I went to an estate sale this weekend where they had a lot from a
jeweler/lapidary estate and got quite a bit of equipment. One of the
items is a larger wax injector and a compressor to go with it.
However, the only thing I noticed that could be a problem, aside
from not being able to test it, was that there is a small screw type
hole on the lid of the wax injector where something is missing. I
looked online, and there does seem to be such a thing on others…but
I cannot see it clearly. Is it just a screw that fits in there so you
can release air pressure? If so, I should be able to just take the
pot with me to Lowe’s and get one that fits or is it a special part
that I have to track down, like a valve of some kind? I only paid
$40 for both the injector and the compressor together…
$40.00 sounds like you got a very good buy. A compressor pump alone
is worth more.
The top of a wax injector should have a threaded hole for a presser
gauge, a threaded hole for a pressure release valve and an
unthreaded hole to use with a stick thermometer.
There have been many different kinds of wax injectors made over the
years, mine has four fittings in the lid.
1 air inlet
2 safety valve
3 temperature gauge
4 pressure gauge
you need to find out which one is missing and what thread the hole is
and then see if you can find a replacement. A competent engineer
should be able to work it out for you, I suggest starting with 1/4"
BSP at a guess. A photo would help.
The hole could be one of two things. Either it is where the pressure
gage attaches for the air pressure or else it is for the
thermometer. You can use a cooking type meat thermometer with the
dial and the long steel probe on it (preferable to the glass ones
which I always break).You can tell which is which by looking at the
underside of the top. The pressure port hole goes all the way through
the top. The thermometer port has a long hollow tube that is sealed
at the bottom end and extends down into the wax pot to measure the
heat of the wax. My wax pot is from the early 1980’s and still works
fine. Sounds like you got a bargain.
On my larger injector the top has 2 threaded holes. One holds the
pressure regulator and gauge, the other an over pressure relief
valve. The relief valve can also be used manually, though most
regulators will automatically vent when turned down. Safety feature,
a very good idea but not absolutely necessary. My little injector
doesn’t have one… I’m not sure whether to fear the ‘safety police
folks’ or the possibility of a sky light in my basement studio. You
should be able to purchase the relief valve or steal one off of a
garage sale pressure cooker. Just a needle valve with a spring or
weight. If any of this doesn’t make sense just buy a relief valve,
I’ve been living on the edge for far longer than actuarial tables
recommend, but have learned where the edge should be.
Two things come to mind with the hole in the top of your old wax
injector. One is that it may be for a pressure relief safety valve,
but are you sure it is a threaded? Most wax injectors have a tube
that connects to and penetrates the top, the tube is sealed at its
lower end which sits an inch or two above the bottom of the wax pot.
This exists for the insertion of a thermometer and facilitates an
easy read of wax temperature without the hassle of a remote measuring
device.
I went back to the sale yesterday to look at the last day leftovers
(at 1/3 price, of course) and found a brand new thermometer for the
wax pot for about $2.50…I turned on the pot and it powers up, but
I need to be there long enough to babysit it to see if it works
properly…don’t want to burn my studio down if the thermostat
doesn’t shut it off on time!
Yes, got a lot of great buys at the sale. Was very happy I
went…it will make a huge difference for my studio…now I just
have to find room for everything!
I went back to the sale yesterday to look at the last day
leftovers (at 1/3 price, of course) and found a brand new
thermometer for the wax pot for about $2.50.....I turned on the pot
and it powers up, but I need to be there long enough to babysit it
to see if it works properly....don't want to burn my studio down if
the thermostat doesn't shut it off on time!
Unless it’s gas fired, chances are the wiring inside will melt
through and the powering will cease long before your shop catches
fire. But heat it up the first time outside if you’re paranoid. (No
compressor)