Alloy Polishing for Sandcasts

[kp]

What do you guys think about a thread which talks about members recipes for polishing alloy covers, fork outers etc. I have my own polishing system including a large HP power source. I have been doing my own polishing for years now and find it very difficult to reproduce the factory finish. In my view all factory parts were polished but I don't know what with.
I've found that sisal mops (polishing wheels) using a red grit (medium fine) seems to reproduce the finish for me but it is very difficult to get the brushed look. I also clear coat my parts and simply use a clear laquer from a rattle can. I do make sure I use good product. I'm not sure what the factory uses but there must be a better and easier clear coat that one can use. A fellow I know in the UK uses wax polish as the coating to protect the finish He says he puts around 3 to 5 coats over the part and reckons it keeps the corrosion away and lasts for ages and only does a maintenance coat yearly.
OK lets get some discussion going as I'm open to any new ideas on this topic and I would love to my work as close to factory as possible. I understand Vic World has a process he swears by. Does anyone know what this is KP

[Mad Matt]

KP,

I have been polishing my aluminum, and leaving it raw.  That way it can be touched up more easily every so often.  I figure once you clear coat it, then to fix it, it would have to be stripped and re-polished.  I do have a Caswell polishing wheel, but its such a dirty job, I have been sending mine to the chrome shop for polishing.

Eastwood makes a rattle can clear that I have experimented with. http://www.eastwood.com/diamond-clear-gloss-set.html  I have not used this on any restorations because I am just worried about the durability.

Once again, I leave it raw and touch it up.  I use metal gloss polish for the touch up, you can also use their sealer as a protective coating. http://www.metalgloss.com/.  This metal gloss stuff is FANTASTIC, it really works well to clean up old chrome and take the bluing off of exhaust pipes as well.

Also, some of my production parts for Kewlmetal are finished to match the OEM brushed aluminum.  They are powder coated clear.  I think this is a nice option for the durability.  I will find out from my powder coat shop how they are doing the brushed look.  But for powder coat, I have the Eastwood gun in my garage. They are selling the gun for $69 ! http://www.eastwood.com/hotcoat-powder-coating/powder-coat-guns/original-hotcoat-powdercoating-gun.html

I have a toaster oven for small parts, and I recently added a full size oven in my shop.  I love having the powder coating capability at home and I use it a lot.

Matt

[markb]

I've tried the Eastwood rattle can Diamond Clear and had trouble with it sticking to my covers.  I also tried this:
http://search.eastwood.com/search?w=diamond+clear+extreme&p=Q&ts=custom
It's expensive but its bullet proof.  Nothing touches this stuff when its dry.  I've tried gasoline, acetone, aircraft remover, nothing touches it.  But that's also the disadvantage, it's totally unforgiving if you make a mistake like get a run.  The only way I could get if off was bead blast it.

Matt, you mention matching OEM brushed aluminum.  Do you have a process for doing that?  If so I'd be extremely interested.  Also on the clear powder coat, do you ever have problems with yellowing?

Mark

[Mad Matt]

Mark,

For the brushed aluminum finish I know we send the parts to the chrome shop for polishing.  These are machined 6061 T6 Aluminum parts.  I know he belt sands the parts first to remove any machining marks, and then polishes with coarser wheels and grit than for mirror polishing.  For the brushed finish, there is a brush stroke direction to the finish.  I am going to talk to my chrome shop and get some more specifics from him such as what wheel and what grit, etc.  Then the parts are sent to the powder coaters for the clear.  We do not have trouble with yellowing, but you must of course use a UV protected clear powder.

Thanks for the info on the Eastwood Diamond clear.  I have tried the rattle cans but I have not tried the extreme diamond clear.

Matt

[donzie]

Ever wondered how boat companies coat these huge aluminum surfaces like on party barges etc. or what about truck lines with polished aluminum tanker trucks.
$60 / quart.... but super easy to use & a quart goes a looooong way.

http://www.sharkhide.com/acinfo.html