Finishing Wheels

[Ron Earp]

How are you guys finishing your wheels?

I've got a set of knock on Halibrands from RF and I need to finish the centers. Finish, as is powder coat, paint, ceramic coat, etc so they'll have color.

Right now they are bare aluminum.

I wouldn't mind using paint, something that will mimic magnesium.

Any hints on priming? Paint type? Prepping the aluminum?

Thanks,

Ron

 

Ron-

Here's some ideas on painting aluminum. First, we usually use an epoxy primer followed by a polyurethane topcoat. For polyurethanes you can choose either an acrylic (standard car-type finish) or a polyester. The polyester is more expensive but more abrasion-resistant and also chemical-resistant than an acrylic. Color and gloss rentention are close, depending on the manufacturer.

As far as prep, we typically use a solution called Alodine 1201 (I think that's right). You can use Alumiprep 1000 (again, I think that's right) to clean before using the Aldoine. What the Alodine does is to basically amodize the aluminum so as to make it ready to receive paint. This system works well and should give very good performance.

I'll double check my product codes for the above two products as regards precise numbers and also get a contact number.

Let me know if you have any other paint questions.

Best,

Pat

 

You may want to consider the following products for coating your wheels.

Endura EX-2C. It is an aliphatic polyurethane and is used for the protection of all types of transportation equipment (land, sea & air). Priming is with EP-2C primer/sealer. Blast first with 70 mesh grit to obtain a ½ mil to 1 mil blast profile. I used this on my KVA frame and it worked really well. It is a very hard coating. It has high gloss and color retention and outstanding resistance to chemicals, abrasion and impact.

Another coating you may want to consider is PSX-700, which is distributed by Ameron. It embodies the properties of both a high performance epoxy and acrylic polyurethane in one coat. I became interested in this coating as it was claimed by Ameron that it could be applied to aluminum with only a solvent wash. Coatings will not normally adhere to aluminum without providing a blast profile, or treating the surface with Alumiprep and Alodine (as used in the aircraft industry) to provide adhesion. Blasting will distort thin gauge aluminum and is therefore not always practical and the Alumiprep and Alodine process can be expensive. As I was skeptical about the claim that only a solvent wash was required I asked General Paint to run some adhesion tests on aluminum test panels, which revealed exceptional adhesion. (1700 – 2000 pounds on pull tests) on a surface that was only solvent washed. I did the same test on a surface that was treated with Alodine 1201 and got pulls of 1500 – 1750 pounds (also very good). PSX 700 is expensive (about $204/gal) but you do save on preparation costs. This is the only coating that I have found that can be applied to aluminum without blasting or surface treatment with the two products below. PSX-700 will not chalk (as an epoxy will) and maintains a good gloss. It is probably not quite as good for impact as polyurethane.

Quite often aluminum wheels are powder coated, as you probably know. If you go with powder you may want to consider a polyurethane.

Alodine 1201 and Alumiprep 33 can be used for thin gauge aluminum panels such as aircraft skins where blast cleaning would result in distortion. The Alumiprep is a phosphoric acid based cleaner, which produces a chemically clean, and corrosion free aluminum surface. The Alodine is a chrome conversion coating that offers the best affordable substrate for both paint adhesion and corrosion resistance. You do not need either of these two products if you can blast the surface to get an anchor profile without running the risk of distortion. Blasting would not distort an aluminum wheel.

I have data sheets on all the above products and can fax them to you; however, they are available on the net or from the industrial coating suppliers.
Please feel free to contact me if I can provide any further information on the above products or process. Hope this gives you some ideas.

 

[Brian]

An engineer can probably help here, but I recently read where sandblasting aluminum wheels is a no-no, something to to with inducing surface stresses and potential crack propagation. I will try to find the source and get back to the forum with it. Brian

 

HI Brian. I hope you can provide some information about this as I would be very interested from an engineering standpoint.
I am a corrosion technologist and have worked in the aircraft and petrochemical industries for the past 45 years and cant say that I have ever come across cracking of aluminum as a result of blast cleaning. But I keep an open mind as there are many interesting conditions that are sometimes realised too late. I have been involved with blasting and coating of aluminum for the past 10 years ( large rotating drums and fabricated components) and can say that we have never had any problems with cracking as a result of blasting. I also contacted a Nondestructive testing lab today to see if they had ever come across this and they said they had not but would let me know if they find out anything about it.

Mike.

 

[Jim Rosenthal]

Ron: the Alodine/Alumiprep process is not that hard to do and can be done easily by anyone who paints airplanes; they use it all the time and it is not high-tech. I think the products are made by US Paint, which makes Alumigrip, a polyester paint used on airplanes. It is very tough. I recently had my boat painted and we used the A/A process on all the aluminum parts such as window frames, trim, and then painted them with aluminum-colored Imron and clear coated them. They still look like metal but don't have to be polished, and they shed dirt much better. If they will hold up in salt spray they will hold up anywhere. US Paint has a website and also their products are used frequently at airplane refinishers. Good luck.

 

[Guest]

Mike, am I pretty much out of luck in my search to find a clear coat for polished aluminum that will adhere and maintain the polished luster of the metal? I have tried Eastwoods Diamond Clear and was not satisfied and a two part product called Glisten from the makers of POR-15 has had some positive testimonials. I would really appreciate any help in this area. Otherwise, I plan to just polish with Weenol of something similar on a regular basis. This will keep the luster but won't protect from scratching.

 

Hi Lynn.
I have never used clear coat but I understand from talking to a friend that has an industrial coating shop that Endura has a good clear coat but he has no experience with it. The product is Endura EX-2C clear coat.The local supplier advised me that if you use it you should first use Alumiprep 33 cleaner and then Alodine 1001. The 1001 is clear and will not turn the surface a Gold color he said. Henkel Surface Technologies (248-583-9300) can provide data sheets and advise you re the best Alodine conversion coating to use for your application. I would advise you to talk to them about preping aluminum.
My friend with the coating shop clear coated aluminum wheels on his Bronco and blasted them first with Sil 4. This resulted in the surface being a light grey color after coating. He said if he did it again he would use a fine white grit to blast as this would probably maintain the aluminum appearance. which ever way you decide go it would be best to do a test plate first to ensure that you get the results that you require. I have data sheets on the Endura. If you need them I can Fax them to you.
Hope this info helps a little.

Mike

 

[Mark Worthington]

The wheels that came with the kit I bought from Bob Lawrence are gorgeous! Here's a pic:

I can contact the shop that polished and sprayed his wheels and ask them what technique they used. I'll probably have the centers resprayed anyway because, even though they're beautiful, it's unlikely they'll go with any paint scheme I would put on the car. Pity.

 

Hi Mark.

Where can I get a set of BRM replica wheels like yours.

Mike.

 

[Mark Worthington]

Mike, you can obtain the BRM replicas from Roaring Forties.

 

[Robert Logan]

Mike,

We manufacture our own wheels as I could not get the wheels I wanted. Usual story !!

We also manufacture Halibrand copies which look real close to the originals. Both the BRM's and Halibrands are normally 16 inch but we also manufacture them in 17 inch and we also have just made our first set of Halibrand bolt - on wheels and again these are available in both 16 and 17 inch.

I must take off my hat to Bob Lawrence, he made a stunning job polishing the orange wheels shown in the photograph above.

Best wishes,

Robert