Paint aluminum vs powder coat

[ooby]

My aluminum AMYA J-Class mast at 115.5 inches needs one or the other, so I sought my brothers advice, which I'll post here for broader benefit as an FYI.

We have painted numerous aluminum articles here at the shop. Done properly, it takes a five step process: acid etch, alodine, zinc chromate primer, top coat primer and top coat (two top coats close together). This is the process we use on full size masts, and it's more expensive than powder coating.

Powder coating aluminum, if done properly, needs the zinc chromate primer, or it will not last. It is difficult to get any stuff to stick to aluminum: zinc chromate is mandatory. There are some powder coating shops that will skip the zinc chromate primer unless they are told to do so.

[JCJ]

ooby,
in the racing industry all of our aluminum parts are anodized. Many colors are offered including clear. Might be a little pricey but its virtually weightless and would scale nicely.

Another process to consider is a gunkote type finish also used in racing for steel suspension pieces but would work on aluminum. It was developed by the gun industry to replace the old blue corrosion coating.

I'm just not a fan of paint and powder coat of these type of pieces.

[ooby]

JCJ, I'm impressed, but how does one who knows little-to-nothing about the "racing industry," make it happen? Local auto parts store?

Many thanks for your insight.

ooby

[JCJ]

ooby, non of this is racing only stuff.. for the anodizing just look for a local chrome shop type place. This is what I have locally (if this link works)
http://www.google.com/search?hl=en&q=indianapolis+anodizing&btnG=Search



http://www.kgcoatings.com/gunkote.html http://www.brownells.com/aspx/NS/store/ProductDetail.aspx?p=1150

diy if you're creative. Gunkote is just a brand name, many other similar coatings available.

I'm happy to help, please keep me posted on what you end up doing and how it all works out.

[ooby]

JCJ, I like the options you presented. I'm guessing both would be lighter in weight than either paint or powder coat...good!

Thanks, and I'll first check with a chrome plating shop.

ooby

[CG Bob]

Caswell Plating has an anodizing kit (http://www.caswellplating.com/kits/aluminum.htm), but it is expensive.

[Shaun Hendricks]

Anodizing scratches off easily in my experience. Any number of 'anodized' aluminum wheels that people paid big $$$$$ for can attest to it. I also understand that anodizing is a hardening process that can affect the surface durability of aluminum. Making it tougher but more brittle at the surface.

I have painted aluminum with success but the process must be repeated if it's always going to be in the weather. Just plan on doing it every year or two. I also tend to 'rough up' the surface with steel wool prior to priming and painting. It's also easier to patch a scratch in paint than anodizing.

Powder coating, never done that. I have looked at a couple of guns but I was told that for full hardness it needs to be baked on. It's a helluva autoclave that can handle something 116" long. I have worked with several powdercoated pieces of aluminum and it's tough and appears durable. Didn't scratch or dent. Not as lustrus as paint but pretty sturdy.

As an odd choice, how about something like a rubberized or vulcanized coating? Bedliners and other 'plastic' coatings might stick well enough and take more abuse than most other items. May be a bit heavier and not as pretty as paint, powder coat, or anodizing, but should be much tougher.

I don't know, just tossing ideas out here... :confused:

[ooby]

Bob and Shaun, many thanks for your thoughts. It's too early for a "final" decision, but you valuable input certainly gives me more to consider.

ooby