Blasted alumium hull finish

Got a curly one

I have a client that wants a blasted finish on his new alloy hulls to achieve a seudo matt military type finish. We experimented with various oxides, glass bead etc to get the shade of grey correct. Client's happy but personally I dont like the coarse surface finish and possible changes that will occur with exposure.

If anyone has another method (non paint)that produces a flat grey military looking and a proven durable finish I would be interested in learning.

Thanks

 

As you know, weather causes a patina that will acheive the desired effect. I would convince him of that.

 

Baking soda is a good fine blast medium, I've heard. I haven't used it but you might check it out. My guess is it will leave a more uniform, matt finish.

 

I have used baking soda on several restoration projects both marine and architectural (historic bldgs) Its great if envioroment is protected, residue salts go down the drain and it dosent damage substrate - old wrought iron/glass windows, alloy or FRP hulls.
I tried it out for this project - on marine alloy it came out bright rather than a darker grey shade. If you want to remove anti foul between tides with a ready to prime finish its bullet proof.

 

The best acid to vlean aluminum is the Hydro Fluorhidric, combined with Phosphoric acid, they brighten alumminum. I suggest to look for aluminumm cleaners extra strong. These cleaners are used for alumminun boxes on trucks. Also they are used for cleaning of refrigeration conderses (aluminnum fins on copper). Look for the strong formulation

Hydro Fluorhidric is a dangerous product

 

HF is very dangerous, eat flesh faster than hungry croc, the reason I never use it plus its hard to control the over all consistency of the etch.

 

Its important that once HF has been used to remove the oxidisation, that a clear sealer be applied such as Nyalic or similar, which stops any further oxidisation.