Carbon Fiber Speargun Build step by step

[Black_Reef_Co]

I think my next build will be a multi stage loaded roller.

I guess the only draw back that this design may potentially have is
1. a very short band unless rear rollers for top deck of the gun is used, because a roller is 1 to 1 pull on the top and bottom if the top deck is not used you would need a rather large butt for the rubber to anchor onto.
2. because of the 1 to 1 pull on top and bottom the starting point for the rubbers on the bottom deck of the gun has to be inline or less than the connection point of top line to shaft, guess you could call it the ready to shoot position.

I think the two reasons above is the biggest problem with these guns as if you wanted to use this system you need to place the rear roller ideally behind the notches on the shaft because if you don't the rubber will not be on the rear roller when the gun is not cocked making it a pain to load, but because you want lots of force transmitted into the shaft over a period of time you cant just just pull the cords onto the rest tab and shoot.

@Black_Reef_Co looks like your guns solve these problems with a larger butt and larger loading handles? also i can see you designed the guns specifically for this system especially the origami range where the bands are hidden and will not interfere with holding the gun and maybe potential rubbing of rubber on the hand when shot. potential ouchie if your not wearing gloves?

Correct. A band inversion is somewhat needed at a specified barrel length. But then again you lose performance and somewhat defeat the purpose of the design when you invert bands around another wheel in the back. Given, there are other benefits to the rear wheel set such as reduced recoil. But above all, my design is an alternative for snapping wishbones on a wishbone riser. A good challenge I recommend would be to pursue/create a new method for protecting the longevity of a roller wishbone. Alemanni does this by having a crescent riser with smooth edges. Couple other companies have done similar, but few have innovated.

It's been about 3 years of R&D into my optimized designs with an array of different manufacturing techniques. Of which a design patent is definitely in the works for. But I truly despise band guns to begin with and plan to pursue a new route soon. Simultaneously Ive been trying to steer a few others[manufacturers] in the same direction to bring some sort of standardization when the time and newer alternative is proper.

 

[GRAPHITE SPEARGUNS]

Correct. A band inversion is somewhat needed at a specified barrel length. But then again you lose performance and somewhat defeat the purpose of the design when you invert bands around another wheel in the back. Given, there are other benefits to the rear wheel set such as reduced recoil. But above all, my design is an alternative for snapping wishbones on a wishbone riser. A good challenge I recommend would be to pursue/create a new method for protecting the longevity of a roller wishbone. Alemanni does this by having a crescent riser with smooth edges. Couple other companies have done similar, but few have innovated.

It's been about 3 years of R&D into my optimized designs with an array of different manufacturing techniques. Of which a design patent is definitely in the works for. But I truly despise band guns to begin with and plan to pursue a new route soon. Simultaneously Ive been trying to steer a few others[manufacturers] in the same direction to bring some sort of standardization when the time and newer alternative is proper.

does Alemanni have a roller that uses only a line on the top deck to my memory he doesn't. i guess the wish bones can be a problem especially if the rubber goes all the way through front rollers as well but with it only being the line on the setup were talking about its slightly less of a problem. much less tail flick when the shaft leaves the muzzle.
Do you think there is a problem with bands being to short lets say we make a 90 band stretch roller at 360% so rubber cut to 25? any experience with faster degradation due to shorter bands? maybe they stretch out faster?

 

[Gjoss]

Correcto. Minus the easier to load part as my "black reef style" true fusion band design has excessive stretch profile to take full advantage of the smaller platform. I build stout guns not meant for most people. But there's a reason for it: Latex has a terminal velocity that is dictated by many factors but most importantly by acceleration which is confined by distance in our speargun application. And Latex has a parabolic curve in regards to stretch %. Pete is prob shaking his head to the band stretch I use but people love it and newer rubbers seem to last plenty long even with the aggressive stretch

All of my guns have interchangeable wheels to run a multi stage loading single roller, coined a "mono roller" by Alemanni. So anyone can load them if they're simply strung up differently. I recommend trying out this band design. Inverted is stupid to me because it runs a pulley system on the "hot side" instead of the loading side which is outright silly for the added complexity

My hot take: If you're able to load higher tensioned bands, then roller is the way to go. Rollers are superior in that they can run very high band tension for higher performance, combined with heavier shaft profile capabilities with minimal recoil in a smaller package. Whereas a traditional gun under equivalent band tension would encounter shaft whip and unmanageable recoil... So all comes down to: Can you load 350%+ tension? Go roller.

Hope this helps with something! -- Quade

Thanks I think it definitely makes sense, not sure what you call the hot side though.
That's what UK spearfishing looks like:
So its not really a power game, but because you need to adjust fast recoil is a fierce enemy (its often that you have to take a shoot in a less than perfect position).
Btw your guns look great!

 

[GRAPHITE SPEARGUNS]

So its not really a power game, but because you need to adjust fast recoil is a fierce enemy (its often that you have to take a shoot in a less than perfect position).
Btw your guns look great!

I think this is where a invert may actually be useful you could easily rig up a 80 or 90cm barrel go with two bands one thick 18mm and another 16mm or if you want three bands go 2x 14mms, solid 7mm shaft, with the two band setup its the same as loading a gun with two bands super easy, if you want lower power take a band off. The good thing with the invert and the roller is the recoil is much less, the invert i use for most of my hunting has some but very little almost to the point i could in theory shoot at any angle without bracing the gun.

 

[popgun pete]

The rear rollers on an inverted roller allow you to put more rubber on the gun which has a degree of pre-stretch. When bands are pre-stretched you shoot off the top section of the cocked to shoot energy graph and leave the rest remaining in the gun. By doing this you can harvest a lot of energy from the long bands without overstretching a shorter length of rubber. Because there is only limited real estate on a speargun body use is made of top and bottom decks to run the bands over and that requires a second roller set. Recoil that speargun shooters complain about is actually the jerk or rate of change in acceleration. By spreading the force application during shooting over the full length of the gun body rather than just the rear section to just past mid length that lowers the jerk. That is all there is to it. Like any gun or cannon the conservation of momentum law still applies. What spearfishers don't notice is recoil pushes them and their gun back in the water as the gun shoots. That is the mass of you plus your gun versus that of the spear. The better you and the gun are coupled the less recoil you feel. Some guns in the past used arm braces to improve gun coupling, but those guns were usually spring guns which held at mid length tended to tip upwards in the hand.

 

[rollerGR]

I think this is where a invert may actually be useful you could easily rig up a 80 or 90cm barrel go with two bands one thick 18mm and another 16mm or if you want three bands go 2x 14mms, solid 7mm shaft, with the two band setup its the same as loading a gun with two bands super easy, if you want lower power take a band off.

That's actually a light setup for a 7mm shaft. 1x 17-18mm + 2x 14,5mm bands are great for 6,5 or 6,75mm shafts. 7mm ones usually go with 1x17,5mm + 2x16mm or even 1x19mm+2x16mm

 

[rollerGR]

Recoil that speargun shooters complain about is actually the jerk or rate of change in acceleration. By spreading the force application during shooting over the full length of the gun body rather than just the rear section to just past mid length that lowers the jerk.

This is true and tests have shown the same. Particularly the longer rubbers utilized in a roller, invert roller (through the pulley) or fusion system produce a MUCH smoother acceleration curve. It's funny how when rollers started becoming popular people were thinking that the shaft taking a few milliseconds more to reach max velocity was a bad thing, but it turned out it was good and better than conventional spearguns, and that it's not even the velocity itself that matters (conventionals always have slightly higher max shaft speed, 36-37m/s compared to 35-36m/s in roller/invert guns), but the smooth and prolonged charging of the shaft with kinetic energy.

 

[VARJAC]

Hello everyone after reading and re reading many forum posts on gun builds I have decided to finally upload an ongoing build I am currently working on.
All my gun builds start with a computer model. I go through many many many iterations to come up with something that I like and find worthy of building. During the computer process im looking at what im building (this one is a inverted roller with rear roller) and how i can make it. Everything is scrutinized and re imagined to work with a 3d printed optimized for a carbon fiber process.

All those little lines are different versions of spearguns i go through to create a final design. This is only 1 file of many.
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With a design chosen i can mock up bands, rollers, handle, screw holes, trigger, muzzle, line guides and anything that need some thought before actual building begins.

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With the design finalized i can finally make some physical stuff.
First is the mould for the body, because my 3d printer is not 1200mm long i have to chop the mould up into several bits and join them post printing i had the brilliant idea of adding a location hole for a wooden dowel to be inserted into but later found out this would be to difficult to pull off as the dowel was not consistent size, a bit bendy and glue would all get pushed off when inserting into the hole.

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so I decided to place them all in a line and epoxy them together.
For people following along 3d printed in PLA .6 nozzle, .3 layer height, enclosure (important) a lot of time took almost a week to print it all!
POST PROCESSING is written in caps as it is literally the most most most i repeat most important part when it comes to a carbon fiber mould (in my opinion)

First glue all the pieces together mine was done on top of two shafts to keep the with the spearfishing theme and they seemed pretty straight.
After the epoxy is dry (24 hours no excuses) the plastic is sanded with 40 grit to take of high spots, imperfections and better adhesion to epoxy top coat.
Epoxy is then applied with a black die so when i sand it back i dont go to deep into the plastic. This epoxy coating is used to help demould the carbon from the mould if this epoxy coating is not there the carbon will stick to the mould and you will have to destroy the mould (ask me how i know).
Next is wax, i use a my hands with glove to apply the wax leave it on for 10 mins then buff it off do this 5 times or you will have problems (with me)
I also applied PVA (not the glue) for this first use but for my next builds i can just use wax.
Weight each mould so you know exactly how much carbon to epoxy ratio you will use
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Carbon Fiber, please wear a mask
For the people who are interested in the process i am doing a WCM (wet compression moulding) process this process is usually reserved for high pressure high heat steel moulds but i have plastic some clamps and a dream.
Carbon used 200 gsm twill 300 gsm uni directional.
The layup is different for the top skin and bottom, because this is an inverted roller most of the bending forces are applied to the top skin thus more carbon for the top.
layup for top is twill x4 uni x1 twill x1 uni x1 twill x2
layup for top is twill x3 uni x1 twill x1 uni x1 twill x1
I also add local reinforcement layers to trigger area, bolting areas and muzzle.
The carbon is layered on using spray adhesive and pressed into all the corners for each layer.
I compress each layer with the male mould to compress and also test that im still able to push the fibers without messing up the side walls.
The last layer of twill i try to keep a good amount of over hang as this allows the side wall to not be squished from the male mould pressing down.
Now its time for epoxy if you remembered to weigh your mould after the post processing stage you can get the perfect 50 50 ratio of carbon to resin, I like to do 60 resin 40 carbon as spearguns dont have to be that light weight and need good compression strength (epoxy).
I recommend not using west but a good carbon fiber laminating resin as west can be to thick. Pour the resin in small amount at a time and press the resin into all the corners with a brush. No photos as resin laminating is stressful af.
After the resin has fully saturated the carbon slap your male mould on and clamp it up!

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after 24 hours because of all that beautiful post processing your mould will pop off with with minimal effort.
trim it up (wear protection please)
and see if the skins fit together.

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i am currently up to this stage of the gun and will post periodic updates as i go!
if you have any questions please ask and ill try answer to the best of my knowledge!

hey dude. would you be willing to send me the STL file for your mold? would love to give this a bash myself.