Linen Backing

[Sempertiger]

Just wanted to pass the info. Was picking up some linen cloth this evening and noticed that not everything with the "linen" label is in fact 100% linen. Most of it was 60% linen and 40% rayon (plastic)

I picked up a bit of both. the 100%linen is significantly tougher to rip! Plus, I imagine it works better with the gules that we use, since it's all natural.

JS

[PatM]

Rayon is actually wood, not plastic. It may be "plasticised" as it is processed from the wood fibers but that's not the same as plastic in the sense we usually think of it.
 Fortisan backing was used in the past and Rayon is the same thing with a different name.

[dmikeyj]

A trick I learned from my seamstress wife.  Carry a lighter with you, and test burn a thread if you are not sure, linen/silk/wool (natural fibers) will be hard-ish to get started, and will mostly stop itself.  The man made fabrics will burn easier, quicker, and curl into hard little ends.  Silk does the curling a bit too, but the burnt end can be separated with your fingernails, whereas the plastics will not separate so well.  The smell is different too, the poly/rayons have a very plasticky, acrid smell, and the natural fibers smell like burning hair a bit.
If you are buying new fabric, it should all be labelled, this is what we do at the thrift stores, where you never know what is what.  Hope this helps.

Mike

[Sempertiger]

Rayon is actually wood, not plastic. It may be "plasticised" as it is processed from the wood fibers but that's not the same as plastic in the sense we usually think of it.

I didn't know that. your post inspired me to do some research. because of it's lower durability, I Still don't think it would be as good as pure Linen for a backing. What are your thoughts?

Mike, I'll be carying a lighter with me when I go looking for material for now on. Great tip!!!

[Sempertiger]

as a side note. I'm going to be backing a test bow with some linen. When I made my Daughters bow, I used three layers, but that was just a guess. is there a guide on how many layers of linen are needed? is 1 enough, should i do 10? is the magic number somewhere between? Is there a magic number?

[Sempertiger]

looks like I answered my question through the search function. Since the cloth doesn't add structurally to the bow, and exists only to keep splinters down, there is no reason to put more than a single layer.

[PatM]

I don't really buy that theory. Nobody seems to ever put on more than one layer to test that theory.
 A wood or bamboo backing is always put on with some reasonable thickness to demonstrate incrraased structural integrity. Why should linen be any different?
 As far as comparing rayon to linen, you have to at least test similar weight of cloth.
 No sense comparing heavy Linen artist's canvas with shirt material.

[Sempertiger]

I imagine it could be fairly easy to test. you would need to have say 3 different groups of materials being tested, using the Standard Bend Test, as described in TBB V1. one group with 3 or 4 wood sticks, one group of the same wood with a single layer of linen, measured to the same 1/2" square dimentions, after the linen is applied. Then a third group with the same wood and a measurable amount of linen backing, say 1/8" thick, with the same 1/2" dimentions after backing is applied.

I'm guessing that your theory, Pat, is that the linen backed pieces would react, in the same direction, as doing the exact same test with a so called "working back?"

sounds like a fun test, and if my assumption of you Theory is correct, I imagine that the test would prove that a measurable amount of backing  does in fact do more work than given credit for.

[DLH]

Would one piece only be used to cut down on weight since each additional backing would add more mass to the bow from more glue? I'm just guessing haven't tried it or anything though.

[Sempertiger]

This isn't my idea, but I'm applying it to this application. If the heavier backing does "work" then in theory, you could make a narrower bow for a given weight of pull, thus less mass over all.

I think I learn a lot by rereading the chapter in TBBV1 on design. I think there is a sentence where the author of that chapter says he doesn't care if a bow is made from good wood, bad wood or spaghetti noodles, if the bow is designed correctly for the material being used at the desired pull weight, then it should perform the same as a bow made out of anything else, provided the second bow is made with the same scrutiny.

JS

[PatM]

Yes, I think a linen backing could be made to basically simulate a bamboo backing. Really, how is it different?
 There is simply no reason to think that strong non-stretchable fibers set in a matrix should be different from the same material naturally occuring in the same form.

[Hrothgar]

I agree Pat, several layers of linen may not increase the poundage like sinew would, however the additional layers would add additional protection in preventing a bow back from blowing out. With the first osage bow I made I was in such a hurry that I 'decrowned' a couple knots. And not wanting to remove several more rings, I put a linen 'patch' over the knots then applied 2 more layers of linen over the entire bow. That was 10 years ago and it still shouts fine.
    I also have trouble buying into that extra weight thing. A person could apply 2 or 3 layers of linen and it wouldn't be as 'heavy' as a single layer of cow rawhide (or bamboo or hickory).
   In certain instances I have to think it is advantageous to apply an additional layer of linen to prevent a bow that is already 9/10 ths broken from becoming 10/10ths. JMO.