Jump to content


  • Posts

  • Joined

  • Last visited

Posts posted by liambesaw

  1. It is a really good wax.  Luckily very close to me.  

    Another great wax, but with different properties, is reed wax from brackers.  Both are the best waxes I've used, and SPS crystal wax is a product that Mobil oil no longer makes (or at least that was the last news), so there is a limited life on it.

    You cannot let it freeze, I know that's not a big deal for you @CactusPots, but could be for others here.

    Reed wax is nice because it can freeze, but also is a decent wax in general.  And is available into the future.

    I do hope mobilcer-a continues to be available, but I have a good back up just in case.  



  2. Can you use a respirator while you're there?  Not likely necessary, but if you're worried about silica in the air, that's one way to keep using the studio and still feel safe.

    If dry clay on things is the worst it gets, it sounds like every studio I've been to.  Silicosis is no joke, but there are measures you can take personally to prevent it.  There's a lot of fear around it, which is understandable!  But there are much more dangerous things you're exposed to in a studio that no one talks about.  Silicosis is rare in potters now, because people are more aware of what causes it and how to prevent it.  Be aware, but don't be paranoid.

  3. I do it myself, but a friend has hers done by the kiln techs from our local pottery store and the cost is 400 including parts and labor.  She has a 818 as well.  So if you remove the cost of the elements, pins and connectors, that's around 200ish for labor?  Seems expensive to me, but we live in the Seattle area which is very expensive in general.

    I recently changed the elements in my 14cuft oval kiln and it took me about 3 hours.  Not too bad.

  4. Freezing slip will cause water to leave parts of the slip, leaving drier clumps when thawed, but a little bit of time in a blender or magic bullet or whatever will set it straight.

    If it's casting slip, the water will separate and the deflocculant and other salts present (I'm looking at you neph sy) will crystallize.  Would be a bit more of a task to thaw out casting slip.

    What will work fine at keeping mold out though, is a tiny pinch of copper carbonate.

  5. 7 hours ago, Mark C. said:

    I poured my wedging table in 1972 out of plaster -if I recall it was casting plaster (a bit harder than #1 pottery plaster) its about 5-6 inches thick and weighs a ton. Now nearly 50 years later

    its still good as new-and I can slam a 25# pug on it with no cracks. Its open on all sides with a solid wood base. I store 500# of clay beneath it-I have two  of these made into one unit with 4x4 legs ,one for white clay and one for brown clay-they have held up to the test of time.  I had to move them in 73 when I bought this place .I would not move them again-to heavy.Back then that casting plaster was darn near free price wise.Overrall width is about 6 feet and about 28 inchs deep for the unit-a slot of 3 inches separates the two plaster sections.

    Casting plaster is weaker now days, at work we switched from casting plaster to pottery plaster #1.  Much better quality and strength, and quicker setting time too!  

  6. 8 hours ago, oldlady said:

    victor, there is a member here, glazenerd, who advised me on how to fix the problem i had with copper carb.   i used to buy it, (1970s) as a greyish-green powder but now it is only available in a bright green that looks more like lime jello.

    glazenerd advised me to put vinegar over the powder in a bowl until the powder was covered with vinegar and let it dry.    boil and bubble, bubble, bubble.   a scum formed on the top when it dried, only a couple of days for my amount.   i tossed the sheet of scummy stuff and the powder left works very well.   i sieve through a 60 mesh sieve and use lots of green glaze.  no problems.

    thanks, nerd, hope i said that at the time.

    Just so you know for the future, this makes copper acetate, a water soluble copper salt, and is a more toxic and problematic version of copper for glazes.  It will flocculate your glaze and may recrystallize over time.

  7. 31 minutes ago, Callie Beller Diesel said:

    @liambesaw Back in the day there was a couple of raku artists that would spray their pots with one of the cobalt salts for some truly beautiful results, but I expect there’s some solid health and safety reasons people don’t do it a lot anymore. I want to say they used cobalt sulfate, but I’d be lying if I said I remembered exactly.

    That is... Scary as hell.  If anyone reads this in the future, never SPRAY any metal salts, ever.  They're all toxic, and don't provide anything special that you can't get some other way.  The spray itself, toxic, the fumes from evaporating when it hits hot pottery? Toxic.  And toxic in some of the worst, most heart breaking ways.

    Sheesh. But that's not fuming, fuming is introducing the salt (preferably as a powder) to the kiln during cooldown.  Still hazardous, especially if firing indoors, but not nearly as hazardous as spraying the salt mixed with water!


  8. 2 hours ago, Callie Beller Diesel said:

    I mean, there’s not a huge amount of ceramic safety issues regarding cobalt because we’re not exposed to enough of it, so those search terms won’t bring it up. When there’s no data available for potters and cobalt based illnesses and we’ve been using this stuff for hundreds of years, you’ve got to wonder a bit.  So then you have to think “who else handles this stuff, and how do they get sick (or not) doing it, and can those circumstances be replicated somehow in my studio?”

    Some fuming processes that use cobalt salts could and do definitely present health and safety issues. Cobalt wash? Not impossible, but highly unlikely. 

    Also, that mug is lovely!

    Is fuming cobalt a thing? I didn't think kilns got hot enough for that

  9. 2 hours ago, thiamant said:

    Hello, Im going to write another post since this topic was brought up somewhere else...

    I'm concerned about fumes releasing from my kiln because it's located in my house. I have a Nabertherm small kiln (60L). So these are the manufacturer indications for vent system:



    I was thinking on doing something like that (its a passive system) to exhaust the kiln. My supplier suggested me not to use a fan extractor because it would also extract a lot of temperature and therefore more power consumption and/or less kiln durability (kW out, kW in). In fact, the manufacturer recommends closing the bottom valve at approximately half firing so that the kiln can keep the temp up efficiently. So instead, I thought I would just turn on a fan from the inside of the room pointing to the window. Any suggestions? Can I just use aluminum flexible tubes? Can I substitute the chinese bell for a horizontal reflector? I want to be as minimal as possible since it's a small kiln and also I don't have much room for a very complex setup. My main concern is fumes, not heat.   @liambesaw @Bill Kielb

    If your kiln is having trouble reaching temperature while vented, that means it is underpowered.  Kiln vents are not a strong flow of air coming through the kiln, they are fairly passive and are designed to remove fumes.  A fan in a window is good enough for a garage, or detached building, but if your kiln is in a living area, I would suggest getting a vented hood or bottom vent, whichever your kiln manufacturer recommends.  


  10. 3 hours ago, thiamant said:

    Ok, the german supplier just confirmed that it is Chromite Fe2+Cr2O4

    Is this safer to use than Manganese dioxide?

    if you don't eat it, it should be fine.  Manganese dioxide is quite safe to handle, you just do not want to inhale it, or the fumes from firing it.  The same goes for iron chromite.  Don't eat it or inhale the dust or vapor.

  11. I don't think there's any rules.  You might wear out your kiln faster if you're gonna be dumping a bunch of soda into each firing, but it's not a sin.

    As far as happy accidents go... From what I can tell, the entire point of wood firing is to have an entire kiln of happy accidents. If you don't want happy accidents, use an electric or gas kiln and things can be a whole lot more predictable.  




  12. 6 hours ago, hlipper said:

    But is it unsafe to do because of the fumes? Or is the smell the only issue?

    I lustre fire outside, but the overglazes do not vaporize, so it should not be unsafe.  This is assuming you're using modern overglazes, not lead fluxed overglazes from pre-1990.

    Modern overglazes are fluxed to the surface with either bismuth salts or silver salts.  The nonvolatile (the compoundes that do not evaporate after application) compounds in lustre overglazes are pine rosin and metal salts.  The pine rosin is there for local reduction, and will generate a tiny amount of carbon monoxide during firing, but it likely converts to carbon dioxide before it even leaves the kiln.  The salts reduce to their metallic form.  

    Take that with a grain of salt, but I would be more comfortable firing lustres in a vented kiln than I would firing a speckled body.


  • Create New...

Important Information

By using this site, you agree to our Terms of Use.