Best Method for Emblems

[jaeger6]

I am casting these emblems (see below) and I am trying to come up with a time effective way of sanding the face in preparation for polishing. Currently, for the sample parts, I am simply sanding them with sand paper on a flat steel table. Works well but is very time consuming. It's quite important that the face be sanded as flat as possible with very minimal "diving off" of the the sharp corners.

So, I am looking for a powered alternative. I have been considering a belt sander, or one of those rubber expander wheels

The sanding belt has the draw back of how to hold onto the part while sanding. The part is only .170 thick.

Do you think the expander wheel, with the proper technique is capable of not rippling the surface?

Any other suggestions?

[mpierich]

Originally Posted by jaeger6

I am casting these emblems (see below) and I am trying to come up with a time effective way of sanding the face in preparation for polishing. Currently, for the sample parts, I am simply sanding them with sand paper on a flat steel table. Works well but is very time consuming. It's quite important that the face be sanded as flat as possible with very minimal "diving off" of the the sharp corners.

So, I am looking for a powered alternative. I have been considering a belt sander, or one of those rubber expander wheels

The sanding belt has the draw back of how to hold onto the part while sanding. The part is only .170 thick.

Do you think the expander wheel, with the proper technique is capable of not rippling the surface?

Any other suggestions?

I wouldn't use the expander wheel unless the part is less or equal to the width of the wheel. I have one, and the edges dig in easily and the hard surface does make ripples easily.

A tabletop belt sander would be ideal in my opinion. I'm sure you could come up with a temporary adhesive to put on the back of the emblem to get a handhold on it. Maybe rubber cement a cardboard handle on there. Also use a stop at the near end of the sander to keep it from flying off the belt. Use low speed grinder's grease and the sanding will look 100% better.

[jaeger6]

I think I could come up with a holding fixture.

Grinder's Grease? Is that like Du-all's stick wax?

[mpierich]

Originally Posted by jaeger6

I think I could come up with a holding fixture.

Grinder's Grease? Is that like Du-all's stick wax?

I believe it's animal fat. If you use the high speed grease for a belt sander it'll gum up your belts. It has a higher melting point. Low speed has a low melting point. I believe Caswell has both. Don't use too much. And use a belt cleaner frequently.

[jaeger6]

Ah, yes. I found it. Caswell calls them Coated Abrasive Grease Sticks. Thanks a lot for the tips!

[mpierich]

Originally Posted by jaeger6

Ah, yes. I found it. Caswell calls them Coated Abrasive Grease Sticks. Thanks a lot for the tips!

Yep, that's the stuff. Use the F-26 for your belts; the F-10 works OK for the die grinder, etc.

[baz]

Originally Posted by jaeger6

I am casting these emblems (see below) and I am trying to come up with a time effective way of sanding the face in preparation for polishing. Currently, for the sample parts, I am simply sanding them with sand paper on a flat steel table. Works well but is very time consuming. It's quite important that the face be sanded as flat as possible with very minimal "diving off" of the the sharp corners.

So, I am looking for a powered alternative. I have been considering a belt sander, or one of those rubber expander wheels

The sanding belt has the draw back of how to hold onto the part while sanding. The part is only .170 thick.

Do you think the expander wheel, with the proper technique is capable of not rippling the surface?

Any other suggestions?

i woud go with the belt sander.
different options for holding it .
when casting th part i it possible to leave some kind of a holding point in the back .something that could be quickly ground or cut off after the sanding .

or using a flat rectangular piece of wood about 1/4 inch larger than the emblem make a frame around the four sides that will extend about .125
put your emblem face down on the belt sander put that frame on top of it
and start the sander , the framed sides will hold the part and give you .045 free space to remove material

[84Supra]

try an ordinary palm sander. It won't round of the corners like hand sanding or expander wheels will. You'll get a fairly flat surface as if you were using the table or belt sander. If you catch an edge, it won't throw it like the belt sander will, possibly damaging your emblem.