Surface Preparation of Aluminium

[acidic]

Hello,

I've been browsing this forum for the past several weeks and there seems to be a host of very useful information. I am rather impressed by the level of expertise - now, a question for the pro's

I am looking for a surface preparation method for Aluminum Alloy 6061
(Datasheets: link dead).

The specific application is for protective coatings. Phosphoric acid oxidization according to BAC 5555 (ASTM D3933-98) was already attempted but unfortunately I cannot achieve a constant voltage while running a current <2A. I believe this is required to obtain the desired properties; please correct me if I'm wrong. Further, the process has several steps and very time consuming.

It would be a huge help if anyone could recommend parameters for grit-blasting. Based on my review, alumina grit can provide a sufficiently rough surface for adhesive bonding, but there is the issue of contamination. I have an ultrasonic cleaner at my disposal and pressurized air. From what I've found online, it might be worth trying: blasting angle of 30-40 degrees, separation distance 150-200mm.

What blasting parameters can you recommend for Aluminum Alloy 6061?

Thanks in advance

[acidic]

Bump!^

[CHI3]

A little more info is needed to help.
When you say contamination, do you mean interface contamination?
What type of blasting system are you using? (pressure or suction)
What air pressure are you using? typically the pressure type is around 25psi and suction type is around 60psi.
What is the size of your blast nozzle? 1/4" is good
What size media? somewhere between 24grit and 54 grit works well.
Your blasting angle and distance looks good. Make sure you don't dwell.