Flesh Side Fuzzies And Glue

[Tiara]

I want to glue a caiman backstrap to some veg tan, flesh side to flesh side. The caiman has quite a bit of fuzz on it. I removed a lot of it with a wire brush but don't know what would be an optimal amount to leave prior to gluing. How much should I sand off or would it be better to singe off? I plan on using Weldwood gel with 2-3 coats on the caiman and 1-2 on the veg tan and letting dry in-between.

[Dwight]

Tiara, . . . I'm sure you have a good logical reason for doing so, . . . but why so many coats of contact cement?

One coat is all that is needed, . . .

As far as "fuzz" is concerned, . . . if I can cut it off with my scissors, I do it, . . . sometimes lay my big ugly round knife down on it and drag it along, disconnecting what I can, . . . but unless the fuzz is big enough and ugly enough to make a lump, . . . the contact cement or the glue will grab it, and keep it in place.

Take all said above with one more piece of understanding, . . . I've never worked with caiman, . . . a couple of cavemen, . . . but never caiman

May God bless,

Dwight

[Cyberthrasher]

I've only worked with the lizard scrap I have, so I don't know what it all is and if it matches the caiman. I do, however, end up with some pretty stringy stuff both there and on some cheaper cowhides. I do just what Dwight says when there's fuzz and string on it. If it's not enough to bulge, just leave it instead of making more work for myself. If it needs a haircut, shave it off with a knife or something. The contact cement doesn't care what's there, why should you

[Tiara]

Hi Dwight and thanks for the reply.

My reason for 2-3 coats on the caiman is that the other pieces of it I've worked with suck up so much of it that one coat on each piece didn't seem to give good grab. I watched a video on Springfield leather's site describing how 2 coats, with dry time in between gives a more secure hold. The other caiman was from a different hide that was rough but not fuzzy and with a firmer texture and still sucked up a lot of the Weldwood.

The fuzz is probably 1/4 inch long for about half of it and an 1/8th inch or less for the rest. Enough of it that I wasn't sure if it would weaken the bond when it's flexed. I think I'll take most of it off.

[Tiara]

Cyberthrasher,

My late husband was an engineer specializing in composite materials. The fuzzies if long enough and enough of them are going to act like an aggregate. Roughing up smooth leather before gluing is often recommended. How rough becomes too rough? In any project my husband and I did that involved a composite material, which ranged from pouring concrete with both sand and gravel in specific ratios to the mud and reinforcing with rebar, the amount of filler ie the fuzzies to the bonding material made a difference. The bonding material didn't care what it bonded to but the effective strength in shear and compression forces made us care.

The fuzzies might give a good surface to glue ratio and add some strength to prevent separation or might weaken the bond by tearing themselves. Since I'm not yet familiar with the properties of the materials I'm using, asking those who are experienced seems sensible.

[Cyberthrasher]

don't worry, nobody's knocking you

The fuzzies themselves act as a "roughing up" to give the glue something to adhere to. But, at 1/4" you'll probably want to shave it down. I watched that same video from SLC, and you what they meant was to let it sit for a few minutes so it's dryish (tacky) and then add another coat, which will re-activate your glue you already have in place. If you let the first coat cure all the way, then you're effectively just gluing to the glue. I've had mine get sucked up pretty bad when I was gluing to some foam, so I just added more on the first coat that was applied to the foam and it's held in place pretty solid.