Epoxy

[Buemaker]

Have anyone tried this epoxy for glass bows?

[Appalachian Hillbilly]

I use it for knife handles. Have not looked at it for bows?

[Mad Max]

Is it Flexible Bue?

[Appalachian Hillbilly]

Yes, that is one of the reasons knifemakers use it. It also has a long open time. Not brittle at all. EA 40 is cheaper by volume  though.

[Mad Max]

 

[Mark R]

Yes, I have used it on one bow, I had some extra material and wanted to try something new, I still have the bow and it shot good for over a year then looked like a spot under the clear glass by the fade, but no delam or anything appeared to get worse so not sure,  It was one of my first a 54" highbred with not alot of deflex in the riser fade so for my draw at 27" it's probly fine but I have a friend who has a32" draw and he's kind of like my tester and I wanted him to shoot it a bit to see what he thought, he liked it but I know now that the design was way to short for him, the bow still seems fine for me to shoot but I would'nt sell it or let anybody else use it. It was one of my first, it's 50lbs and the handle shape is a bit short but I can get used to it when I shoot it a bit. Other than the spot under the glass it still seems to be fine but EA 40 is a proven epoxy for bows so that is what I use exclusively. If I hear of others who have used it successfully I'd be a believer, like was already stated EA40 is cheaper by volume so no real reason for me to change.

[Mark R]

Also If I remember correctly its thinner than EA40.

[Mad Max]

What do you use over there Bue?

[mmattockx]

You don't usually want a glue that stays flexible, it will allow creep into the fades and other areas where there are stiffness changes. A glue that dries hard doesn't allow that to happen. If anyone wants to use West System epoxy the 105/205 combo is the one you want.


Mark

[Buemaker]

Max, I use Smooth On. The one I pictured in this thread would be easier for me to get. If not suitable for limbs I guess it could be used for risers.

[Mad Max]

You don't usually want a glue that stays flexible, it will allow creep into the fades and other areas where there are stiffness changes. A glue that dries hard doesn't allow that to happen. If anyone wants to use West System epoxy the 105/205 combo is the one you want.


Mark

Lots of people use smooth-on for bows and all bow flex

[mmattockx]

Lots of people use smooth-on for bows and all bow flex

They do, but the glue line sees hardly any strain at all due to it's lack of thickness so the glue doesn't need to be flexible. Does EA40 not cure hard?


Mark

[Flem]

I think Bob Burton used G-flex to build some convex/concave vintage Hill style bamboo bows.
I have used G-1 and G-2, which were made by a Canadian manufacturer originally, but are now made by System Three. Both were "flexible" epoxy and G-2 was marketed as a epoxy for the manufacture of sport equipment because of its elastic nature.G-2 is eleven times more elastic than EA-40! I use Smooth-On Epoximite 100, which is three times more elastic than EA-40, without issue.

If I had some G-flex, I would use it without reservation.

[avcase]

Two or three years ago, I was having a lot of bonding issues, so I created a large number of test samples using different adhesive combinations. I tested these in controlled destructive bend tests. I learned quite a bit from this!  Of the adhesives I tried, I found that the Gflex gave the best bond performance if I was bonding unidirectional carbon to unidirectional carbon, carbon to glass, or glass to glass. The thinner West System 105/205 produced the best bond to wood laminates. So now when I’m building a bow that requires the strongest bonds possible, I spread Gflex on the glass or carbon laminates, and 105/205 on the wood lams.  The two adhesives are 100% compatible with one another.

One possible reason the flexible epoxies work best to very stiff materials like carbon or glass is because it is forgiving of slight variations in the bond strength between the two pieces. It kind of averages out the shear stresses between the two high modulus materials.

I’m sure other epoxy products can perform just as well or maybe better.  In tension or compression, even the most brittle epoxy or glue should be able to handle more elastic strain than glass can handle.

Alan

[Mad Max]

Thanks Alan

[Buemaker]

Here is some info I found on the Gflex. Looks like it needs very little clamping pressure.
https://www.westsystem.com/wp-content/uploads/650-8-Instruction-v2.pdf

[Mark R]

I know most bowyers use EA 40 its a proven product, so no need for me to R and D something else. I'm curious what the bigger Bow manufacturers use if different from EA 40, might be some trade secrets.

[mmattockx]

The thinner West System 105/205 produced the best bond to wood laminates.

Alan,

Did you use the 105/205 epoxy as mixed or did you use any thickening agents? It is quite thin as it comes out of the can.


Mark

[Longcruise]

I know most bowyers use EA 40 its a proven product, so no need for me to R and D something else. I'm curious what the bigger Bow manufacturers use if different from EA 40, might be some trade secrets.

Some are using Huntsman.

[Buemaker]

Some use Huntsman TDR1100-11. I think BW use it.
Longcruise, we posted at the same time.