Sturgeon skin adhesion issue

[Kidder]

So I attempted a sturgeon skin backing for the first time. However i got really poor glue adhesion and I’m looking to figure out why. The issue appears to be that the glue didn’t adhere to the back of the bow but did adhere to then sturgeon skin. The only thing I can think of is that somehow the die I used on the back of the bow isn’t compatible with the glue. I used TB3 for glue and fiebing’s pro dye to dye the wood. Thoughts?

[Gimlis Ghost]

Did you leach out oils from the surface?
Trisodium Phosphate (TSP available at paint and hardware stores) solutions will draw oils out of wood. I use this to restore oil damaged furniture and gunstocks. With surface oils removed glues and finishes better penetrate the wood.

[Pat B]

Is that Feibing's leather dye? Antique dye?

[Dances with squirrels]

Some things that come to mind... how were the gluing surfaces of the wood and sturgeon skin prepped? Sturgeon skin is oily and should be degreased. Did you do that? How? After dying the back of the bow, did you allow it plenty of time to dry? Did you check for and remove excess dye residue? Was the skin dry, wet, or damp when you glued it on? Did you size both surfaces with glue and allow it to soak in and dry for a while before applying a fresh coat of glue to both pieces again just prior to laying the skin on? Was there excess glue squeezing out the sides as you worked the skin down against the wood? Did you wrap it? If you didn't wrap it, how much extra skin was sticking out past the sides? How long did you let it dry? How and when did it come loose? As it dried? Afterwards, when the bow was drawn? Keep asking yourself those kinds of questions and the answer might come to you.

The glue may not have been the problem in your case, but I prefer hide glue for sturgeon skin.

[Pat B]

The reason I asked if it is antique dye is that it is a thick paste that could prevent adhesion.

[Kidder]

Is that Feibing's leather dye? Antique dye?

It’s Feibings pro dye leather dye. They have two different ones. I had thought at one point this was oil based dye but the ingredients show alcohol based if you zoom in on the picture. The issue is also clearly one of adhesion to the back rather than the skins. They’ve basically peeled right off with all the glue left on the skins and none on the back.

[Pat B]

Why dye the back. Aren't the sturgeon skins opaque?

[bownarra]

You have to be careful about dyes and glues. Ask Titebond - they will know

[Kidder]

Why dye the back. Aren't the sturgeon skins opaque?

They are slightly opaque. Dying the back black really darkens the look and makes the scales pop visually.

[Pat B]

Any time I apply sinew, rawhide or skins to a bow I scrub the wood with Dawn and warm water and rinse with boiling water and wash the backing with Dawn and warm water and rinse with warm water. Oil in the hides or sinews and finger prints and natural wood oils can cause adhesion problems.

[PaSteve]

What Pat said. I used to use lye to clean the back but now use Dawn dish soap because it's much easier to work with.

[Gimlis Ghost]

If anyone wishes to try TSP for any reason the method requires painting the surface with a strong solution of TSP and water, enough to soak into the surface. As the solution dries the TSP re crystalizes drawing fat molecules into the crystals. Rinsing away the crystal with water or simply brushing them away with a dry brush completes the de greasing process.

If one wished to get really primitive, in medieval times they used human urine which was left to age in a iron pot, the resulting liquid is high in Oxalic acid (Wood Bleach).

PS
You might try using Accraglass fiberglass bedding compound. It comes with small packets of concentrated brown and black dye. A thin layer acts like a powerful glue. Normally a little oil in the surfaces don't affect the bond.
Only the tiniest pinhead of the dye is needed to color the compound.

[timmyd]

I used that dye on my last Osage self bow before gluing snake skins. I used TB3. Sized the back and the skins first and I had no problems with adhesion