Well, it's kind of difficult to say how to polish this piece. The surface looks pitted to me, but that may just be on the photo. If it's actually pitted, there isn't much to polish. I would probably sandblast the piece in that case.

Otherwise, a magnetic tumbler with needles would do the job. These are terribly expensive, or could be easily built at home: http://www.youtube.com/watch?hl=en&v=3_FpiTzVYP8

Nice work!

Ditto beat me to the response. I own a magnetic pin polisher and that is the way to go for small pieces that have a lot of detail. Buffing will wear down the details where a magnetic polisher will preserve them. Actually the machine is burnishing the piece, so use normal methods to remove any really rough spots first.

Ed

Hi Steve, it turned out great, your wife should be pleased with it I think!

Looks like you are on a good track to produce many more pieces in the future!

- Michael

thanks for the advice, the caster did tumble them, but they don't remove what left of the spruce (is that the right term?)

The Surface is a bit pitted, but still look pretty good to the naked eye, 14MP DSLR with the image cropped to 100% shows up so all the detail ;)

In case anyone is interested , I used Best-cast , NJ, USA, for the casting, and they use Rhino has their CAD software so where happy to work straight from a MoI file :)

To remove the remainder of the sprue, you just take an ordinary file and file it off. The nearer you get, the lighter you go. Change the filing angle ever so often to avoid file marks. Once you are almost there, change to sanding paper wrapped around a stip. 400/800/1200 and it should be as polised as the rest.

For a next production run, ask your caster *NOT* to tumble it. A second look at the picture makes me believe to see an orange peel surface, sure sign that he tumbled in a rotary tumbler, and for too long. Build yourself a magnetic polisher with needles, and the surface should be much better.

Hi Steve, eh! How to say it is a mess! Polish this object is very difficult. I don't know wicth kind of result you can obtain only with the magnetic tumbler.
I do not know exactly the procedure that they used to develop the model for the fusion.
As a rule there is provided a model by removing (cutting of a block of material) or by stamp 3D.
Lately you use 3D printers that produce the resin model. This methodology facilitates the pre-production of the object because the plaster is poured (negative mold) directly on it. With firing of the plaster, the resin melts and remains empty and the mold is filled by molten metal.
The surface of item can be irregular for three reasons: the use of a resin model that melts into the plaster cast (and leaves the impurities), a model not polished or use of any product release agent (silicone spray or talcum powder) to facilitate the removal of wax from silicone rubber, (fourth reason: problems during the fusion... but we think that it's not our case!).
When the resin is dissolved into the plaster surface (I think your case) is always a little dirty. It' s impossible to get a good result even if the resin model is perfect!
Can you solve the problem in two ways:
1. Achieve the object directly in the metal by removal of material from a block of metal (expensive procedure and mono-productive).
2. Making the resin model and make a silicone rubber mold. Revenues from it for your item and use it in wax for casting (cast in plaster). The subject will probably be similar to what you now have in hand, but much cleaner. The surface will be nearly perfect because it uses an original model of a perfect and faithful rubber (expensive procedure initially, but then economic and N-productive).
There are other reasons for this problem, but these are the most important.
I hope not to have you created more confusion than before...
Objects with large glossy surfaces are not easy to achieve with fewer steps and in economics.
Now you may be partially hidden by a sandblasting. And then hand-polished letters and a lily... but I know it's not the same result.

Thanks, FiL

Not sur what process Best-Cast used dut at some stage, the made a silicone mould.

I hit them a bit with a metal mop-head on a mini grinder. They are not polished but at least they are a bit brighter :)

The next batch, we are trying a local caster that offers full finishing/polishing. first sample should be ready in 7 days :)

Cheers, Steve

Hi Stevecim,

>I hit them a bit with a metal mop-head on a mini grinder. They are not polished but at least they are a bit brighter
I know, is always better than nothing.

>The next batch, we are trying a local caster that offers full finishing/polishing. first sample should be ready in 7 days :)
I'm sorry. I'm on the other side of the globe!