Flattening sinew?

On the sinew backed wood bows i've made i've had good results from a very firm burnishing. No fibers are cut through when you do this. I use an extension bar from a mechanics socket set - round easy to grip and very hard or you can use a glass jar.

I tried compressing the gelled sinew layer, but I was not very successful. It caused parts of the backing to slide sideways. Maybe I should have waited a full day before doing it.

I've made it just on wooden bows yet, but saw it in a korean hornbow film.
It works but have to wait for the white color appears and it start to be hard (have to experiment the perfect time for it). Than have to press it strong with bone or glass. It makes the surface flat and shine but not as perfect U wish. Anyway after this schould fill it up with less glue :wink:

When sinewing, I prepare strips of the thinnest available plastic bags. The thinnest here are from laundry bags and produce bags. After applying the sinew, it is covered with strips of the plastic bag. You can continue to even out the sinew through the plastic like clay. The plastic is pulled tight over the wet sinew. Now it will dry evenly as the wood and or previous sinew absorbs the moisture. After about 8 hours, the plastic is peeled off and allowed to dry a little and is then reapplied this time lightly to allow some air to come under.

Some hours later it is again peeled off, inspected and the plastic laid lightly on top of the sinew to keep the drying slow and even.

But a word of caution. If the process is kept too slow, mold will start to grow which is very detrimental.

You will notice that even if the sinew is half dry already, by applying these plastic strips, the moisture content becomes more even and some shaping of the sinew can still occur.

If your technique is good there will be no cracking and the surface will be smooth and even.

Thanks for the advice!
I have thought about using a plastic film instead of the inner tube for wrapping because it is transparent so I can see if something goes wrong. Shaping it beneath the plastic sounds like a better idea. I will try it!

Daniel

I should have said that the plastic is not wound around the bow but just stretched over the surface of the wet sinew. The thin sinew at the edges dries first progressing to the thicker part on the back.

I am very soubtful about the good sense of using plastic bags,
Traditionally the best solution is once the sinew and glue have dried to the touch wrap the sinewed limb with natural fibre string compressing the glued sinew onto the core. The natural fibre will not impede the drying of the sinew backing while the clamping effect of the binding will improve the adhesion of the sinew to the core and may even have aslight wicking effect drawing moisture out. I have read that glued sinew can rot if not dried sufficiently.

Rgds,
Luke

Luke; Is this something you have done? I would like to see a picture of the result.

My technique is not based on a theory but on experience. But what works for one is not always what is good for another.