Hawaiian sling cup/butt is breaking

[Karo]

Hey guys.
I new to spearfishing. I do shoot a slingshot, though.
I made a Hawaiian sling so I can enjoy slinging under water too.
The problem I'm having is that the cup/butt (plastic) keeps breaking.
I made one out of aluminum and it gets deformed.
I guess the reason being is that the butt is pulled straight towards the barrel by the elastic.
Is it just the way it is?
Any help is greatly appreciated!

 

[Karo]

Ok, I see there is not interest to help a newbie.
Feel free to delete my account.

 

[Apneaddict]

Sorry to see you leave.

 

[Northspear]

Hi there,
I know this thread is fairly old and the member OP probably gone. Still I do have the same problem, the cup holding the spear of my sling keeps breaking. I tried wood, hard plastic and even rubber. My last idea would be ironwood as the handle is, or metal. Do you guys have any suggestions how to solve the problem?

 

[Northspear]

I'm back with a couple of tests and after a trip to the hardware store and looked for alternative for the cup. I came up with a kind of nylon spacer as advised in other threads concerning diy Hawaiian slings. In my case it's a hose connector out of hard plastic.
In addition I lenghthened the rubber a bit, this did help, too. A second advice is not to dry shoot the sling without the spear. The cup gets too fast and is not slowed down by the mass of the spear and gets destroyed by the handle rear no matter what material! (Somehow I was too excited about my diy project and had to test it in every way, not adviseable...)
For further readers with the same problem try those options, they might help you, too!

 

[cdavis]

Odd problem. I've shoot a sling for years and never seen it. Just some ideas, Does the shaft fit the cup reasonably well? Maybe you are seeing some side to side stress? When the spear diameter is well matched to the cup, plastic works fine, although metal is more durable. Dry shooting I've not tried, sounds like a good way to nail you fingers. Can you post some pics?

You can order cups sized to standard spears, they are cheap if the shipping is reasonable.

 

[Northspear]

Hey,
Thanks for your reply. I added some pics in my gallery, don't know really how to insert them here in the thread.
I used a 8mm drill, the spear itself is 6.25mm and 140cm long. The spear fits perfectly in the new cup.
I cut the handle out of a single piece of ironwood. The bars coming up at the front and rear and are supposed to be used as a flashlight holder. I rigged the rubber the way you recommended it in other threads and it works well. I'm going to add a ca 3 m mono line to spear and handle, since the water here is quite murky. If you have additional suggestions I'd love to hear them!

About the fingers try shooting: I can sing a song about that one, you just do that once.....

 

[cdavis]

I like your shooter. The bands do look short. I'll assume you are stronger than me. General guideline, you should be able to draw and hold the draw without serious strain, shaking, etc for about 30 seconds.

The cups look fine. The plastic might be a little light, but the wood looks fine as long as its good wood and the spear fits well. I'm mystified on your problem.

 

[Northspear]

Thanks for your comment. 30 seconds should work for me. My fear is, that the rubber might be too weak to drive the spear. Now with this set up the spear flies and punches with force around twice to three times the spear length. Gotta try that in the water soon!
I believe the reason for the cup breaking was my own stupidity shooting it dry and without the spear....
I will upload a picture with the spear as well.