Topic: Looking for peoples process on Leaf Spring prepping for Gun Blueing.

[Morsel]

Hello all, I've been searching around and trying to find people methods for getting leaf springs ready for final gun blueing. I know you are not supposed to blast leaf springs, and I also know I'm going to need to remove the black paint they were painted with and then soak in evaporust, which I've already made my jig for to handle the large pieces.

The main question I have I guess is preparing the surface prior to blueing and when I'm removing the paint, do you use a wire brush or wheel, or some other surface preparation, do I use my "Crud Thud" to strip the paint and surface prep? I assume we want these as clean and nice as possible without blasting, which everything else I've blasted and the metal is beautiful prior to blueing.

Anyway, any thoughts or opinions would be greatly appreciated.

thanks,

Jason

[67gta289]

I know that Eaton Detroit Spring can shot peen them for a cost.  I had them do my new rear springs as well as my original front coils, turned out great.

[Morsel]

I know that Eaton Detroit Spring can shot peen them for a cost.  I had them do my new rear springs as well as my original front coils, turned out great.

That's something, do you happen to remember what the price was and how long they took to do it, I assume shipping wasn't to cheap since these are so heavy...

Thanks for the response,

Jason

[67gta289]

I want to say about 25 bucks per spring.  I live in the area, so shipping was not an issue.  I would guess that would be the catch.

For those that are ordering new, they can request it before they ship.

[Morsel]

I want to say about 25 bucks per spring.  I live in the area, so shipping was not an issue.  I would guess that would be the catch.

For those that are ordering new, they can request it before they ship.

Yeah, I called, going to be too expensive in the long run and take too long, but I did learn that I'm going to shot peen them myself, learned the process and sounds like it's really not that different from blasting for the most part. So I'm going to give it a shot. I'll let you all know how it goes...

Jason

[BKnapp]

I am glad you posted your question. My next project will probably be my rear suspension, which won’t start until winter. I figured the “not blasting springs” was a bit of a myth. Obviously an aggressive, heat producing industrial blast should be avoided, but was planning on glass beading mine.  I might be taking a different approach.

[Bossbill]

I would think shot peening would remove my stamped in numbers.

Don't know why media blasting would be bad ...

[jwc66k]

I know you are not supposed to blast leaf springs,

Really. The biggest problem I had was putting a 4 foot long spring in a 33 inch wide cabinet. 
As Bill said, shot peening will obliterate any part number markings.
I used an old stainless 24 X 36 X 3 inch steel pan, the type that was used in restaurant steam tables, to phosphate the spring sections.
Jim

[Bossbill]

SNIP ...
I used an old stainless 24 X 36 X 3 inch steel pan, the type that was used in restaurant steam tables, to phosphate the spring sections.
Jim

I need to go to my restaurant supply store and  get some of those long pans. I can't even fit my accelerator Z bend piece in anything.

And yes Jim, I read your post on the subject!

[edit to correct spelling of Jim!]

[Morsel]

Really. The biggest problem I had was putting a 4 foot long spring in a 33 inch wide cabinet. 
As Bill said, shot peening will obliterate any part number markings.
I used an old stainless 24 X 36 X 3 inch steel pan, the type that was used in restaurant steam tables, to phosphate the spring sections.
Jim

So Jim, are you saying that blasting them isn't a problem? I heard and read that you should never blast leaf springs because it does something to the tempering. But thanks for the info on the numbers, definitely watch out for that while I'm doing it.

And yes, already have a rig setup one my blast cabinet, made a dental dam at the door out of rubber and made a small slit in it that I can slip one end of the long sprint into, blast it and and then flip it, has tight seals and all, it'll get the job done that's for sure

Jason

[midlife]

I sand-blasted mine out in the driveway with a portable pick-up tube in a 5 gallon bucket of sand.  These were replacement springs, so ruining an OEM set was not an issue.  I cleaned them up, painted them (gasp!), and installed them.  Never had a problem in 20k miles thereafter.

[Morsel]

Well, I use glass bead as my media anyway which is less brutal, maybe what I'll do is blast them clean with the glass and then give them a soft peening with shot afterwards since I have the media anyway... can't hurt I figure...

Thanks for all the info everyone...

Jason

[Bob Gaines]

Well, I use glass bead as my media anyway which is less brutal, maybe what I'll do is blast them clean with the glass and then give them a soft peening with shot afterwards since I have the media anyway... can't hurt I figure...

Thanks for all the info everyone...

Jason

You will not see or experience any difference regardless IMO.  Given the many dozens I am personally aware of (both show and track)and hundreds and most likely thousands others that have sandblasted/bead blasted etc and put back into service without issue the practice would suggest that it is only a issue under the most extreme of conditions. Just my 2 cents.

[Bossbill]

Media blasting is for cleaning. You have to get into very large industrial media/sand blasters before you could introduce enough heat to de-temper a spring (around 650F to start). I've seen sheetmetal get deformed by industrial (ship) sand balsters.

Shot peeing is generally not for cleaning but to relieve stress in metal (plastic deformation) to prevent cracks.

Peening is a good idea in a spring and while it might do some amount of cleaning, that's not its main purpose.

The media process is abrasion. The peening process is plasticity (thanks WIKI).

[jwc66k]

I don't know where the old wives tale about bead blasting harming a heat treated part started (Here be dragons and sea monsters), but -

You have to get into very large industrial media/sand blasters before you could introduce enough heat to de-temper a spring (around 650F to start).

- that was the reality. I've blasted thru a ripped glove only to get glass beads all over everything. There was no appreciable heat there.

Media blasting is for cleaning. ~~
~~ I've seen sheetmetal get deformed by industrial (ship) sand balsters.

More reality.
I play games with blasting too. After the item is blasted, I've used a VERY CLEAN (oil and grease are your enemy) wire brush to change the look of what I've blasted, mostly before zinc plating.
One hint - do not handle any item after you've blasted it. Wear rubber gloves, or use shop towels. Be paranoid about keeping the item clean.
Jim