The next day, I ran over to the local Canadian Tire and picked up a few rattle cans:
This build is also documented on my website MYNOCK'S DEN
, as well as the RPF, but figured I would share it here as well.
With my main character in Star Wars the Old Republic being an armed-to-the-teeth Bounty Hunter, I wanted to make myself something bounty hunter-ish. And, what better bounty hunter-ish thing to make than a blaster?
I've always liked the look of Eleena Daru, the Twi'lek in SWTOR trailer "Deceived", especially her nice pair of...
...blaster pistols (get your mind out of her lekku!). And now that I am rocking the same heaters in game, I figured I would try my hand at making this type of blaster.
I started the build process by importing a photo of the blaster into my CAD program and tracing the outline.
I then pulled the shapes of each major part out into 3D.
After about 40 hours of work (which included learning the program by following a course on Digital Tutors), I had completed my baster model.
I knew the blaster would be too big and awkward to print all as one or even two pieces, so I split the model into all the major pieces, and created a separate STL file for each part.
In the above photo, you can see I built little 1mm high walls around each object to help with adhesion to the build plate; I was having a lot of issues with the plastic curling on the build plate for several of my test prints, which almost made me tear my hair out on a few separate occasions.
So, I figured I'd experiment a bit by creating a small short wall at some distance around the object, which would increase the surface area of the raft underneath; the idea was that if curling occurred, it would happen far away from the main object, and hopefully not reach the main print in the middle.
The wall approach proved to be unnecessary in the end, as I eliminated curling/lifting completely by enclosing my printer (FlashForge Creator Dual) in plexiglass, which reduced the temperature differential across the build plate. I also increased the density of the raft base layer to 0.9 (maximum), and made the raft 3 layers thick, which stuck to the build plate like glue!
(The FlashForge Creator is based on the Makerbot Replicator 1 design, and despite the "Made in China" sticker, is an AWESOME, SOLID printer, by the way. The 92 overwhelmingly positive customer reviews and a 5/5 star rating on Amazon is what sold me on it despite me having my heart set on another machine that was twice the price. I do however baby the **** out of it, and keep my allen keys, and light-weight silicone oil close at hand. At the time of writing, I have 67 print hours on the little robot without a single hiccup that could be blamed on the printer itself. If I could change a few things about it though, I would do what I've already done - enclose 3 of the 4 sides to keep the inside nice and toasty; I would also add some LED lights like the original Replicator, to illuminate the build plate. Some have actually commented that the absence of LEDs on the Creator is an improvement over the original Replicator since LEDs in that model would sometimes short/fry the motherboard. I think I will add some battery operated LEDs in the corners of the casing, and mount a switch on the outside; I only really need the lights a few seconds at a time to check the progress of the build, so no point in hardwiring anything to the printer's own power supply).
Prior to increasing the raft settings and enclosing the printer, I also tried using the ABS soup method (ABS + acetone + smearing on kapton tape), but found that this made the object stick to the surface so bloody hard, I was afraid I would break the build plate arms trying to pry the print off. Printing in ABS at 235C with a build plate temperature of 110C using a thick, dense raft in an enclosed system I found produces no lifting or curling of plastic whatsoever! No ABS slush or hairspray products necessary!
Printing of all pieces (not including the failed-due-to-lifting test prints) took a total of 23.38 hours.
After everything was cleaned up and sanded, the assembled blaster took shape!
Next came the molding. I filled plastic container half way with plasticine, sprayed the blaster with mold release (plasticine can be a NIGHTMARE to clean off), smoothed out the surface, poked some registration holes with the blunt end of a sharpie, and sprayed the whole thing with more mold release.
Since I did not have anything other than Rebound 25 silicone left, I took a chance and decided to give it a shot. Half way through the pour, I realized "uh, oh. I'm not gonna have enough for both sides!" DOH! I poured it in anyway, figuring I'll make one half now, and the other when I get another batch of silicone.
My wife was just finishing up laundry, so I tossed the tub onto the dryer, the shaking of which would help dislodge any bubbles trapped in the silicone.
The next day, I peeled the mold out of the plastic container, cleaned off the plasticine, and viola: finished half mold.
After doing some research, I went ahead and ordered a gallon kit of Mold Star 15, a pourable Smooth-On silicone with a 4 hour demold time. Due to the tensile differences between Rebound 25 and Mold Star (which is a bit softer), I would be unable to use the Rebound 25 mold, and would therefore have to mold from scratch. *Sigh*. All that Rebound 25 . haste really does make waste.
Learning from my mistake with the Rebound 25 half mold, I decided to do a triangular mold shape rather than a square to save silicone. I built up the base layer with plasticine warmed up on the fireplace, and built up the walls using ABS sheets.
After pouring Mold Star 15, and letting it cure, the first half was done.
I then replaced the ABS walls, sealed the cracks with plasticine (some people use hot glue, though I found plasticine do the trick), and sprayed the inside with mold release to ensure that the two halves of the silicone remained separated. During this step, I picked a low-key spot on the model that would interfere with the detail the least, and created a pouring hole using plasticine.
I did not think this through very well, however, and so it proved to be yet another dumb-dumb move.
Due to the complex shape of the gun, and the overwhelming number of undercuts, the potential for air becoming trapped was extremely high. I realized the error of placing a pour hole in that spot almost as soon as I poured the silicone. Once it cured, I decided to skip the mother mold step for now, and do a test cast.
Just as I predicted, the casting came out completely ruined on one side as a result of air getting trapped.
So, I filled the pour hole with silicone, and relocated it to the butt of the blaster by cutting into the mold with a utility knife; having the mold standing up with the muzzle being perpendicular to the ground and the pour hole in the hilt would ensure even filling of the mold cavity, which would (in theory) eliminated trapped air. I have no idea why I didn't think of doing it this way first.
Next, I created the mother mold support out of Plasti Paste I. I started by building up a layer of plasticine half way up around the rubber mold, making some deep indents in the clay to act as registration keys. I then slapped on the Plasti-Paste and allowed it to cure. I then turned the thing over, removed the plasticine, sprayed mold release on, and applied Plasti Paste to the other half, creating two separate halves of the mother mold.
Finally, I was ready to cast! using a $10 set of elastic straps I bought just for this project, I assembled the two halves together, strapped them up, and poured in my Smooth Cast 65D. Once the resin began to turn white (which I could see through the top of the pour hole), I laid the mold down, and left it to cure.
Demolding revealed a near perfect casting of the Twi'lek blaster! Some air bubbles managed to stick around despite my careful pouring and mixing, but it was nothing that couldn't be fixed up with some Bondo later.
(In the next photo: original, 3D printed master on the right, with the resin clone on the left).
After removing the pour hole excess material, and using Bondo to fix up trouble spots, the blaster was ready for priming!
I printed off two more levers, each of which took 50 minutes; while these prints were going on, I cast the second blaster pistol, and got to work on prepping it for priming. Two hours later, I had both blasters primed and ready for the final paint job!