I’ve been doing some work and it involves shaping small aluminum parts. I polish it to a high gloss and right now I’ve been putting some auto wax on it.
I would like to clear coat it. Whatever I do I know it won’t be that durable but I would like to try to do a good job. I have some aerosol gloss Behlen lacquer.
Should I get some sort of poly urethane product? It might be more tuff.
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might be a little of a crapshoot since I've never shot it on aluminum but I have had surprisingly good luck with CAB acrylic lacquer on steel plates and cast things. The advantage it has over nitro lacquer is it's harder and it wont yellow with age.
Aluminum has some unusual properties but most of my knowlege base there comes from welding it as opposed to clearcoating it. Its not much help, but better than a swift kick in the shorts.
"Sometimes when I consider what tremendous consequences come from little things, I am tempted to think -- there are no little things" - Bruce Barton
Thanks RW!
Here's what I've been thinking. Soat them in napha with a little gentle scrubbing. I don't want to take the polish off. Then use soem vinegar to etch them a bit. Rinse well without touching them. Them shoot them with an aerosol can of paint that has UV protection. I only need a thin layer.
Is there a mail order place that has a good quality outdoor paint in aerosol cans. I have two of these that are the size of a half dollar. Aerosol should be fine.
Use acrylic spray. Heat the parts to about 80 degrees centi before spraying. I have had very good results with this approach. Remove the wax first of course.
I called a friend from church that rebuilds wrecked trucks and cars. He's going to have an aerosol can for me on Sunday. His supplier comes around every week. It's going to be a high quality clearcoat with UV protectors in it.
He said the napha would be fine but discouraged the vinegar acid etch. It might turn the aluminum.
He said it is a poly urethane of some sort.
I think I'm good to go. Thanks!
I agree with him about the vinegar. Don't use it.
Do use the pre-heat approach - The coat will adhere better and be more durable sooner.
80C~ = 176 F
He mentioned the temp being important. I will follow his recomendations. It's somewhere around that temp. I use a light to help set things. I think I need a temp guage to make sure. It's easy to get them too hot. I started using the light to set the J-B weld I use for inserts. I was letting the J-B weld sit in the basement and it wouldn't cure.
Put them in your oven for about 20 minutes at 175. Take em out and spray them. It works fine
175* is 50* to high. And don't put them in your kitchen oven.Don't pre heat the part beyond 80*F. High temperatures drive the flow agents (binders) and solvents off before the top coat can level out and adhere. It will also inhibit additional coats from adhering properly, lose of adhesion and failure are guaranteed. The exceptions would be top coats specifically designed for high temperature applications, and clear coats are weak in that area. Clears have no pigments in the truest sense of the word. Clean off the automotive polish with a solvent, several times. Modern automotive polishes are high in silicone base ingredients. Armorall is almost impassable to remove from automotive finishes, There are very specialized products commercially available to remove silicone based waxes and glazes.Nothing in the automotive paint lines are baked at over 140*F. and even lower temperatures are utilized in the collision repair industry. These are much higher quality primers, base coats and clear coats, than you buy in an aerosol can. Most sell for well over 160 per gal. without catalyst or reducers. Read the container directions they apply to that product specifically.Ron
Your advice is counter to my experience. Oh well.
Needless to say: take it out of your oven before you spray it!
;-).
Depending on the mass/surface area/volume of the part it will cool somewhat between your oven and your spraying area. Perhaps this accounts for some of the temperature discrepancy?
My Dad (the inorganic chemistry professor) had a paint kiln in our basement when I was a kid. It was set to 80 degrees centigrade (about 175 deg F) He used it as I described. I now have the oven and am using in the same manner (I used to use my kitchen oven). With acrylic spray on steel or aluminum, this technique results in a finish that cannot be 'finger-nailed' and is quite impervious to most abuse. But that is only my experience. Perhaps others have different experience.
Absolutely agree... clean that auto polish stuff off!
Popa, have you thought of having them anodized? Now work on your part and pretty cheap. Plus, it doesn't wear off, chip, yellow, no runs/drips, etc. See if you have a shop nearby that will throw it in with their other pieces. Being small they will fit in virtually anyone's tank from the sounds of it.
One thing to note, it can't have any steel, so something like a threaded insert will pose a problem. But if it is simply aluminum, no problem. Have them clear anodized or you can even have them colored if you ever get the whim. They have to be finished as you want them to appear (ie. polished, satin, etc) before they get anodized.
Jake
They have steel posts in them so I can't have them anodized. Maybe in the future.
My understanding is that the finishes for metal are much different than for wood.
There's an interesting product in the hot rod/street rod industry called Zoopseal, that's used to seal and protect polished aluminum engine components and wheels: http://www.zoops.com/zoopseal.asp Since it's not a clearcoat or paint you don't have to worry about it chipping or flaking. It's supposed to work very well, but unfortunately it's pretty expensive.
I went to the Zoops site and read up on it. It sounds interesting and I might go to it in the future. From what I read, it goes in to the pores of the metal and isn't a coating at all. There is a primer/degreaser that is used before and a product that cleans off residue after the sealer has dried.
It is more expensive than I care to lay out right now. But in the future I might. I've only made three of these parts so far for this guy. He has a website with my part on it and it says in big letters, sold out. I better get moving on these.
For now I'm sticking with the rattle can from my friend with the autobody shop. He asked me if I wanted to shoot these two parts and give him back the can. Nice guy. I told him I might need the can for the future. How much can a rattle can cost?
I'll talk to him about temps and technique. He started to tell me how to shoot it. I'll listen. Couldn't hurt. A strong nation is built on good council. I'm pretty good with a rattle can.
I like the words rattle can. Heck, I like painting with them too. But only when it comes out right. When it doesn't the air turns blue!
Edited 3/30/2006 3:57 pm ET by popawheelie
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