TOPIC:

andyaus wrote:

JR I would be interested to know, after blasting with aluminium oxide what finish the Walnut shell media would yield?

Huh? I don't have any Aluminium Oxide, I got the glass grit instead as it was much cheaper, and had the potential to be a little gentler. If you mean use the walnut shell as a post- treatment to that ... well, I'm still not going to do it: based on what it did as the first treatment, there's no way it's going to be up to the job of smoothing the finish the glass grit left. There may be some circumstances under which the walnut shell is ideal (I'd like to try it for paint stripping on plastic for example) but I'm certain that Tamiya pot metal is not going to be it.

On the positive side, the glass bead has arrived, no information on size given but it feels about twice as fine as the glass grit & a lot smoother/slipperier. It's still sitting by the front door as I need to break it down into smaller quantities so I can move it to the shed; I've also got a longer air hose coming so hopefully now setting up, blasting a small batch & tidying up again afterwards won't be a three day event

Jonny wrote:

andyaus wrote:

JR I would be interested to know, after blasting with aluminium oxide what finish the Walnut shell media would yield?

Huh? I don't have any Aluminium Oxide, I got the glass grit instead as it was much cheaper, and had the potential to be a little gentler. If you mean use the walnut shell as a post- treatment to that ... well, I'm still not going to do it: based on what it did as the first treatment, there's no way it's going to be up to the job of smoothing the finish the glass grit left. There may be some circumstances under which the walnut shell is ideal (I'd like to try it for paint stripping on plastic for example) but I'm certain that Tamiya pot metal is not going to be it.

More of a curiosity question than an implied request

Put the parts through the 2nd stage of blasting with the glass media, I found that the new tip help here aswel with the time to complete flash fast The glass seemed to clean itself with the increased flow so the parts came out without any browning

Of course I couldn't help putting some of these parts together And me being me there was always going to be some shiny bits

Looking good

The finish looks to be the very clean/bright end of factory, I don't know if that's ideal but I suspect that's probably as good as restoration of pot metal parts is going to get - getting rid of years of stains is I think always going to mean going back to bare metal, and for consistency that then has to be done all over. You seem to have a avoided the rough, very porous & vulnerable "white" finish that blasting usually leaves - I'm hoping mine come out the same.

Jonny wrote:

Looking good

The finish looks to be the very clean/bright end of factory, I don't know if that's ideal but I suspect that's probably as good as restoration of pot metal parts is going to get - getting rid of years of stains is I think always going to mean going back to bare metal, and for consistency that then has to be done all over. You seem to have a avoided the rough, very porous & vulnerable "white" finish that blasting usually leaves - I'm hoping mine come out the same.

It's not as bright as you think (the lighting isn't helping) The finish after the glass is great, I'm wondering if I added some colour to the glass how it I could tune the finish to the parts

Hope no one minds me chipping in. Has anyone tried soda? It's a bit slower than glass bead but 'cleans' more that erodes the ally.

Just a side line, I tried making what I call plastic aluminium. I bead blasted plastic very lightly then using a zinc etch primer I ended up with this.

andyaus wrote:

... I'm wondering if I added some colour to the glass how it I could tune the finish to the parts
...

Sort of "blast dyeing" ... I'm not sure why you'd want to, unless you want to make the bits look old, artificially, without the damage/stains ... even then I think there are better/more permanent ways of doing it (colour wash, satin lacquer, etc).

Just spotted that the glass beads I got say "medium" on the tub, but still no actual dimensions. They still look pretty tiny to me ... with this stuff in the cabinet, a tiny air leak is apparent in one corner when the hoover has built up a vacuum - you can see the beads "boiling"

Anyway, this is the result of bead blasting at 50psi with a 5mm nozzle, having previously used glass grit - first pic is lit by "warm white" (but in reality, a bit pink) LEDs, second by camera flash - it's not quite as matt as the first pic, not as shiny as the second, somewhere in between so you'll have to take a mental average ...

Very interesting finish, Zinc etch primer eh