protective film for aluminum?

[Georgeandpat]

There is a protective film made for glass and mirrors that is not unlike window tinting. We use it on the mirrors of the public restrooms that I help maintain. When it gets scratched by vandals we replace the film rather than the mirror itself. I wonder if this would work on the aluminum skin of a teardrop? Perhaps it would also keep the skin shiny. I don't know how well it would hold up in the sun and weather though.

[DestinDave]

I wonder exactly what Airstream trailers are coated with. I did some detail work on an Airstream a few years back and the owner was adamant about using pure paste wax (no cleaner added) so I wouldn't scratch the factory coating and invalidate his warranty. I used an aluminum protective coating in the marine industry which was impervious to UV, fuel, acid, salt, dirt, grease - basically anything except abrasion. Application was very tedious and had to be just right for an effective finish. It was also very expensive (my cost for 8oz kit was almost $400) which was enough to do all the metal on a 42-46 foot boat. I am looking into the possibility of kits for teardroppers but I feel like it will probably be cost- prohibitive. More on this later - when I have more info.
Maybe Doug or Steve F would know about coating raw aluminum with automotive clear-coat. Is that possible or is the metal too oily?

[roger-c]

George and Pat
Airstreams are sprayed with a clear ploy sealer to protect the aluminum.

roger-c

[Georgeandpat]

It seems like every thing I do to the aluminum makes it worse. I'm thinking that some natural oxidation might actually give it that vintage look!

[Terbeau]

I think the clearcoat used on most auto finishes would work well. It is a catalyzed finish of some sort but is specifically designed to resist UV, bugs and most everything else an owner can throw at it. The only problem might be getting adhesion to the bare aluminum. I don't think that would be insurmountable. Stop by an autobody repair place and ask.

Ralph

[doug hodder]

Maybe Doug or Steve F would know about coating raw aluminum with automotive clear-coat. Is that possible or is the metal too oily?

I'm going to experiment doing a scuff random finish on my top aluminum skin. Using a 4" grinder with 80 grit sanding disk. I've done it on high tech kitchen cabinet insets and it looked great. I top coated with Varathane, and it did yellow slightly over 8 years, this time automotive clear coat. The scuff finish should provide "tooth" for the top coat. It's all in the middle of the thought process right now however. Also thinking of a turned machine look. Like on a Ravens flatbed trailer for those trucker types. Doug Hodder

[DestinDave]

Doug.... just a thought. In ref to the clear coating I've used on aluminum towers and rails on boats, the final step before applying the finish was a spray rinse of a 50-50 mix of distilled water and isopropyl alcohol. This was to clean the metal of any residue and (according to the factory) set the Ph of the metal to accept the bond.
Normally when painting aluminum it's necessary to acid-etch and then apply a coat of epoxy barrier coat, sand, then finish coat. Hmmmm

[doug hodder]

Dave, there are primers that can be applied without etching, if painting, you can get away with a quick sand, wipe down with lacquer thinner and shoot primer then paint, acid etching is necessary if not doing any other prep work. I've shot lots of fire fighting equipment (trucks) this way. If you're not going to sand, yes you do need to etch. I can only speak from experience in drier climates, like Colorado. I'm sure that the paint suppliers in more wet areas might have other suggestions. For me, I don't want to have to use an etch on top of my scuff finish as I don't want to take away from any of the brilliance of the scuff. Painting aluminum and clear coating aluminum are apples and oranges. Etches that I have used in the past created a dull finish, and marine environments are a whole 'nother critter, especially salt water... I'm still trying to find out the correct combination for what I'm trying to achieve, If I screw it up, I'll strip it and do something else. Finishes have changed in recent years and I'm drawing on experience that goes back 20 so it was long long ago on a planet far far away. doug hodder

[D. Tillery]

Doug, I'm a big fan of decorative polishing. If you lay down a pattrern then everyday wear and tear scratches will blend right in. I do a lot of decorative polishing with clear coat over. One example:http://www.mrcustomsteel.com/coil%20couch.htm That is clear powder coating but I have also used 2 part automotive lacquers and water clear one part lacquer. I clean with lacquer thinner and adhesion has never been a problem. Application problems due to high humudity abound in S. Texas but spraying lacquers in CO should be a dream.

For polishing out scratches in aluminum work in stages of grit of sanding disks followed by Scotch Brite pads. Any welding supply should have a kit for this to attach to an angle grinder. But you can never match that matte mill finish until after years of oxidation. I think the best thing to do from there is to go mirror all over or grain it like SS and lay down a decorative pattern.

D. Tillery

[doug hodder]

D Tillery, glad to hear that you have used the same process that I am thinking of. I've only done this treatment for interior use, but was thinking that catalized clear coat would work on the exterior. I use a sanding disk on a grinder and work the pattern 1" x the footprint of the grinder, then turn it 30 degrees and over lap the pattern. When you walk around the material after it is done, it throws a real flash, looks really different, and you're right. It covers up a ton of problems, scratches, dings etc..... I'll see how it goes. I have also found a laminate product that imitates the same finish, thought that might be good for the galley. I wish I could remember who it was by, Formica or Chem Metal??? I'll do some research. PS I have limited experience with powder coat. Can it be coated and then bent for the radius of the back galley deck, without any fatique problems?? Checked out the link, is that in aluminum or stainless? It's awesome!!!! Doug Hodder

[MarksMG]

Hey Doug I just wanted to give you my opinion on powder coating. I do some powder coating as a hobby on the side. It is not a good idea to powder coat then try to form the material. It will crack the same as paint if it is bent at a very sharp radius. Also the dies from forming will scratch the finish.

Mark

[D. Tillery]

Doug, Mark is right about powder coating not holding up to being put through a press brake. However it is more flexible than paint or chrome so it is good on springs. I don't think it would hold up well on a counter top. The finish in the link is clear powder coating over polished mild steel. Prep is polish with steel wool and wash with lacquer thinner.

After working with both SS and Aluminum over the years, I would not bother coating it, just use a good automotive clear coat wax. Use SS or bronze wool and Scotch Brite pads. No steel wool.

D. Tillery

[doug hodder]

I'm not thinking of hard breaks or forming the material, just the bends over the top and deck of the trailer. Also what has been your experience with clear powder coat. Doug Hodder

[D. Tillery]

Powder coating should be flexible enough to bend over the roof of a tear. Take a sample to your powder coater and play with it to see how much it will actually take.

Where do I start on clear powder coating? Prep must be perfect because everything shows under it. Coater must have a very clean shop and oven. It is prone to running and yellowing if you put too much on and/or cure too long. Undercure shows hairline cracks that don't show up for a few days. Hard to cure test because it has no color. They say it holds up to prolonged sunlight but it does not. But when done right it is beautiful. I really like it as a second coat over another color or texture. It is easier to touch up than colors, with clear finger nail polish. You can paint over it with wet paint (numbers, art, etc) and remove the paint with paint thinner without hurting the powder coating.

I'm a big fan of powder coating but you have to know its limitations.

D. Tillery