[beemdubya]

today i glass beaded aluminum wheels. i usually wouldnt use an etch primer but i almost feel i have to. the wheels have some pretty tite spots and sanding them doenst seem like much of an option. now im not sure if i could just epoxy these or if i would need an etch primer first.. but i have never used etch under epoxy.. does that even work? what would you guys suggest?

PS: the wheels are 3 piece i have then apart and im only painting the center section.

[crashtech]

Well, I would want to use PPG's DX503. It converts the surface of the aluminum to something with better adhesion. After that, a wet-on-wet epoxy sealer, then paint.

[beemdubya]

would a regular metal conditioner work? i have two kids.. one is ppg somehting or otehr and the other is the por-15 metal prep.. i really like to stay away from metal conditoners though.. i like to stay away from etch primer too but i dont think i could sand these wheels with 80 grit very good.. i use spi epoxy if that makes a difference. what grit is the glass bead equivilent to?

[mrcleanr6]

thats funny you bring up metal ready and epoxy as barry and i had this conversation 2 days ago. not sure what the wheel centers are finished with. if they are just painted and you beaded off the paint then i probably would use the metal ready. they are aluminum so the metal ready will foam up white while it etches the metal. just let it sit a couple minutes then really rinse them off well with a hose. i remember your last problem with the metal prep but if you rinse it off well you wont have a problem. not sure about epoxy over etching primer. you'll have to wait for barry to chime in on that but assuming the acid from the prep screws things up then its probably not a good idea.

[crashtech]

SPI's tech sheet for epoxy primer says it's direct to metal. I've always been trained to etch the metal with something, though, especially on something like a wheel that will kinda take a beating with temperature extremes and cleaners. Unfortunately, the SPI tech sheet does not state whether using a chemical metal treatment is permissible. On PPG's DP line, it IS allowed, and I have done it many times with excellent results. If you do decide to chemical etch, use the correct product for aluminum. They are not all alike!

[Bee4Me]

Glass bead does not really etch,it "polish's" as the beads just pound the metal. They remove scale (oxide) which cleans aluminum giving it a "new" appearance. Bead comes in different diamiters or grades. I use #13 in my cabinet for light cleaning.Aluminum Oxide will give them the etch your looking for and a nice "scratch" for the epoxy to adhere to. The more pressure you blast with,the deeper the scratch. Aluminum "cleaners" come in 2 types. Alkaline and acid. Either will clean the oxide off but alkaline type's will remove grease,dirt,etc where as the acid type won't. A good cleaning with soap & water after the blast should do fine but you need to get the epoxy on as soon as possible before the oxide starts building back. This is how I do painted aluminum and have had good results with it. Polished is a whole 'nother story.Bulldog AP and crossed fingers.

[beemdubya]

The wheels were anodized. i used oven cleaner to get the anodixzing off and then rinsed them off well... dried them. and then stuck them in the cabinet. there completly bare aluminum now.

I have some aluminum oxide media as well as the glass beads. maybe ill do a little testing and see what gets more bite. ill blast some aluminum with the alumnum oxide media then epoxy it and see how well it adheres. and ill try a piece with glass beads and metal ready.

[mrcleanr6]

blast it with the aluminum oxide definately. thats going to prep it good. all my metal here gets sandblasted and epoxied with barry's stuff. just be sure its real clean before you spray.

[Bee4Me]

The Oxide will discolor the aluminum some but don't sweat it.Your painting so pretty isn't the game.That's why we use bead so's not to stain or etch the crap out of it.
Be SURE to clean your cabinet out GOOD, BEFORE you put bead back in as the residue from the oxide will essentialy screw any bead work by staining it.
I dump it and use my shop vac to get as much residue out,then wipe it down (with in reason) with a damp rag,turn on the ex. fan and let it air out good then dump the bead in.

It's a PIA to switch media and I usually do my Oxide work outside with a portable job for this reason."course,When it's 30* outside,I'll do it.

Mike.

[BarryK]

If they were mine!

This is what I would do (is this the only right answer? NO!)

I would blast with the aluminum oxide , was with wax and grease remover.
Blow real good with a blower, let set for 30 minutes and than spray two wet coats of epoxy with proper flash times between coats.

[baddbob]

I agree with Barry, sandblast with the alluminum oxide or silica sand and clean well then apply two coats of epoxy. Get the epoxy on nice and smooth so you can go directly to paint the next day.