Patrick Veerkamp on wed 28 aug 96
I'm making a water dispenser for my office. Basically a large jar with a
spigot that you invert a bottle of water on top. Never made one of these
before though I've seen them for sale in various shops and have said
"Looks easy enough, I should make one of those"...and so I have. I'd
like some advice re: the installation of the spigot. I found a nice
brass one that has rubber washers that are supposedly to function as a
seal to prevent the thing from leaking. Problem is that they don't.
Maybe I'm not torqueing the nut tight enough. But before I bring out the
large wrenches and break the thing I was wondering if there isn't some
type of sealant that I might use to improve the seal on the finger
tightened nut. I have some silicone sealant that I purchased from Ace
Hardware but there is a caution on it that says NOT FOR INTERNAL
CONSUMPTION...and Uncured product will irritate lips, gums and tongue.
Yikes! Don't think I'll use it around my drinking water. Any advice?
ROBERT POGSON on wed 28 aug 96
Patrick firstname.lastname@example.org wrote:
PV> I'd like some advice re: the installation of the spigot. I found a nice
PV> brass one that has rubber washers that are supposedly to function as a
PV> seal to prevent the thing from leaking. Problem is that they don't.
PV> Maybe I'm not torqueing the nut tight enough. But before I bring out the
PV> large wrenches and break the thing I was wondering if there isn't some
PV> type of sealant that I might use to improve the seal on the finger
PV> tightened nut.
Let's see if I get this straight: you made a ceramic vessel with a hole
for the spigot and you have a leak at the place the spigot is attached.
The rubber washers seal by filling all space through which water could
pass between the spigot and the vessel. Rubber is fairly firm so the sealing
surfaces must be fairly smooth and parallel for the seal to take place.
Sealing has to take place between the washer and vessel and between the
spigot and washer. I suppose there is a good surface on the spigot. Assuming
your vessel is glazed or otherwise rendered impermeable, I would suspect the
seating surface on your vessel might be rough or scratched. One way to be
sure of a flat sealing surface would be to snug down the washers and spigot
GENTLY while the clay is leather hard. The pressure of the washers will mould
the clay to a suitable form. After drying slowly to prevent cracking, slight
abrasion with a very fine sandpaper or emery will give additonal assurance.
Once fired, there is little you can do but to try grinding the surfaces if
you can identify the irregularity, or tightening the pressure nut a little
more. I would not worry about crushing your vessel as ceramics are very
strong in compression. If you are trying to seal a flat surface to a round
surface you will be trying to BEND the ceramic which is risky.
In vacuum technology we use certain greases to lubricate such seals so
they slide into place better and fill any microscopic defects. A vegetable
oil product like Crisco might work in your case. It keeps a very long time
without refrigeration so I doubt any biological problem would result. Wipe
off any excess that might contact the water.
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