Best material, in your experience, for work kilt

[The Wizard of BC]

I would guess that over the past 14 years I have tried just about every fabric I could get my hands on.

I assume by work kilt, that you are asking about non-Tartan fabrics so I will leave those until last.

I would rate the absolute worse fabric that I have ever worked with to be a light nylon similar to that used in boxing ring shorts. Far too light weight and revealing. And never, ever allow it to get wet. It becomes transparent.

Second worse in my opinion would be leather. It is heavy and requires a special sewing machine with a walking foot to sew it. Once you put a needle hole in, it is there to stay. It requires special cleaning methods. Leather is stiff and does not swish well at all.

Third worse would be 100% cotton fabrics. This includes cotton prints like Camo that have the design only on one side. Cotton is a unique fabric. It continues to shrink throughout its entire life. So a kilt made of cotton will shrink in length unless you stretch and iron it after each and every washing. Cotton wrinkles just by looking at it and it will not hold a crease so every pleat must be edge stitched inside and out.
Included in this are denim. Today I refuse to make a kilt from denim after one customer who did not want to iron his kilt thinking, that like his denim jeans, would form fit to his body. Well, it did try to form fit. By shrinking. Until the pleats were short enough that their own weight would no longer pull the pleats down and the entire kilt stuck out like a ballet tutu.
The cotton fabrics also include the 'Carrhart' style of duck canvas. I have some that came off the exact same looms that produce the Carrhart brand fabrics. Yes, this fabric wears like iron but unlike carpenters coveralls that have legs inside to stretch the fabric back out, it will wrinkle and shrink just like denim. I had one customer who washed and dried his kilt, with a dozen hard rubber dryer balls, over 100 times in a vain attempt to get a duck canvas kilt to take on the softness of his beloved Carrhart coveralls.

Of all the solid colored fabrics that I have used, the best would probably be a Polyester and Cotton blend fabric similar to that used for "Dockers" brand slacks. This fabric is wrinkle resistant due to the 65% Polyester content. It machine washes and dries well and is fairly color fading resistant. But this fabric must still be edge stitched like cotton and will not take the compound curves that are necessary to an Iconic wool kilt to take its famous shape.

If you want to have a Tartan kilt that is not wool may I suggest you take a look at the Polyester/Rayon blends offered by the UK weaver "Marton Mills". This is the fabric which is used by myself and USA Kilts. This fabric is known in the UK as P/V. Short for Polyester/Viscose with Viscose being the British term for Rayon.

This name P/V was quickly adopted by the Sailkot, Pakistani makers to mean almost any synthetic fabric. It is quite common to see the term P/V used for Acrylic and Acrylic blends where there in no Polyester or Rayon at all.

I have been very happy with the Poly/Rayon fabrics and use it exclusively in my rental fleet. Rental kilts go through more abuse, in a shorter time, than almost any other kilts. I have some of my rentals that have been rented, and then machine washed and dried over 50 times, and they look as good today as the day they were made. They have not been touched by an iron since the day they were made and the pleat creases are as sharp and the fabric as wrinkle free as the day they were made.

If you want a solid colored work kilt my choice would be a 13oz 65% Polyester/ 35% cotton - "Dockers" pants fabric.
If you want a Tartan work kilt my choice would be "Marton Mills" 12oz Polyester/35% Rayon blends.