Q about fishglue and rawhide

[simk]

I just rawhide backed a yew. what is the minimum time to wait before unwrapping the rawhide?
 I'd like to go to bed as soon as possible...i took FISHGLUE. normally I'd probably wait 3-4 hours. thanks for advice!
cheers

[Pat B]

I've never used fish glue but with hide glue I remove the wrap after about an hour. The glue has gelled well and the wrap has smoothed it out.

[simk]

Thank you very much PatB  I thought it might doesen't take too long...good to know.

[simk]

it came off again  will redo tomorrow. maybe a little thicker glue and wait a little longer  🤔

[DC]

Fish glue doesn't gel as quick does it?

[Pat B]

How are you degreasing the wood? I scrub with Dawn and rinse just before adding the sinew. Never had a lift off since I started degreasing that way.

[simk]

DC: It's a learning process  failing for me is the most effective way of learning - I almost started to like it 😁

Thank you PatB: I sanded the back with 320 grit, then cleaned with acetone, then sized with thin glue... why do you degrease? what grease? Is there fat to degrease that comes from the wood (yew) itself or do we degrease only because of the fat that may is left from our fingers? I know certain woods, e.g. ipe, are greasy...but yew?

I think in that case I just didnt wait long enough - the glue was still liquid when I took it off again. I will use thicker glue because the rawhide itself always seems to soak a lot of water.

Cheers

[Marc St Louis]

Fish glue does not gel.  You will have to wait until it dries

[Pat B]

Hands and fingers can add grease to the wood. I've also heard that solvents can pull oils out of the wood. Don't know if that's true but since I've used Dawn and boiling water I haven't had any problems. The sinew backed bows I made before I used acetone and the sinew lifted.

[simk]

thank you for assistance and knowledge 👍✌️ 2nd try was morr successful. same process, drying time 5-6 hrs 

[JW_Halverson]

Sanding to 320 grit has also made the wood surface very smooth. After you clean up the old glue, degrease, go over it a few passes with super low grit sandpaper such as 50 grit or 80 grit. Don't go at it hard, but two or three passes down the length of the bow will give shallowgrooves that will fill with glue and create a deeper mechanical bond with the glue.

[mmattockx]

Sanding to 320 grit has also made the wood surface very smooth.

I would agree with that, 320 is very smooth as a surface prep for glue. I wouldn't go finer than 120 on something like this unless the glue manufacturer had a specific recommendation to go finer.


Mark

[simk]

thank you JW! I finished tiller and shot it a little. everything is fine even without wrappings at the ends of the rawhide  (yet). 320grit was mainly to get rid of last little toolmarks. didn't want to groove or sand that lovely holy back...doing so would have broken my heart. the rawhide is very thin and flexible so that I think there's limited strain...? is it really necessary to rough/groove the back? did you ever have properly glued rawhide come off?

[JackCrafty]

Fish glue has a limited shelf life in a liquid state. Maybe 3 months. Unfortunately, most fish glue sold does not have a correct expiration date.

Besides, fish glue in a liquid state is designed for musical instrument makers who need a glue that will "break" at the joints in the instruments when components need to be repaired or replaced.

In other words, commercial fish glue is not designed for permanent assembly.

If you make your own, or use the powdered variety (very rare), it works better.

[simk]

the glue is just fine jack. rawhide sticks where and how I want now. glued several lam bows with this glue. no fail. it was the false application only. unwrapped too early. cheers