Die-cast aluminun

[bmh]

Was wondering what advice I could get on the cosmetic restoration of die cast aluminum parts like gear case covers, oil pump covers and such. I have some parts in good servicable shape, but they look 50 years old......so before I do somthing I'll regret I figuired I should ask someone who has alredy made the mistakes. Thanks in advance
Brian

[Robert Luland]

BMH, I got something for ya. There’s this guy that sells a low temp aluminum-brazing alloy. I’ve seen him for years at swap meets and such. This year he was at Reinbeck and I scored a couple of bundles of the stuff. This stuff really works. You got to practice though. So grab your trusty ball peen and go out front and find some Pacific rim made junk heap and get yourself some pig metal to practice on. I’m going to scan the document that came with the rods and post it. Bob

[bmh]

Actually I'm more interested in restoring the finsh on a part that has been repaired, or was run hard and spent the last 20 years in a milk crate of junk. I think bead blasting would leave it to satin. I have some NOS die-cast , and it has a real smooth, yet not polished look. I've tried emory compound on a buffing wheel wuth a junk part and that just looks like a really bad polish job. Any ideas?
Brian

[bmh]

actually I'm more interested in making the visible portion of a repair look like die-cast again, or restoring the finish on stuff that was run hard and spent the last 20 years in a milkcrate with all sorts of other junk. I have some NOS stuff, and virgin die-cast has that real smooth , but not polished look. I think bead blasting would leave the finsh too "satin". I've tried using emory compound on a buffing wheel on some junk parts and that looks like a real crappy polish job, not die-cast. Any suggestions?
Brian

[Robert Luland]

BMH, I have been faced with the same dilemma recently. I have a 1965 XLCH I’ve been restoring. The brake drums and shoe plates just don’t look right glass beaded. I’m going to try polishing them only so far, wipe them off with lacquer thinner and shoot with a clear coat of lacquer. I tried clear Imron in the past but it turns yellow as all plastics do after a while. I to seek an answer to this plight. Bob

[Kojack]

I think Mr. Cotton suggested walnut shell blasting a while back. You can get the glass bead in different mesh. I use the fine stuff and give the part a rub down with scotchbrite but still, it's not quite the same. One problem I had once was the die cast part had a really even, smooth surface but just under it the casting was very porous. The porosity started showing through after bead blasting. Be careful.

[Perry Ruiter]

Actually I'm more interested in restoring the finsh on a part that has been repaired, or was run hard and spent the last 20 years in a milk crate of junk. I think bead blasting would leave it to satin. I have some NOS die-cast , and it has a real smooth, yet not polished look. I've tried emory compound on a buffing wheel wuth a junk part and that just looks like a really bad polish job. Any ideas?
Brian

Here's a link describing how the Harley Hummer crowd refinishes aluminum to get that fresh die cast look ... Perry

[bmh]

Thanks Perry, I'll give that a try.
Brian

[T. Cotten]

I think Kojak was referring to my use of steel shot blasting to cosmetically dress sandcast and rougher pieces than die-cast.

By no means am I a casting authority, but most often,.. before1970.., 'die-cast' refers to potmetal pieces.
The aluminum exceptions that come to mind are such as the difference between '49 sand-cast fork legs and brake backing plate, as compared to the die-cast pieces that followed.
It seems like camchest covers may have bounced back and forth, with Alcoa late Knuck and early Pan covers obviously diecast, while Duo and '65+ covers seem sand cast.
Pancover reinforcing rings were undoubtedly diecast, as evidenced by the circular injection 'sprues'.

Walnut hulls certainly give a satin finish to a polished repair, but a trained eye can spot any dressing beyond "authentic".
Refinishing any given piece will always require art as well as technology.


...Cotten

[bmh]

The art is were the fun starts.And yes a good eye will always pick up on texture or sheeen that isn't right. As for blasting things to strictly clean things, there is a plastic media that looks like ground up detergent bottles. Stuff is tough enough to take carbon out of heads, yet wont harm the metal at all. You can even blast off little bits of stuck on gasket without messing up the machining marks on the part.
Brian