Silk backing questions and discussion

[Sparky Buckwheat]

Hello!  I'm new to this forum, however I started building bows about a year ago after watching bows being made at the North American Longbow Safari then learning how to build one on Sam Harper's Poor Folk Bows website (amazing build-along - Thanks Sam) and I am now totally hooked on the hobby/addiction. I have built 7 functional bows and had 6 blow ups.  I am amazed how much I learn when a bow breaks (Rule #1 - duck and cover!).  I have been scowering the online forums ever since reading the TBB1 backing section about Clarence Hickman and his stretched silk backings he was making back in the 1940's. I got a hold of some unwanted silk noil fabric from my mother in-law (raw, thick, short stranded silk fabric that looks more like cotton or linen) and I have managed to build a form using a ratcheting trailer strap that allows me to stretch the silk out during the glue up and I have made four successful bows (3 Ipe and 1 Red Oak) with it.  Interestingly, I used this technique and applied it to a hickory backing strip I used to attempt a Perry reflex bow and when I took the backing off the form after gluing the stretched silk on, the hickory strip pulled into a reflex.  I have read many opinions on the use of "silk" as a backing (it does provide tension and support as it is strong in tensile strength, it doesn't do anything because it stretches too much, linen and sinew are better, etc, etc.), however I am curious if anyone has experimented with stretching silk cloth on a bow as a backing and If so, what results were obtained?  Also, does anyone have any information/ experience on the various types of silk fabrics, fibres or wools (Noil, Charmeuse, Tussiah, Taffeta, etc...) and thier use in bow backings?  Most of the discussion I have seen on silk does not mention the type of silk used or the thickness. I have been using G2 Epoxy from System Three.  It seems to work well with the silk and if you are using a dye free cloth, the backing dries on almost transparent!

FYI - This post may be put on other bowering forums so if it looks familiar, it probably is me.

Thanks for your insight/input in advance!

SB

[Pat B]

I've used silk as backing on a couple of occasions but never drew it into tension before adding it. I just laid it on the bow like other backings. Silk makes a great backing but I doubt you'll get much performance from it. I did back an osage bow one time with a course black raw silk fabric and it is the only osage bow I've made that fretted, and it fretted the entire working portion of the belly. That tells me it overpowered the bow so I guess some performance could be expected from that type of silk backing.

[George Tsoukalas]

Yes, I've backed many a bow with silk and have stretched it by hand and put it down.
It will hold down splinters.
There's some info on my site. Jawge
 http://georgeandjoni.home.comcast.net/~georgeandjoni/index.html

[KellyG]

SB,
you cant start a topic like this and not give us pics of what and how you do it. Sounds interesting.

[Sparky Buckwheat]

Will post some pics soon.  Not used to this stuff yet.  Thanks for the replies

[Sparky Buckwheat]

So, here are some pictures of some of my silk experiments - hopefully I havent violated space rules with this.

pics 1 and 2 - My basic form - this was my first experiment with the silk.  The form is a 2x6 with a trailer tie down rachet on one end.  I just screwed the silk into the form using a piece of scrap wood.  I added clear packing tape to the 2x6 edge that the bow is clamped to as epoxy does not really stick to the stuff (although it does take some prying to get it off)  The second image shows the rachet.  I put the silk under tension before applying the bow and clamps.  The rachet seems to be under a lot of tension.

   

     

This is what the back looks like right off the form:

     

The next two images are of the finished back of the bow.  The bow is a 60" ipe/silk.  She pulls 35#@26" and was my 4th bow - it has been a very reliable bow and has put at least 1000 arrows out there.

   

     


Next are some pics of the hickory backing strip for my first ill-fated R/D bow that blew up due to a nasty hinge I gave it at the end of tillering.  The strip was flat before I did the stretched silk glue up.  When I pulled it off the form, it reflexed a little bit.  This is why I am asking if anyone else has tried this way of using silk as a backing... It seem pretty interesting to me.

     

     

     

I am just beginning my learning, so I am curious to hear feedback and input on this stuff!


Cheers!

[Wolftrail]

I have used silk a few times.  You are better off to use glue sizing first before you lay it down.  The wood color will come through the fabric.
And why use silk because its natural, this is a website of traditional archery use Nylon or Polyester its stronger than a silk tie.  The options are endless with patterns and colors. Fred Bear in his early days was using FG backing before going 100% FG.

[KellyG]

Well that looks awesome. I wonder what the different colored fabrics would look like. I also wonder if TBIII would work.

[Pat B]

Kelly, yes TBII works but the end result will have a brownish hue to it and it won't be as transparent.
Wolftrail, you really don't need anything as strong or heavy as nylon or polyester and both of them will hold too much glue, adding excess weight. They will work but the nice thing about silk is it is thin and strong and doesn't soak up too much glue.
 Brown grocery bag makes a good baking too and is plenty strong enough once you add the glue.

[Wolftrail]

Originally posted by KellyG:
Well that looks awesome. I wonder what the different colored fabrics would look like. I also wonder if TBIII would work.

I have so far only used TB3 but my next step is to use G2 epoxy.  I have heard stories about creeping using TB.  In the long run Epoxy must be the long term solution is it not.

[Sparky Buckwheat]

Kelly,

In regards to other colours of silk, I actually just finished tillering a 70" Ipe/Silk pyramid bow for my friend.  I ran out of undyed silk so I only had a pink silk noil in the correct length.  I was a little worried as the bow is for a man, but as you can see from the picture the colour is a nice, deep maroon after the epoxy (no finish applied).

     

I am quite happy with how the bow turned out, it still has to be final sanded and finished, but it pulls 47# @ 32".  He is a giant British guy, so he has a long draw.

   

   

I also have a dark blue silk, but it turns BLACK with the G2 epoxy.  I have not tried TB3 yet.