On 19/9/21 10:19 am, Daryl wrote:
> On 18/9/21 11:19 pm, Noddy wrote:
>>
>> *Caution: Automotive related post warning*
>>
>> Like most of the rest of the country we here in regional Vic have been
>> in lockdown, and like a lot of people in lockdown I've been inspired
>> to do some of the things I've been meaning to do. Actually, lockdown
>> hasn't made a hell of a lot of difference to me now that I'm fully
>> retired, but I'm using it as an excuse to do a few things I've been
>> meaning to do for a while.
>>
>> One of those things has been to get into Vapor blasting.
>>
>> Vapor blasting, vapor honing, water blasting, wetblasting, whatever
>> you want to call it. The process is basically wet media blasting, with
>> the emphasis being on fine, non destructive finishes on things like
>> cast alloy and zinc for items such as inlet manifolds and carburetors.
>> In applications where you're looking to restore an original cast
>> finish, or prepare a zinc bodied carburetor for recolouring, it's
>> ideal as it produces a near perfect surface finish without casing
>> damage like dry blasting can.
>>
>> There are a few specialist businesses in Melbourne who offer vapor
>> blasting services, but as none of them are anywhere near me and I
>> currently can't get to them anyway I decided to build my own cabinet
>> and see how well it would work.
>>
>> This is it here:
>>
>>> https://www.imagebam.com/view/ME3NX9H
>>
>>> https://www.imagebam.com/view/ME3NX9I
>>
>> The cabinet itself started life as a 350 buck "over the counter" dry
>> blasting cabinet that I've modified to run as "wet" machine, which
>> basically meant sealing every possible gap to prevent leaks. In order
>> for the process to work, it needs a supply of a "slurry" of media
>> mixed with water pumped up to a hand-piece that is then hit with high
>> pressure air. The "blasting" process works the same as any
>> conventional dry blaster but with the media suspended in water it
>> provides a softer action that polishes more than bites, and leaves a
>> nice "as new" finish on cast alloy without turning it into a dull
>> chalky finished mess like dry blasting does.
>>
>> As can be seen in the pics, the collapsible motor bike stand
>> underneath the cabinet holds a 30 litre plastic tank which is where
>> the media slurry is kept, and inside this tank is a 240v dirty water
>> pump that both agitates the mix to keep the media suspended in the
>> water, and to pump it up to the gun.
>>
>>> https://www.imagebam.com/view/ME3NX9L
>>
>> The pump sits freely in the bottom of the cabinet and is held in place
>> by it's own weight on the base of the media tank. It's made that way
>> on purpose so different medias can be used simply by swapping out the
>> tanks. Tank swaps take less than a minute.
>>
>> Using the machine is very easy, and it's controlled by foot switches.
>> Light for the cabinet is supplied by a 24 inch 12v light bar that is
>> driven by a power supply in the electrical cabinet, and is always on
>> when the power is on. The pump is a 240v unit that is controlled by a
>> 12v switched relay that is activated by one of the foot pedals, and a
>> marine bilge fan is plumbed into the back of the cabinet and wired
>> into the pump control circuit so it is activated whenever the pump is
>> running.
>>
>> The other two pedals control the air solenoid valve to supply high
>> pressure air to the gun, and the windscreen wiper that wipes the
>> inside of the cabinet glass. All three pedals are momentary contact
>> types, but thanks to a basic Arduino logic controller and a 4 port
>> relay board they operate as latching switches so you don't have to
>> hold them down.
>>
>>> https://www.imagebam.com/view/ME3NX9J
>>
>> So, how does it work? Well, for a first attempt that's still being
>> played with I think the results are excellent.
>>
>> This is the machine being used to clean up a Holley float bowl that
>> was pretty grubby to ready it for plating:
>>
>>> https://www.imagebam.com/view/ME3NXA4
>>
>> And the final result was very satisfying:
>>
>>> https://www.imagebam.com/view/ME3NXA6
>>
>> The bowl came up like new with zero abrasive damage which is something
>> that usually never happens with these things during a dry blast. Even
>> when using dry soda blasting some of the very fine lettering gets
>> taken off as the case zinc is very fragile, but in this case none of
>> it was damaged at all. This bowl was blasted wet with Soda as the
>> media at 40psi, and it came out clean enough to plate with no other
>> work required.
>>
>> As for cast alloy, a fine glass bead slurry produced the best results.
>>
>> This inlet manifold here is an original Phase I GTHO part that has
>> been sitting for many years after having been dry bead blasted by
>> someone else. As a media ratio test I stuck it in the cabinet and
>> blasted the upper runner that is visibly cleaner in the picture, and
>> although the photo doesn't capture the difference as well as I would
>> have liked the result was quite astounding. The Alloy finish went from
>> a dull, powdery one to as new smooth, and I was very happy with it.
>> The ratio of the water/media slurry was 10:1, with very fine grade
>> glass bead used.
>>
>> To try a mix of different medias on different parts of the same item I
>> used an old alternator:
>>
>>> https://www.imagebam.com/view/ME3NXAA
>>
>>> https://www.imagebam.com/view/ME3NXAC
>>
>> This is actually the alternator off my old Mitsubishi Forklift, and as
>> it needed a reco I thought I'd pull it apart and give it some new
>> bearings and brushes and use the cabinet to clean it up as I was doing
>> it. As can be seen it was pretty grubby and discoloured. To clean this
>> up the Stator, Rotor and Regulator pack were blasted with Soda, and
>> the alloy housing with glass bead. It came up like brand new.
>>
>> Playing around a bit further I upped the glass bead to water ratio
>> slightly and tried it out on an old water pump.
>>
>> Before:
>>
>>> https://www.imagebam.com/view/ME3NXAI
>>
>>> https://www.imagebam.com/view/ME3NXCJ
>>
>> And after:
>>
>>> https://www.imagebam.com/view/ME3NXCM
>>
>>> https://www.imagebam.com/view/ME3NXCP
>>
>> I'm not re-using this water pump and it's going into the scrap bin as
>> it's past it's use-by date, but the purpose of blasting it is to try
>> to get the process to replicate an "as new" finish as close as
>> possible for restoration work, and even though it's still very early
>> days here with this I don't think it's doing a bad job. Here's the
>> blasted water pump compared to a brand new one:
>>
>>> https://www.imagebam.com/view/ME3NXCT
>>
>>> https://www.imagebam.com/view/ME3NXCW
>>
>> As you can see there isn't a hell of a lot of difference in it, and
>> it's even less distinguishable to the naked eye.
>>
>> Finally, just as a "fuck around" to see how well it coped with general
>> cleaning, I tried this old rocker cover which was half covered in
>> paint and half in rust. I forgot to take a "before" pic, but the end
>> result was impressive:
>>
>>> https://www.imagebam.com/view/ME3NXE8
>>
>>> https://www.imagebam.com/view/ME3NXED
>>
>> The total time to do this was under 10 minutes, and while I would
>> normally dry blast something like this to provide a bit of an "etch"
>> to the surface in preparation for painting, the finish on the tin is
>> quite amazing. It's *very* smooth, and surprisingly resistant to
>> rusting like dry blasted metal does as soon as you touch it.
>>
>> In all, I'm quite pleased with the outcome and think the initial
>> results have been excellent. Total cost of the project thus far has
>> run about 700 bucks, and while I'm still sorting out teething problems
>> like minor water leaks and the Arduino PLC being a little unreliable
>> at times I'm very happy with how it's turned out and am looking
>> forward to producing some quality restored components with it.
>>
>
> Nice results, those of us who actually work on cars know how difficult
> it is to get parts clean and looking like new.
>
>
Those of us who work on cars just fix the problems the cars have. Who
gives a shit how the cars look as long as the parts are clean enough so
that contaminants aren't introduced where they can cause damage..

--

Xeno

Nothing astonishes Noddy so much as common sense and plain dealing.
(with apologies to Ralph Waldo Emerson)