Carol Ryan-Aube on fri 19 aug 05
I hope this isn't one of those "why don't you read a book" or "look in the
archive" question. I have been looking in my books and I looked on the
archive (I found waxing but not bubbles) and I haven't found the answer.
Maybe it is so obvious that I should automatically figure it out. Oh well,
here it goes -
When I put the wax bottoms on my bisque ware, the wax bubbles up from an air
pocket beneath and makes a small circle on my nice waxed ring. Sometimes it
bubbles 2 or 3 times. I am a perfectionist and I hate seeing the little
circles after the piece has been glasses. I was really observing yesterday
and I noticed that it didn’t happen as often with smaller bowls and item.
The smaller items I put down flat in the wax and they worked better. The
larger items did terrible when I put them flat down. Than I put them down
at an angle so the air could escape before the wax came up. However, this
did not work for all of them and especially the larger pieces. I use an old
electric frying pan - I have it on hot enough to keep it melted nice but not
hot enough to make fumes.
I allow myself one bubble but if there are more - they go back to be
re-bisqued again. I had at least 7 of them yesterday. I tried painted on
the wax with a brush but was quickly disappointed with my straight lines.
I don't know what I would do without my daily reading of Clayart - Thank you
all for you time and your sharing. Any suggestions will be greatly
appreciated.
Carol Ryan-Aube
Palmer, Alaska
It was in the 80’s for a couple of days last week but now back to typical
August weather - wet - high in the 60’s and low in the low 50’s - Fall is
on it’s way - the fireweed is finished blooming.
Mark Issenberg on fri 19 aug 05
I also use a electric skillet,, i plug it in and what till its all melted ,
i then pull the plug.. i dip bottoms , no bubbles.. Maybe you are using it to
cool.. I put the plug in after a half hr if im still doing bottoms
Mark
lela martens on fri 19 aug 05
I know what you mean about that bubble. My frying pan`s bottom is so uneven
though, the air is usually released as I turn the pot so the wax is level on
all sides.
For pieces too large to fit the pan, I use an old compass. The pot is placed
on a lazy-susan,turn-table. The point of compass rests on that, the pencil
alighned on the pot where I want the wax line. Then retate the
turn-table.This gives me a straight line to follow with the wax-resist brush
or sponge. Or, while trimming, use a tool to make a gentle indentation to
follow after bisque.
Best wishes, Lela
> The
>larger items did terrible when I put them flat down. Than I put them down
>at an angle so the air could escape before the wax came up. However, this
>did not work for all of them and especially the larger pieces. I use an
>old
>electric frying pan
Carol Ryan-Aube on fri 19 aug 05
>I also use a electric skillet,, i plug it in and what till its all melted ,
>i then pull the plug.. i dip bottoms , no bubbles.. Maybe you are using it
>to
>cool.. I put the plug in after a half hr if im still doing bottoms
>
>Mark
>
Mark - No bubbles?! are your bottoms flat or do you put a foot on them. I
think the air is getting caught in the middle and comes out under the foot.
I noticed that the ai bubble ones do not wax completely in the center -
probably other air bubbles?
Thanks for your advice -
Carol
Kathy Forer on sat 20 aug 05
On Aug 19, 2005, at 7:58 PM, Carol Ryan-Aube wrote:
> think the air is getting caught in the middle and comes out under the
> foot.
> I noticed that the ai bubble ones do not wax completely in the center -
> probably other air bubbles?
There might be some surface tension (the ability of a substance to
stick to itself) creating a vacuum.
Would disturbing the air or the skin of the wax before you dipped make
a difference? To get rid of bubbles in plaster, you might gently shake
a supporting table.
Maybe there is a cleaning or wetting agent for wax.
You can also experiment with dipping at a different rate of speed,
direction or motion.
A small variety of graphics:
http://hyperphysics.phy-astr.gsu.edu/hbase/ptens.html#bal
and LaPlace's Law
The larger the vessel radius, the larger the wall tension
required to withstand a given internal fluid pressure.
Temperature also affects surface tension. Many kinds of cooler
substances float so the top layer of the wax will always be cooler. Try
putting the wax in a double boiler or pan filled with water, a bain
marie, or a crock pot. That might help to maintain temperature. It's
also a good way to melt wax.
Kathy
Bob Santerre on sat 20 aug 05
Kathy Forer wrote:
> On Aug 19, 2005, at 7:58 PM, Carol Ryan-Aube wrote:
>
>> think the air is getting caught in the middle and comes out under the
>> foot.
>> I noticed that the ai bubble ones do not wax completely in the center -
>> probably other air bubbles?
>
//////////////////////////////////////////////////////////////////////////////////////////////////////
Wax bubbles are a common problem on pieces that have been trimmed to
leave a recessed center in the foot or if the bottom is slightly
concave. Air is captured and expanded by heat and as you manuever the
piece in the wax a bubble escapes and splashes wax up the side of the
foot leaving a wax bubble above the line of the rest of the waxed foot.
As noted in one response, the cooler the wax the less the captured air
will be heated, thus lowering the possibility of an escaping bubble.
Setting the piece into the wax at an angle will decrease the volume of
the captured air and also help the problem. Lifting the piece out of
the wax quickly and carefully (keeping it level) will also prevent a
certain number of these "accidents". Making sure your waxing pan is
level also helps.
In any event, unless it's a really big bubble this should not require
re-bisquing (and you may just get another bubble the next time you wax
so how many times will you want to go through this cycle?). The wax
bubbles usually do not penetrate into the clay very far (the clay is
relatively cold and the wax freezes before it can penetrate deeply) and
it's qiute easy to scrape off this small amount of wax (back down to the
wax line your trying to get) with a knife. I use an Exacto knife or
(the dreaded) box cutter to scrape off the wax and just a bit of the
bisqued clay surface. If I'm still worried that there's wax in the clay
that will resist the glaze, I may sand the area a little with a small
piece of sanding screen to be confident that I've removed all the wax
(note: Sometimes the knife will leave a dark metallic residue on the
clay. Ignore this, the glaze will cover it and it will disappear in the
firing.)
Depending on the shape of the foot this operation can be a little
tedious to do, but the results are certain (the wax can be removed by
scraping it away), whereas re-bisquing is much more time consuming and
the likeihood of getting another wax bubble is very high.
Some folks use wax scraping as a "painting/design" technique. Try it ,
you'll like it!
Bob
bonnie staffel on sun 21 aug 05
I agree that those bubbles are annoying. I roll/rotate my foot rim into a
very shallow layer of melted wax and then with a brush already in the pan,
paint the inside of the foot ring by brush. If you add a little Lamp Oil to
your wax, it will melt a little faster and not build up too thickly.
Good luck.
Bonnie Staffel
http://webpages.charter.net/bstaffel/
http://vasefinder.com/bstaffelgallery1.html
Charter Member Potters Council
bonnie staffel on sun 21 aug 05
You can wax your pot bottoms an easy way by just inverting your pot on the
wheel, center it by tapping, rotate your wheel and use liquid water wax in a
squeeze bottle followed by your wet brush and you will get a nice line every
time. You can also wax your complete bottom with this method especially for
pots that are too large to fit into the electric skillet.
Warm regards,
Bonnie Staffel
http://webpages.charter.net/bstaffel/
http://vasefinder.com/bstaffelgallery1.html
Charter Member Potters Council
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