Here's what may be a dumb question. I have an Edelbrock YBlock manifold, a 553 tri power manifold. It has been polished by a previous owner. Is there any way to restore the unpolished look of a cast alum manifold ? I do not like the polished look. If there is no way to restore it then I may just sandblast the crap out of it and have it powder coated silver grey color. Unless someone has a pristine unpolished manifold and wants to trade Any ideas, or am I nuts. Larry.
You know? I think Langey is right, look for a true blasters and ignore my sage(NOT) advice. While your there lick the exposed wires too........ Doc.
Ok, well I am going to ship the whole tri power to Dick to have the carbs overhauled and proper progressive linkage and fuel lines installed. After that I'll decide if I can live with the manifold or if not I have access to a blasting cabinet and can do it myself. If I did blast it and didn't like the way it turned out I could always go the powder coat route.
Bead blasting won't restore an as cast surface. You will need something much more coarse. I used "Black beauty" once but I was not really satisfied with the results. I couldn't make it look freshly cast again...only dull. You can get some light texture but nothing near a cast aluminum intake.
I "unpolished" an intake with sandblasting. Gives the intake a very smooth "satin" look. It does not look like "as cast". I blasted mine with the intention of painting it, and paint it I did. (I used Silica sand for the blasting media). I say sandblast it, then buy a BB gun and give the gun and intake to a neighbours kid. In a month or so you will be happy and that kid will never forget what you did for him.
sand blast, then bead blast. The sand blast is very course and the bead blast smooths it out a little. It will not be like new cast aluminum, but it will be close.
I do a bunch of vintage motorcycle restorations and sometimes I have to make a side case back to a cast look where a boot or something had rubbed against it. It's not an easy process, takes a lot of time. I take 36 grit sand paper and a hammer and beat the grit of the paper into the aluminum. Move it around and keep rotating the paper to get a random look. The heavier the weight of the paper the better. Some grinding discs work well too. You are basically reversing the pattern. It was cast against sand. Now pound the sand back into it. This is the only thing I have found to give you the depth of the cast. After you beat all of the shine off of it, you can then sand blast it with a heavy grit sand. If it's to stay bare after, don't glass bead it. Use some aggressive mag wheel cleaner like Eagle one. The mag wheel cleaner will give it more of a dull fresh cast look. Glass beading will give it a little sheen. There is a bunch of other little techniques I use wile doing this also. I welded a little Roloc disc holder to the end of an old hammer and I use the 1/4 turn discs and hammer away. I use disc adhesive and glue the paper to a thick paint stick and hit that. I cut big hard backed grinding discs into different shapes to get into tight places. If you have a body shop "Jitter Bug" I use the end of that too, to beat against the surface to speed things up a bit. Happy Hammering, ZILLA!
Lamar Walden, Waldens Speed Shop, has a reskinning process for cast aluminum parts. Had a set of aluminum heads with a bunch of welding on them "reskinned" for a restoration project, they looked factory fresh. I also know a cheating racer who modified his production intake, because the class called for only production manifolds. He cut apart and enlarged all the intake runners. When done he smoothed out the welds and then ran a needle scaler across them. Pounding the weld areas produced a texture real close to as cast.
The casting foundry that supplied my old shop with aluminum castings used steel shot to clean them before being shipped to the machine shop....
Here's how I did something similar with a needle scaler. Larry T http://www.jalopyjournal.com/forum/showthread.php?t=356311&highlight=needle+scaler
There are some new high heat powder coat finishes available that are real close to cast. It would be cool to match the exhaust manifolds with the intake too. By the time the motor gets a few miles and a little road film and oil stains on it it will have the authentic look you want.
Folks, we have a winner!! Find a good and well equipped engine/machine shop that can do shot peening. Tape all of the machined surfaces real well, high quality "body tape" (the black stuff) works better than duct tape. It sits in a machine and gets tumbled with steel shot which makes it look OEM again. Anything else looks like a blasted intake (fake). Look at a new one at the speed shop and you'll see it. I also think doing it over a polished surface might net you a better than OEM but still OEM finish. Cost should be minimal.
Bead blast it and forget it. Sand blast is a bad idea, I've done it but unless the sand is just about wore out IE used and reused a tone, it will leave it looking real porous.
Problem solved, traded for another manifold which has not been polished. It's an Offenhauser which will go well with my Offenhauser valve covers. The whole system is now on the way to Dicks Hot Rod Place in Indiana
SOS pad, ok so you no longer need to remove the finish, but SOS pads do a nice job for me, i don,t like the look of bead blasting, i like smooth but not polished.
The aluminun foundry I worked for also used steel shot for a lot of castings that had to be welded up. You could not tell the difference between the non-welded vs welded up castings. The wheel abrader was huge (room sized) and with the steel shot it wore the inside out very quickly but it was very excellent at removing chrome from bumpers .
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