Posts by Don Paul

Quote from Ramon

Well guys, a friend professor at the University of Malaga I calculated the speed of the output shaft and the force or power in Joules, I think this hope I send the correct calculation formula.

So is 36 mtrs / sec. output speed, with a power or force of 463 joules, for fusil 105 > 1'40 flecha x 6'5 mm grueso

The theme would be better with a speed meter, but I have.

The elastic potential energy accumulated by the deformation of an elastic, releases a force equivalent to its deformation to recover its original state.

If the square equivalent to double the deformation force released.

;):)

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Ramon these were made 30 years ago.;)

Cheers, Don

Speaking of rubber... here are some multi dia hook ups from 30 years ago. Don't let Ramon know there is not much that is new.;)

Cheers, Don

Here is the 5/8s Primeline showing 60bs for the single band leg @ 350 stretch.
It looks like I'll go back to green dyeing some secret stash I have stowed away.;)

Cheers, Don

The scale bracket from bits from the junk drawer. I do pass some stout cordage between the handle as a back up.

Cheers, Don

Quote from Dan

I don't understand, is the green tape all that's holding the scale against he pull of the band?

You just read my mind brother, I was in the process of taking another image of the scale bracket (possible severe bodily injury) :nono: that hooks over the back. I'll post another image Mon for guys that want to take out teeth with a flying scale.:nono:

Cheers, Don

That is some funny ass shite.
I'm getting me some whiskey and heading for the beach.

Cheers, Don

Stretched the Acid Green Salvimar single band segment to 380% stretch for a pull of just 40lbs. so we are looking at 80lb per band from this stuff. That is about the same as I used to record with the cheapest dive store 5/8 thirty years ago. Other then the bright color I see no advances with this band material. My old rubber notes list the rubber I was sourcing (and testing) from France at the time making 132lb at the wishbone.
That is why this stuff felt so wimpy. Tomorrow I'll elongate it again and give it a 4hr soak and lb pull #.

What may work out on fly weight thin shaft euro guns shot by vegans with bent elbows, may not be the trick setup for US speros that want to kill fish at 20 feet. I bet I'm going to hear some one tell me the Acid Green is smooth shooting, with little recoil, well that is what the gym is for, turn that skinny vegan arm into a bar of steel to cock that manly gun.;) then you too will not need close stalking skills.;)

Cheers, Don

Quote from Brendon

So fresh water would work?
I was planning on taking it to the boat launch but the drive is about 30 minutes each way. Much more convenient to walk out the back door.

Salt water is about 1.025 g/ml @ 39 degrees F
Fresh is about 1.0 g/ml

Cheers, Don

Quote from Brendon

Is 42" of stretch a lot for bands? I thought this gun was pretty small..

A question about ballasting. Iso it stupid to attempt to ballast the gun in my pool? I know things float different in salt but walking out back to the pool is so much more convenient.

No prob....your not trimming out a 12 # tuna gun. You can also take it to a marina dock and bring duct tape and fishing wts.

Cheers, Don

All hail the home shop...where the smell of fresh wood chips inspire great times .
Your hooked now...this will be the first of many.
Nice work mate.

Cheers, Don

Such a shame thieves took that gun.:( You need to build another some day.

Cheers, Don

Quote from Marco

So, you didn't like the salvimar bands?

No, I'm giving the 10' section I have to a girl.;) ...but I'll save a piece to test this weekend and report back.

Cheers, Don

Quote from Asher

Yea I'm talking about the line wrap hooks, do they hold the line for the shooting line wraps?

Yes, you got it.

Cheers. Don

I always start on balsa or pine,;) Pin all the bits in line,

There can be some monster calico just inside a ledge up your way. I think open track will be good for you there.

Cheers, Don

Hi Asher, Bretto hasn't been here in a bit but maybe I can help if ya post a pix of the ''tab things'' . Are you talking about the line wrap hook?
I'm going to take a guess at the over hang at app 12'' plus the sliptip and adapter.
Cheers, Don

Welcome and thank you for your service mate. I have not spearfished on Hawaii but talk to my old friend, Brian Yoshikawa owner of Maui Sporting Goods (92 N Market st # A) he also has a dive shop now on the big island.
Tell him Neptune Don Paul says Aloha.

Mahalla, Don

Quote from sdeisen

That's intetesting to hear. Well some times you have to sacrifice a little performance to get that tomato & basil Italian look I suppose.

I now have 10' in-case I ever go back to a pole spear....come to think of it these Acid Green would be smokin on that new roller polespear.

Cheers, Don

I found a great band for chicks and roller gun guys. ;):bouncinboobs:Salvimar Acid Green 16mm. Any chick regardless of size should be able to cock this stuff at 380 stretch. This is also the band I would recommend for you wheelie gun guys. <img src= " height="23" srcset="https://spearfishing.world/forum/images/smilies/emojione/1f606@2x.png 2x"> Next week I'll get my scale from storage and see whats up, clearly it won't be shaft speed on my larger game gun.

Cheers, Don

Welcome, good to have you.

Cheers, Don

Quote from Brendon

After thinking more about the build, I've decided that an enclosed track is not a good idea for me. With wanting this to be a jack of all trades gun for a while, I fear shooting into a rock hole and blowing the end of the gun out.
With that said, how deep do most people cut the open channel for a 9/32 shaft?

If it's 9/32 shaft and 2 bands, just make it deep enough that the shaft doesn't roll off. I've had 6' barrel guns with only 1/8'' groove and the fish slayers in Tahiti have no groove.

Cheers, Don