bamboo backing: wood glue or epoxy?

[AndrewS]

No question - but another thesis:

the epoxy is for laminating, but first for laminating glas, carbon and so on. It is also ok for wood/wood laminations.

Some kind of resorcinol is used for laminting wood to waterproof multiplex wood boards, other kinds are resistent against salty water and are used for wooden boats. Also some kinds of resorcinol are heat resistent until 170° / 180° C ( 340° F/ 355° F) and some kinds are good for that all.

In my personal opinion resorcinol is best for wood / wood.

... and hide glue (may plus a wrapping of sinew, rawhide or thin bark) is the traditional way.

[HH~]

Ok, i will play

For laminating WOOD!

H.H

[AndrewS]

First play with your computer and read something about the different glues....


Epoxy is a plastic resin. It can be used in many ways - as an adhesive, as a coating, for almost all materials (concrete, stone, steel, wood, for flooring) and as an adhesive matrix for modern fibers (glass, carbon). It does not swell and is therefore not joint-filling, it needs heat to cure optimally but it resists heat in the cured state only to a limited extent.

Cascamite is a urea adhesive for exterior wood and also for boat building.  Cascamite has a light glue line.

Resorcinol is an adhesive especially for woodworking / structural woodwork (especially for exterior woodwork, boatbuilding and construction with resinous and oily exotic woods) based on resorcinol and phenolic resins with formaldehyde. Always easily recognizable by the dark (red or brown) glue line.
Recorcinol glue is easily joint-filling and very resistant to high temperatures.

None of these glues are made specifically for bow making, because the market is very small after all.
For laminated bows made of modern materials (wood core, glass and/or carbon backing and facing), epoxy has established itself as the universal glue.
Cascamite and Resorcinol are only optimally suited for wood and therefore also for wood/wood laminations (professionally for waterproof glued multiplex boards (screen printing plates)). 

I have the best experience with Resorcinol myself and it is my first choice for glueing wood. It is gap filling and I can temper the bow with the heatgun after glueing without porblems (with epoxy I have had often problems at this point). The open time of the Resorcinol I use is 90 minutes and thats optimal if you had to fix the lams by clamps.

I have no experience with Cascamite so far.

I also have experience with Epoxy and in my opinion it is not as good as Resorcinol for wood/wood joints.

[HH~]

Thats all well and good here in USA we big companies who make all kine adhesives. Some make two port epoxies that were designed for all sorts of laminating ie putting space shuttle tiles on (yeah we go to space a bunch) anyWho's. Where was I? Oh, yes, after producing these adhesives they have some that were found to work very well with wood Lams or porous materials, (wood, glass, some ceramics) some have charracteristics that work well with laminating. One is they do not shrink .0001 or less when cured. . . . . Ding Ding Ding and they were found by bow makers to work very well. I'm sure you'll send data spec sheets for us and tell us whats best for even big bow Companies like Black Widow and Bob Lee. I know what they use and it works.

Oh yes, to be clear as to your old PM to me,   HH~ does not refer to Heil Hilter

HH~

[Marc St Louis]

Thanks to you all!
I have tried to laminate once with pva before ( gorilla ) and the bamboo delaminated... i suppose my glue line was not perfect as i don t have the tools to make something neat. so ill try epoxy this time (west system). my glue line again is not perfect but still quite decent really. it will hopefully keep things together.

I wouldn't use the Gorilla pva glue for anything but simple low stress gluing as it is low quality

[bassman211]

Smooth on has never failed me. It is my go to for all my glue jobs pertaining to bows. Even tip over lays. Until it does fail I have no interest in trying any thing else. If it works it works.

[AndrewS]

Thats all well and good here in USA we big companies who make all kine adhesives. Some make two port epoxies that were designed for all sorts of laminating ie putting space shuttle tiles on (yeah we go to space a bunch) anyWho's. Where was I? Oh, yes, after producing these adhesives they have some that were found to work very well with wood Lams or porous materials, (wood, glass, some ceramics) some have charracteristics that work well with laminating. One is they do not shrink .0001 or less when cured. . . . . Ding Ding Ding and they were found by bow makers to work very well. I'm sure you'll send data spec sheets for us and tell us whats best for even big bow Companies like Black Widow and Bob Lee. I know what they use and it works.

Oh yes, to be clear as to your old PM to me,   HH~ does not refer to Heil Hilter

HH~

Sure, BW and Bob Lee use epoxy to glue their fiberglass laminates to backing and belly, what else.

Not sure if I will send any data sheets....

Also, I'm not sure if the epoxy was developed by aerospace and rocket scientists in the US. I think epoxy was developed by Paul Schlack (Germany) and Pierre Castan (Switzerland) in 1930s, but that's another topic...
Today, epoxy is produced worldwide by various companies.

As I have written several times, epoxy also works for wood/wood joints.
However, there are adhesives that work better for me, that's all.

I have had laminated wood bows (several laminates Osage with a backing of bamboo) from American bow makers with the dark glue line typical of resorcinol glue. That was in the 1990s.
As far as I remember Urac was quite a popular glue among bow makers at that time ( Didn't Dean Torges recommend it too?).
I don't know if it is still in demand today, or if it is even produced today?


And sure I will not call you little Adi in the future....

[Dances with squirrels]

I believe Urac 185 is now Unibond 800.

I've used them, and liked them.... Resorcinol too, but I liked Resorcinol for Z splices under the handle leather where I couldn't see it. I like invisible glue lines. But Smooth On ea40 works fine for splices too. Smooth On is great for wood to wood, wood to glass, wood to horn, and more. It's my go-to glue for bow work, except for special occasions where hide glue or thin viscosity CA is more appropriate. I got tired of having so many different glues around, some going bad before I could use them. No such worries now.

[HH~]

Yep, bier, H Bombs and jet engines.

Glue not so much... 

HH ⚡️⚡️

[AndrewS]

@HH~

All right, I know you know where Barthel gets it


P.S. A guy named Otto Hetzer from Weimar has developed the casein glue at the beginnning of the 20th century (that was a revolution for wood construction)
... epoxy has developed in 1930iger in Europe (Germany and Schwitzerland) and resorcinol  glue has developed in 1942 in the USA....

and cause that's the fun of life: beer is not german innovation. I think the Sumerians and Egyptians
 have had beer a few thousands years before.....
but since 1862 The company Merck from Germany sells Benzoylecgoninmethylester (Cocainum) developed by  Albert Niemann (Göttingen, Germany) or a german guy named Friedrich Gaedcke. May be this was the stuff that make Coca Cola famous...
And since 1898 Bayer sells diacetylmorphine that is developed by the work of the british Charles Romley Alder Wright and Felix Hoffmann (Bayer) - this is the stuff for heroes...

last but not least: moreover, i believe that national socialist coding is recognized as such in the u.s. as well.

[Tommy D]

Does anyone who does use epoxy resin to glue backings add any fillers? Like microfibres? I know that it is often recommended in wood boat building applications to do a clear coat of the two mating surfaces (preferably after they have been warmed slightly so the absorb the resin) and then a thin “mayonnaise” consistency of epoxy mixed with a filler is added. Obviously this is helpful where mating surfaces aren’t perfect, but I wondered if it adds any strength. One issue with epoxy believe is you can apply too much pressure and have a dry joint.

Would be interested in others experiences?

[PatM]

That is for when you are bonding when using  an epoxy not specifically formulated solely  for bonding.  It's thinner and more geared for the process of laying on glass and coating.  You certainly can add thickeners and use it for gluing backings.  DC on here did that for all his bows.

  The epoxies typically used for gluing on backings by most come pre-thickened and need no additives.

[Tommy D]

  The epoxies typically used for gluing on backings by most come pre-thickened and need no additives.

Thanks - somewhere on Primitive archer I read someone post that these “thickened” epoxies are not as strong as the unthickened versions. That’s why I was curious.

[HH~]

The advantage to the two part adhesives is they do not shrink during curing. So if you have a small variation in a glue line as long as you fill it and its not right in fade it will fill that void. With a wood glue it shrinks a CHIIIIT Ton. Have a bad glue line your asking for a problem right off.

Hedge~

[PatM]

  The epoxies typically used for gluing on backings by most come pre-thickened and need no additives.

Thanks - somewhere on Primitive archer I read someone post that these “thickened” epoxies are not as strong as the unthickened versions. That’s why I was curious.

 Not enough to worry about if true.