Danehunter
Well-Known Member
INSTALLATION TIP (for foam filled stocks):
1.) drill proper size hole for mounting the cup
2.) using an awl make a "cone" shape in the foam
3.) Be sure the "cone-shaped" area is clear of all debris
4.) fill the"cone-shaped hole" with a good bedding epoxy or JB WELD
5.) insert flush cup and wipe off excess epoxy after the cup is fully installed
** If the cup is a limited swivel type (i.e. not 360 deg. swivel) be SURE it swivels in the correct arc and if not then turn the cup until it is properly lined up. (Do NOT ask how I know this.)
Making a cone in the foam stock is a way to make the epoxy wider than the entrance hole in the shell material so the epoxy anchor cannot easily be pulled out. It makes the shell material (carbon fiber, fiberglass, Kevlar, plastic) a "wall" against which the cone can bear instead of relying entirely on the shell material to hold the cup threads.
When I was a ski shop tech this was how we mounted ski bindings in skis (XC and alpine) if they had foam, balsa wood or honeycomb cores. Believe me, ski bindings put FAR more torque and pulling force on these holes than your sling should ever do and they hold very well.
You can use this technique if your flush cups ever pull out and need to be replaced. AND you can further strengthen repairs by using a thread-mating HeliCoil insert then screwing your cup base into the HeliCoil. This is when the cup pulls out and enlarges the shell material too much. It is a very common solution to this problem with skis and it is amazingly strong. Just be sure the HeliCoil or similar insert has inside threads that match your flush cup! Usually these inserts use an Allen wrench (that's larger than your flush cup threads) to insert them.
Is thisTMI?
1.) drill proper size hole for mounting the cup
2.) using an awl make a "cone" shape in the foam
3.) Be sure the "cone-shaped" area is clear of all debris
4.) fill the"cone-shaped hole" with a good bedding epoxy or JB WELD
5.) insert flush cup and wipe off excess epoxy after the cup is fully installed
** If the cup is a limited swivel type (i.e. not 360 deg. swivel) be SURE it swivels in the correct arc and if not then turn the cup until it is properly lined up. (Do NOT ask how I know this.)
Making a cone in the foam stock is a way to make the epoxy wider than the entrance hole in the shell material so the epoxy anchor cannot easily be pulled out. It makes the shell material (carbon fiber, fiberglass, Kevlar, plastic) a "wall" against which the cone can bear instead of relying entirely on the shell material to hold the cup threads.
When I was a ski shop tech this was how we mounted ski bindings in skis (XC and alpine) if they had foam, balsa wood or honeycomb cores. Believe me, ski bindings put FAR more torque and pulling force on these holes than your sling should ever do and they hold very well.
You can use this technique if your flush cups ever pull out and need to be replaced. AND you can further strengthen repairs by using a thread-mating HeliCoil insert then screwing your cup base into the HeliCoil. This is when the cup pulls out and enlarges the shell material too much. It is a very common solution to this problem with skis and it is amazingly strong. Just be sure the HeliCoil or similar insert has inside threads that match your flush cup! Usually these inserts use an Allen wrench (that's larger than your flush cup threads) to insert them.
Is thisTMI?
