C7ZX-A Intake SNAFU. Restoration to CAST appearance?

[428GT500]

I, on the advice of a few others used mag cleaner on the intake, which didn't look too bad, but as usual the low areas between the runners had some corrosion. It wound up making the manifold look like it had a powdery white on it. So I decided to put it in the dish washer and run it with some Cascade.  Once again, the outcome was less than expected. I took it to a powder coater I used and had him blast it with plastic media as I was trying to keep the grey original cast appearance. Well, strike three. It was so mild it didn't get some of the mild corrosion on the flat areas between the intake runners and the finish isn't even. Does anyone know a process that isn't extremely pricy or works well to restore the surface more to look like a new cast finish? If no one knows a proven fix, does anyone make a paint that mimics the almost flat color of cast aluminum that's on the grey side instead of bright silver that I won't have to worry about damage from fuel if any winds up on it while the carbs are being tuned?  Anyway, pointers to a shop that does these things or a process I can do at home would be very helpful.

                                                                                                                           Regards,
                                                                                                                                      -Keith

[chris401]

My employers media blaster worked pretty good on my Street Master. After I make repairs Ill soda blast it. We have out blasters set at 82 psi.

[Ford428CJ]

This is what I have done in the past and still do. A buddy of mine owns a machine shop. I pay him to use his hot tank. Get some Castrol GTX Super clean. Or I like the Parts Master Purple Cleaner the best. But anyway...

 I run it in the hot tank for 10mins. Spray it down with the cleaner and let it sit for a min or so. Run it for another 10min. Pull it out and hose it down with hot water. Spray it down again with cleaner. Soak it. Back in the Hot tank again for 10 mins. Pull it out, hose it with hot water, then air hose it dry. That works the best and looks really nice when its done! I'll post pics of one that I did...

[Ford428CJ]

He is a 6.0 Diesel intake I did for a customer... EGR crud in the runners and plan old nasty on the outside! Here it is all done up

[chris401]

You have proven most Ford guys wrong. You CAN polish a terd. Nice job on intake, I have done a few delete kits and none looked that good when I was done.

[Bad Byrd]

Personally if it was me and you can get your hands on any..............a 50/50 mixture of Sodium Hydroxide, And Sodium Chloride will make that think look like it just came out of the box!

Or any alkaline or Acid cleaner for that matter. Aluminum will etch at one extreme or the other..............so Alkaline works and Acid works. However I would always prefer Alkaline and then Acid.

The other option is to actually have it blasted with Garnet............vs media. Media isnt aggressive enough on these old cast Ford parts, but a finer Garnet will bring that back to life as well.

[Ford428CJ]

You have proven most Ford guys wrong. You CAN polish a terd. Nice job on intake, I have done a few delete kits and none looked that good when I was done.

Thanks Chris! This had over 100,000 miles plus... So you could imagine how bad it looked. I always try for an "A+" job! I dont prove most Ford guys wrong... I prove it can be done! LMAO  ok, maybe not all the time but I give it my best. Love those Sick Liters...

[babybolt]

There is no one cleaning method that applies to all circumstances, for a variety of reasons.  Early original intakes are cast from different aluminum than the new ones.  I think they were cast from 321 which is an alloy close to 319 that is used today for waterpumps.  Its not quite as strong as the 356 used in manifolds today and I think 319 tends to get dark stains easier.  319 is supposed to be more corrosion resistant than 356.  Anyway combine the different alloys with the age of your intake and the varying environmental conditions to which  intakes are exposed and the result is there no magic process to clean them.  Also some intake have been glass beaded in the past.

The hot parts washer is a good starting point, just make sure to use fresh powder as old water can stain the intake worst than it went in the washer.  Sometimes after washing the intake, your done.

I like plastic media the best.  It comes in varying sharpness and hardness so results vary.  As it ages it gets more rounded and smoother.  Its more expensive than glass bead, but lasts much longer and does not cloud up the blast box like glass bead.  And plastic does not imbed particles (not much anyway) like glass bead does into the surface.

But plastic will not remove stains as you found out.

Sometimes the best option is good old fashioned hand rubbing - use a scotch bright pad or those detergent impregnated steel wool pads found at grocery stores (these things actually work great).  You may have to use iterative processes to get the look you want - ie - reblast it as the final process.  Or use some of the wheel cleaners in spots.

I have not found any paint that can really match the look of bare aluminum.  Krylon used to make a color called Dull Aluminum which was great but have not seen it available for years. 

When you do get the intake to a bare aluminum patina you like, keep it sprayed with WD40, along with your aluminum valve covers and carb.  Typically on the kind of intake your talking about its not like you will be running it through salty winters or back and forth across the US on a daily basis.

[Ford428CJ]

Huuum.... Never new that about being different material.... The new stuff does stain in my opinion, just like the old stuff did. I thought it was how they cast it that made it different. Not disagreeing with you at all Babybolt.

 I was never one to use media on my intakes. Too afraid that some media would get left behind. The part has to be clean of any oil and what not before you blast it. As for the hot tank that I use, the water is dirty! The trick is to hose it off with hot clean water before it dries out. I also like to use a soft brush while cleaning.


 Lets do a little experiment then. I have an old crusty PI intake that is covered in 1/4" oil soaked crap! LOL I'll make sure to take pictures of it before, during and after.... Just for fun. I have been meaning to do that anyway. Now I have a reason too. LOL

[Barry_R]

Stainless shot media works to leave a pebbled finish similar to a new head casting.
Because thats how they prep new head castings....

[ScotiaFE]

You may have some and I repeat you "MAY" have, success with Aluminum Magic.
A low pressure glass bead will give the best result to preserve the original cast texture.

http://lloyds.targetnetwork.net/aluminum-magic-aluminum-cleaner-935-ml-31-6-oz-bottle-wsprayer/

[Ford428CJ]

Think Babybolt is right about the 2 different types of material... Ill post pics here soon.

[cjshaker]

Just to throw in my .02 cents worth, I've always used glass beads. But like most of the other processes, you have to make sure the beads are fairly new and clean if you really want that fresh aluminum look. Otherwise it will impregnate fine powders of whatever varnish, stains, rust or whatever else has been blasted before. I've had NOS intakes before and frankly nothing will ever give it that NOS look again, but glass beads give a very close even silver finish. A fine steel shot like Barry mentioned works good, but I always keep glass beads in my cabinet for a variety of other parts to clean.

I ALWAYS tape up all the ports and holes so nothing gets inside of the part. Blow it off after, carefully peel off the tape....then wash it like there's no tomorrow and blow dry it before it air dries.

Here's a shot of my engine. The air cleaner was glass beaded, then I ran 60 grit in long strokes to replicate the factory process of rough machining and belt sanding. The intake was glass beaded and it looks just like the new Edelbrock waterpump. The valvecovers were NOS.



And a more detailed look at the intake. As long as the glass beads are clean, it will look like fresh cast aluminum.

[428GT500]

That manifold looks phenomenal! I wish you were local, I would seek assistance!

                                                                                  -Keith

[babybolt]

Stainless steel shot blast is pretty much what most casting facilities use when the casting is an appearance item.  Some still use regular steel shot but then they have to be careful not to let it sit or get rusty - or let some employee run his dirty cast iron block in the machine during lunch hour.  Unfortunately stainless shot is very expensive and for us garage guys I don't think it would work in our typical siphon feed blasting cabinets - its density is too high to be sucked up the siphon tube - but then I never tried it.

Glass bead is OK, its cheap.  But like everything else, it comes in different grades and I see a lot of guy turn the pressure up to 90 psi and blast away.  At that pressure the bead breaks down fast and turns to dust, and the usual garage blast box doesn't have enough suction to really evacuate the box properly.  If you turn the pressure down, then the time to clean the parts goes up substantially.  Glass bead, like garnet and the crush slag media also open small pores in the casting surface.  Which is why the foundries use shot peen, it closes the surface.

As near as I can tell, 356 wasn't available as casting alloy until after the muscle car era.  At least not for intakes and heads, not sure about wheels.