This page shows how I made my first aliens Pulse Rifle grenade, this version is known as the M40 High Explosive. I have used pictures from the film and information freely available to hopefully recreate something that resembles the film used item.I have since found a web site with more Aliens munitions on, and have set to work on a few other version of it.
As always I start of with a block of resin, or in this case a rod of resin, using a piece of old plastic pipe with one end sealed up, then wax spray applied to the inside, then polyurethane resin poured in and left to set. Once the resin is set, it is removed from the tube by taping one end lightly with a hammer, and it slides out. (Well in theory it should anyway.)It is then placed in the chuck of the lathe to be faced off. When it is a perfect rod, the surface is marked out to give a plan to work to. The first things to do are the three main grooves which are all the same depth. When these are done, the rest can be worked out from there.
With the grooves done, its time to turn the rod round to do the other end. It seems the grenade body is based on a standard 12 gauge shotgun cartridge, so a flange round the base is machined to replicate this. The centre part where the priming cap would have been, has been slightly recessed on the grenade unlike the proper shotgun cartridge. Once then base is done, there is s angled section that has knurling on it, so the flat is machined at an angle, and knurling added round it.
Once the main body is finished its time to make a mould of it as I need more than one. The mould is made using a piece of plastic drain pipe cut in half. Half the pipe is filled with super sculpy and the finished grenade body is then pushed into it. The edges are smoothed out and locking tabs are made in the surface, so the second half locks together. A hole is then cut in the top section of tube to pour the silicon in. The two halves are then taped together, and silicon poured in.When the silicon is set, the bottom tube is removed and Vaseline applied to the end section with the keys in it, then the tubes are taped back together minus the super sculpy and more silicon applied. As this is to be rotary cast, end caps are made so it can be placed in the chuck of the lathe for spinning. The reason its being rotary caste is to get it looking metal like, and to do this aluminium powder is added to the resin then centrifugal forces push this to the outside when itís spinning.
With the main body in the mould, its time to start with the bits to make the plunger depress. This consists of a plunger rod, and end cap to sandwich a spring between them. To make the plunger another rod of resin is machined down in two stages, to give the plunger and collar around it.
With the plunger done a collar is also made for the bottom end to sandwich the spring an allow the plunger to function as intended. In order to keep the spring in the right place a small recess is machined in both the plunger and end cap to keep it central.As with most things I make, I like to make as much as I can to avoid having to rely on outside sources for parts, as this can prove a problem if the source runs out, leaving you high and dry for parts. This was the case with the end cap, which I believe is an actual cap for a shotgun cartridge, however finding these proved difficult, so making one was the easier option, and also allows for variations which we will come to later.Also by making and casting stuff yourself, you can chose the colour its made in, or changed it at a glance.
The finished rough casts, of all the parts laid out. The grenade body is cast using the aforementioned aluminium powder in the resin for effect. The cap is cast in red resin, and a pinstripe line of white added when finished.To get the alloy effect, the resin needs rubbing with wire wool. This removes the softer resin, and leaves the alloy powder on the surface which comes out shiny.So thatís how I made my Pulse Rifle Grenade. Quite simple in terms of making, but things that do something, (i.e. the pushy button) are always much better than static items.