Posts by Don Paul

Quote from red tide

Don,
You and I have come to the same conclusions and we have never met or dove together. I say " Learn to hunt and the shooting is easy." Shooting a speargun is like shooting a shotgun - Point and shoot, don't aim and shoot. The only fish I have ever hunted that needs more than two bands is a big tuna and that is because you need more power to shoot through the fish. 30 foot shots are for dreamers and should never be taken.
Cheers,
G.R.

Hey G.R. you guys use guns...

Here I am crazy enough to pull the trigger on 6 hot bands and no cup holder:@

Quote from Dan

Seatec huh. That will raise the price of a spear. Weaken the shaft in a high stress area too.

I'll just shoot with no flopper and aim for complete pass through/use the whole spear as a slip tip <img src= " height="23" srcset="https://spearfishing.world/forum/images/smilies/emojione/1f606@2x.png 2x"> Naw, I think the flopper can actually help balance out the spear, and you can make the spear go around corners by bending up the tip <img src= " height="23" srcset="https://spearfishing.world/forum/images/smilies/emojione/1f606@2x.png 2x">

When you stone the fish it won't matter if you stress it. and yes I tune my Tahitian shafts this way.
Don

Now that were all diving deep and getting close to our fish. Here's a example of a straight shooting low drag
flopper.

I love to see you guys thinking about these factors.I have a very close friend (John Warren) who worked with Bucky Fuller. John and I designed and tested in pools for 25 years. Another great speargun mind is a friend known as Popgun Pete. I have major issues with typing so please don't ban me if I don't contribuite
allot of data. All my reports were hand written back in the old days. I would like to stimulate your young
creative minds, this is what your new blood can do for our sport.
The most important thing I can tell you is buy or build a gun that shoots well, then keep shooting it until
it is a part of you and your mind. Aim to kill fish or brake the spine, shoot it well and you will develop confidence to make kill shots.With enough water time you may never try to sight down your gun barrel agian.You will see the fish's form. extend your gun and pull the trigger as the shaft later finds is mark.
Invest in your staking skills and safe bottom time as much as in your gun technology. work to get closer rather than add more power and range.
I will be happy to try to share a little of what I have learned about guns a little at a time.
All the best, Don

Quote from Dan

Don, thanks for the warning, I'm reminded how the structural integrity of the handle could be compromised. That cut out is for the original line release which I didn't like. Still this handle has a lot of meat, it's very solid, it's not a plastic shell.

As Val Kilmer once said; '' Ive seen things.... you people wouldn't believe''......

Quote from Marco

You forgot to mention woobling, which I think is VERY important.

Marco, a good word for this is called Spline Cycle, it occurs in archery as well as our sport.
Cheers, Don

Dan, I could not see the power band on this gun so I don't know how stressed the handle is.
If you drill another hole for another pin please be careful not to reduce the structural integrity of the handle
under compression loading. It looks like a rectangle cut out is close to your pin hole, vector cracks could lead
to catastrophic failure of the handle when loading leverages are high. Chicks dig scars but some times
holes in the chest or abdomen are too painful.;)
Cheers, Don

Quote from hau

Tin Man---IMO, tapering the bands does make a difference.
1. I cut and grind the ends of my bands as much as is possible. I do not know anyone that trims their band ends as small as mine.
2. IMO, another item that is important to spear speed and flight and accuracy is the shooting line itself. I think that how much the line effects the spear becomes very evident the first time a spearo freeshafts. I know that freedivers do not freeshaft, but I was just mentioning freeshafting to illistrate factors that effect spear flight. This is just my opinion and not to advocate that freedivers or anyone else freeshaft.

Your on it mate.
Don

Quote from Tin Man

Does tapering the ends of the power bands have a beneficial hydrodynamic effect then? It's a much larger area than the end of the shaft, multiplied by several bands. But only over the band stretch length, and not the entire shot distance.

Yes, salt water is almost 900 times denser than air, I used to shoot threaded articulated wishbones
in the late 70's with one 17mm band. I found that after I ditched the ''sea ancors'' and ground long tapers
on my band the speed on my test gun shaft increased by 2 meters per second. 50MPH is 22.35 Meters
per second FWIW. Some Italian gun builders scratch their heads at the bundles of poorly constructed
power bands and thick rope wishbone some sell. Here in the US we sometimes keep adding HP rather then
design the car body to have less drag. Same with our guns.
Cheers, Don

Brett I looked back on some of my old gun notes. One of my poured (open)tracks on my guns is West graphite
#423 and the mix was 30%graphite and 70% MAS slow cure Epoxy.I waited 72hr before milling.
The graphite makes the epoxy more brittle at higher graphite ratios. I need to go back and read your build
to see if your going ET or open deep rail?
Cheers, Don

Quote from Dan

I've had these wishbone inserts in and out of salt water for a week now and not even a little stain, so they're truly stainless steel.

Don, what about your mod?

I'm sending you a package at the end of the week.
Don

Top of the Morn Brett, I'm off to grab a cray in this cold Cali water, back at you latter. Do you have your
graphite particulate yet?
Cheers, Don

One more.

Here's a reworked shaft.

Here's one more showing the line release. I don't have any of the muzzle yet.
Don

Here's another line release on a target gun.

Quote from hau

Don Paul--Personally I am going to continue using the same (2) 9/16 bands that I currently use with my RA 120cm rail barrel for this 120cm ET barrel. IMO, it is very easy to overpower a pipe gun and adding power is NOT one of my reasons for designing this ETPGB.

Another item to consider is that this ETPGB is going to be HEAVIER than almost any RAIL barrel.
1. Good==because the felt recoil, barrel flex and muzzle flip will be decreased with the added barrel weight.
2. Bad===because the ETPG MAY not float enough for some spearos in some applications. (Like me with a reel AND UW cam).

Thanks hau, 2- 9/16 at 300% elongation will not over power a 7mm shaft of 17/4 ph shaft with fixed flopper.
You will need slightly more power as your shaft will be dragging a bit of water behind the tail, this will be dependent of track slot width and any boat tailing applied to the shaft.

Cheers, Don

Quote from hau

sdeisen---IMO, I think that many here would agree that the worst case REAL LIFE senareo for an enclosed track gun is when the shaft is fired and the shaft hits something solid before the shaft TOTALLY exits the enclosed track. IMO, this is when the enclosed track is stressed the most and when most enclosed tracks tear out. What that means to me with this 120cm ETPGB is that I cannot shoot the ETPG towards any hard coral back stop LESS than 40in from the end of this gun without concern for the safety of the ET.

What size bands and how many?
Don

Just spent the day with my boy at the beach. Now I'm alone drinking Irish Car bombs.
One half pint Guinness
One shot Jameson
One shot Baileys
Shoot it fast.... and don't let the shot glass hit your teeth.

Merry Christmas Happy Holidays and Happy New Year !!!
Cheers Don