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Letter 24060
Mill addition for Aluminum Enamel
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For Aluminum Enameling what should be the mill addition for the
suspension of the frit? In our case, we do Aluminum Metallizing on
the mild steel objects, where by you get a rough finish of Aluminum
of about 50 to 80 microns; this is then coated with the aluminum
enamel. Our problem starts when the coating is left to dry before
firing, this water based application before getting fully dried
develops very tiny bubbles all over. Is this because the metallized
Aluminum reacts with our mill additions? cause for suspension of the
milled frit we use about 2.5% of Boric Acid, 2.5% of Potassium
Hydroxide, 0.5% of sodium silicate and 0.5% of Sodium nitrate and 1%
of borax.
Are these the only suspending agents for Aluminum Enamel or should
we try some thing else? are we using more of Potassium Hydroxide? or
is the Boric Acid giving us the problem? can any one doing Aluminum
Enameling specially on metallized surface help? We will be grateful.
Tanvir Bharucha
an enamel works - Mumbai, Maharashtra, India
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Your mill addition is probably too reactive. Try reducing the
amount of KOH.
Best regards, Charles
Charles Baldwin
frit supplier - Cleveland, Ohio
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