David Hewitt on mon 28 jun 99
Dear Rick,
I routinely spray my pots, perhaps about 60% of what I make, so I
venture to make some response to your questions in the hope that they
will help.
With regard to thickness, this I vary according to the glaze I am using
and the effect that I am after. I have a piece of blue tack stuck onto
the edge of the turntable in my spray booth so that I can see where I
have started to spray and when I have got round to the same spot. I
spray either two or three or four coats according to what I am after. A
semi-opaque glaze over a coloured slip I may give two coats. A glaze
with a stain where I want the strongest colour that I can get, I will
give four coats. Four coats with my spray gun is about the maximum that
my pots will take before they become saturated. As they approach
saturation the surface starts to get a pimply appearance. I know that I
have then reached the limit. I do not touch these pimples and they do
not show on the glazed pot. If I want to apply four coats, I may well
apply the first two and then leave the pot to dry for around 30 minutes,
particularly if it is very thinly thrown and I judge that it will easily
become saturated.
I do not measure the gravity of the glazes I mix, but judge how much
water to add by the 'finger' test. I am sure however that the amount of
water has a bearing on how the spraying works on the pot. Also I would
imagine that some glazes are not so easy to apply as others. Perhaps I
am just lucky with the ones that I use. Others potters may well be able
to add to this aspect. My main control, therefore, is a regular and
uniform application of the glaze with the spray gun and counting the
number of coats applied.
David
In message , Rick Malmgren writes
>----------------------------Original message----------------------------
>Dear George,
>
>Thanks for your "brain-dump" about spraying, I found it very timely as I have
>just bought and started using the Central Pneumatic HVLP gun that you
>described. The problem that I am having, and I had the same problem with a
>standard spray gun, is blisters in the glaze just as I am getting the final
>thickness on the glaze that I want.
>
>The glaze seems to lift in small areas that vary in diameter from a pencil
>eraser to a pinhead. I can push them down, but that is a pain and can smudge
>overlapped glazes, and at times I get crawling from the blisters that don't
>reattach.
>
>I would also appreciate any thoughts you might have on the general process of
>spraying, how do you determine thickness for your glazes? I generally count
>revolutions, and also occasionally scratch through the glaze to see the
>thickness.
>
>Thanks,
>Rick Malmgren
>RMalmgren@aol.com
>Lothian, Maryland USA
>
--
David Hewitt
David Hewitt Pottery ,
7 Fairfield Road, Caerleon, Newport,
South Wales, NP18 3DQ, UK. Tel:- +44 (0) 1633 420647
FAX:- +44 (0) 870 1617274
Own Web site http://www.dhpot.demon.co.uk
IMC Web site http://digitalfire.com/education/people/hewitt.htm
David Hewitt on wed 30 jun 99
In message <05a501bec175$66fddc40$97b58dd0@oemcomputer>, Dave
Finkelnburg writes
>
>
> I spray all my larger pieces, so I was very interested by your excellent
>description of how you judge glaze thickness. Are you single firing or
>spraying on bisque? Thanks!
> Dave Finkelnburg
> dfinkeln@gemstate.net
Dave,
I am spraying on bisque.
I find spraying a very useful way of applying a glaze. One advantage is
that you can test a very small quantity of a glaze on an actual pot
rather than just on a test tile.
David
>
>-----Original Message-----
>From: David Hewitt
>To: CLAYART@LSV.UKY.EDU
>Date: Monday, June 28, 1999 8:21 AM
>Subject: Re: Blisters in sprayed glazes
>
>
>----------------------------Original message----------------------------
>Dear Rick,
>I routinely spray my pots, perhaps about 60% of what I make, so I
>venture to make some response to your questions in the hope that they
>will help.
>With regard to thickness, this I vary according to the glaze I am using
>and the effect that I am after. I have a piece of blue tack stuck onto
>the edge of the turntable in my spray booth so that I can see where I
>have started to spray and when I have got round to the same spot. I
>spray either two or three or four coats according to what I am after. A
>semi-opaque glaze over a coloured slip I may give two coats. A glaze
>with a stain where I want the strongest colour that I can get, I will
>give four coats. Four coats with my spray gun is about the maximum that
>my pots will take before they become saturated. As they approach
>saturation the surface starts to get a pimply appearance. I know that I
>have then reached the limit. I do not touch these pimples and they do
>not show on the glazed pot. If I want to apply four coats, I may well
>apply the first two and then leave the pot to dry for around 30 minutes,
>particularly if it is very thinly thrown and I judge that it will easily
>become saturated.
>I do not measure the gravity of the glazes I mix, but judge how much
>water to add by the 'finger' test. I am sure however that the amount of
>water has a bearing on how the spraying works on the pot. Also I would
>imagine that some glazes are not so easy to apply as others. Perhaps I
>am just lucky with the ones that I use. Others potters may well be able
>to add to this aspect. My main control, therefore, is a regular and
>uniform application of the glaze with the spray gun and counting the
>number of coats applied.
>David
>In message , Rick Malmgren writes
>>----------------------------Original message----------------------------
>>Dear George,
>>
>>Thanks for your "brain-dump" about spraying, I found it very timely as I
>have
>>just bought and started using the Central Pneumatic HVLP gun that you
>>described. The problem that I am having, and I had the same problem with a
>>standard spray gun, is blisters in the glaze just as I am getting the final
>>thickness on the glaze that I want.
>>
>>The glaze seems to lift in small areas that vary in diameter from a pencil
>>eraser to a pinhead. I can push them down, but that is a pain and can
>smudge
>>overlapped glazes, and at times I get crawling from the blisters that don't
>>reattach.
>>
>>I would also appreciate any thoughts you might have on the general process
>of
>>spraying, how do you determine thickness for your glazes? I generally
>count
>>revolutions, and also occasionally scratch through the glaze to see the
>>thickness.
>>
>>Thanks,
>>Rick Malmgren
>>RMalmgren@aol.com
>>Lothian, Maryland USA
>>
>
>--
>David Hewitt
>David Hewitt Pottery ,
>7 Fairfield Road, Caerleon, Newport,
>South Wales, NP18 3DQ, UK. Tel:- +44 (0) 1633 420647
>FAX:- +44 (0) 870 1617274
>Own Web site http://www.dhpot.demon.co.uk
>IMC Web site http://digitalfire.com/education/people/hewitt.htm
--
David Hewitt
David Hewitt Pottery ,
7 Fairfield Road, Caerleon, Newport,
South Wales, NP18 3DQ, UK. Tel:- +44 (0) 1633 420647
FAX:- +44 (0) 870 1617274
Own Web site http://www.dhpot.demon.co.uk
IMC Web site http://digitalfire.com/education/people/hewitt.htm
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