Sanding Inside HF's

[Mark Levitski]

I know a lot of you don't bother, especially on forms w/ small openings.
But from those that do: How do you reach and with what? I can reach just under the rim w/ my fingers, and the bottom with a small mandrel. It's the transition past finger reach that I can't seem to figure out. I tried some surgical clamps, but could not create the right padding for the abrasive.

Thanks.

[Jim Sebring]

You might try some ceramic tumbling media since you can run the turning on the lathe like a concrete mixer.

The only source I'm aware of is a fellow in MI that sells two different size granulations to black powder cartridge rifle shooters for cleaning their cartridge cases.

Here's his contact info: dkittydave@aol.com. (517) 669-9801. I haven't used the stuff but I'm surprised hf turners haven't discovered this method of smoothing up the insides of their turnings. The ceramic media should last about forever when used with wood.

[Ken Fitzgerald]

Mark....I have a large set of curved hemostats I use for the transition areas.

[Allen Neighbors]

Mark, I made a tumbler with a geared motor that turns about 55-60 rpm, and just throw in a handful of rocks that are small enough to go through the opening. A friend gave me some silicone carbide scraps that I put in with the rocks now, but just rocks will work. This technique also takes out soft grain before the hard grain, making the inside like water ripples.

[Mike Minto]

Mark, I made a tumbler with a geared motor that turns about 55-60 rpm, and just throw in a handful of rocks that are small enough to go through the opening. A friend gave me some silicone carbide scraps that I put in with the rocks now, but just rocks will work. This technique also takes out soft grain before the hard grain, making the inside like water ripples.

Allen, that is very interesting. Could you post a pic with a form mounted and the unit either turning, or set-up with a bowl full of abrasive? Thanks.

[Richard Madison]

Interesting indeed. Show us your rocks Allen. Should work for anyone with an EVS/VFD lathe. Quantity and shape of the abrasive material could make some difference in the results. About how long do you tumble the usual hf?

[Bob Borzelleri]

I always thought that one of the primary appeals of doing hollowforms was eliminating 1/2 of the sanding.:cool:

[Bob Hampton]

the best idea ive done for this is i use a piece of flat alum bar about 1/8th thick ...bend this until u have a gentle "S" curve to it ..make sure the ends are flat for about and inch..on the opposite ends glue on some velcro on the bottom side and then use the round sanding disc or cut some from sheet stock and start sanding.
the curve of the bar will allow u to get all the way down to the bottom ..if u make one end kind of a steep bend that will allow u to get the rim also
Bob

[Denis Puland]

with various types of media and have given up on it as a replacement for sanding.
It does do what I would call a ( half **ssed ) job of smoothing the surface but not even close to a sanded finish.

My 2 cents worth.

Denis

[Paul Atkins]

Maybe you could velcro some paper onto a few gerbils and toss them in there for a while.

[Allen Neighbors]

Here's a shot of the tumbler with a hollowform mounted and spinning. I mount the piece at a tilt halfway through the tumbling cycle, so it will get the top and bottom a bit more evenly.
I leave it tumbling for about 8 hours at a time, total.
In this shot I have a brown bag taped to the back of the motor, with a fan blowing to cool it, since at 100 degrees in my shop in the summer made it run a little hot. Since this photo, I have mounted a small pancake fan directly on the end of the motor, and now it runs cool all the time.
The ordinary rocks I use inside are granite gravel that is in my wife's carport. I just step out the door and get a handful and put it in the form, with a piece of tape over the opening.
Well, I've lost the only two pics I had of the tumbler with a form in place, trying to resize the pics with Windows Picture manager. They've just disappeared... I got a message (some files could not be saved), and when I cancelled the operation, and clicked (don't save). The photo was gone.
It'll have to wait until I get back home around the end of this month, before I can take more.