Achieving "As Cast" Finish

[James B.]

How do I get back to an as cast finish on cast parts I am restoring (differential, front suspension pcs, steering gear box etc. etc.)? I've looked in the archives and find lots of posts on applying a protective finish on the part once the original finish is restored but nothing on how to achieve that finish. I have tried sandblasting, glass beading, Evapo-rust and Naval Jelly and found non of those are effective at removing 48 years of rust and returning the correct finish. I assume there is some kind of media I could use in a sand blasting cabinet or might it require some kind of chemical bath?? Will appreciate any suggestions, Thanks, Jim B

[Joe L.]

Re: Achieving "As Cast" Finish

How do I get back to an as cast finish on cast parts I am restoring (differential, front suspension pcs, steering gear box etc. etc.)? I've looked in the archives and find lots of posts on applying a protective finish on the part once the original finish is restored but nothing on how to achieve that finish. I have tried sandblasting, glass beading, Evapo-rust and Naval Jelly and found non of those are effective at removing 48 years of rust and returning the correct finish. I assume there is some kind of media I could use in a sand blasting cabinet or might it require some kind of chemical bath?? Will appreciate any suggestions, Thanks, Jim B

Jim------



In my opinion, there is absolutely no way of restoring the exact, as-original finish of an iron casting. Any type of abrasive restoration method, no matter how "gentle", will not result in an exact, as-original finish. Some chemical methods will come close but none that I've ever seen will result in an exact, as-original finish.

[Alan S.]

Re: Achieving "As Cast" Finish

Hi James,
There maybe some info in this thread that may interest you.
I'm now using the liquid used in black oxide coating to 'stain' the cast parts a little which seems to make them look not so 'fresh'.
Regards,
Alan

https://www.forums.ncrs.org/showthread.php?107029

[James B.]

Re: Achieving "As Cast" Finish

Joe and Alan, thanks for the responses. Alan, I had printed off the thread you referenced and was thinking about some of the suggested methods. I will try a couple- I am sure my wife will like used motor oil in the kitchen as I try to handle and wipe down heated spindles!! Also, will try your idea of the black oxide.

[Alan S.]

Re: Achieving "As Cast" Finish

Hi James
What is it with wives and this idea that the oven and dishwasher (and even the bath tub) should only be used for certain things?
I don't get it!
Regards,
Alan

[Don L.]

Re: Achieving "As Cast" Finish

Hah! You guys is phunny. She has to leave the house SOME time...

I'm watching this thread with interest, since I'm planning to re-finish my steering links, tie rod ends and front stabilizer bar before I put the car on the road this season.

[Stuart F.]

Re: Achieving "As Cast" Finish

yah, I know what Ya mean. My wife complains when I wash my baseball hats in the dishwasher even though I use a special plastic shape holder and spray on detergent that's designed for just that purpose. Hard to convince the wife that that's what dishwashers were designed for in the first place.

On parts that are either new or very clean, I have found that "Cast Blast" paint looks almost original and keeps them that way for a long time.

Stu Fox

[Gary B.]

Re: Achieving "As Cast" Finish

...On parts that are either new or very clean, I have found that "Cast Blast" paint looks almost original and keeps them that way for a long time.

Stu Fox

Stu,

Unfortunately, more than once I've also observed chassis judges take a deduct with the note "cast-blast paint; should be natural". Granted that was not for a new part, but rather something like the rear differential on a C2 that had been crusty before being blasted and painted. Nearly impossible to make some things look original again.

Gary

[Wayne L.]

Re: Achieving "As Cast" Finish

Evaporust is a liquid for soaking. May take a day or two. It does wonders! It only removes the rust. I did a cast iron three speed tail housing recently. It was the first time I have seen real gray cast iron! I get mine at Harbor Freight. It is environmentally friendly and can be disposed of in the sewer system.

[Mike E.]

Re: Achieving "As Cast" Finish

I am sure my wife will like used motor oil in the kitchen as I try to handle and wipe down heated spindles!! Also, will try your idea of the black oxide.

Get a pair of welding gloves, heat the part in the oven carry it back out to the garage and apply the oil.

Mike

[Gene M.]

Re: Achieving "As Cast" Finish

Get a pair of welding gloves, heat the part in the oven carry it back out to the garage and apply the oil.

Mike

use the barbecue grill, that is man's turf.

[Phil D.]

Re: Achieving "As Cast" Finish

use the barbecue grill, that is man's turf.

I used the bbq grill to cook up some manganese phosphate splash shields just last weekend. Another way to get a nice blue-grey cast iron appearance on a differential is literally to flash rust it first, then quickly stop the rust with Ospho. Sounds radical since you've just blasted the rust off, but it works and the stuff is readily available at many hardware and home centers. After blasting all it clean, it will look too shiny of course. First brush it all over with muriatic acid, rinse very thoroughly and towel dry. You'll notice it starts turning orange very quickly. Don't stop between steps. You have to work fast as you don't want rust to build up, just a light haze of orange as if pollen had settled on the hood of your car. Now quickly brush it all over with Ospho. Its amazing. It will turn a nice blue-grey color right before your eyes. I know it says on the bottle that you can use Ospho like a primer, but you actually want to wipe all the excess off with a clean absorbent lint-free cloth, otherwise whatever isn't absorbed will dry white. Next, treat it with whatever rust protection you prefer, perhaps some of the ones mentioned in this thread already. I used Gibbs brand.

[Don L.]

Re: Achieving "As Cast" Finish

yah, I know what Ya mean. My wife complains when I wash my baseball hats in the dishwasher even though I use a special plastic shape holder and spray on detergent that's designed for just that purpose. Hard to convince the wife that that's what dishwashers were designed for in the first place.

On parts that are either new or very clean, I have found that "Cast Blast" paint looks almost original and keeps them that way for a long time.

Stu Fox

Hi Stuart. Hope all is well with you. I'm heading your way in mid-April, staying at Orlando's Four Seasons resort for a long weekend. Maybe I'll run into you while you're cruising in the '63.

When you say "Cast Blast", are you referencing the spray made by Seymour Paint?. I want to touch up tie rod ends and maybe my center link. I might do it the (better/right) way I am reading about here, but I just don't know how I would heat a long part like the center link to set the oil.

[Terry M.]

Re: Achieving "As Cast" Finish

Hi Stuart. Hope all is well with you. I'm heading your way in mid-April, staying at Orlando's Four Seasons resort for a long weekend. Maybe I'll run into you while you're cruising in the '63.

When you say "Cast Blast", are you referencing the spray made by Seymour Paint?. I want to touch up tie rod ends and maybe my center link. I might do it the (better/right) way I am reading about here, but I just don't know how I would heat a long part like the center link to set the oil.

Neither the center link nor the tie rod ends are cast part. Both are hot forged, and that leaves a very different finish than cast iron parts.

[Brad S.]

Re: Achieving "As Cast" Finish

Jim, when i did the cast parts on my 69 I took them to my buddies at engine machine shop. The bake the parts in an oven first to remove oil and then the put them in a steel shot rotating blast cabinet and they came out with a finish that is very very close to as cast finish.