I recently bought a set of cast vertical and horizontal stakes from Casti
ng Specialties. The castings are unfinished. I’d appreciate any advice
abo ut how to do the finishing. Do I use a bench grinder, an angle grinder,
or something else? What kind of abrasive do I use - aluminum oxide,
silicon
carbide, or what? The castings are in “semi-steel”. Do you think it’s t
oo much to do myself and I should look for a shop to finish them? Help!?!
Ellen, Through the years I’ve made about 3 dozen stakes, beakirons and
hammers, although I built them up from weldments and not castings. Plus
softened and reshaped about 2 dozen commercial stakes and hammers. With
castings one has to worry about porosity and be prepared to send back any
which do not meet specifications. In the grinding polishing stages I used
a 4 inch angle grinder for final shaping (I believe the grit is 35 or
therabouts), then on the same tool mounted an 80 grit sanding disc for
first polishing. Sometimes 120 grit discs are available; I use them
preferentially. This is the last machine use and is doen until all is
perfectly smooth.
I switch to 220 grit cloth backed sandpaper cut in strips so I can use it
like a shoeshine boy holding one end in each hand, going until all the
scratches are polished out. One has to keep the strips wide enough so that
the paper edge never touches the metal because the edge will gouge. The
next is 300 grit and I usually use wet or dry sandpaper so as to keep down
the dust, then 400 grit then 600 grit. For shaping tools I stop here, but
will polish down to 1200 grit for my planishing hammers. I repolish before
each planishing, as to make sure of the finish however. For these hammers a
polishing wheel with tripoli makes nice finish if 1200 grit sandpaper
isn’t available. Tripoli is also a helpful way to see qhickly if you’ve
missed any deep scratches from the earlier stages of sanding.
I think the most important thing in finishing a new hammer or stake is to
soften it very well. By softening I mean to grind off all the sharp edges,
giving each edge a radius so as to not leave dents. This is a procedure
that can only be learned by experiance however; one should not be afraid of
making the tools too rounded. It seems to be the tendancy to leave edges
too sharp then spend extra time cussing the dents they leave in the silver.
Between a sharp edged stake polished to a mirror surface and a nice soft
rounded tool polished with 300 grit I’ll take the latter any day. (This
also gives you a topic for inventive conversation if you meet someone
utterly stoopid at a party or social event. “Well, I spent all day
softening my hammers…why yes, softening…well, first you soak them
overnight in softening oil then you put them in the rubberizing
machine…”) Geo.
Where can you buy the castings? To finish them I would start by sanding
them with a belt sander. The little 1 by 30 inch belt by delta at about
$70 from home depot or a slightly cheaper one from harbor freight will
work. Use a slck belt without the metal backup plate for the belt. This
will clean up a surface pretty quickly without puting flat spots in the
stakes. Start with a coarse belt but move fairly quickly thru the ranges to
the fine grits. Finish the surface on a buffing wheel. tripoli or Zam will
put a good polish on . You can buff them from the start by starting with a
coarser compound. you should to start with a grit that eitherway gets a
uniform surface fairly quickly. I can’t tell really what the best grit to
start with without seeing the pieces. Jesse
Thanks to the folks who provided suggestions about finishing stakes. I’m
not done yet, but I’ve begun. I started with a 4 1/2 inch angle grinder
with a coarse wheel. That took the rough stuff off pretty well, but it
made a mess. I finally worked outside to avoid the cleanup. Next, I’m
going to use a mill file to get the contours right. Then, I plan to use an
80 grit Norton wheel, then a 120 grit wheel on the angle grinder. I ordered
the wheels from Graingers. After that, I’ll polish using grit from Rio,
starting with 120 and working my way up to at least 600. After that
(probably about 5 years from now), I’ll polish by hand. It seems like it
will work. I’ll let you know. BTW, I bought the castings from Casting
Specialties in Cedarburg Wisconsin. Their phone number is 414-375-2430.
The address is P.O. Box 32, Cedarburg, WI 53012. They have vertical
stakes, horizontal stakes, and hammers in rough castings. Thanks again for
all your suggestions.