Flax backing re-visited

[KenH]

There have been several previous discussions on flax backing bows.  But all of those discussions dealt with straight bows or at most mildly reflexed designs. 

Has anyone flax-backed a seriously reflexed design like the Akkadian gull-wing design below? 

[Onebowonder]

Never have tried FLAX backing - but I'm curious and will be watching the thread, pardon the pun. 

...which makes me ask, when doing a FLAX backing, do you use Flax fibers, thread, or fabric in an adhesive matrix?

OneBow

[KenH]

Combed flax fiber, not twisted thread or woven linen.  At least in flat-ish bows it can add 10-15% to the draw weight.

[Tuomo]

I have made some flax fiber backed bows. It is very good backing material in straight bows but not suitable for radical designs in my opinion. Remember, flax is stretching only about 1-1.5 % - a bit more than wood at best. I have broken a few flax backed bows, which were bending too much – I just wanted to test what flax can tolerate. But I think you should try!

Flax fiber backing can add quite much draw weight. I made a test: I had white oak bow, 36# @ 28” and I glued 30 gram flax fibers with hide glue. After drying the bow was 53# @ 28” – that was almost 50 % increase in draw weight.

[KenH]

Would you use hide glue?  Or TBII?   Why?

[Tuomo]

You should use absolute hide glue, or any other animal glue. Glue flax just like sinew - make about ten bundles, comb them, soak in glue and put in the back of the bow. I tried TBIII but it did not work. Hide glue was very easy option.

[paco664]

where is a good place to get the flax fibers like you guys are using?

i found some yarn made of ramie/bamboo/flax and used it to back a board bow that lifted a tiny splinter... used tb2... let dry for a week and a half and then tried my darndest to break it....


i couldn't...

[Tuomo]

I am using plumbers hemp - easy to get almost everywhere and usually very good quality for bow backing.

[paco664]

I am using plumbers hemp - easy to get almost everywhere and usually very good quality for bow backing.

thank you kindly!!

[PatM]

I don't think plumbers in North America use the same stuff as plumbers in Europe.

[KenH]

I purchased flax "stricks" from an online shop selling all sorts of knitting/weaving supplies.  Do a search on "Flax Strick"...

[mikekeswick]

Remember that flax is very resistant to stretch and will therefore put quite a load on the belly.

[KenH]

That's what's got me 'worried', Mike.  With that much curve I'm afraid more than just a little flax will overpower things.  I'm thinking to flax the set-back handle area out to the start of the 'shoulder' curves, and let the outer limbs alone.  I'm going to start with just a thin layer and see what happens before thinking about adding a second layer.