Cleaning up Rocker Cover

[Garry]

Trialed using ground walnut shells for peening the rocker cover then a coat of high temp clear and the results are really great.
Now I need to do the inlet manifold and so it starts again.

[Larry & Norma]

Hi Garry,assume you mean 'trialed'. Do these ground walnut shells have a trade name?

[Garry]

Larry

I did mean trialed and the material is commercially supplied but a friend gave the material to me to try.  I will find out the brand name for you.

Garry

[mdsalemi]

Any firm supplying materials for "blasting" or "sand blasting" will in all likelihood carry the necessary walnut-shell media.  Here in the USA I don't know if there are branded items--it's probably processed in bulk and repackaged under many names.  I know Harbor Freight, Summit Racing and Eastwood all carry it.

Don't forget a chemical clean--you can search some of my other posts on the subject as it has come up before.  Check with a commercial supplier in your home country, but what you want is an "aluminum brightener" or "aluminum cleaner"; just google those and you'll come up with plenty.  They do not harm the surface of the aluminum.  They are common in truck cleaning.

[Larry & Norma]

I was thinking of using very fine wire wool. Is that too abrasive?

[Garry]

Larry,

I tried a spare cover i had with a copper wire brush in a drill but it was too abrasive to the surface and it is just not quite right.  The Aluminium is quite soft and is easily knocked or scratched or damaged so what ever you use needs to actually be equal to or softer than the original material or there is risk of damage..  Using a softer material like Walnut and I have also tried glass bead (which I actually think is a nylon) also does an excellent job, I would not recommend using any form of wire or abrasive pad.  To get the job done commercially is also not overly expensive but if you go that route, I would suggest that you give them the inlet manifold as well and the accelerator linkages and any other bits that you want cleaned up. In AUst. it would cost around $100 for the lot. What you must do after peening is to ensure you wash the items in warm soapy water to get rid of any fine material left over to avoid getting it into the oil supply from contamination on the cover. Then give then a coat of high temperature clear gloss or satin depending on your preference.

I have not got the name of the material yet but Michael is right any abrasive supplier for 'sand blasting' will have various types of material and one suitable for aluminium.

Garry

[Iconic]

Garry,
Is the cover you show in the picture covered in gloss or satin clear coat?
It looks fantastic. Thanks for the tip.

[Garry]

I put a gloss on it but it is not a really high gloss.  Have only done about 100km since doing it last week so am still seeing if the paint will hold ok.   I have used it on other parts without problems so should be fine.

[mdsalemi]

FYI, my local powder coater has clear powder coats in many levels of gloss/satin--designed specifically to take a freshly cleaned casting and protect it in that "just cast" look...for many years.

If you are trying this yourself, I'd use a chemical clean rather than any kind of abrasive blasting--much easier to control and more forgiving.