SAAC Forum

The Cars => 1967 Shelby GT350/500 => Topic started by: mlplunkett on September 03, 2019, 01:22:17 PM

Title: Best method for original finish on aluminum intakes?
Post by: mlplunkett on September 03, 2019, 01:22:17 PM
I have collected original Shelby intakes for my two projects and need some input on restoring to the original aluminum finish. The C7ZX has had some minimal effort to polish the surface so I figure some media blasting can get it back to normal but what media is best? The S7MS has been painted black and I want it back to bare aluminum so I will probably start with chemical stripper and then finish with media blasting. On a related question has anyone found a method to preserve the fresh aluminum from grease and oil stains? I was wondering if a flat clear paint would work.
Title: Re: Best method for original finish on aluminum intakes?
Post by: Bob Gaines on September 03, 2019, 01:46:42 PM
I have collected original Shelby intakes for my two projects and need some input on restoring to the original aluminum finish. The C7ZX has had some minimal effort to polish the surface so I figure some media blasting can get it back to normal but what media is best? The S7MS has been painted black and I want it back to bare aluminum so I will probably start with chemical stripper and then finish with media blasting. On a related question has anyone found a method to preserve the fresh aluminum from grease and oil stains? I was wondering if a flat clear paint would work.
A clear coat will typically dramatically change the look of the aluminum compared to one with no clear.
Title: Re: Best method for original finish on aluminum intakes?
Post by: csheff on September 03, 2019, 02:34:19 PM
clear and even a metal protectant will darken the manifold
Title: Re: Best method for original finish on aluminum intakes?
Post by: Bob Gaines on September 03, 2019, 02:39:35 PM
Stains can typically be cleaned with spray carb cleaner . Not too much of a issue if you stay after it and don't let it build up over many months.
Title: Re: Best method for original finish on aluminum intakes?
Post by: Rickmustang on September 03, 2019, 03:17:32 PM
Vapor blasting looks good on intakes and valve covers. Does not mark the surface.
Title: Re: Best method for original finish on aluminum intakes?
Post by: Bob Gaines on September 03, 2019, 03:21:50 PM
Vapor blasting looks good on intakes and valve covers. Does not mark the surface.
It leaves them too shiny however.
Title: Re: Best method for original finish on aluminum intakes?
Post by: 6s1640 on September 03, 2019, 06:17:36 PM
If you have an aluminum part that has had some repairs and now shiny spots, you can tone down the repair area to match the aged surrounding aluminum with Clorox Bleach.  It works best also in the sun.  The heat accelerates the oxidation, but the sun will tend to try out, so repeated applications with a brush will dull those shiny spots  to a nice aluminum gray.   I have also let sit over night to wake to a lot of whited oxidized aluminum easily brushed off.  Patients is the key to get to the right level of aging.   Rinse well with clean water when done.

If you have a freshly media blasted aluminum part, a spray bottle with Clorox Bleach might be in order to cover the entire part to tone down.  Be sure not to perform on your wife's favorite table cloth.   You will get in trouble.   Do it outside.

Best of luck

Cory
Title: Re: Best method for original finish on aluminum intakes?
Post by: papa scoops on September 03, 2019, 07:51:34 PM
you can use an automotive urethane, prefer heat resistance, clear if you add 50% flattening agent to it. it will dry with no shine and be easy to keep clean. cleaners wont hurt it, and with no shine or yellowing! phred
Title: Re: Best method for original finish on aluminum intakes?
Post by: Drew Pojedinec on September 03, 2019, 09:05:26 PM
I clean with carb or brake cleaner and soda blast them.
Glassbeads do leave it too shiny, and there is the possibility of the beads embeding.

If really really nasty, I will blast with garnet and reblast with soda.
Title: Re: Best method for original finish on aluminum intakes?
Post by: sg66 on September 03, 2019, 09:26:18 PM
Stains can typically be cleaned with spray carb cleaner . Not too much of a issue if you stay after it and don't let it build up over many months.
+1 on carb cleaner

I did this 30 years years ago by bead blasting then pressure washed at a self serve car wash and when dry, soaked it with WD-40. The claim is that WD-40 gets into the pores and seals the aluminum. 

I went to take a pic tonight and noticed some crud down by the bolt, I hit it with Brakeleen which cleaned it right up and wiped on some WD-40 circled in blue. The WD-40 should dry to the same color the next time the motor heats up.

This is also a fairly common practice for people who restore aluminum motorcycle heads.
 
Edit: added pic with better light and dried WD-40
Title: Re: Best method for original finish on aluminum intakes?
Post by: Bob Gaines on September 03, 2019, 10:26:54 PM
This is what a vintage intake looks like when it is new. Notice the dull somewhat porous texture. How you get to this point is the challenge.
Title: Re: Best method for original finish on aluminum intakes?
Post by: mlplunkett on September 03, 2019, 11:34:33 PM
The new Blue Thunder intake looks just like that. If I can get the original intake to look like that I'll probably put it up for sale to someone who really needs an original and I'll use the BT item. Think soda blasting would do the trick?
Title: Re: Best method for original finish on aluminum intakes?
Post by: roddster on September 04, 2019, 10:13:07 AM
  I've been through this.  Used to clear coat everything aluminum.  But, seems that glass beading, then leaving it like that works well.  Even after fuel spills and such, cleans up nice with no staining.  That is if it isn't laying there for months and months.
Title: Re: Best method for original finish on aluminum intakes?
Post by: Drew Pojedinec on September 04, 2019, 11:25:55 AM
This is what a vintage intake looks like when it is new. Notice the dull somewhat porous texture. How you get to this point is the challenge.

That is pretty much what blasting it with Garnet looks like.

About two year ago I bought a dozen different medias to try on a dozen intakes, trying to chase that look.
Title: Re: Best method for original finish on aluminum intakes?
Post by: acman63 on September 04, 2019, 01:04:36 PM
Heres an intake that was sent to us for restoration.  was very very rough to start with.  getting the finish to look even is very difficult.  Its a many step process to get it to this point.  If anyone wants the steps we take in this email me,  I have it on my laptop   jim@shelbyparts.com
Title: Re: Best method for original finish on aluminum intakes?
Post by: 67GT500#1594 on September 04, 2019, 06:08:05 PM
Personally, I blasted mine with recycled glass, used the wifeís high end dishwasher and then hit it with some aluminum acid wash. No clear coat. As before, if it gets stained use brake cleaner on it.

Big shout out to Drew Pojedinec for restoring my carbs! Ainít they pretty!!
Title: Re: Best method for original finish on aluminum intakes?
Post by: Vcode on September 04, 2019, 09:07:34 PM
Post on the CJ forum on vapor blasting.

https://www.428cobrajet.org/forum/index.php?topic=26343.0
Title: Re: Best method for original finish on aluminum intakes?
Post by: mlplunkett on September 04, 2019, 10:55:05 PM
Personally, I blasted mine with recycled glass, used the wifeís high end dishwasher and then hit it with some aluminum acid wash. No clear coat. As before, if it gets stained use brake cleaner on it.

Big shout out to Drew Pojedinec for restoring my carbs! Ainít they pretty!!

Tell me more about "aluminum acid wash". Would that actually be muriatic acid?
Title: Re: Best method for original finish on aluminum intakes?
Post by: Bob Gaines on September 04, 2019, 10:58:46 PM
Personally, I blasted mine with recycled glass, used the wifeís high end dishwasher and then hit it with some aluminum acid wash. No clear coat. As before, if it gets stained use brake cleaner on it.

Big shout out to Drew Pojedinec for restoring my carbs! Ainít they pretty!!

Tell me more about "aluminum acid wash". Would that actually be muriatic acid?
I use Eagle One products .
Title: Re: Best method for original finish on aluminum intakes?
Post by: shelbydoug on September 05, 2019, 07:42:26 AM
Personally, I blasted mine with recycled glass, used the wifeís high end dishwasher and then hit it with some aluminum acid wash. No clear coat. As before, if it gets stained use brake cleaner on it.

Big shout out to Drew Pojedinec for restoring my carbs! Ainít they pretty!!

Tell me more about "aluminum acid wash". Would that actually be muriatic acid?

It's just the "heavy duty" duty wheel cleaner. Don't leave it on too long though.

Incidentally, don't buy it in California. It will cause caner. Buy it in another state, then you won't get sick.
Title: Re: Best method for original finish on aluminum intakes?
Post by: Bossbill on July 12, 2022, 11:45:56 PM
This one?
https://www.napaonline.com/en/p/EGOE1TMG23

The MSDS lists phosphoric acid as the number one ingredient.
Title: Re: Best method for original finish on aluminum intakes?
Post by: JohnSlack on July 13, 2022, 12:16:48 AM
I've come to like Soda Blasting.. I will probably soda blast a BOSS 302 intake manifold later this week.

John
Title: Re: Best method for original finish on aluminum intakes?
Post by: shelbydoug on July 13, 2022, 08:07:19 AM
Put one in a dishwasher with PlatinumPlus detergent.
Title: Re: Best method for original finish on aluminum intakes?
Post by: Rickmustang on July 13, 2022, 09:50:50 AM
Vapor Blast in Houston for any aluminum parts
Title: Re: Best method for original finish on aluminum intakes?
Post by: Bob Gaines on July 13, 2022, 10:16:58 AM
Vapor Blast in Houston for any aluminum parts
Vapor blasting leaves aluminum intakes too shiny IMO at least compared to original.
Title: Re: Best method for original finish on aluminum intakes?
Post by: roddster on July 13, 2022, 06:44:27 PM
  I used to stress about just leaving it a natural finish. Used to clear coat it.  Then finally just bead blasted it and didn't coat it.  Surprisingly it has not stained, yellowed, or even dirtied up.  Last time I did it was about 5 years ago now.
Title: Re: Best method for original finish on aluminum intakes?
Post by: Royce Peterson on July 13, 2022, 09:01:38 PM
  I used to stress about just leaving it a natural finish. Used to clear coat it.  Then finally just bead blasted it and didn't coat it.  Surprisingly it has not stained, yellowed, or even dirtied up.  Last time I did it was about 5 years ago now.

I just had a C6 case (behind a 428CJ) treated with a process described as "vapor honing". It turned out very well, looks like a brand new C6 case. I bet it would look great on a aluminum intake manifold. Cost me $95 for the case, my guess is that an intake would be around $50.
Title: Re: Best method for original finish on aluminum intakes?
Post by: Bob Gaines on July 13, 2022, 09:40:38 PM
  I used to stress about just leaving it a natural finish. Used to clear coat it.  Then finally just bead blasted it and didn't coat it.  Surprisingly it has not stained, yellowed, or even dirtied up.  Last time I did it was about 5 years ago now.

I just had a C6 case (behind a 428CJ) treated with a process described as "vapor honing". It turned out very well, looks like a brand new C6 case. I bet it would look great on a aluminum intake manifold. Cost me $95 for the case, my guess is that an intake would be around $50.
I suspect that the vapor honing and vapor blasting are a similar process. It doesn't surprise me that the C6 case came out looking smooth and shiny surface like new given the surface. That sounds like a very fair price too. A intake has a dull and porous surface when new by comparison. The vapor blasting/honing is good for many things but not for a recreating a fresh cast intake look IMO. It comes out too shiny.
Title: Re: Best method for original finish on aluminum intakes?
Post by: CharlesTurner on July 13, 2022, 10:21:24 PM
Vapor honing/blasting is basically just mixing water with a media to make a slurry.  A water-tight blasting cabinet is used with a recirculation system and something like a wiper or water stream to keep the looking glass clear.  There are plans on how to build these with cheap harbor freight cabinets.

So, it depends on the media that is used in vapor blasting as to how the parts come out.  Most of what I've seen comes out too shiny compared to original finishes.
Title: Re: Best method for original finish on aluminum intakes?
Post by: J_Speegle on July 14, 2022, 01:55:50 PM
Would be concerned if cases (like bell housings and and aluminum transmission for example)  are coming out monotone and without the irregularities in the outer surface and finish like original castings.  That is one of the things that makes cleaning so difficult IMHO
Title: Re: Best method for original finish on aluminum intakes?
Post by: Blackcar on July 14, 2022, 02:25:09 PM
Has anyone seen an intake cleaned with a dry ice system ?
Title: Re: Best method for original finish on aluminum intakes?
Post by: J_Speegle on July 14, 2022, 05:15:32 PM
Has anyone seen an intake cleaned with a dry ice system ?

Only in pictures
Title: Re: Best method for original finish on aluminum intakes?
Post by: Drew Pojedinec on July 18, 2022, 05:51:53 PM
For what itís worth.

Iíve taken to using zinc shot for restoring intakes.
Expensive, but it is the most original finish Iíve found so far.
Title: Re: Best method for original finish on aluminum intakes?
Post by: Drew Pojedinec on July 18, 2022, 05:52:56 PM
Hi. Iíd drew. I can do all kindsa neat obscure stuff. But Iím not smart enough to post photos correctly.
Title: Re: Best method for original finish on aluminum intakes?
Post by: Bob Gaines on July 18, 2022, 07:14:06 PM
For what itís worth.

Iíve taken to using zinc shot for restoring intakes.
Expensive, but it is the most original finish Iíve found so far.
Drew, I have a very high regard for all of your work. The intake looks nice however it does not look like it did when new. The surface in the picture is too smooth and shiny.The process like so many others peen the porous surface closed and leave a smoother finish . When new the finish was dull and porous . To know what a intake historically looked like when new you only have to look as far as a new over the counter intake sold by Summit, Jegs ,Scott Drake etc.  I have seen and had NOS intakes over the years . For example the recent Scott Drake introduced repro of the S2MS intake when I had one in my hands noticed that the surface of the aluminum looked identical in texture and finish to vintage versions. It is not a big surprised as I believe the process is the same although I am sure equipment advances make production quicker and cheaper relative to the old ways.
Title: Re: Best method for original finish on aluminum intakes?
Post by: CharlesTurner on July 18, 2022, 08:56:44 PM
A few period photos... even in black/white, the finish is as Bob notes.
Title: Re: Best method for original finish on aluminum intakes?
Post by: Drew Pojedinec on July 18, 2022, 10:18:39 PM
Yessir Mr Bob. The closest I got to the dull stark white was when blasting with fine Garnet.

I think what you see in the images I took is probably ďbrighterĒ than reality.

Pictures as they are, often misleading. Especially black and white photos.
Smoother I 100% agree. But I think there is no way around that. When something arrives trashed, itís kinda just whatever you can do to get it to where you can.

Appreciate the input. All aiming for the same thing
Title: Re: Best method for original finish on aluminum intakes?
Post by: J_Speegle on July 18, 2022, 11:11:11 PM
I think what you see in the images I took is probably ďbrighterĒ than reality.

Pictures as they are, often misleading. Especially black and white photos. ...


+1 Especially the brightness added by the flash used in some many of these film cameras of the time
Title: Re: Best method for original finish on aluminum intakes?
Post by: JD on July 18, 2022, 11:33:47 PM
Hi. Iíd drew. I can do all kindsa neat obscure stuff. But Iím not smart enough to post photos correctly.

Drew, I'll never be able to do what you can, beautiful work & really glad you help and contribute.

(Rotated ...)
Title: Re: Best method for original finish on aluminum intakes?
Post by: Drew Pojedinec on July 19, 2022, 01:02:14 AM
+1 Especially the brightness added by the flash used in some many of these film cameras of the time

It is fun being a investigator of sorts with auto archeology. Half the fun with trying to restore carbs to ďoriginalĒ vs pretty was just this. Finding nos examples, trying to figure what aging added. Same with intakes, finding those hidden sections that were covered etc and maybe retained a few sq inch section of unoxidized finish.
A thing I have to remind myself tho when making something to a standard, is that the original manufacturer did not. They were just making a product. Variations due to batches, or a million other factors left most things wildly variable even when new.
Holleys to a much larger extent than something like raw aluminumÖ. But the point stands.

Iíll try to find the intake photos I took when testing fine garnet. I do not believe it looks correct, but maybe it will send someone else down the path of experimenting with it.
Title: Re: Best method for original finish on aluminum intakes?
Post by: shelbydoug on July 19, 2022, 08:56:48 AM
Here's the thing, it depends on which casting you are talking about.

The Cobra single 4's are the most flat, non-gloss ones. Similar to the oil pans.

The GT500 2x4's have a slight glow to them.

The C60A T/A I have has a definite glow to it so if you ask me, they are all different and there is no standard between them.

Now before the bickering starts, of those three, I have two that are original finish. The C7ZX and the C60A. They are from THIS planet and not delivered here by Martians, and yes they are in New York and no the air in not different here.

Title: Re: Best method for original finish on aluminum intakes?
Post by: csxsfm on July 19, 2022, 09:25:48 AM
My favorite finish has some random gas and oil vapor stains.
Title: Re: Best method for original finish on aluminum intakes?
Post by: Drew Pojedinec on July 19, 2022, 09:37:34 AM
Oh godÖ Iíll regret this.

I totally agree with you Doug. 😂😂😂😂

Probably has to do with the casting sand, or moisture content, etc. I have a lot of original, never molested units that vary greatly.
Title: Re: Best method for original finish on aluminum intakes?
Post by: shelbydoug on July 19, 2022, 01:21:12 PM
Oh godÖ Iíll regret this.

I totally agree with you Doug. 😂😂😂😂

Probably has to do with the casting sand, or moisture content, etc. I have a lot of original, never molested units that vary greatly.

It happens but I'm ok with that but you may not be forgiven here by some of the others!  ;)

Look out. These guys like food fights. The Cherry Jello is the worst. It really stains.
Title: Re: Best method for original finish on aluminum intakes?
Post by: 6R07mi on July 19, 2022, 01:32:16 PM
has anyone had seen what water vapor blasting produces?
It appears to affect the surface finish the least because it's mostly water droplets.

jim p
Title: Re: Best method for original finish on aluminum intakes?
Post by: J_Speegle on July 19, 2022, 02:33:13 PM
has anyone had seen what water vapor blasting produces?
It appears to affect the surface finish the least because it's mostly water droplets.

jim p

Yes and as mentioned it's a bit smooth and shinny IMHO compared to other castings. Haven't seen (that I know of ) the dry ice look yet

It's not just what is used to clean but allot of other things, such as how long its cleaned, pressures and so on. a 2% solution will clean allot of you run it through for a long time.

At one time decades ago we use to use walnut shells. cheap and plentiful around here at the time from the shelling companies Still use it for some things in the bowl cleaners

Title: Re: Best method for original finish on aluminum intakes?
Post by: CharlesTurner on July 19, 2022, 03:34:27 PM
has anyone had seen what water vapor blasting produces?
It appears to affect the surface finish the least because it's mostly water droplets.

jim p

Was mentioned earlier in this thread.  It's a media slurry.