'Compound' Spring Powered Speargun (concept)

-Paddy- said:

I have recently modified my RA speargun.

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Love this roller head Paddy... any chance of being one of your friends... just what I'm looking for but in aluminium... stainless steel is good too... so that I could use wire rope rigging instead of all that rubber flapping about. I could then rig similar to yours above and calibrate for power with my own band set up...

I've ditched the handle mould idea and gone for a slim handle to hopefully avoid that gun hand ache you get from overgripping after a few hours fishing. This version below is now ready for 3D printing... bar minor adjustments and some final Batman/James Bond/Bladerunner styling and smoothing out. The cavity for the trigger mech is based on the Ermes Sub Ocean from here but I can change the dimensions to suit whichever trigger I eventually get. I've also used the MVD roller muzzle here. I've also used a Rob Allen rail barrel for dimensions so that everything is interchangeable. Now all I need is the money (which may take a while) but the components are reasonable at £126 delivered for all 3 above... If the 3D printed handle is comparable in price to the RA vecta handle then around 2-3 hundred £'s in total would be the price of a good quality euro gun anyway.

foxfish said:

Why not carbon fibre or fiberglass? how will you treat the alloy to stop it furring up in salt water?

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My eventual finish will will depend on the alloy mix in the scrap ally I use together with my final degree of polishing... but in general terms gun maintenace will be much more satisfying when taking it apart and cleaning with mild acids like vinegar and lemon juice... ally will polish up well with commercial metal cleaners too... gun maintenace is a pleasure after all and rinsing out my plastic euro gun pales into insignificance!
Aluminium's durability, strength and minimum-corrosive nature along with a garden shed full of old ally window frames are some of the reasons to choose it over carbon or glass fibre. I've also got the makings of a home made furnace which I have already used successfully with small aluminium casts... so it's also a case of making use of experience and the equipment I already have.
Besides that I'd like my gun to be as reflective as possible... not as threatening perhaps!

After spending a bit of time researching the 3D printing options for this gun I thought I would pass on some of the latest developments...
Having used imaterialise before I uploaded my latest 3D file to get a price and it was far too expensive... even in the most basic material... more about 3D printing materials later. I then tried a few other well known 3D printing services with pretty much the same results at Sculpteo, Shapeways and Ponoko...
So after looking around a bit more I came across 3DHubs which specialises in local 3D printing. This site lists all your local businesses and individuals who provide 3D printing services to the public... the difference in prices from the big companies is extreme to say the least and the myriad of choices a little bewildering. I got a quote for a third of the price I would have paid to imaterialise etc... in a material of my choice and better still in a silver metallic colour rather than just boring old black or white... so that I can actually use the 3D printed gun after making my casting molds. I don't even have to pay postage either!
Anyway time for some pictures... how about 3D printed (component) spearguns in wood-ish? Apparently you can sand, carve and varnish it too!


or self designed trigger mechs in Copper or Brass?

Presumably this is still very expensive... but then again perhaps not! In the last couple of years the budget 3D printer for your home PC has dramatically reduced from around £2000 to about £300-£500... each reel of material (the green stuff below and the wood/copper/brass materials above) are between £20-£45 and can print 20-30 smallish models on consumer 3D printers. The self build 3D printer below left is £325 on ebay and with inexpensive upgrades and experience you can actually match the quality of even the biggest online print services... and currently used by quite a few of the 3DHubs operators. The 'Up' mini printer (right below) is £465 and comes ready to print.


Finally, even if your 3D prints are a bit on the low resolution side there's even a budget way to make them look absolutely outstanding by using an acetone vapor bath (nail polish remover) to smooth them out...

Anyway I hope at least some of this information will help anyone who may be interested... personally I'm wondering if I should wait until I have the money to buy my own 3D printer rather than spending anymore hard-earned on 3D print services!

A gun (or very similar) I bought from a second hand shop in the mid 70's called the Hurricane and what I'm clearly trying to recreate here now... although I didn't actually realise that until I came across this picture online. I lost it very quickly of course but we obviously keep these memories for nostalgic purposes... and for when we're old and stupid

kwtony said:

None of these metal printed parts will hold up in the elements. Brass nor copper are strong enough for a mech. There is a reason manufactures make them from stainless.


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Agreed... but the 3D stainless steel printing might... eventually.
The above post was just for interest really... I'm actually using the Meandros S... mostly cos it's the only one that fits my 3D design but also cos of your (and others) recommendation on other threads...

I've now also managed to design a custom muzzle...



makes it a lot easier and only around £10 extra when added to my 3D print costs (£85 ish). I also plan to design a mount at the front of the muzzle for a torch/bullet camera... not quite sure how yet! I've been looking for an online Spearo shop where I could get everything in the same place... save on shipping... Diveshop Greece seems to be one of the best... so when ready I'll be using the Meandros rollers and 'Short' trigger mech and Bucanero rail tube... which brings the parts cost down to around £85 delivered. I'll also need a commercially available loop band/wishbone.
I've now resigned myself to version 1 being plain black, same old ABS plastic... I'll put my aluminium dream on hold until I become rather more skilled with my home foundry... with the fine detail I'm after I'll be needing plenty more evening classes making double sided alginate (dental) molds!
Initial estimates for complete gun are looking around £200... not exactly cheap... but still half the price of what I would've spent... and probably still not got what I actually wanted for my style of 'gloom, foam and gully' fishing... from even a good quality, small, euro style roller gun.
Although I have to say that the Seatec mini roller 60 is as cheap as chips at a 100 euros... didn't exactly get rave reviews though...

I'm trying to keep the complete length to around the 55-65 cm mark so that it's as hydrodynamic as possible... waving those gurt long 90's... even 60's... which are nomally closer to 80cm's from tip to heel... feel like a Knight's lance. I can shorten the barrel to whatever I like but lose accuracy the shorter it is... I do tend to miss more than I'd like to admit with my Mares mini sten... spear lengths and band thicknesses will need testing too of course. No reason I can't have a few different barrel/band length combinations to suit the immediate viz/conditions either! A few more weeks of 'fiddling' left but I'm in no hurry.