I currently am thinking of making a ceramic whistle and I am wondering how to deal with the srinkage of the clay when it is fired.
I have found these sites on building one
http://www.geocities.com/rvelaz.geo/xochi/constri.html
http://www.cr.k12.ia.us/hard/Arts/Visual/flute/cf2.htm
but they do not seem to worry about the srinkage, is it a problem or am I not correct on the clay srinking?
Thanks for your help
Silante,
Ben
The one ceramic flute that I have is totally out of tune and plays quite poorly. I don’t thing that they worried about shrinkage 
Erik
The one I have is in tune and it is easy to play as well as having a great sound. I think I can duplicate this if I get enough information.
Making a porcelain flute come out perfect after firing is an acquired skill but there are some “tricks”. If you make the borelength a little short,you can plug the end with a wooden coin shaped plug and bore a small hole in the center. Slowly increase the size of the hole until the fundamental pitch is correct.
Making the toneholes a little larger also helps. After firing and shrinkage you can reduce them(flatten pitch)with layers of clearcoat. Begin with tuning the lowest tonehole and work your way to the voicing/embouchure end or use the same technique as the bore end correction(bored coin plugs).
Overall,reducing a hole flattens pitch and increasing a hole sharpens it. Raising the overall pitch of a clay flute is done by increasing the voicing size and vise-versa.
Calculating the shrinkage can be done by impressing a ruler on a sample tile and then measure the increments after firing.
Talk to some experts at…
http://groups.yahoo.com/group/Ocarinaclub/
Thomas Hastay.
I just thought I’d bring this thread up, as it has some good information pertaining to a recent thread.
I’m confused, the original poster askes about shrinkage, stating that the authors of the articles referenced don’t seem to be concerned with it, yet the more detailed article on mexican historical flutes clearly states in one of the first few paragraphs that he uses a clay that shrinks 8%.
Seems to me that this was mentioned for a reason - Construct your flute 8% longer, and wider than you’d like the fired peice to be. No doubt working with clay will require some trial and effort anyway, so measure before and after firing, to measure actual shrinkage rates and adjust from there.
Final tuning and voicing adjustments will need to be done after firing anyway, but if you allow for the 8% (assuming you use the exact clay mentioned), you should end up fairly close after the first try.
Loren
On 2002-08-25 08:23, Loren wrote:
Seems to me that this was mentioned for a reason - Construct your flute 8% longer, and wider than you’d like the fired peice to be.
Loren
Actually, if there is an 8% shrinkage, you would need to increase the length by 8.7%–just one of those quirky things about percentages.