How do you eliminate black compound residue left on aluminum part??

[mickyd]

I am having difficulty removing a black compound reside that is left on my aluminum part. This happens on the initial polishing when using black compound on spiral sown wheel. See the photo

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What is the cause? How do I prevent this from occurring?

[Alexw]

I'd say that isn't residue, its marks in the alu. Ive got similar looking marks on my rocker cover and i continued to use 320grit sandpaper on it until they went away or i stopped for fear of making the cover to thin. You might find you can't get rid of them tbh.
All mho and limited experience.

[mickyd]

I'd say that isn't residue, its marks in the alu. Ive got similar looking marks on my rocker cover and i continued to use 320grit sandpaper on it until they went away or i stopped for fear of making the cover to thin. You might find you can't get rid of them tbh.
All mho and limited experience.

I'm sure it IS compound reside. Prior to polishing, I washed the part in mineral spirits. This residue wasn't there before I started buffing with the black compound. After buffing, I noticed it. I was able to remove it by scratching with fingernail.

[KENLUDE97]

Brake cleaner, work pretty well and is cheap'ish. Acitone (sp) i hear works well too.

GL

[mickyd]

I need to reword my issue.

The problem I am having with the black compound residue is that it is not buffing off. Why is it there to begin with?

No matter what direction I try to buff it off in, it won't come off. I'm having to take it off with chemical cleaner. If that is NORMAL, I am ok with that. If it's NOT NORMAL, I'd like to know how I can prevent it from happening to begin with. Is it my process? Is it cheap compound? Is it that the part is too hot, too cold?

[PULIDOS]

I'm not suprised you'r having residue problems having had a closer look at that pic...what proscess have you done leading up to that stage, cos it appears damn rough to me...

[mickyd]

I'm not suprised you'r having residue problems having had a closer look at that pic...what proscess have you done leading up to that stage, cos it appears damn rough to me...

The part is cast aluminum. The surface is "as cast", with no work to it other than mineral spirit wash prior to buff. The "as cast" surface has a lot of pits on it but I am sure that is not the root cause because the other side is even rougher yet the all the compound buffed off OK.

Incidentally, I have also had this problem with residue remaining on a part that initially much smoother than this prior to first buff.

[wildwilly911]

welcome to the world of aluminum polishing. the part should be sanded first to remove casting parting lines. buffer speed and wheels are important for the first polishing steps, you either need a courser wheel or the part needs to be sanded. you also need to be pretty aggressive on the first step polishing. carb or brake cleanr work great for removing the black stuff

[PULIDOS]

Clean the item with paint thinner/brake fluid or similar, rake the wheel well, grab a thick rag a hold it to the wheel to try try to remove any residue already on the wheel, re-rake the wheel, carry on with the progress, sparingly with the emery/ tripoli of whatever wax you're using....pits will hold any wax in them and if you fail to clean the pits between each process you will continue to cross contaminate.

[baz]

other factors could also cause this , wheel saturated with compound , not enough heat /friction when buffing , not enough pressure or too slow , sometimes working on a cold piece of aluminium could cause this .
but like others said good starting point would be to make the part smooth to begin with because looking at the pic tells me you skipped a few steps