Open Track Wooden Spearfishing Gun

What's more satisfying than making something out of wood? The answer is probably, making something out of wood that can also get you dinner as well. Well, I can't really help you actually get a nice sushi dinner using this speargun, but I can show you how basic woodworking techniques and joinery can help you build a beautiful, solid wood spearfishing gun that will stand the test of time.

The gun is also oddly midcentury/danish modern-esque but that's neither here nor there.

What are you gonna need for this build from a tools perspective? A table saw, router, drill press, and chisels are a good start. A hand drill or driver is helpful.

For lumber? Oily hardwoods are the standard. Teak for the most part. However, because I had this rosewood on hand, I went with that. Mahogany, while less oily, is also often used for spearguns as well.

Other items!? GLUE! A couple different kinds of epoxy (although that's not entirely necessary and we'll get into that later".

Items not shown in the video that make the gun functional: power bands and a line anchor.

Now onto the build!

First things first, I'm gonna rough cut everything down to a manageable piece. This ended up being a 50" long gun so I cross cut it just a bit above that to allow for a little error during the initial stages. Then, to take out all the variables as far as twisting and curve over time, I cut this into strips about 5/16 or so for a glue up.

Since rosewood is notoriously difficult to hand plane without a high angle iron, I scrape these down till their acceptable for a glue up with a card scraper. I'm a big fan of card scrapers and manage to keep mine pretty sharp by burnishing them regularly. They're not the best at getting things perfectly flat in the same way a hand plane would, but it gets the job done. If you're one of those fortunate rich folk with a drum sander, this is also a good place to bust that out.

Now rosewood is an incredibly oily wood, so to ensure that the glue up bonds properly, I wipe everything with denatured alcohol to pull out the surface oils. You’ll want to keep wiping this down until the rag runs clear. And if you’re doing this yourself, note that it’s going to take a lot of passes to be acceptable. This is the same process if you're using teak as well.

I applied epoxy as a finishing product on this speargun. However, a number of spearguns, especially the more expensive ones from teak do not have epoxy. If you're going to go that route I would highly suggest using a water rated glue such as Titebond III for your glue up to prevent any later catastrophes.

Then I build a mold for the glue up, which is really some melamine constructed at a right angle and held together with counter sunk screws. This will give me some reference surfaces that I'll use later to mill the glue up square.

Arranging the glue up takes a bit of strategy. You want to arrange the strips in such a way that the forces of the curvature of the strips will counteract each other and keep the stock flat over time. If all the bends are facing in one direction, you’ll likely have a bend in your finished product.

Out of the clamps, I use the melamine mold as the reference surface as stated earlier and joint the exposed top on the table saw. That’ll give me a start to be able to get the rest of the stock nice and square.

Then it’s crosscut to final length.

The mortise for the trigger mechanism is measured and marked out. I’m going with the neptonics reef trigger mechanism because it’s relatively cheap and it’s pretty no frills as far as install is concerned. Some of the larger mechanisms such as their tuna mech have rounded ends so you don't have to break the chisels out, but if you're familiar with any of my work, you realize that I'm a big fan of my hand tools.

Then to the drill press to hog out the bulk of the waste. I used a brad point bit but a forstner would have been preferable. The mortise is cleaned up with sharp chisels. Also, since I’m not a spear fisherman, and rather just a woodworker making a speargun, I didn’t realize the top of this mechanism needed to be just proud of the surface, so to cheat on creating a through mortise I ripped the top off on the table saw. Had I just cut the stock down to the begin with to just shy of the thickness of the mechanism, that would have taken care of that step without the fix.

The cross pins are marked and drilled. As well as the line release, and if the mechanism works on a dry fit, we’re good to move on.

For the pistol grip, I did another lamination on a much smaller scale and the same principles as before will apply here.

Because I’m going to attach the grip with a drawbored mortise and tenon, I’m making a rosewood dowel on the dowel plate.

To cut the track, I run it on the table saw with the dado stack. If you have a router table, that’s also another good option. I make a pass which ends at the trigger pocket, and then flip the stock so the opposing side to the fence, is now resting against the face. Then I start from said trigger pocket back through the muzzle. That’ll ensure that the track is even and centered.

The muzzle needs a little more meat for power bands so I glue and clamp on a cutoff with band clamps.

The grip is cut to angle with the miter gauge and the mortise for the grip is hogged out on the drill press, before being cleaned up with chisels, much as you did before.

The tenon for the grip is cut down on the table saw with a tenoning jig and the miter gauge and all the awkward bits are finished with hand tools. When I mention awkward bits here, I'm referencing the little rear area above the grip. The tenon itself is perpendicular to the mortise, whereas the angle of the grip is not. Therefore, to prevent me from having to make a highly calculated and awkward cut on the tablesaw, the Japanese pull saw was the better option.

The butt end is shaped on the spindle sander before holes for power bands are drilled on the press with a forstner bit. Each hole then gets a chamfer with the plunge router to accommodate for the tugging forces.

And then the whole stock is rounded over with a roundover bit in a trim router.

To make the grip more ergonomic, I’m using a power carving disc on the angle grinder and shaping it to fit my hand before sanding down with a drill attachment pad. The drill attachment set is nice because it gets me in all the little nooks and crannys and the kit comes with a wide variety of sand paper grits, after which the whole stock is sanded.

The hole for the dowel to drawbore the grip is drilled, then the grip is dry fit and the same brad point bit is used to mark the center of the hole. After that, the punch marks just a touch toward the shoulder to create the offset and that hole is then drilled. The dowel is then driven in, which will draw the joint tighter together and fix it into place without adhesives. The excess is trimmed away.

The trigger mechanism is designed for more blue water guns with these extra long triggers, so to have it fit behind a trigger guard I cut it down with the angle grinder. I also fine tuned the fit with a file and the drill attachments as well.

With an off cut, I’ll saw out a trigger guard and that’ll get mortised in just ahead of the trigger pocket and glued in place.

I wanted a magnetic track (also known as a mag track), so I’m drilling for some magnets which will be friction fit into the base of the track. No adhesive will be applied there. However, the finishing process with the epoxy will ultimately lock these into place from the outside in.

Then for finish, Mas epoxies was kind enough to send me out some product to try. I started with penetrating epoxy to create an eggshell barrier that’ll help the other layers of finish be applied evenly and seal out the wood from the elements.

Then it’s on to a 2:1 epoxy which will give another protective layer that is more substantial than the penetrating epoxy and gives this gun a little extra integrity from the outside.

As a final topcoat, I’m going with Bristol finish, a spray-able urethane topcoat. This is an alternative to spar finish that will provide for an additional layer of protection as well as an awesome silky sheen. Ultimately I applied around 8 thin coats over the speargun without the mechanical components. The topcoat has a nice feature in that if you apply the coats at approximately one hour from the next, no sanding is required between coats, very similar to lacquer. You could keep on going with the coats if you'd like but I didn't want the speargun to look too plastic with too many layers of varnish.

I’m going to cut down the cross pins to final length for the trigger mech and those will get tapped in with a friction fit in the event the mech ever needs to be removed or replaced. To measure the cross pins, I used a pick and marked the depth with blue tape, and then transferred that onto the stainless cross pin. You can do this process with a number of different methods, but marking a probe and transferring the line just makes sense. I will add, that when tapping them in, use the factory machined end as your entry end first that way you won't risk damage from some shoddy filing and sanding when the end of the cross pin exits the hole.

Then the line release is installed with a friction fit as well, and the reel is mounted with some stainless screws.

You're done! You're finished! Rejoice! Pop the bubbly... knock over a trash can. You earned it.

In the event you don't watch till the end of the video, the big flaw here in my first speargun was the fact that the trigger was set a bit too far forward for comfort. The fix for that is to mortise the grip directly behind the trigger pocket. On a redo, I would actually do a double offset and then use the end of the trigger mechanism itself to create the pressure to close the mortise off. That would ensure that the grip is pinned securely and that the trigger is in the correct comfortable placement, which is about 3/4" to 1" back of where it is presently.

All in all, this was a fun build and I'm pretty excited to try another one, perhaps with a different track style, such as an enclosed track.

Let me know if you have attempt one of these in the comments and if you have any questions!