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ronfire

Build hydrastone bats

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Thought I would start a new thread on building bats as I have never cast any

Looking for some advise on building hydrastone bats. I will have plastic inserts for the wheel head to reduce wear.

Do you pour the finished ( top) side into a mould then add the pins in with a template. I can build a mold with an exact rim height and then place a bottom mold on top for pin placement - this would provide a nice smooth surface  for the top.

Or right side up on pins or the wheel head and when close to dry finish the top with a rib or can you trim as it dries?  Does the Hydrastone produce a good finish on top when poured onto the wheel head that it does not require finishing.

Can you sand the product smooth after it is cured to produce a top finish?

How thick do you make them, hope to see one on Monday at the shop. Would 5/8 be good for a 12" bat?

Also thinking of building some 6"square ones for bat inserts.

 

  I have always made them with MDF  but looking at improvements for my new  Skutt wheel I get Monday :D:D

Edited by ronfire
typo

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I would pour them right on wheel head with a laminate band that sticks up 1 inch past head surface and pour with the inserts in place and scrape top smooth with a steel straight edge 

sponge smooth when plaster is set hard enough-its learning curve and a skill to do these steps as plaster sets. Much easier to work at the right time. You can soften the edge as soon as you pull the band off with a small scrapper and sponge.

5/8 is pretty thin and I feel is to thin.

Mine are 1 inch or more

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Hi Ron,

Hope you like your new wheel!

As all our kitchen tools and dishes are strictly off limits - no "borrowing" for the studio - I'd kept an eye out for suitable casting vessels at the local thrift stores, and now have a collection of cake and pie pans, etc. for casting plaster bats and slabs. The large ("large" is relative, eh? 2x9x15" is large for me) rectangles are handy for reclaim. Smaller diameter bats - 6", 8" - are nice for smaller pieces (as Mark has pointed out) - easy to handle, take up less room. Larger diameter bats - 10" - for larger pieces, more leverage to stay put, also absorb and move water faster, more surface area.

I cleaned and smoothed the bat molds, soaped them against sticking, poured them thick (1.25" or more), tap tap tapped out bubbles, left them on a level table to set up, and rounded off the top corner whilst the plaster still a bit soft and wet. The cast "bottom" is the working surface - smooth and tight with a nice radius edge.  We also smoothed off the "top" with a metal straight edge whilst the plaster was still moist and a bit soft.

From there, wasn't looking to solve the plaster/pin problem - I use a clay bat to hold them, however, I put the clay bat on a plastic bat, hence no moving pins and I can switch between plaster and other bats in a wink, also avoiding corrosion on the wheel head. A clay bat can last a long time, just cover when not in use, mist it a bit when needed. Sometimes I'll stick the plaster bat down with clay fingers on the side instead...

Pottery plaster pulls water! I'm wiping the bottom of the bat with a wet sponge before sticking it down, and also the top before putting down the clay ball; from there, the clay in contact with the plaster turns to tar almost immediately - some adjustment in procedure may be required.

Still curious, would you try same clay and bat(s) on your new wheel (that you were using on your old wheel) and let us know how it works out?

 

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Ron here a photo of my bats in studio taken 8 years ago to the day-also on My Birthday in 2012.The bats are  in piles -there are two sizes I use-all made from pie tins.

This room 14x 8 is the throwing room only also drying up high on shelves -glaze and wedging etc is thru a 5 foor wide pass thrugh to a 12x23 room-main studio.Heated by natural gas heater.Two extruders on the wall as well.

 

Edited by Mark C.

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I made hydrostone bats few years back. I drilled out the holes for the pins with a forstner bit big enough for pins with vinyl tubing to protect the plaster. I used silicone cake pans

Wear a mask when drilling plaster

 

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Just about to start making some Hydrastone Bats. I measured the Hydra-bats and they where just over 5/8 inch thick .

1" plaster bats work , Hydrastone ifs far stronger so I thought I would try 3/4"

I found some airline that fits perfect over the pins.

I made a mold  from 1 of my new mdf bats and drilled 1/4 inch holes so I can place in the pins. Used some brass strips I had to form an outer band and some silicone to put a finger edge under the bat when done.

I was thinking of using past wax as a mold  release as it would not soak into the MDF as much as a liquid product. I have heard others use Murphys Oil Soap.

Any recommendations on what would be better? 

Once the Hydrastone starts to set up I can place the mold on the wheel and finish the surface and a slight bevel on the edge while it is still in the mold. Hopefully it will release without having to remove the banding. I should be able to help it by pushing on the bat pins.

I also made up some 6x6 grid on laminate to build bat inserts, this will work well to pour in any extra Hydrastone after pouring a bat.

 

 

Screen Shot 2020-03-17 at 5.52.29 PM.png

Edited by ronfire
added to

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Update on the bats

They are working great. Sure like how the clay releases from the bat without wiring off and the clay stays flat while drying.

The only issue I had was the bat pins became a little tight and out of place, wonder if the hydrastone shrunk a little on the final drying. Fixed it by using a dremel and making the plastic inserts a little larger.  

The important  part of making the bats was to make sure the plaster as even in the mold so they would be the same thickness  all the way around.

 

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