Sinew Adhesion: How can I tell if it's good?

[WhistlingBadger]

My failed experiments with dogbane might have me a little paranoid, so I need opinions.  I've got one layer of sinew on a juniper bow.  Some of the sinew is obviously well-adhered, almost transparent and tight against the wood.  Other bits, I'm not so sure about.  They're opaque and pale colored.  It was a little cool when I put the sinew on, and I'm afraid some of the glue might have partially set up before I had the sinew down all the way.  I went back the next day, slathered the whole thing with thin glue, and wrapped it overnight...but these opaque parts still worry me.  Is there any way to know whether the sinew is really stuck on before I add another layer?

I really don't want to steam this off and start all over, but that would be preferable to putting on three more layers then having it come apart on me during tillering.  Thoughts?

[WhistlingBadger]

OK, I have a plan.  I'm going to cover the questionable spots with warm, wet wash clothes, then wrap that in plastic wrap for a few hours to re-hydrate the sinew and glue.  Let that sit for a few hours, probably overnight, then remove the wet cloth and wrap it really tightly in an ace bandage for a day or so, before letting it cure again.  I think that should do it.  Wish me luck.

[Marc St Louis]

You could hydrate it back up like you said and then use heat to liquefy the glue again, not too much heat mind you as you wouldn't want to cook your sinew

[superdav95]

Ive had top do the same before wb.  I did as you suggested and it worked.  I used an old t shirt cut into long strips about 2" for my wraps and then used inner tubing cut into similar strips about 1/2" leaving small gaps in wrapping.  I did as you did too with adding another layer of glue first and allowing it to set up to at least dry enough to the touch but not fully dry.  When wraps were done i noticed that i had to scrape off the excess glue fused to the t shirt.  it was a bit of a pain but my adhesion was very good and solid.  I suspect that when i laid down my sinew initially it was too dry perhaps or I didnt size quite enough maybe.  it may have been a combination of a number of things.  These days I make sure i do many size coats especially on bamboo.  I also make sure my temp is not too cool when laying sinew.  it gels too fast as it is so i use a heat source to keep it from setting.  I spend some time on smoothing it out during this time.  it help to get it stuck down good.  once this initial layer is down i then move it to somewhere cooler to slow down the drying. This is important to keep it from rapidly drying and splitting or creating inclusions or lighter spots that may not be as solid and transparent when dried.   little splits here and there will likley be fine but larger ones in the working areas could be a problem.  I think your plan of approach is a good one.  I dont know that i would use steam.  add a little glue and allow it to gel up and then wraps and heat.  most of my wraps were somewhat saturated with excess glue but did the job to repair.  As was said you wont need much heat to get it soft again.  best of luck!  keep us posted

[WhistlingBadger]

I didn't see Dave's and Marc's suggestions until after I did the deed, so I didn't do it exactly as you suggested, but it seems to have worked.  I soaked some wash clothes in hot water, wrung them out lightly, covered the limbs, and wrapped the whole in plastic wrap.  Let it sit like that overnight.  The sinew was nice and soft, so I wrapped it in plastic wrap and really tight ace bandages for several hours.

(The plastic keeps the bandages from sticking, Dave.  Works really well.  How, oh how, did our ancestors get anything done without plastic wrap?  Or zip ties???)

Everything looked a lot smoother, more transparent, stuck down really well.  Let that dry for a day, and yesterday put on another layer.  I had a space heater going in the room so the glue didn't set up so fast, and took some extra time to really smooth out the sinew, removing any twists.  Wrapped that up with plastic/ace bandage overnight, and unwrapped to cure this morning.  Seems to have worked nicely.

I plan to let that cure for a week, then add a strip down the middle to mound it up just a bit, then one more full layer and a snake skin.  Let that cure for a good month or two before I start tillering.  As Tom Petty said, the waiting is the hardest part...

[superdav95]

Good save WB!  Glad it worked out.