Question: Rear Crossmember - powdercoat ?

[BayouBeastie]

I am pulling off rear cross member tomorrow. I want to galvanize and powdercoat it. But suspiciously I haven't seen any others do this.

Am I missing something that makes this a bad idea?

[LI90]

Just do one or the other, no reason to do both. Are you looking for it to be black?

[BayouBeastie]

Yes I want it black. I was thinking of doing both to decrease chance of future rust. After using the Google it seems this is a sort of normal thing.

Does powdercoat prevent rust inside the crossmember? (For that matter, does galvanizing get inside the crossmember?).

Thanks

[LI90]

I guess that makes sense if you are thinking really long term - I'm sure someone on the forum will chime in.

[nathanwind]

Galvy is a dip so it'll get inside. Powdercoat is sprayed on and then baked, so it won't get into the internal nook & crannies.

Galvy is going to give you the best protection, but powdercoat will give you the black finish. Also be aware that you'll need to grind & weld at the connection points when you reinstall to have bare metal to weld to, so touch it up adequately when it's welded back in place.

[Brewie212]

The powder will not want to Adhere very well to the Galvi unless you etch it with an acid or blast it.

[nathanwind]

Originally Posted by Brewie212

The powder will not want to Adhere very well to the Galvi unless you etch it with an acid or blast it.

I thought it would stick to fresh galvy ok, but weathered galvy you need to etch? Or was it vice-versa?

[rijosho]

If you want to galvanize then follow these pointers

http://www.defendersource.com/forum/...rts-72794.html

[Brewie212]

The last dipping process during Galvi coating is what causes adhesion issues for paint and powder...

[BayouBeastie]

Thanks all for the help so far. Looks like powdercoating the rear cross member isn't an inherently bad decision. I will do so over galvanized using the helpful hints from you all.

Aloha from Louisiana.

[evilfij]

Powder coat over galvanizing is probably the worst idea. Galvanize it, etch and paint immediately after and you have a fighting chance of it sticking for a while and then just touch up with a rattle can (black appliance epoxy is the best paint I have found in a can) as needed. Powder coat if it fails (it probably will) and it will be impossible to blend in and touch up.

[nathanwind]

Originally Posted by evilfij

Powder coat over galvanizing is probably the worst idea.

The American Galvanizers Association doesn't think so.....ah, but what do they know ...
Preparing HDG for Powder Coat | American Galvanizers Association

[Shagey71]

Welding is the real problem here, not a paint vs. powder coat debate. Whenever I weld frame rails, I go in with a door wand from a drain hole/other access and spray the crap out of it with an etch primer, and then preferrably with a high nickle content primer (typically red colored) to seal the weld area. Of course before I weld the frame sections, I'll clean the piss out of the inside of the frame so my primer gets good adhesion and gets in the pores.

[Contractor]

Powder Coating over Galvanized is not a bad idea.


Pretty much most exterior decorative railings that you would see on a decent commercial job are going to be powder coated over galvanized. I'm doing it now and places like Disney, Carowinds, Six Flags, etc.....all use the same process.

[sonoronos]

powdercoat over galv is awesome!

[wcampbel@nas.edu]

So if I buy a galvy rear crossmember can I just take it to a powder coater and they can coat it black? Or are most local guys going to stay away from messing with galvy covered stuff?

[evilfij]

For an exterior fence sure, for a rover rear crossmember? No way. First, you are going to have to grind off the ends of the powder coat to weld it on (which will also probably melt the inside powder coat when you do weld it). Second, the rear cross member gets hit with rocks and salt spray. Both of those things introduce areas where it can fail and peel and how are you going to touch it up? I am sure it will look good for a while and probably a long while if you are somewhere without salt, but eventually it will peel. Maybe I am traumatized by all of the rover brush bars, ladders, light guards and racks I have seen where the powder coat failed (admittedly they were not galvanized), but I just don't think it is a good idea.

[CDN38]

I galvanized and powder coated the high brake light bar on my 90. 10 years on, it still looked perfect. I'm sure some day an archaeological dig will find it perfect condition, in a pit next to a pile of rust and a powdery lump of what used to be aluminum.

On the 110, I galvanized and powdercoated the steel fuel tank cradle, retaining strap, rear seat seatbelt anchors (that are in the forward part of the rear wheel wells) fuel filter housing.. my thing is if it's steel, galvanize it, then powder coat. Never had any problems with adhesion or chipping. (galvanized my side frame/B pillars, and then painted them.)

Just like getting paint done, when it comes to powder coating, there's multiple levels of quality, and one of the key things to a good job is prep.

[rdavisinva]

Originally Posted by BayouBeastie

I am pulling off rear cross member tomorrow. I want to galvanize and powdercoat it. But suspiciously I haven't seen any others do this.

Am I missing something that makes this a bad idea?

Powdercoating any chassis in part or whole is a very bad idea.
Once the power coat is chipped or damaged moisture gets between it and the metal and without galvanizing with rust badly under the coating.
If you galvanize powdercoating will just get in the way.
It will chip crack and become useless, the only difference is the frame underneath will have the usual coating of zinc oxide under the blistering powdercoating leaving the frame still protected, but with all the blistering cracking coating falling off.

[Red90]

The problem with this thread is that "powder coating" is like saying "painting". There is a large range of materials, application procedures and preparation that could be used.

Regardless a rear crossmember rusts from the inside out, so not coating the inside will end up rusting out.