Polishing advice needed

[SScnc]

I'm thinking about getting this vibratory polisher from Harbor Freight...

http://www.harborfreight.com/cpi/cta...unction=Search

I want to use it to polish "medallions" I'll be machining on my CNC'd X2 then, later I'll be casting them from zinc. They are about 3.75 in. diameter and .250 thick.

Would this be good for polishing these "medallions" ?

What media is recommended for a bright clean finish ?

Thanks

[SScnc]

I had searched here on the zone and I didn't find the info I needed so I just searched on Google and found the post I needed:

Vibratory polishers and aluminum

Thanks anyway.

[ViperTX]

Well zinc is pretty soft so you will have to experiment....hmmmmm....stainless shot works on silver....I would try that. Rice and walnut stuff works....but much slower.

Paul

[SScnc]

Thanks Paul,

Actually, I've never cast metal before but thought zinc would be good to try. I have CNC'd injection molds and built a plastic injection machine and that has all worked out excellent. I'd like for my metal casting mold to be steel, do you suggest a different metal other than zinc to start with ?

[jalessi]

See the link below for good direction.

http://www.steelmedia.com/metal-poli...%20and*%20Zinc

Your masters need to be free of tooling marks and high polished.

Most zinc casters use silicon rubber molds.

http://www.tekcast.com/i16//information.html

Jeff...

[SScnc]

See the link below for good direction.

http://www.steelmedia.com/metal-poli...%20and*%20Zinc

Your masters need free of tooling marks and high polished.

Most zinc casters use silicon rubber molds.

http://www.tekcast.com/i16//information.html

Jeff...

Great links ! I was not aware of the Tek setup, very interesting. I know what you mean about the master needing to be high quality, on my injection molds I spent allot of time polishing with a Dremel and Flitz, to the point of mirror.

I'm going to check out the silicon rubber in depth.

Thanks for the help.

[Harryman]

Vibratory finishing is similar to hand finishing in that you'll have to start with abrasive media (plastic cones or pyramids) and work finer through burnishing (steel or ceramic media) and then polishing (walnut shell or wood pegs).

Some zinc alloys might oxidize in the burnishing stage because of the water. Steel shot is also heavy and will tax that HF cheapo tumbler, don't expect it to last too long under that load. Get stainless instead of carbon shot, I like the finish carbon will give but it's a pain to maintain (it rusts) and unless you use it everyday, too much trouble.

Polishing to a mirror finish can take a really long time in dry media like walnut shell, burnishing will get you most of the way there and for many items is good enough.

[SScnc]

Regarding the high temperature silicone for mold making, can you recommend a supplier for it ?

Same for the zinc if you don't mind.

Before investing in a spin casting setup I want to make one mold and just pour the zinc in and see how it turns out and go from there. That's the plan anyway ???


Thanks again, I think this is just what is required.

BTW, my polisher hasn't arrived yet. Looking forward to trying that out too, thanks all for the advice.

[jalessi]

SScnc

Do you have a instant messenger?

[SScnc]

No, I don't

[jalessi]

It would be simple to download.

http://messenger.yahoo.com/download/

Spin casting is going to yield much better results verses attempting some sort of pour.

Tekcast has a 75 pound minimum order for rubber.

Do you have a vulcanizing press?

By the way, what is your name?

Jeff..

[SScnc]

It would be simple to download.

http://messenger.yahoo.com/download/

I'll check into that.

Spin casting is going to yield much better results verses attempting some sort of pour.

I'm sure it would, I'd just like to get a look at a part doing it that way before spending more for a spin setup.

Tekcast has a 75 pound minimum order for rubber.

I thought there might be another supplier where I could buy a small amount to begin with.

Do you have a vulcanizing press?

No, I really have no metal casting equipment. I was also hoping that there was a two part mix for this type of silicone so it could be poured like I've done with urethane from Tap Plastics.

By the way, what is your name?

It's Steve

Thanks for your replies and help.