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Cleaning up hollow spheres


#1

Greetings,

I was wondering if anyone knows of a way to nicely clean up the
seams on (small) hollow metal spheres? And by nicely, I pretty much
mean perfect. I don’t want to see any remnants of either a seam or
efforts to clean it up.

Filing and sanding is great, but because you’re filing on a tangent,
there’s a tendency to flatten out the plane along which you’re
filing, making for a very slightly perceptible, uneven surface. I’m
also working with mokume gane, so that complicates things just a
little in terms of maintaining the depth of pattern on the surface at
the seam.

I’ve done the standard progression of filing, sanding, but nothing
seems to give me the perfection I’m looking for. Is it possible, or
could it be that I’m a wee-bit too OC? :wink:

Thanks in advance.
Tamra Gentry
http://agjewelrydesign.etsy.com


#2

You may want to try this, but it does require that your sphere is
very round. After you’ve done your initial clean up with a coarse
file, put the bead aside.

Make a mandrel from sterling silver. I have a mandrel that is made
from solid wire, just over 4.2 mm but you can also use tubing if you
have it or want to buy some. If you’re using solid wire take a large
round bur and cut into the end. Cut deep enough so only the very edge
of the mandrel comes in contact with the sphere.

Using the least amount of solder possible solder the mandrel onto
the sphere. Normally when I make a sphere I fuse the halves together
so there’s no problem soldering the bead onto the mandrel. If you
solder the halves together make sure you use the hardest solder you
can. When soldering the mandrel onto the bead use the softest silver
solder you have. Solder the bead onto the mandrel only after you have
drilled at least one hole into the sphere for hot gas to escape.
Soldering a closed hollow object is extremely dangerous and puts your
safety at risk; It also could destroy all the work you’ve done to
this point.

Normally I solder the bead over the spot where one of the holes will
go. Let’s say for sake of visualization that the holes are at the
north and/or south pole of the bead. Don’t place the seam at the
equator, but offset from it. Don’t cover the seam with the mandrel.

Now place the prefiled bead in a rotary headpiece. Make sure the
bead is close to the headpiece. If a lot of the mandrel is showing
the mandrel could easily bend if the bead gets too much pressure
placed on it at a too high rate of speed. So, always use the slowest
speed you can and the least amount of pressure necessary. Once the
bead is mounted in the headpiece, slowly rotate it. Make sure that it
is turning true. Sometimes you can bend the mandrel a bit to make it
turn more true, but the best thing is to have a very round bead set
perfectly on the mandrel.

From here I would take some 180 grit sandpaper and hold it against
the bead. Experiment a bit. Sometimes I use the sandpaper on a stick,
but I always end up holding the sandpaper against the bead by hand.
Remove only enough metal to get below the file marks, them move
quickly to higher grits of paper.

Once you’ve achieved the sanded finish you desire, take a saw and
cut the mandrel off as close to the bead as possible. I usually hold
the bead against the sawblade and slowly cut the mandrel until it’s
nearly cut through. I hand cut the rest of the way. Here you will
need to file and sand the remaining part of the mandrel and the
solder off the bead, but if it is near where the hole will be
drilled, or in an area away from the equator of the sphere,
distortion will be visually minimal.

Remember to always file and sand in a flowing motion across the
surface. If your wrist is locked and you are filing facets into the
surface you’ll always have distortions.

Larry


#3

Hi Tamera,

As to the thickness at the seem of your sphere, If you can start with
more thickness there, it might help in the finishing process.

Good luck, Julz


#4

Hi Tamra,

Have you tried using emery belts, like those used for belt sanders
but made with cloth, and using it like you are polishing your shoes?
Perhaps using a piece of soft leather charged with polishing
compound. This the process my husband used to sand round machine
parts and the nose cone when he built an aluminum airplane.

Let us know.

Best,
Nel


#5

Tamra,

You can push any shape deep into floral foam and it will hold that
shape. Then line it with polishing papers (not regular sanding
papers b/c they’re too stiff) and use it to conform exactly to the
spherical shape. Lastly, just rotate the metal through until it’s as
smooth as you want it.

You can find floral foam in flower supply places or in flower shops -
very inexpensive. Just be sure to get the kind that is for fresh
flowers and is designed to hold water; the other kind is for silk
flower arrangements and is too hard to work with.

Jeni
Chilly in Ohio


#6

If they are beads (two holes at opposing poles) slip a piece of hard
steel wire (music wire) through the holes and then grip the exposed
ends and apply the bead to a rotating tool like a sanding wheel,
deburing wheel, or polishing wheel on a polishing lathe. You need to
hold the bead at an angle to the rotation of the wheel to get a good
bite by the abrasive. In other words the wire needs to be held at a
different angle than the axis of rotation of the wheel. The bead
will rapidly spin and allow the spherical shape to be maintained.
This will rapidly clean up the beads seams and with practice you can
work virtually the whole surface of the bead.

Jim

James Binnion
James Binnion Metal Arts


#7

Thank you for the responses! Someone mentioned that perhaps I am
indeed too OC, but I thought I’d see what you think, so I posted a
photo of what they look like here:

http://tinyurl.com/seeing-a-s-eam

I forgot to mention that there is just one hole in them, so
unfortunately, I can’t do the thread-through trick. Bummer! The
floral foam idea sounds interesting and I might try that out for the
heck of it.

Thanks, all.
Tamra Gentry
http://gentrydesignco.typepad.com


#8

The following technique works for patterned or textured beads where
excess solder is difficult to remove.

Tack solder (melt two lumps of solder placed on opposite ends) just
below the inside rim of one of the bead domes. Flux, and then place
the tack-soldered dome on top of the other dome. Heat the outside of
the bead at the seam line to pull the solder out to the rim. Stop
heating when the solder flashes at the rim all the way around; no
sanding will be needed.

Hope this helps.
Nancy
www.psi-design.com