What is the best material for sails?

The traditional source of sail material ("Drafting Linen") is now almost unobtainable (replaced by drafting mylar). It was a very fine fabric, but tended to yellow after a few years (I have a model that has become dark brown.) A fabric sold by some of the hobby suppliers as "Balloon Cloth" is really just a fine canvas, and unsuitable for most work.
{John O. Kopf}

The following material was provided by William E. Boebert, Historian, U.S. Vintage Model Yacht Group:

Finding authentic cotton sailcloth for our vintage pond boats has been a problem since the formation of the Vintage Model Yacht Group. Bill Bithell, the 80-something years young builder and sailmaker, used the last of his 1939 bolt of cloth to make twenty sets of sails for the boats that showed up at the 100th anniversary regatta of the Marblehead Model Yacht Club in 1994. (But there were scraps to use to match possible "hits"). After that the search was on, in the US and overseas, and led me and the other Group Historian (Charley Williamson) on a merry chase through mills, defunct suppliers, the Smithsonian, an the American Museum of Textile History. Finally, a message to this list triggered a web search which lead to a supplier in, of all places, Annapolis, Maryland. This person also has some material which may be of interest to the scale crowd.

But first ....

A couple of messages have mentioned "balloon cloth." Herewith the official description, from an airplane maintenance textbook of 1940:

"Balloon fabric is used in several applications in aircraft such as pliable backings for package racks, hat racks, etc. Light cotton gauze, woven tightly and with great precision, is run through a rubber mill; the crude rubber is squeezed through he pores of the cloth and sheeted on both sides. The rubber is then vulcanized. The threads per inch in warp and filling vary from 120 to 140 .. the weight of two-ply balloon cloth is generally 11 ounces per square yard."

Obviously, what we wanted was the material before the rubberizing process. Not only was this cotton tightly woven, but it was also made from "long staple" cotton. This is a special breed of cotton with unusually long fibers. Varieties are called Egyptian, Sea Island or Pima cotton.

Two things that are not balloon cloth: Grade A Aircraft fabric, which is long staple cotton woven 88 threads per inch and subject to a strict FAA certification process (and extinct), and the stuff from Model Shipways I got from Dromedary, which is about 60 threads per inch.

In the course of our search we turned up a suppliers catalog with swatches: the material varied from 82 to 126 threads per inch and 2 to 6 oz per square yard. We got aced out of the last of mill's run of "down cambric" (a glossary of cotton cloth terms is at the end of this message). This is a lightweight cotton cloth used for down pillows and comforters -- the tight weave is needed to keep the feathers from poking through.

Well, after another bunch of adventures we located some down cambric in the UK, which was awkward to purchase but at least available. Then a message to this list mentioned Swiss pima batiste. Did a web search, and got a hit on Kiyo Designs of Annapolis. After a bit of conversation and exchange of samples, Nancy Hoyt (who runs the place and really knows her stuff) found the following candidates:

Everything runs about seven bucks a yard (45" wide) except for the lawn, which is thirteen (same width). All would be suitable for scale work, being at least twice as fine woven as the Model Shipways material, fine enough to be translucent. The lawn, in particular, looks pretty good for furled sails -- it's very fine and tightly woven. The batiste is a more open weave and would look good for sails in older boats.

Nancy did a fair amount of digging to find this stuff for us, and I hope that this message doesn't trigger an avalanche of one yard orders which would be more trouble for her than it's worth. The best thing would be if one of the suppliers who are on this list would buy a bunch and resell it.

Appendix:

Definitions lifted from The Internet Centre for Canadian Fashion and Design - The Textile Dictionary:
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