ways to clean up
Daily wet mopping or hosing down to a floor drain
is good. An existing room can be modified in one area for potter's
wheels by raising the floor 6 inches. This way the floor can slant
toward floor drains. This part of the room is divided from the rest
of the room by a cement block half wall. Students can hose down the
wheel area at the end of every work session.
Large wet sponges are essential to clean work tables,
counters, wheels, and small floor areas. Use repeated sponging with
washed out sponges to remove clay haze.
How to Clean & Work
With Less Clay Dust
smoothing clay reworking
clay studio design
page is meant to give ideas for reducing clay dust because long term exposure
to clay dust may lead to silicosis. Silicosis can be a fatal lung
ailment. With good habits clay work can be a healthy lifelong career
as it has been for many people of many cultures in the past.
Dusting, sweeping, and vacuuming are not recommended
for clay because these methods put dust into the air. Depending on
the heating and air conditioning system, dust might be circulated to other
areas as well.
Some people place "walk off" rugs at the doorways
to try to get the clay from tracking to other areas. These rugs are
impossible to clean in a safe way unless they can be rolled up and totally
laundered in a large commercial facility. Vacuuming simply pulls
the dust to the surface where it is picked up and spread by traffic.
Some say the smaller silica particles that pass through a vacuum filter
will stay airborne for 4 days. I use a piece of outdoor carpeting
at the door of my studio. I hose it off on the driveway and wash
it in a kids plastic swimming pool.
The particular clay you are using is not an issue.
All dry pottery clay makes silica dust when walked on. Keep it wet
to avoid dust.
Students can be instructed to use wet sponges
to immediately spot clean any drips around the wheels and pick up all crumbs
before they get walked on. Train them to carry two clean sponges
from the sink so the first sponge gets the mess and the second sponge removes
the residue. This can significantly stretch the times between total cleaning.
Some potters have a shop vac outdoors with a small
pipe through the wall for the vacuum hose. They use a shop vac that
can have water in it and it can pick up water. By locating it outside,
any dust that might be blown out of the vac is dissipated outside.
I would only use a vacuum if it is outdoors where the dust can dissipate.
is at risk?
Teachers are much more at risk than students
because of the time spent in this environment. However, students
need to learn proper respect for the dust in case they decide to
continue working in clay over a period of years.
If cleaning makes any dust at all, it should be
done at the end of the work day so the dust settle out of the air before
the space is inhabited.
In the days before they knew about the hazards of clay dust, the workers
who sanded the mold marks from greenware in pottery factories died within
a few years from silicosis. Never work on dry clay. Smooth it by sponging.
If it is too dry, spray it with water. It can be wrapped in plastic,
and sprayed again until wet enough. Do this gradually, but repeatedly
to avoid expansion cracks from the water. With a bit of practice,
it is possible to completely soften a piece with damp cloths inside the
to rework scrap clay without making dust
Large chunks of clay that are too hard to use do not need to be broken
before soaking. Once clay is totally dry, any size piece will slake
and turn to mush if you place it in clear water. Do not stir it until
it is all mush, or it may seal the surface and prevent the water from penetrating
the clay cracks. This does not work with large moist pieces because
they are not porous enough. Just allow them to dry before placing
them in water.
It is difficult to mix clay without making any dust. Moist trimmings
should be immediately placed in a plastic garbage can of water.
Once the clay is mush, you can take extra water off the top. I
dip the water into another garbage can so the suspended clay is not lost,
but just becomes part of the next batch.
The thicker mush is then dried until it is ready to wedge. There
are various ways to dry it. Place it several inches thick on any
porous material. I like canvas better than plaster because I hate
it when small pieces of plaster get in the clay. The pieces of plaster
expand after firing. This breaks the pots or causes pieces to pop
out of the surface. Canvas on the webbing of an aluminum lawn chair
allows the clay to dry from the bottom as well as the top. Porous
bisque trays would also be safe for drawing out extra water.
When clay is nearly dry enough, make it into large arm size coils.
Make big arch forms from them and set them around the studio overnight
to firm up. When the clay is ready, seal it in plastic until
you are ready to use it.
from dry clay without inhaling dust
Dust masks must be tight fitting on your face and have serious dust filters
that are rated for very fine dust. Look for the NIOSH rating when
purchasing a dust mask. I use masks with #TC-21C-166 and #TC-21C-231.
There is probably no way to mix clay from dry clay and be absolutely
dust free. Either buy premixed moist clay or use good a good exhaust
fan and a very good dust respirator. By working very
carefully, you can minimize the dust as you mix clay.
Exhaust fans must blow the dust outside and be powerful enough so that
you can see the dust moving away from you. There must be a source
of clean air. If you have to place your face in the dust, do not
inhale until you are back in clean air.
If you are using a power mixer it should be placed between you and the
exhaust fan. If the mixing or other dust making activity is done in the working studio, plan do
it at the end of the workday so airborne dust settles before you inhabit the
dry clay into the mixer or into a mixing container. Place
dry clay all the way down in the container. Do not drop it.
Put it gently and slowly into the mixer or container so no dust raises
from the event. Close the mixer before running it. Be
patient. Retire to a clean area while the mixer runs. When
opening a mixer, back off, hold your breath, and wait in a clean air place
while the air clears at the mixer.
designing the ideal clay studio or classroom
Launder clay clothing often.
Remove clay shoes before entering house.
Do not wear clay cloths in the
house. Keep some environments totally clay free.
Use a separate building, rather than in the house where you eat and sleep.
Provide an outdoor area or a separate and properly ventilated room for
Provide an outdoor area or a separate and properly ventilated fireproof
room for firing.
Make it easy to hose down the floor. A smooth sealed surface is easier
For areas that cannot be hosed off, equip it with a vacuum cleaning unit
that is located outside with inside pipes and hoses.
table covers for clay work in art classes
- Clay slabs often stick to the surface on which they are formed. Therefore, rolling slabs between two canvases allows the canvas to be peeled off of the clay to release it.
- Coils cannot be rolled on a smooth table without sticking.
- Provide canvas table covers that can be sponged clean and rolled up or stacked away. Do not brush them or shake them indoors. Periodically clean them seriously by hosing outside on a sidewalk or parking lot. They can also be soaked in a plastic wading pool.
- Some teachers use the back of gessoed painting canvas.
- Dupont Tyvec made as house wrap is an alternative to canvas.
- Shower curtain liner plastic may work as a table cover for some things.
- Velcro fastening felt around the edge of the tables can be used to attach covers that have Velcro hook tab attached to the canvas back corners. Sticks along the edge of the canvas allow fastening canvas with c-clamps.
pounding and wedging surfaces
- Do not allow clay pounding on loose canvas covers on tables in a classroom because dust will be liberated.
- Pounding and wedging can be done on thick slabs of concrete or plaster
- Plaster can be tightly covered with heavy canvas to prevent plaster chips from contaminating clay. Dampen the canvas slightly to prevent dust. Scrape clay off with plastic putty knife and sponge it clean when finished.
Back to Ceramic Hazards Page
to Goshen Art Department Safety Page and Links
© Marvin Bartel, 2001. Last updated December, 2005.
All rights reserved. Copying or publishing is prohibited without permission.
Disclaimer - This page is in progress and posted by
Marvin Bartel - There may be other hazards not included here, so just because
something is not listed here, does NOT mean that it is safe to eat, drink,
touch, or inhale. If you know of a ceramic hazard not mentioned here, please contact me.
Many materials have not
undergone tests for every possible hazard, and illnesses are not always
attributed to the correct causes. Therefore, treat all materials with respect.
Use common sense. I take creative risks in artwork, but I try to avoid risk in my working methods.
Back to Goshen
College Art Department Safety Page.
Updated 10-17-2001, Marvin Bartel