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Pawelpksa

Shrinking ratio

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Hi, I try to make porcelain scales for straight razor. Crazy! Yes, but I want to try. Has anyone tried something similiar?

My first challange is to measure it's lenght and width properly to foresee shrinking level. Normally my porcelain shrinks (for the given temperature) to 0.84 of wet dimention.

Do you have any help, experience regarding this? Does shrinking change depending on the shape of the body - scales are think and long.

The other challange will be the deformation in firing process (bending).

Any hints?

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It's going to be difficult at best. Shrinkage will vary slightly depending on form, and method of construction. The chances of getting them to fit on an existing thing are very slim. You'd be better off making the scales first, and fitting everything else to them.

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10 hours ago, Pawelpksa said:

Hi, I try to make porcelain scales for straight razor. Crazy! Yes, but I want to try. Has anyone tried something similiar?

My first challange is to measure it's lenght and width properly to foresee shrinking level. Normally my porcelain shrinks (for the given temperature) to 0.84 of wet dimention.

Do you have any help, experience regarding this? Does shrinking change depending on the shape of the body - scales are think and long.

The other challange will be the deformation in firing process (bending).

Any hints?

If you have access to a hydraulic/pnuematic press you could make press moulds and use pressure to help mitigate warping and help keep shrinkage uniform.  You could also make them very quickly that way.

Edited by liambesaw

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High plasticity= high memory= high shrinkage= thin&long warping.  Your shrink stats equate 16%: that is very high. Which means  it is a soft clay with higher water content.

choice a: wedge moisture out until it is firm.  Shrinkage should be around. 10%. 

Choice b. Use a porcelain tile body. 10.5 to 11.0 shrinkage. 

You will find the challenge to keep in straight while drying to green ware. Keep it flat, perhaps lightly weighted. The drier it is when forming, the greater chance of success.  Enjoy the rabbit hole.

T

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AMAZING!

congratulations on doing what could have been impossible.  you did it beautifully.

could you please define the word "scales" as you use it?  if it means the mix of colors, that is usually called marble and the process marbling.  scales usually mean overlapping small pieces like the scales on a fish.

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16 minutes ago, oldlady said:

AMAZING!

congratulations on doing what could have been impossible.  you did it beautifully.

could you please define the word "scales" as you use it?  if it means the mix of colors, that is usually called marble and the process marbling.  scales usually mean overlapping small pieces like the scales on a fish.

I think the "scales" in this case are the individual handle pieces on the razor...definitely a job well done!

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Nice work! 

 Glad you did this and had success. We have special projects for students just for such an occasion to show that with some care these things can be fit.

The  vessels below take some planning but in the end fit up is achievable with reasonable advance preparation and reasonable knowledge of their clay body shrinkage.

82C6AEFF-9CC2-47D5-8BDE-4C293F4BABC1.jpeg

FED5ADF8-15FB-426C-9E67-E2B34F739BD3.jpeg

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Hi,

Scales are those two pieces of marbled porcelain on the handle of the razor. That was the main challange - to make them precisely at the desired dimentions and plain. Then drill the whole and pin them with hammer. At any time it could have broken easily. All the pieces are thrown on the wheel while the scales are cut from marbled porcelain.  I have you exact shrinking ratio but it will not help to repeat it - it is much dependant on the firing temperature and the mixture of porcelains, maybe also on the size of the piece and its shape..

If you want to read a bit more you are welcome to the two following posts in my blog:

about the scales

about the final assembly of the razor

Bill - great job with top vessel, impressive

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