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CactusPots

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Posts posted by CactusPots

  1. Everything will alter the crackle/crawl glazes.  Dipping, brushing, pouring, applying with a baster.  Thickness of glaze is critical.   

    Thickness, cone  firing of bisque, cleanliness of bisque.

    My opinion is they are cool if you can accept inconsistency in final results.  The best will be really good and the worst will not even be acceptable by my loose standards.  You should see some separation as soon as the glaze is dry, but too much and the firing may cause the platelets to separate from the pot.  Stalactites are no good.

    I have used a lot of Coleman's shino crawl and currently using more Hopper reticulated.  Like Min says one is well fluxed and the other is not. 

  2. I always describe cones as measuring temperature and time the way a speedometer measures speed and distance.  If there was a meter that measured heat work that way, that might be useful,  but otherwise the thermocouple probe itself is only giving half the information.  I suppose with a programmable controller on a newer electric kiln, you guess the controller is doing this for you if you use their cone fire program.

    My question would be if anyone has actually verified the programmed climb rate and  temperature against cone packs.  How close is it to expectations?   Dead on at cone 6?   I have zero experience with electric glaze fire, so this is interesting.  In my gas kiln, I watch the cones above stated 2000 and 10 is usually down around 2150 or so.

    As usual, if I need correcting in stated facts, please bring it.

  3. On 5/27/2021 at 4:27 PM, liambesaw said:

    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!  

    If you were casting a plaster wedging table, the thing to do would be to cast in a piece of expanded metal.  Used mostly for lath and plaster, I think, it's like chicken wire or hardware cloth, but more metal, less space.  Be like rebar in concrete on steroids.   My wedging table is still solid after 25 years and maybe 2" thick.  Well supported also.

  4. I have an excellent local supplier, but lately I've been ordering more stuff remotely.  Got very good service from Seattle Pottery on some crystal wax and where shipping isn't a killer from Bailey.  I'm in So Cal, so my clay comes from Laguna through my local guy.  Don't want to ship that.  Especially with the increases in price in the last year or so.  Soldate 60 has gone from 12 to 16 per box.  Ouch.  

    From what I hear, Laguna isn't such a treat to deal with directly.

  5. I've used a couple of Smooth On products for building plaster press molds.  One thing I've learned is to plan to use the entire batch you buy.  Once opened, there's a shelf life as described in the product descriptions.  Very complicated to calculate volume needed for some projects.  Since I'm only building a 2 dimensional form, as opposed to a 3 dimensional model, I've gone to multiple layers of latex.

  6. Personally, I like canvas over plaster, but I doubt if anyone here has my advantage of working outside year round.  My studio is mostly open and under a covered patio.  The dirt road I live on puts more dust on our cars than builds up in my not very well maintained studio.  I believe air flow is better than filtration if you can do it. 

  7. I make planters primarily for cactus and succulent collectors.  So my molds are mostly round or oval.  From about a cereal bowl up to a wash basin in size.  Other techniques for other shapes. 

    Panty hose would work ok for smaller pieces.  I tried a fabric called "4 way stretch" from a basic fabric shop.  It moves like panty hose fabric, but you can get it in yard lengths.    It works ok if you can pull it tight and pin it securely to the mold.   I have it on a large round styrofoam mold with lots of thumb tacks.  Too hard to get all the creases out on anything but a round mold.  It does work great.

    The cling wrap is so very thin, I can't see any marks on the clay even when I'm not careful to get the overlaps of the plastic out.  Mugs are so small, I'd question hump or slump molds as a viable option, unless you're talking pour molds.

    I want the mold out as soon as possible.  The work has to stand on it's own feet as soon as the outside is finished, so I can work on the rim and inside fresh.

  8. I've been using a layer of plastic food cling wrap as a release agent on my hump molds.  The super thin plastic leaves no impression apparent to me on the clay.  It sticks to the clay but releases without issue from the mold itself.  This technique really perfects hump molds IMO.  I can form the body, add feet, textures, and a rim, immediately turn it over, remove the mold  and finish the inside.  Cling wrap is available in 18 inch widths.

  9. I'm going to add a third leg to Hulk's continuum.  You could be anywhere between the 3 legs. 

    A studio potter in my estimation, is closer to a artist in that they may not be concerned with volume the way a production factory is.  It's harder to use the "hobby" label on serious studio featuring all the necessary tools and a 20+ year investment in time.  There are lots of reasons why the income from the process may not be required for necessities, not related at all to lack of skill or dedication.

    In My Opinion (since I'm not one), a production potter is in fact limited in the amount of new directions their work can take.  Must not mess with the market's expectations.  Especially functional (kitchen) ware, which must meet relatively narrow parameters.  Those 100 mugs Liambesaw is making can be done (by him) in the amount of time of 1 sculptural or mainly aesthetic piece.  If the criteria is which is easier to sell, that's a no brainer. 

    So IMO (again) the criteria for production potter is related to income stream.

  10. 4 minutes ago, Mark C. said:

    High purity iron oxides are sold thru most outlets

    laguna/axner-https://www.axner.com/ironoxide-red.aspx

    US pigments-https://uspigment.com/product/iron-oxide-red-high-purity/

    I have used both with same results-I use it in same amounts

    Since I'm a laguna person I use them the most.

    I have a 50# bag of each including the old standy spanish red Iron Oxide which I still use in other iron glazes

    I think that is THE RIO available now.  The Spanish RIO is generally not available anymore I believe.  The stuff they are calling natural is what I was getting as brown iron oxide.

  11. 12 hours ago, Mark C. said:

    There is no easy in ceramics is my view no matter what cone temps 

    That said the glaze from a CM article in past decade

    Iron Cristaline glaze cone 11-12

    synthetic bone ask tri-Calcium Phosphate 12%

    Talc----I use Sierra lite-                                               9%

    Whiting                                                                               9%

    custar feldspar                                                               48%

    EPK                                                                                        6%

    silica 325 mesh                                                              16%

    synthetic red iron oxide                                             11.5% 

    Total 99.5%

    It likes it hot

    I fire it to 10-11 myself for best results but it looks fine in cooler areasas well just less crystals

     

     

    I hate to even ask, as my materials storage is really full.  I did think I had every available raw glaze ingredient, now you ask for synthetic red iron oxide.  O Well.

    It's not even on Baileys or Laguna catalog.  Where to get?  I assume it's more "powerful" than red or even black iron oxide.   Is that the difference?   Is there a substitution ratio? 

    What difference would I see if I ran tests between RIO and synthetic?  For that matter Bone Ash and the synthetic?   Just More Better?

  12. 12 hours ago, Min said:

    Interesting thought, care to elaborate on this?

    Challenge accepted.   Both have inherent complications, gas firing simply has more.  No where is gas easier or simpler. 

    Obviously, first off, the management of atmosphere.  Balancing damper and gas pressure.  Knowing the kiln well enough to work with uneven reduction.

    Putting aside the modified electric to gas conversions, a typical gas kiln costs substantially more than a typical electric kiln.  I would describe the typical gas kiln as about 24 cubic ft and the typical electric as 7-10, so a typical gas kiln has a larger footprint.

    An electric kiln is more likely to have an automatic programmable controller

    If someone asks advise such as " I want to do some ceramics, the space I have is my garage"   Electric kiln.  Rarely does someone start with a gas kiln now.

    If I think of more, I'll modify this post.

     

  13. 4 hours ago, Mark C. said:

    (Not many of us firing cone 10 anymore I think.)

    On this forum its 99% cone 6 but thats not refective of what I see in my area of the world (western state shows)

    I will add out local JC just switched to a all cone 6 program as they had to move the pottery shop to a new building (standar class room) and lost their Tech funding and it was easier for one instructor to fire electric with store bought  glazes than mix all the glazes and fire a gas kiln-this switch was done for ease of use for 1 instructor . It was a bit of a shame as the local high school has a cone 10 program and that JC had a 40 year cone 10 program so kids where all working in cone 10 thru high school and junior collage now they switch to cone 6 . Our State collage still is cone 10 and cone 06

    I only know potters firing to cone 10 out west here making a living-even our local public clay center with classes fires to cone 10

    I see only a few potters in cone 6 at shows in the west-most all are still cone 10.

    I'll bring the glaze formula in today from studio and post it -its glaze day for me glaze and load two kilns

    Not surprising to me your explanation is mostly centered around academic ceramics.  That's where most ceramics happens. 

    Also, Cone 6 electric is just easier in every way than cone 10 reduction.  Some of those ways are a very big deal.

  14. 13 hours ago, Mark C. said:

    Ok in another thread bone ash was brought up -that was all about Oribe glaze

    Todays update after mixing glazes this am for me is all about bone ash

    So on that  synthetic bone ash I just finished a full 50# bag of it  today (this bag was a gif to me )as I use it only in my red/black (high Iron) saturate glaze also  I use synthetic red iron only in this glaze. I have another 50# bag ready to go. The cost of this has really gone up lately. I used up 50#s in less than a  decade  in only one glaze -my Red-Black cone 10 glaze

    I still use my natural bone ash in any other glazes like Oribe -I use very little in this application

    Now its still  avaliable in both forms  at least thru Laguna Clay Co /Axner

    and  my guess most other outlets

    natural bone ash for me is  about 1$ per# for 50#s much cheaper than  synthetic made from cow bones

     synthetic tri-Calcium Phosphate is 3.09 a # in a 50# bag for me

    Mind you my prices are lower than yours but the relationship is the same so you can see what you are using

    So your cost will tell you what type you have.

     

    In terms of use this double use of synthetics give my glaze a super rich color not found in most iron saturated glazes. Its more costly to make but worth it. It about the 4th or 5 iron saturate glaze I have used in my line of forms over the past 45 years . Since its so bright it jumps out. I no longer use lesser Iron saturates.

    I got this glaze in a issue CM about 6-10 years ago-I do not recall exactly

    This is cone 10 reduction fired but will pop at cone 10 oxidation as well

    I use it on Porcelain 

    I can post it if there is interest 

     

     

    I'd like to see the glaze.  Would this be considered a good food safe glaze? 

    Not many of us firing cone 10 anymore I think.

  15. I'm convinced the best cookies for this are cut soft brick.  I use a bandsaw with a shop vac attachment, because as previously noted I'm a tool geek.  Cut on a bandsaw, they're perfectly even and absorb glaze really well.  They're easy to grind off if needed.  Without the joy of tools, a hacksaw and some patience will net a box full.  They can be reused indefinitely.  At least until they perform the glaze soak function.  Most any old softbrick will cut into nice cookies.  Don't need to use new ones, just have hoarder friends with piles they'll never use.

     

  16. Follow up on the original post.  Rented a very large wet tile saw.  Thing had a 20 inch throw. It was loaded on my truck with a fork lift and I ran it in the bed of the truck.  Went through the SC shelves like butter (almost).     New damper works fine on 2 firings so far.  Problem solved and 1 warped shelf eliminated from the rotation.

  17. 46 minutes ago, neilestrick said:

    The whole reason for the emergency shutoff is to take the human out of the system. It's not just about preventing the kiln from burning down the studio, it's also about shutting it off so it doesn't over-fire and ruin the work, the shelves, or the kiln. People get busy with other things, and people get distracted, especially in emergency situations, and especially with a kiln that only requires attention every couple of hours. That's why shutoff systems are required by code.

    What temperature would a cone 10 firing shutoff system be set at? 

    Inattention kills, that's for sure.  I see it everyday on the So Cal Freeways.  Maybe self driving cars will eventually be better.  Hard to say.

    Now that I think about it, what emergency control do non computer control electric kilns have?  Lots more of those around than gas kiln these days.

  18. On 3/16/2021 at 2:07 PM, neilestrick said:

    I highly recommend putting a new high limit shutoff back into the system. You never know what could happen that would prevent you from being able to turn it off. They're inexpensive and easy to wire up.

    I'm curious as to exactly what scenario or event a high limit shutoff system could backup where an experienced operator in attendance could not.  I'm looking to know the emergency that would cause the backup to trigger.  Like the operator has a heart attack, while waiting for cones to drop.  

    I ran into similar consultations when I was a telecom tech.  The client would ask about backup systems and I would always ask what emergency are you protecting against?  A power failure is much different than a hard drive failure.   You can't protect against every possibility, so consider what you think is more likely to happen.

  19. The belts come directly from Laguna.  Replace all 4 and keep any that have no cracks when you bend them as spares.  The wheel will run perfectly fine with 3 belts, but is noticeably under powered when centering more than about 15 lbs of clay.

    There really is no good upgrade for the belts such as changing both pulleys and using a V belt.  In order to get torque from a small motor, the drive pulley is as small as possible and the driven pulley as large as practical.  The drive pulley on the Pacifica is only about 3/4".  I couldn't find a V belt pulley anywhere close to that.

    I always get my electric kiln work done by the local pros.  Can't help you there.

  20. Cone 10 stoneware here.  I don't glaze the inside of planters either.  I know potters that also specialize in planters for xerophytes (cactus and succulents primarily) who do glaze the inside.

    For most house plants, I still wouldn't glaze the interior.  It's actually a complicated subject.  A lot of ins, outs and what have yous.  The soil mix is going to have more to do with the water retention that the inside surface of the pot.

    To me the number one reason is I can stack another pot inside for the glaze fire.  Very economical.  Also no wasted glaze.

  21. To me, the difference between a casual potter and a studio potter is the studio.  A casual potter may not have a complete investment.  I know a few potters that outsource their firings.  A casual potter can be quite complete with just a bag of clay and some off the shelf glazes or even just one iron wash.   It's a fine hobby with almost no investment at that point.  A studio potter most likely reinvests his sales in facilities and equipment for quite a long time and so has a large degree of versatility.  At that point, is freedom to make whatever comes to mind.  Creativity is the push.  Not to say that casual potters and production potters aren't creative also.

    A production potter has the investment, but requires a return on the investment.  Both material and time.

    I've always thought ceramics was particularly wonderful because there are so many ways to go about it.  The process is the reward.

     

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