I'm familiar with Alodine for corrosion protection but I had assumed
anodizing would be better for something like a combustion chamber vs. a
structural part where a painted on style coating would be be acceptable.
There is also some light corrosion in the drilled cooling holes of the
chamber so I was worried about the effect on the cold side heat
transfer. I had planned to use some SS tube brushes to clean up those
holes anyway because I thought there might be some coking left over from
previous runs. I wasn't 100% sure it was coking (previously discussed)
but when I shine a light through the holes, some are slightly darker
than others so I'm assuming that is coking residue. I may bathe the
chamber for a few minutes in the Klean-Etch then run the tube brushes in
and out with a drill.
-Bob
On 07/22/2017 11:15 PM, Lars Osborne wrote:
I might be corrected, but typically aluminum corrosion only affects the surface and I have not seen it be bad enough to cause structural issues. It should not effect the heat treatment.
Send a pic? I probably wouldn't bother unless you are concerned about contamination control.
Also, an easy way to avoid corrosion is conversion coating. It has effectively no build up. It is not terribly expensive, and you can also get felt pens to apply it yourself.
For any amateur, I would suggest MIL-DTL-5541 Type II (non-toxic) In Class 1 for parts that need to be electrically conductive, and class 3 for parts that do not.
Thanks,
Lars Osborne
On Sat, Jul 22, 2017 at 7:44 PM, Robert Watzlavick <rocket@xxxxxxxxxxxxxx <mailto:rocket@xxxxxxxxxxxxxx>> wrote:
I forgot to empty the water out of some my aluminum parts after a
cold test and now there is white/gray corrosion on portions of the
parts. A stainless steel wire brush worked for the areas I could
get to but I was thinking of using a chemical etch to get to the
inaccessible areas. MIL-C-38834 is recommended but it's just
35-45% phosphoric acid and deionized water. Klean-Strip
Phosphoric Prep and Etch appears to be readily available. Any
suggestions? Also, what does light corrosion do to the heat
transfer properties of aluminum? Do I even need to bother?
Thanks,
-Bob
