I saw a 3d printed smart gun on eBay and decided to buy one. This is actually the second one I've tried buying, the first was last October and not only did it not turn up but the seller ignored all my messages and I had to go direct to eBay for a refund. On the other hand the second gun (from a different seller) actually turned up so that's a plus point already.
The kit is advertised as easy to assemble and I thought I go through the process here.
To start with these are the parts I got in the kit (the battery parts seem to be a bonus):

As well as the parts in the kit I also bought these:

The M10 threaded rod is to be passed through holes in the main parts along the length of the gun. As this next photo shows there are also smaller holes for pins that will make sure each part is correctly aligned. There are some short sections of threaded rod included in the kit for other parts but the cost of shipping full metre lengths meant the seller did not include the main length. You actually need just over a metre (by about 75mm) so that is why I bought the second length (which only added another £4)

As well as the required threaded rod I've also chosen to buy an M10 half nut and some plain motorcycle grips. I think the purpose of the grips is obvious and I'll get to the nut later on.

that might be a nice gateway into buying a 3d printer.

Threading the main body parts over the rod was pretty easy. As mentioned before I needed to cut a small piece of he second rod to mount the muzzle at the front of the gun. For glue I used super glue on the joining faces and aligning pins for most of the parts but for those at the extreme ends I put epoxy-resin glue into the hole I passed the main rod through for extra strength.


There is a slight discontinuity in the body near the rear of the receiver. It looks like the sloping part may have been made a little short, resulting in a step.


I considered leaving a gap between the two pieces and filling it with a mix of wood, plasticard and milliput but there are mounting holes underneath these parts, one on each part, for another component that would not fit if I did this. Then I decided that making a thick plasticard plate to go on top of the sloping section would be easier anyway and let me raise the top of the part to the correct level.

Now I'm up to adding the details around the main body of the gun. Most of these are straight forwards enough but the forward grip needs some work.
This has a short length of the same rod that is used in the main body of the gun. This would cross the main length of rod so with that in place the grip mount will not sit on the top of the gun as this picture of a test fit shows.

I didn't want to cut the main rod at this point so I instead cut down the length of rod inside the grip mount so it fits like so:

This is where I used the M10 half nut I bought. This fits in the gap between the barrel and the barrel shroud so by screwing the rod through it I anchored it better than could be achieved with glue.

To fix the grip mount I used a mix of superglue and epoxy around the exposed rod. The grip itself was glued to the side of the mount with more super glue and epoxy.

Curious... Without a length of rod, into the grip itself, do you feel it will hold over time?
A lot of the gun's weight will be supported just by holding the grip, no ?

Are you familiar with the trick of mixing baking soda with the superglue to fill larger gaps? It also accelerates the cure time, and it can be sanded after curing to shape if needed.

Between that, water thin, gel glues and a spray of kicker, you can build a space shuttle out of recycled soda bottles...

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DON’T call me eighty-five.

Assistant Superintendent Leach,
Fiorina 161
"Serenity Through Confinement"

Being 3d printed the gun is pretty light but I don't know how strong the grip of the glue would be over time. Since it came with the rod for the grip I'm trusting that the person who made the kit thinks it is needed so I'm going along with it.




This is a trick I've not come across before. I may have to try that at some point in the future.

The glue would hold the pieces together; however, hollow parts will end up breaking within the part, past the glue line, if not properly reinforced.

_________________
DON’T call me eighty-five.

Assistant Superintendent Leach,
Fiorina 161
"Serenity Through Confinement"

Here's the main body of the gun with the extra parts added. Other than the forward grip, I just sued superglue to fix these in place although some feature pins to reinforce the joins.


The final part of the main assembly was the drum mag. This was in three parts, a front and rear body plus a very thin piece for the handle. I can't tell if this is supposed to be this thin or if part of it failed to print properly but it is far too delicate so I reinforced it by gluing a thin sheet of plasticard along the length before fixing it to the back of the drum mag.

The real thing is bent like a U shape:

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AKA: Simon

Yes, I ran an image search and came up with that but I wasn't sure if the prop was supposed to be different. I couldn't think of a means of making the U shape with all the bends so I settled on something flat instead. It was better than what I had before:

It's about time I update this so here we go with the use of plasticard to fix the step in the upper body and also to reinforce some of the weaker points of the model.
Firstly the body where there is a step at the top of the slope. Here I used cardboard to create a template that I then copied to 2mm thick plasticard.

Here it is glued into place.

I've made a pdf of the template just in case anyone else gets one of these.


The 3d printing process has left a couple of parts of the model weak and prone to damage so I'm reinforcing these with 0.5mm thick plasticard.
The first of these is the detail on the top of the gun just behind the forward grip. I placed a piece of this along the inside of each vertical side.

More significant though is the rear grip trigger handle. I can't understate just how fragile this is, a slight knock and it snaps. After twice attempting to fix it with just glue and pinning wire I decided to glue 0.5mm thick plasticard to either side of the handle as well, starting with a paper template for the shape.




Even with this the handle broke again where it meets the body and I had to drill and pin it using coat hangar wire.
Now I need to use milliput to fill the gaps.

Looking really good so far.

I've a [few] spare Magura clutch/brake levers, they're the long version, which in my opinion, is too long to be screen accurate, but they're still excellent. Happy to send you one if you want to try replacing your one [you'd just need to cover postage}].

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Cpl Aron "septic" Williams
A10/TQ0.0.82146E1

Thanks for the offer, but the way the gun is constructed does not lend itself to replacing the lever. If you look closely at the very first picture in the thread you can just about see that the handle is a part of the entire rear piece. To swap this for another lever would require digging out a hole to take it. That may have been possible before assembly but I don't think I could do it now. Thankfully the combination of a thick wire pin and the plasticard side plates seems to have left the handle pretty sturdy. At least strong enough that it won't snap as soon as it is looked at.
The issue seems to be with the direction of the grain in the handle. This runs across the handle instead of along it and I suspect that if it had been printed as a separate piece with the grain in a different direction it would be far stronger. Even better would have been to print a duplicate of an actual break lever so that it could easily be swapped for a metal one.

All good.
Re handle, I would be tempted to remove and replace with a long section of alu or copper tube, but you'd know better than I if that was at all feasible.

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Cpl Aron "septic" Williams
A10/TQ0.0.82146E1

If I'd known at the start how fragile the handle was I may have been tempted to remove it and drill out a hole to take a metal replacement before assembling the gun.

Here is the gun with the gaps filled:




And painted:


I'm not quite done at this point though. Remember those grips I bought? I want to add those. The gun's own grips are slightly too narrow to just take my grips over them so I used plain corrugated cardboard as filling material. Each grip needed two pieces to get the correct width:

Front grip attached:

Rear grip attached:


And finally the finished gun:


To conclude I'd say that the pros and cons of this gun are:
Pros -
Relatively cheap.
Detail looks good.
Light.
Very easy to put together.

Cons-
Some parts are VERY fragile.
Needed to correct rear of body.

Overall I'm very happy with this purchase.

I think it came out really well!

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My entry-level prop and costume tutorials: viewtopic.php?f=3&t=12751

That has come up real nice!