Cheap Compressors

Jewelry Discussion
1

In my search for an affordable wax injector I found one for
about $250 but it requires an air compressor. Charles Lewton Bain
mentions that an old refrigerator compressor will work but where
the heck would you find one? Any ideas here? The compressors for
sale in jewelry catalogs are all high end and ridiculously
expensive for this use, they’re more what I would buy if I was
airbrushing again…Dave

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2

No! not for the fridge compressor I know nothing about casting
or the pressure needed for this but I am wondering if you
could you use the small 12 volt compressors that are used to
pump up car tyres they have a PSI of 200 - (260) they cost about
$40 Australian dollars. You can get bigger ones then this for
about $250- $300 I don’t know what the PSI is for the bigger
version.

Just a thought
cheers
Marjorie Lord
Australia

3

Hi Dave,

You might try Harbor Freight or some other import tool company
in your area, they may have a lower priced compressor Home Depot
or other building/home supply stores may also carry a lower
priced unit.

For used refrigeration, air conditioning compressors try the
yellow pages under the appropriate heading for shops that service
that kind of thing. You could also watch the want ads in you
paper for cheap used refrigerators or AC units.

Dave

4

Orchid Digest Post:
Re: Cheap CompressorsFrom: Anthony Lloyd-Rees cutter@opalsinthebag.com

Hello Dave, I know a few people that have a foot pump hooked into
their wax injector, it doesn’t need many pounds. Hint: the two
cylinder types seem to last longer as they are a bit more
sturdily built, a bike pump would even do it.

web site: http://www.opalsinthebag.com
e-mail: cutter@nospam@opalsinthebag.com

From: “Kelvin Mok” klmok@tunnel.cal.shaw.wave.ca

You can find refridgerator type compressors in art supplies
shops but the only advantage they offer is (almost) silent
running. They cost an arm and a leg ($600 up, you pay mostly
for furniture and a fancy paint job). They are really too small
a capacity for any real work outside airbrush painting.

If you have a handyman around just salvage a working compressor
from and old refridgerator and bleed off the refrigerant (may be
a fluorocarbon, don’t pollute the atmosphere). Be careful to
keep the compressor upright as the sump is filled with
lubricating oil which may spill out through the cut tubes.

Other hobby compressors, mostly diaphragm types, are likewise
limited in capacity and over priced as you have found.

The best buy for a compressor is still from a regular hardware
shop such as SEARS. Get a tradesman quality one of at least 3HP
and up, with a 13 Gal tank or larger. A $200+ budget should get
you there.

Outside your jewelry work the compressor will be very useful
for painting your fence and house and I really love air tools
like wrenches, drills, sanders, etc. which are light,
inexpensive and self cleaning. You never have to worry about a
motor burning out when its stalled or getting eletrocuted when
working in a wet environment (wet lawn or floor). Fix up your
fender bender and the savings will have paid for the compressor
already.

Get the largest compressor your budget and space will allow.

Kelvin Mok
Home: (403) 463-4099 | Home FAX: (403) 430-7120

From: ElaineEC@aol.com

Hi Dave, The air compressors we sell at Gesswein for example ARE
expensive because they are virtually noisless. When you pay a
lot for an air compressor (at least from us) you are paying for
peace and quiet. They are designed to be quiet for people who
are forced, for whatever reason, to keep the compressor close at
hand while they work.

I picked up a compressor at Home Depot for about $200 (this was
a couple years ago) and it was 6 HP! It’s noisy!! but it’s good
and inexpensive.

Elaine Corwin
GESSWEIN CO INC USA
Bridgeport, CT 06605
Phone: 1-800-544-2043
Fax: 203-335-0300

From: “Margrett D. Grummon” prycelessg@pinehurst.net

Try a salvage yard or small or a appliance repair store…I’ve
even seen them at flea markets

From: CGrunewald@aol.com

Aloha Dave, Why not use a portable air tank ($30-35).Just go fill
it at the service station. We have used on for years and they
hold 125 PSI, depending how many patterns you shoot in a day, it
lasts quite awhile. Remember to use teflon tape on the fittings
(to help insure a leak free system) and put on quick couplers (on
the wax pot and tank hose), to aid in quick attachment and
removal. We use it, because the compressor we have, is quite
loud (5 HP). I even saw a guy use the spare off his truck!!!
Improvise!!

Regards,
Christian Grunewald
Precision Modelmaking
Hawaii

From: Jess4203@aol.com

Dave: A commercial caster friend of mine who is very handy
answered this question for me back when I was looking for a wax
injector. The pressure needed for the wax injector is only a few
pounds — under 10 psi. He says you don’t really need as
compressor at all if you are not shooting a lot of waxes. You
can use an air tank, get it pressurized somewhere ( there are
still a few service stations with free air here,and I can fill
my tank to over 100 psi ) and connect it to the regulator on your
wax injector. Since the pressure is low and the volume of air is
small, your tank should last a while if there aren’t any leaks.
You could even fill it with a foot pump or some such. There is
even a company locally which sells a $10 kit to convert a freon
tank to an air tank — the kit includes the fittings, hose,
gage.

Making a compressor from a refrig compressor (some kinds work)
or an auto air conditioner compressor should work (I have a
vacuum pump made from a motor and an old auto a/c compressor),
but the problem is that you still need a tank and a switch and
various fittings in order to maintain 5 to 10 psi constant on the
inlet side of your wax injector regulator. I looked into this,
but the parts look like at least $50, and there is a good deal of
fabrication involved. When you have to have a compressor (you’re
going to get a pneumatic hammer handpiece eventually, right??),
$150 should get a used one at the pawn shop or some such place.

HTH,
Roy(Jess)

From: “Sharon Holt” bootsie@netmdc.com

Dave, try Goodwill, used furniture stores, etc., for an old
fridge. If you can’t find that, try one of the paint stores or
big hardware chains for a paint compressor–I picked up a 150 psi
maximum compressor with adjustable setting for 20 to 150 psi for
about $140 couple of years ago (at Lowe’s, of all places!). Good
luck. Sharon Holt

From: Peter and Stephanie Slone SLONE@compuserve.com

Dave, if you’re not doing alot of production you can easily get
by on a foot operated bicycle pump. Most molds inject at 7-10 psi.
Or you can also use a storage tank for compressed air

that you can fill up at the local gas station . these cost about
25 dollars at any pep boys or hardware store.

5

Try St Vincent Depaul or other charitable recyclers of used
appliances. They should have older working refrigerators. Also
try any small appliance repair shop.

Bob B

6

Dear Dave, There is no need to buy a compressor if it is only to
be used for the wax injector. Two inexpensive options are … a

  • use a line from your compressed oxygen tank. b - go to the
    corner automotive store and buy a portable tank for compressed
    air. These tanks are about $25.00. You can fill it at the local
    gas station and at the low volume of air needed for wax
    injecting it should last for months before you need to refill it.
    Just remember to turn the supply off after each use. Bill
    Reidsema
7

My idea is go to Wal-Mart and get a 12 volt DC compressor for
about 30-40 dollars. Get a holding tank made for filling car
tires, maybe about 30 dollars. Find a friend who is either a
auto mechanic or auto-body mechanic and have him rig it up for
you (if you can’t do it yourself.) You might also need a pressure
regulator and a cut-off switch, and air hose with fittings.
Should be able to build the whole thing for less than hundred
dollars. An empty Propane tank (like gas grill) will work also
for the holding tank. Good Luck,

Jim Jessee

8

Dear David, There are at least two types of hand pump wax
injectors available. One is made by Kerr and is not cheap. The
other available from Gesswein or Rio or Swest is quite usable and
sells for less than $150. I use this model everyday and though
its not as nice as a compressor fed model it quite adequate. If
you do only occasional casting, its perfect. At least it will
get your foot in the door, if you do intend to do more than
occasional casting. Check pg. 54 in the current’98 Rio
catalogue; model # 700-425, priced at $146. Shop around, I
recall seeing it for $138.

Happy Hunting, Eben

9

Just for the record, I use the old compressor unit out of my
now-deceased fridge as a vacuum pump. It pulls down about 28-29
inches of mercury fairly quickly in a 10-inch diameter bell jar.
I use the set-up to vacuum RTV moulds and investment. Because I’m
fairly handy with “scratch building” things, I was able to turn
this old compressor into a super asset with about 3 or 4 hours
effort, some welding and some painting. I has a nice little
manifold on it, vacuum gauge, on-of switch, etc. So, you can
use these little compressor units for other uses.

Good luck.
Jeff Booth
Oakville, Ontario
Canada

10

NEVER USE OXYGEN to PRESSURIZE a MOLTEN WAX CONTAINER.

Mixing pure oxy from an oxy bottle with any oil or wax has the
potential for causing spontaneous combustion. A fire fed with oxy
under pressure is not a pretty sight.

If you want to use a bottled gas to pressurize anything, it pays
to understand the chemistry of the products involved. We
don’t want to loose any of the Orchid members.

Another Dave

11 
   There is no need to buy a compressor if it is only to be
used for the wax injector. Two inexpensive options are ... a -
use a line from your compressed oxygen tank.

G’day; I would be very wary about using compressed oxygen for
purposes other than use with a torch, and medical uses.
Compressed oxygen - as one might expect - is a very powerful
oxidant, and is always avid to combine with any flammable
substance, sometimes rather quickly. For instance when one finds
friction not helping when one has to undo or re-fasten a
threaded oxygen line connection, there is a temptation to use oil
or grease to smooth things out. Resist that urge at all costs;
this has resulted in quite a few very violent explosions.

In your safety manual draw a sketch of a grave with headstone.
On the headstone incise the following:

		"Here lie bits that once were Ben.
		  He greased a bottle of oxygen."

I wouldn’t use compressed oxygen to inject melted wax. Nosir!

       / \
     /  /
   /  /                                
 /  /__| \      @John_Burgess2
(______)

At sunny Nelson NZ

12 
   Two inexpensive options are ... a - use a line from your
compressed oxygen tank.

This is an extremely dangerous idea, pure oxygen is an EXTREMELY
good oxidizer, and if there were to be anything which could
ignite the hot, molten wax the result could be explosive. The
other idea of using a compressed air tank and refilling it at the
corner gas station, or with a “bicycle” pump is an excellent
alternative to spending big money on a Quiet air compressor. You
also might note that compressed air can be piped long distances
with out loosing its usefulness, therefor the compressor can and
in many cases is located outside of the shop, and the air is
piped in.

WayneM

13

sorry for late addition, but one way around noisy compressor
issue is to put the thing outside, use METAL water pipe 1/2 inch
is fine if your cutting it down to 10# or so. if you are using
higher pressures add a buffer (storage ) tank near your work.
personally, i use a teflon paste not the tape for fittings

14

I’ve made/used a few refrigerator compressors for various things. They are quiet and don’t move very much volume of air. I’ve coupled them with air tanks to increase the amount of air that they can provide. The price is right if you’re in a mood to scavenge. But, really, given the price of a cheap air compressor at Harbor Freight, you’re probably better off doing that. When shopping compressors, noise is important to me.

Note From Ganoksin Staff:
Looking for an air compressor for your jewelry projects? We recommend: