Dear All, I have set up eight complete workshops in the last thirty
years. Here’s my suggestion on venting. The main concerns are burnout
for casting, fume extraction for annealing & melting, wax work &
spruing, plating and maybe ultrasonic fumes.
The hoods I have used since 1980 are kitchen stove hoods. The brand
name is Vent A Hood. They make all sizes - single, double, triple and
quadruple motored. Absolutely the best product available. I am very
loyal to a good product and company. I have always installed them
myself. Except the largest, I had a four motor (four blowers)
installed by a stove hood company. I have found them used and
purchased them new. I have worn out three or four motors since 1980.
The blower motors last a long time and are easy to replace
(replacement cost about $70.00). I think the last time I bought a
single blower unit the new price was about $225.00. Again well worth
In my current shop I have four individual hoods. Mounted right in a
row. I turn them on as needed. One on for annealing & melting, two on
for burnout, three on for everything. The fourth I use for plating so
I usually don’t cast and plate at the same time. The duct work is
fairly easy to install. The duct work is metal not plastic or cloth.
A bit awkward working at the ceiling. But the duct snaps together and
duc tap seals the run from the unit to the window. These vent units
have different size ducts coming out of the top. It depends on
weather they are a single or double motored unit. Make sure you
don’t reduce the size of the duct coming out of the unit. That will
restrict the air flow. At the window I have replaced a glass pane
with a board with a air flap unit which opens when the unit is turned
on. Kind of like a dryer vent on the outside of your house. Again
make sure you get the right size for your exhaust duct. You sacrifice
part of a window, but your health is the primary concern.
In my first set up. (My parents basement I just used a fan in the
window.) Better than nothing. Currently I don’t vent my bench. Good
room circulation is adequate. Don’t work in a closet. Most solders
are now cadmium free also. So there is not the same concern as years
ago. Most jewelry shops don’t vent each bench. Dental labs on the
other hand do because of all the misc grinding done.
Now I even hooked up a small in duct fan to remove wax fumes from my
spru area. Better to be safe than sorry. I’m sure the wax fumes we
breath will someday be labeled a more specific health risk so I vent
my wax working area at my shop and at school. I have also been steam
dewaxing larger casts more now than before to reduce the pollution
concerns. My shop is currently in an artist co-op building so there
are people who live above me. I burnout at night, and to keep the
neighbors happy my burnout doesn’t stink. I am mostly exhausting the
heat of the ovens.
To steam dewax all you need is a flat cake pan full of water. Heat
an oven to above 250 F. I use an old lab oven with a max temp range
of 300 F. Place flask or flasks on a oven screen in the oven on top
of the hot water in the cake pan. You know the kind of thing you cool
cookies on when they are out of the oven. Spru hole side down. The
wax will drip into the hot water. Leave them in until there is no wax
left in the flask. This can take a while depending on how big a flask
and how many items in it. This is also injection wax. I’ve had no
luck steam dewaxing carving wax so I don’t try. Preheat the burnout
oven to the same temp as the dewaxer. When ready load the oven and
start the burnout cycle. Environmentally compliant. Cool the oven
when done and throw the removed wax out.
To be code compliant all duct work has to have an insulation barrier
between itself and anything combustible. This can be a fire proof
sided house insulation.
I’m sure I’ll think of more later. Got to get to work.