Hello everyone, A few years back I read an article about someone who,
while primarily a lapidary artist, did some lost wax casting to
compliment his work. He used some type of scientific equipment to
pull a vacuum off of his sink faucet. The description of the process
seems adequate for the needs of a small custom jeweler/artist. Since
I reside in California, land of the rolling blackout, I would love to
give something that doesn’t use electricity a try.
Thanks in advance,
Pauline
they were probably refering to a ventury valve Cheap and easy to
insstall and use leon k
Pauline, The vacuum generating device that attaches to your sink does
do create enough vacuum to properly debubblize your investment. It
relies on Bernoulli’s Principle to create a vacuum. The same
principle that creates lift across an airplane wing.
Lester…
It sounds like he was using one of the chemist’s handy tools, a
device which screws into the faucet and will draw a vacum when the
water is turned on. (Used by the chemist for vacuum filtering – it
creates a vacuum which pulls the water in the solution through the
filter, leaving the solid material behind on top of the filter.). I’ve
never tried using it for this, but I rather doubt that it would be
powerful enough for casting. Unless it were a single very small
object being cast, in a small flask.
I sympathize with your power problems, but doubt that this is the
answer. Also, it uses a great deal of water. (Our problems here, where
I live, are water, not power – although your power problems are
causing our (Utah) power rates to skyrocket.)
cheers!
Margaret…)
He used some type of scientific equipment to pull a vacuum off of his sink faucet.
G’day; Most laboratories had what we called filter pumps. These
fasten to a water tap as you mention, and with a fairly high mains
water pressure one may obtain a vacuum of 3cm of mercury - about 28 -
29 inches. They work by forcing water through a small jet which then
entrains air (or other gases) as it enters another tube creating a
vacuum by Venturi effect - no mechanical moving parts. The whole
thing is about 6 inches long and about 3/4" diameter. One can get
metal or glass pumps; I had to make six of the glass pumps during a
glassblowing exam I did over 50 years ago - and they all worked
perfectly. Any lab supplier stocks them and they are quite cheap. But
oh boy! Do they ever get rid of water!
John Burgess; @John_Burgess2 of Mapua Nelson NZ
Pauline, this is not an answer to your electricity problem per se. I
have an Aqua Vac Invester - Caster. I bought it used from a guy who
used to own a jewelry/rock shop. He said it could be plumbed into
your waterline. Mine has a little self priming water pump run by a
1/2 HP motor so it uses electricity. I have a 5 gallon bucket with
water and antifreeze. The unit pumps out of the bucket and drains
right back into it so I run off the same 5 gallons and does not
create a water bill.
I borrowed an electric vacuum pump from a refrigeration supply house
for work. It ran off electricity and used vacuum oil. You were to
change the oil after each use. The oil is not cheep. The machine spit
oil in a thick mist in the air and all over the floor. We were
creating a vacuum to simulate 50,000 feet in altitude. The shop owner
said his pump needed an over haul. Against my better judgment the
boss decided to buy a new pump for our project beings we did reach
50,000 feet in altitude. Just as I thought the first time we ran the
pump and every time after the air in the room is filled with an oil
mist and an oil mess on the floor.
This is why I bought an Aqua Vac. It has worked for me on casting
silver. I have been having a problem casting a key chain in brass. I
do not think it is a problem with the caster. I have been told the
temp. span from liquid brass to solid brass is small. If any one has
a suggestion on how to get the brass to the bottom of the mold before
it gets solid I would appreciate it. It is an oval disc 1/2 inch by 1
1/4 inches. I am casting 1 at a time with a 1/2 to 1/4 inch spruce. I
heat the mold up to 1700 degrees.
Thanks for any help and I hope this helped you a little Pauline.
John Daly
Grand Junction, CO.
Hi John, first , what cfm does your aqua vacuum pump have the capacity
to pull. Do you have a vacuum gauge attached to the system so that you
can see that you are getting the correct amount of vacuum for
investing and casting ? For getting the best results in casting, you
need a minimum of 27" mercury on the gauge and anything beyond 27 is
heaven to a caster. For investing, 27" will barely work unless you
change your water temp. to about 100 oF, However, investment
manufacturers don’t recommend this .
For casting bronze, the temp for the metal is between 1850- 2200 oF .
For casting brass for your item, it may be 1850 oF .Brass smokes a
lot and gives off lead fumes as it aproaches casting temp. Make sure
which metal you are casting. Herculoy bronze is an excellent metal and
can be bought in small and larger quantities from the contenti co.
tel: 1-800-343-3364
Flask temperature ( if your pump is pulling better than27" ) for a
thin item can be as high as 1250 oF (or higher if it’s paper ! ) to
as low as 700 oF if it’s 1/4 " thick or thicker.
Daniel Grandi racecarjewelry.com