Sandblasting aluminium caravans

[Roehm3108]

Was chatting to a "local" (35kms away) auto/camping shop owner last week about cleaning up my Wayfarer.
The panels are that beaten aluminium type in parts and with an embossed diamond shape in others, and the years of gunk has inbedded itself into the hollow parts, which makes it almost impossible to clean out. He suggested sandblasting with a very fine swimming pool filter sand. Sounds feasible to me, but then, I HAVE been known to be wrong before.
Anyone out there tried doing it? What results did you have? My only alternative really is to paint the van, especially if this idea isn't worth considering.
Have already tried the circular wire brush trick (too rough) and a floor polishing scourer (doesn't get into the hollow parts enough).
Ray

[Deleted]

Hi Ray

Brasso or a product called "purple" will clean your alloy.
Although Expect to pay around $25 for a 250mm bottle of Purple. Gunna need a bit to do a "aluminium house on round rubber piers".
Maybe could try kitten car polish with a lambswool buffer. If you end up with a greyish tinge on the alloy after buffing it just wash it in warm soapy water and dry it off with a soft rag or a chamois.

I use "purple " on the alloy on my old motorbikes . It brings them up like chrome.

Try anything but stay away from strong truck washes and acids. It will etch the alloy and turn it powdery looking. twice as hard to clean up than dirt embedded in diamond patterned alloy siding.

Thats all i know about that.....
Goodbye
Gump

[bobshannon]

Hi Ray,
Having played with Land Rovers for years (and now a van with the same type of cladding you describe) there are a few alternatives.
Sandblasting, plastic or bead blasting is too abrasive or damaging on soft sheet aluminium but Soda Blasting really works but the people who do it want between $90 and 400/hour - making that pretty expensive - but the finished job is fantastic - no damage, strips every thing - paint, tar, you name it - off to bare metal.
So to DIY you can use chemical stripping and polishing. Chemtech and (probably others) make an aluminium boat cleaner (http://www.apchem.com.au/Downloads/CPD/Chemtech%20Aluclean%20FandB%20Flier.pdf) that is a mixture of Potassium and Sodium Hydroxide. It works a treat on the diamond patterned sheeting. First take all safety precautions - long gloves, old jumper and overalls, face shield or safety goggles - then use it full strength rather than diluted (you can try it diluted at first as a trial) and with a scrubbing brush work in into a small area and into the pattern, once it starts foaming you will see how quick it rips off the oxidised layer and the dirt in the grooves - then rinse it off with water. If you start at the top and work down you will get a good job. However, the cleaner will cause runs down the sheeting and you should minimise this by rinsing thoroughly as it's a bit hard to get an even tone overall. A bit of trial and error. Once the majority of the oxidation and dirt is stripped off you can then go over it again with the cleaner diluted. I have used the Chemtech and it really works. The finish you now have has a dull grey overall and can be polished. If you get the chemical on you it will burn so rinse it thoroughly and wash with some lemon juice to neutralise it.
Don't buy a cleaner that contains Hydrofluoric Acid as it will etch the surface and it is VERY SERIOUS STUFF if you get any on your skin!!!! If it will etch glass you are no match for it!
After you have the aluminium clean you can then use a 3M green scourer with some soap. The cheap ones put green on the aluminium! Then use an aluminium cleaner (mag wheel stuff) or buff with a machine. You can get sealers to keep it shiny looking. For polishes have a look at p45 of Hi-way Truck Accessories catalogue here: www.hyway.com.au/catalogue/cleaning_maintenance.pdf. Their distributors, stores are here: www.hyway.com.au/stores.htm
Bob
I forgot to mention - one of my friends make alloy bullbars, etc reckons the absolute best Aluminium polish is "Mother's" brand.