Wax Injection

Is it beneficial to leave a wax injector hot for extended periods of
time prior to the start of injecting molds so as to “allow the wax to
age”? I am referring to letting an injector heat up for a day or so
prior to starting. I can understand that this will allow for a
complete melt of the wax and that bubbles would be released. Anything

Tim Glotzbach
Richmond, KY

Tim, I sometimes hook up a vacume pump to my wax pot in place of the
air compressor when I get bubble problems. Usually after just adding
new wax. I pull a light vacume on the pot and then change back over
to the positive air pressure before I start injecting. It seems to
help with bubble problems. Hope this make sense. Frank

Dear Tim, I have found over the years that it is best for us to leave
the wax pot on continuously, 24/7, even though it’s usage is about ten
to fifteen hours weekly. It seems to take mine all day of heating to
get the wax up to the right temperature and consistancy. This also
has eliminated the problem of small bubbles in the wax. Jon Michael

Dear Tim, It sounds okay on an occasional basis. But don’t leave your
pot on all week, week after week. The wax will break down and
oxidize, giving you valve-clogging sludge at the bottom. Regards,
Michael Knight –
F.E. Knight, Inc.
120 Constitution Blvd.
Franklin, MA 02038
United States of America
Voice: 508-520-1666
Fax: 508-520-2402
E-mail: FEKnight@ziplink.net

Tim, You don’t have to turn your wax pot on the day before you are
ready to inject your molds… I turn my wax pot on in the morning of
the day I am going to inject anything… Usualyy you will have a full
melted pot of wax within 3 or 4 hours… I have heard of it taking less
time but, 3 to 4 hours gives the wax enough time to liquify. Actually,
I have left my wax pot on over night, but only by mistake. The last
time I did that something happened to it where the heating element
actually turned off… Thank God it worked again the next time I turned
it on… So in answer to your post… 3 to 4 hours should do it. Marc
Williams http://www.marccogold.com/

Tim In a shop where we would go through 1-2 lbs of wax per day per pot
we would leave the pot on all the time. However some waxes that we
used would break down from this constant heating and would turn to
sludge . With the waxes that were prone to breakdown we would dump
the pots out and clean them out once a month and this seemed to be
often enough to keep them running ok. If you do not do this you can
totally ruin a pot and then have to replace the nozzle and scrape out
the inside. It is not something I would ever want to do again it took
about three hours to clean out the mess. Kerr recommends dumping all
wax pots every couple of weeks.


James Binnion Metal Arts
4701 San Leandro St #18
Oakland, CA 94601

Hi James, Of course Kerr recommends dumping your wax every three or four weeks!!
This is flaky nonsense. If you pressure with Nitrogen (clean, dry, cheap, safe)
instead of air the wax won’t “spoil”. Bubbles are caused by moisture in the air.
Keep the wax at, or under the recomended temperature. John, J.A.Henkel Co.,Inc.
Moldmaking Casting & Finishing

Hi Tim, On small pots you need only preheat the wax for two or three hours. If you
have a large production pot and use a lot of wax, you can leave it on and add fresh
wax in the evening. I do this with the Yasui. Another wax to keep your wax in good
shape is NOT to use compressed air as a propellant. Compressed air has a lot of
moisture in it (especially in the summer months) that will cause bubbles in your
injections. You can purchase an expensive line dryer but, you still have quite a
bit of oxygen present to “spoil” the wax. The solution is to use compressed
Nitrogen. It is clean, safe, very dry, and cheap. The savings from the compressor
not kicking on all the time will pay for it and it will be quiet. John, J.A.Henkel
Co.,Inc. Moldmaking, Casting, and Finishing