Construction Techniques

Theres lots and lots of ways to build most things, and people always find their own ways of working that suit them so all Im going to do here is give some basic advice and relate how I do things.

If that helps a few of you then I can consider the page a success.

As I mainly work with aluminium most of the advice will be geared towards that medium.

TOOLS

Good tools are a must. You may think that buying cheap tools is great but I can assure you that good quality tools will far outlast a cheap set any day. Also they are less likely to break - Ive had a few near accident from inferior tools so now I know better :)

You dont actually need alot in the way of tools to work with sheet aluminium, although the more and better you have the easier it becomes of course.

Required Tools

Good craft knife (Stanley or similar)
Drill, I started with a hand powered drill
Drill bits to match your choice of screw size. (I use 4mm thread screws so a 3.2mm and 4mm drill are ideal)
Flat file
Half round file
Aviation shears (available for about 3-5 at hardware shops or machine mart)
Small hacksaw
Rivet gun (cost about 3) and rivets of course (I use 3.2 mm rivets to match the 3.2 mm drill bit)
Screwdrivers, pliers, hammer

Additional Useful tools

Tap (and holder) in whatever size screw you decide to use (if you want to do threaded holes properly)
Drill press (makes drilling nice straight holes so much easier)
2x Bench vice and 2 x 1 metre long lengths of steel angle - This allows you to effectively make your vice jaws 1 metre long by clamping the angle strips at each end using the 2 vice.

That may look like quite a list but most of the tools are not expensive and some of them like screwdrivers etc I hope you already have around the house.
The only expensive ones are the drill press and vice's. You can pick up a small drill press in the UK for about 30 and I know they are even cheaper in the US from places like Harbour Freight.





TECHNIQUES

Theres only a couple of basic techniques really needed when it comes to making tag guns out of aluminium.

Folding
Unless you have expensive folding equipment the easiest way to fold a piece of sheet metal (aluminium in our case ) is to lightly score along where you want the metal to fold and then place the piece of metal on the edge of a straight bench or other surface like a kitchen worktop with the scoreline along the edge.
Then exert downwards pressure on the part hanging over the edge. Voila a neatly folded edge.
For peices where you cant get leverage with your hands (where its a thin strip you are folding for example) thats where the vice comes in. Simply clamp the edge into the vice.

Easy to say, try a few folds first to get the hang of it. Its easy to do short bits but gets tough to do long edges and still keep them neat unless you have the 2 vice with angle iron.

Cutting straight edges
The easiest way to cut a straight edge with aluminium is very similar to above.
Instead of lightly scoring a line, repeatedly score it with a craft knife then fold it as above.
Then fold it back, then fold it again, repeat as many times as necessary until the metal snaps.
You should have a very straight edge with a slight burr from the craft knife which you can simply file away.





Materials
A quick note on the materials I use. As well as using sheet aluminium (1.5-2mm thick) to create various 'box' sections I also use tube and channel.
Channel is basically an extrusion with a "[" cross section like so :-


Channel


It comes in a variety of widths and depths. I use 3mm thick wall as that is thick enough for great strength as well as adding threaded holes for the screws.
I'll use whatever width suits the design IM building but use mainly either 50mm or 38.5mm wide with a 25mm depth (this nicely matches the 2 common lens widths I use too).





Now Im not going into specific gun design here as you can download a couple of plans from the downloads section but all my guns are made using the same basic principles.

I start of by sketching out rough ideas until Im satisfied with a design. This can take awhile and I often go through 20-30 variations on a theme.
The next step is to draw up a scale drawing with the main dimensions on it so I have something to work from. I used to do this by drawnig it out on a large sheet of paper but I now use a program called CorelDraw.

Corel allows me to do a simple side veiw line art picture (and add colour if I want to get an idea of paint schemes). No matter how you end up with the finished outline drawing always keep your material in mind.

When you have a neat scaled line art then its time to note down the lengths of the major sections. Drawing it out full size is an advantage here as you can measure then drawing to work out a template to make the sections.

Corel also helps me here as it has a dimensioning tool. It means I can draw it full size in the computer, add on all the measurements I need and then print it out on A4 to give me a nice plan to work from.

Heres one of the simple side veiws I did for a gun I built for a friend :-


Side veiw artwork


So when Im sizing things I'll know what size channel Im using and what size the other components are like lens assemblies batteries etc.

Theres nothing worse than spending all this time building a lovely gun case to find out that you cant fit everything in it (yes its happened to me once before).

When going from your initial sketches to the line art one of the most important bits to scale from is the handgrip. If you compare alot of assault rifle grips there all roughly the same size so you can scale just about any design from the handgrip.
In fact when I first did my Pulse Rifle scale plans I used the grip as a guide. When the Aliens Tech manual came out a few years later the stated length was 5mm different to what Id worked it out as.
Not bad for a plan scaled up from a 5cm big picture and a guestimate of the grip size :)


You may notice that alot of my guns use straight edges, thats because its alot easier to do them. If your creative with your design it still looks good anyway (Games Workshop has been doing that for years with alot of its gun designs and it hasnt hurt them any :).

Nearly all of my guns use a length of channel that acts as a main 'spine'. It gives the gun much needed strength and all the other sections usually are fastened to it. For example the morita has a length of channel running the entire length.
It also allows the parts made from sheet to be screwed into place.

One other advantage of using the channel sections that I discovered with my first one was that it makes it extremely easy to mount a lens unit and keep it aligned with the central axis of the gun.
When you fit a tube into the 'U' section it by the very geometry involved lines the tube up with the channel. Often all that needed to secure the tube is 1 screw going through the tube wall and into the channel.

Have a look at how the lens assemblies are placed in the Morita and Pulse rifle plans and you will see what I mean.

This means when you sight down the length of your finished gun you are pointing the barrel in the right direction. It leads to a more natural aiming process and means alot of the time you dont need a scope for accurate shots. Ive seen some other guns in the past where the lens unit wasnt aligned down the centre of the gun (due to how the lens was mounted) so that you had to point the gun at a weird angle to make the lens point "at" the target.
Very strange to use :)

Just keep things simple at first until you become confident with the materials and then you can move on to other more difficult designs.

You could always have a go at one of the plans from the downloads section too.