Well, I think that I have given the prototype gun enough coating to make it sturdy enough.
There are some small bits that still need touching up due to the fact that I can’t give it an all-over coat at once, but have to build the coat up in stages (I have to hold it somewhere while I apply the filler). But, overall, I’ve given the prototype 5 coats of filler. There are also some coats of 2 part epoxy and paint under the filler, but I’m not counting them.
The last couple of coats have been very thin so that the finished surface is as smooth as I can make it. I’ve rubbed the prototype with 120 grit sandpaper between coats to knock off some of the grainy bits in the filler and to smooth out some streaks left by the paintbrush.
You can see the overall shape of the prototype now too. Large body, thick barrel, chunky pistol grip, wavy bottom of the body and flat top.
Next I’m going to be drawing the design onto the prototype to mark out all of the areas that I’m going to etch with the Dremmel rotary tool and the cut-line where I’m going to cut the prototype in half.
Etching the surface is going to be another experimental stage. I know that the directions for the filler say that it can be drilled, sawn and sanded, but the subsurface has a lot of give and the vibration from the rotary tool may cause the filler to lift from the prototype. If it does, I’m going to go over the whole thing with a clear acrylic paint to help to stabilise it.
When the etching is done, I will be moving on to the next stage … making the prototype ready for investing. That’ll involve cutting it in half, removing the polystyrene core using acetone, building up the interior surface with more filler (so that the shell is at least 5mm thick), and of course … fixing anything that goes contrariwise to me.
So far … so good.
I’ve now ordered a truckload of electronic components from eBay (resistors, transistors, capacitors, timer IC, decade counter IC, LED, potentiometers, PCB, e.t.c) so that I can do some more work on the prototype electronic gubbins. I want to have a pulsing LED glowing through some cut-outs in the body and some lights chasing around the barrel of the gun. Here is a crap visualisation of the lights.
The cut-outs will be covered with some inset resin panels and will have a single large LED with a pulse circuit while the chasing lights will be some 3mm LED. Chasing just means that each light comes on in sequence (kinda like the “eye” of a Cylon). The above picture is pretty bad … just something I knocked up in MS-PAINT in a couple of seconds.
The body will not be that colour when it is in the final material, so don’t worry about that!
I want the circuitry to be fairly simple and I’m going to use trim pot resistors so that the cycle time can be varied manually.
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