. The paths and neutralizing seem to address any leeching of acid others complained about with simple "pickle" baths.

Michigan Redi-Coat Site


Anyone ever do this or does anyone have any thoughts. I think I will do this and report back how it all goes.

 

[rkymtnflyfisher]

hoes would need to be tapped

I'm in!

 

[Coolerman]

Nice! Tapping hoes at azz.com Just saw that!

You know... somehow your response just didn't seem appropriate. Then I went to the link...

 

[Weber Sarge]

We have a AZZ galvanizing location 20 miles north of where I live - was really wanting to go the route of galvanizing (hot dip/acid) on my frame when I get around to doing the restoration and maybe even the body itself . I like the idea of the zinc/electrostatic process - sounds promising .
Sarge

 

[Output Shaft]

Duplex coating of galvanized steel is always a bit tricky to do right... as you've discovered.

My thoughts:
I have an ARB winch bar front bumper on my cruiser that I galvanized 20 years ago. It's still in perfect condition. Had always been outdoors and near the beach. My car frame on the other hand is rusting and I try to keep on top of it with linseed oil.

If you galvanize the frame it will outlive you with no other topcoat required.

Even if you galvanize, then do that fancy top coat process described above, you're still going to have to tap out all the threaded holes in the frame. A topcoat won't eliminate that step.

Since a fancy topcoat is not required to protect the frame after galvanizing, its purpose is soley cosmetic; exchanging gray for black.

I would not powder coat over galvanized as it's overkill, difficult to do correctly and the zinc will have to be sandblasted prior to pc...removing a lot of the zinc you just applied.

I have galvanized as many parts on my cruiser as possible; the front bumper, skid plates and (unfortunately) my ARB roof rack.

On hollow structures such as my roof rack, the rack gained 25 lb extra after it got dipped. Went from 75 to 100 lb. As they have to cost the insides if it too. Kinda turned into a fiasco. Way too heavy.

All of my parts that I got back from the galvanizer were a LOT heavier once galvanized. Even the flat skid plates.

On a boxed cruiser frame, it's going to be the same issue: It's going to get VERY heavy once it's galvanized.

I asked the owner of the shop about the weight gain I should expect from galvanizing, and he said to expect about a 25% increase in weight.

For a boxed cruiser frame, you'll be looking at adding several HUNDRED lbs of zinc to your vehicle that you'll be dragging around forever.

That's a LOT of weight.

Based on that, and my experience with the weight gain on my small parts, I personally never would galvanize a cruiser frame.

There is also a very real risk of warping it. Some galvanizing shops won't do car frames because of this risk.

 

[teleskier]

thanks for the input.

Anyone here have experience with electrostatic primer placed in a dip tank?

 

[teleskier]

Also, the zinc plating at Redi-Coat is not a heavy application as far as I know. The place is just outside Detroit - I used to live 15 miles from the place - now 1500 miles. Anyone in the area mind checking them out before I spend 1k in transport alone?

 

[Jdc1]

thanks for the input.

Anyone here have experience with electrostatic primer placed in a dip tank?

My frame was sandblasted, ecoated and then finished with an industrial poly urethane. Pictures are a few pages into my build thread.

I chose this as I was unsure at the time if I was going to be making changes and did not want to interrupt a powder coat.

 

[teleskier]

One more comment here: The parts are actually dipped in tanks to remove rust everywhere including inside the doors etc. The primer is applied by dipping as well. Nothing is left untreated.

Here is a photo:

Sample

 

[srgould41]

Hey, it's a 40! Can you hold your breath? Just drive it in then drive it out the other side and you'll be good.

 

[Healey]

I live in the area, and have used the redi-coat place. I had a chassis dipped there a few years ago. That acid dip sure does a job. I'd recommend the place, but with some cautions. For mostly flat surfaces and c-section frames, it's great. For doors with the crimped bottom sections where the outer skin crimps to the door - beware! Any part that has recessed areas has the potential to retain the initial acid solution will potentially have trouble with acid leaching over time. No matter what they say about the neutralizing bath. It seems that the neutralising bath may not get in all those places. So, my chassis worked out really well. Guy I know with a really nice '70 Chevelle - he had his doors done there and about 2 years later had the bottoms leaching out from acid retention. Had to redo the doors, and of course, get a nice new paint job on the whole car to get a good match. cha ching. No matter what they say - recessed areas are still at risk. For the 40 - the frame would probably be ok to do. The boxed sections are large and have large holes, so the solutions could easily get in and out for effectiveness. On the body - most panels are flat, with few recess areas that I can think of. There are likely some though. Rear sill? Top channels around the tub? Rocker assemblies? Don't do any of the doors. Those ambo doors would be at big risk. IMHO.
The acid will remove everything except very solid metal. So, if you have bondo, or rust, it will be gone and you will quickly see what/where any body work needs doing. Then you will have to install new metal and defeat the e-coat application in those areas.
Conclusion: if you want a good comprehensive metal strip and e-coat primer, then this is great. Cost me about $2,400 to have my Healey done as I recall. Chassis only. I had it acid dipped and neutralized 1st pass. Quickly had my body guy to all metal work. Then 2nd pass had the process repeated, with the e-coat. I asked that he pay special attention to the neutralizing bath. Can't comment on how long the e-coat will last v blast, prime, paint.
The parts/cars are actually dipped in huge tanks. Huge tanks of acid and neutralizing solution. Parts in big baskets and car bodies or frames on racks with chains and hooks to lower them into the bath. The place is in an industrial park down by the airport. It's one of those places - you go in there and look around and smell the fumes in the air - and you just wonder how the EPA lets them be in business. The guy is in business primarily doing parts for OEM's. Large scale stuff. The restoration business is just an aside. He was very helpful though and good to deal with. He's a car guy himself - Detroit iron of course. If it's still the same guy.
Hope this helps.

 

[teleskier]

Regarding the failure of getting acid out of closed spaces: I thought about drilling/cutting some clean 1" drain holes in the bottom of the ambu doors and side doors to prevent any accumulation of moisture in there. It seems to be an issue that would be easily corrected with a small weep hole. Further, this truck lives in TX and will be a fair weather Cruiser for as long as I own it. There is some rattling pieces of metal I cant get out now anyway.

Like this:

 

[teleskier]

Healey: Thanks for your personal insight. When this is done (if I do it) I will plan on visiting to watch - my in laws live 5 miles from there.

 

[snaggletto]

Keep it simple. Blast and then prime and paint. Keep the frame coated with linseed, or fluid film etc. Frames that were not taken care of have lasted 30 years+.

 

[Fast Eddy]

this truck lives in TX and will be a fair weather Cruiser for as long as I own it.

Why worry about exotic coatings then? Just POR it and paint over that.

In CA my 40yo rigs that are not fair weather Cruisers have some surface rust, but nothing worse than that.

 

[White Stripe]

One thing you could do is get a new frame from aqualu and have that galvanized, you could then skip any sandblasting or acid dipping on the frame. The canada exchange rate is really good right now. Then just hurry up and paint it before the 24 hour mark with some paint that is durable yet easy to touch up. As far as tapping out holes, if you apply loctite whether it be purple, blue or red, it acts as a sealant also. So the bolts holes you tap, just apply loctite, and that will prevent moisture from attacking the bare metal threads. I wouldn't use red though, sometimes you have to heat red to get it to let go of a bolt and you don't want to do that to your galvanized frame. If you want to use the stock frame, you could have it acid dipped, rinsed, and then have it baked in an oven-I imagine it getting that hot would force any hidden acid to evaporate, rinse it again, and then galvanize it.
Now as far as inside doors and stuff, what I did was use eastwoods rust converter with a brush, its very runny, kind of like water almost. I just put a ton of it in spots like that, you could even use a sprayer with a wand to reach way in their. I put so much in those areas until its pouring out of the seams in which case its coating everything. Then after it dries, I do the same thing with a primer or paint over top of the converter until its pouring out of the seams. You will have to clean up the visible areas, but thats no big deal. This works well especially on spot weld areas. Just let the converter run down into the spot weld seams, clean it up after, and paint over it all.
As far as powder coating goes, Im not really a fan of it. Once it chips, corrosion seeps into it and it rusts from the inside out. The mag chloride they put on the winter roads here does this really bad where I live.

 

[Captn Conch]

What was it the Aussies used to do (maybe still do?) to the undersides of Land Cruisers...Wasn't it some kind of foul oil/diesel sticky s***e that they hosed on under the LC on an annual basis? I know gear lube is good as mine leaks and throws it underneath coating the frame quite well. My front end I spray with Rustoleum and converter frequently, but the aft tends to stay oily and mostly rust free. However maybe not the best path for those restoring their 40's into beautiful restorations.

 

[Flatlandr]

I hot-dipped, "light" blasted then chassis-saver'd mine. It better not rust, for fks sake!