has been replaced by paint on clothes dryer drums.
Although these examples involve large-volume production items, there are other, smaller applications as
well. In most cases, the replacement was made with
some sacrifce in the performance properties of the
fnished part, notably hardness and scratch resistance.
These properties are greater in porcelain than in most
organic coatings.
If vandal-proofng a telephone booth is dependent
on these properties, there is no replacement. However, if there is room for trade-offs in the performance
properties of certain parts, some organic coatings may
meet your standards. I suggest you have critical parts
coated by a custom coater who is able to provide a variety of coating materials. Evaluate these parts against
porcelain-coated parts and make your decision on
that basis.
n
Removing emulsified oils fRom CleaneR
Q. We manufacture shelving for retail outlets and
painted them on a spray paint line for years with no
problems. We recently installed an electrocoating system where everything is new, including the cleaner
stages, chemicals, type of paint and curing ovens. Now
we are having problems with the presence of emulsi-
COMPACT
SHELF OVENS
fied oils in our alkaline cleaner which messes up the
finish on our products. How can we remove the emulsified oils?
W.D.
a. Chemically, you can either change the stamping
lubricant or change the cleaning solution chemicals.
Physically, you can remove emulsifed oils from the alkaline cleaner solution by ultrafltration. Ultraflters
separate particles from solutions by using selective
membranes. This often is done in the pretreatment
stages of high-volume fnishing lines. With ultrafltration, the oil is essentially removed as concentrated
emulsion from the cleaner solution, and the cleaned
solution is then returned to the cleaner stage. This not
only makes disposal of emulsifed oil concentrate simpler, it also extends the life of the cleaner solution.
Ultrafltration can be done batch-wise or on a continuous basis, depending on the size of the unit and the
rate of production. n
LearnMORE
The Painting Zone
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