PotatOS Project Part 3

[PART 1]
[PART 2] 
[PART 2.5]

Sorry this post has taken me so long to get up, life has gotten pretty hectic with thesis and FYP in full flight now. But hopefully when I get this up I can go back to the idea of updating on Thursdays.

The last post was about molding and casting and I finished with pulling the potato from the mold, so next up is details and finishing. When the potato came out of the mold there was a slight seam on it from where the mold joined together so that was sanded down and given a nice finish with a bit of Isopon and 3M red putty. The scary part was the hole for the eye which sits wedged into the potato and is held in with what looks like staples. This, and the screws the crocodile clips cling too and the brackets for the wires, also required holes, so it was time to be brave and break out the rotary tool. There are 15 holes in total on the PotatOS body, and 8 on the eye piece. Thankfully nothing needed filling and re-drilling as I managed to get all the holes in the right spot on the first try.

Pro Tip: Measure twice and you’ll only need to cut (or drill) once.

After the holes in both pieces were drilled, it was time to prime them to get them ready for painting and while the primer was drying I sorted out some of the fiddly bits. I had made the brackets and the eye staples from various thicknesses of modeling wire. One bracket was an odd shape, and this required inserting wire into some tubing to get the desired look. You could use styrene tubing but after working in an art shop for 4 years I have acquired quiet a large amount of  tubes from the tops of brushes, so I used one of them. This odd shaped bracket and the eye staples needed to be  a darker colour, I painted them with the Warhammer paint “Tin Bitz” (the modeling wire took the paint rather nicely) and weathered them a bit with the Tamiya Weatherline Master Kit C which is used for weathered metal effects. Another little fiddly piece that needed to be made was the computer chip that sits beside the eye, a simple enough shape I made it from a little piece of mdf, and gave it foamex feet, and a foamex circle on top. A hole was made for one of the little red switches that will make PotatOS talk too. Despite it’s simple design this was possibly the most frustrating because it was the one piece I kept dropping, and one leg in perticular insisted on cracking every time it did!

A second coat of primer was needed for the main body but it was time to spray the eye white. This was done with an all purpose satin white acrylic spray paint. This gave the eye a slight sheen, which is what I image the piece was like when it was new, like most of the other white electronics in the game. The eye on PotatOS, however, is filthy and grimy so I took the dry pristine satin white eye and covered it in watered down black acrylic. This wash of acrylic was immediately wiped off leaving behind a dulled while look, with dirty smears all over it. I repeated this wash about 3 times, and touched up the groves in the eye with extra black before I was happy with it. The picture above shows a tester eye piece that has some weathering on it in comparison to the pure white eye that was used for the final piece.

Now it was time to paint the main body, I used Daler and Rowney FW inks for this as they’re the perfect consistency for my airbrush, but painting at night, in a room lit by warm artifical light, meant that the next morning I woke up and the potato was a dark mossy-muddy colour. I also realised I hadn’t glued on my roots, which needed to go on before the paint did, so I sanded everything back and super glued on my little roots which were sculpted from miliput and decided to try painting again, in proper daylight. Handily enough the hole in the potato for the eye, was the same size as a large System 3 acrylic tub, so I used that to prop up the potato as I sprayed. The colour turned out much lighter than the original which was good, and I added detail to it with darker brown where marks in the potato would be and the roots were painted greenish. I tired to keep the  texture as close to the one on the digital model so if you were looking at the two side by side, they would be very similar.

While the main body was drying, I decided to sort out the electronics behind the eye, There was space for 3 LED’s, and one of the red switches behind the eye and the hole in the centre was filled with some sanded down thick acetate which was tinted yellow so the eye would still look yellow even with the LEDs switched off. The 3 LEDs were hooked up to a 9V battery and an on-off switch that were located outside the potato body so I could switch them off to save power and change the battery easily. The wires for these were fed through the hole for the mount into the base that the potato would rest on. The same was done for the sound, which was hooked up to the two mini switches in the eye and the chip, and then fed through the mount to two larger buttons on the front of the base for when the perspex box would sit over the PotatOS.

Once the body was painted, I added in the brackets and the nails so I could shape the black wires and crocodile clips. Rather than having wire randomly contorting and pulling on the brackets I pulled the inside out of some old VGA cable and replaced it with a soft modeling wire that was the correct thickness, then bent this into the right shape. The coloured bands on these cables were added with some plastic tubing slid down the wire into place, and then painted. While the brackets and nails were held in place and glued, the crocodile  clips were attached freely. The ends would be glued to the eye, and the brackets would help keep the wires in place.

The internal support was then sorted out so the potato could be screwed into the stand from the bottom once it was fully assembled. This support was also hollow so the wires from the eye and the sound could be fed through to two switches at the front for voice, and one at the back for LEDs. With this bit figured out, the base was removed and then sprayed white and switches inserted into the holes cut for them. Meanwhile, I began fitting the sound chip, it’s battery and a speaker into the Potato, which were held in place by bits of strong hook and loop pads so they could be remove easily if the needed to be replaced or fixed. The wires from the LEDs were then fed through the hollow support along with the ones for the sound. At this point the extra switches for the sound that were part of the potato, were put in place, and then the eye inserted and secured with it’s pins. The microchip was added and one of the switches fixed into place. Yellow wires that wrap around the potato were added and fixed in place with glue before the black wires with the crocodile cable was added. Finally the black wires were added glued into place at the eye. Screwing the Potato back into the base and putting it gently on it’s side, the wires were soldered carefully to their corresponding switches and tested. Success! One light up, talking, PotatOS!

PotatOS Project Part 2.5 (Molding and Casting)

[PART 1]
[PART 2]

This is just a side post, or half post dedicated entirely to molding and casting. For this project I did  a standard pouring mold for the eye piece, and a 2 part jacket mold for the potato using Smooth-On products. I had never used Smooth-On stuff before this project as I usually bought standard mold making silicone from a local place. Everybody has different preferences when it comes to silicone products but I do recommend you at least give them a shot. I don’t think I’ll be using anything else for a while.

So, lets start with the eye piece!  After a coat or two of primer and a good sanding, I was happy with the smooth finish on the eye, and decided to mold it using the left over OOMOO 30 silicone from my original molding disaster.
To start, I took a scrap piece of MDF and fixed my eye piece to the centre of it using double sided tape. Rather than waste silicone by making a square mold box, I cut the top off a plastic pint glass. I made sure I had enough space at the top to fill in extra silicone as I didn’t want the base being too thin, and used hot glue to temporarily fix the top of the cup to the MDF. It’s a good idea to make sure you cover the entire seam in hot glue to make sure silicone doesn’t start flowing out the bottom of your mold, because if it can it will. You can also see in the background of this image the two parts of OOMOO 30 ready to go, this mixes in a 1A:1B ratio by volume which is super handy.

Pro Tip: It’s always better to mix more than you need, then run out halfway. (This applies to everything)
You can see here that when the two parts of OOMOO 30 are mixed properly, they make a lovely purple colour. When you no longer see any streaks of the original colours, your silicone is ready to pour. Make sure you pour from the lowest part of the molding box, so in my case down the side, and let the silicone build up and level itself out. The great thing about OOMOO 30 is that it doesn’t need to be put in a vacum chamber like a lot of other silicone, it has a low viscosity in comparison to others, and the air bubbles in it rise naturally. If you need to give it an extra tap that’s no problem, but my eye piece mold came out perfectly with no air bubbles what-so-ever.
I originally wanted to trim the middle bit of the mold one I’d pulled the original out, but after I de-molded the eye the I realised the part was thick enough, and the silicone rigid enough so I didn’t need to. The mold was so crisp and clean that no tidying up will be needed for any pulls. Because the potato was going to be made using Smooth Cast 305, I decided to test that out for the eye piece as well, however, because that takes 30 mins to cure, it was awkward to do a slosh cast of the eye. I did a couple of testers using simple fast curing bi resin, and smooth cast 305 and anything that didn’t work out was then used for paint tests later on.
The eye was kinda done in two parts, the first bit was the top because it needed to stay flat and preferably flat on the underside (unlike the white one in that picture), I pour in a bit to cover the top and let that cure. The second part was the sides, it took about 4 layers to get it thick enough, but I poured in a little resin at a time, and rotated the piece making sure the sides were evenly covered while it was curing. Resin sticks to resin so there wasn’t any problem with it cracking or splitting when I pulled it out. I also didn’t need to be too worried about the end of it being too tidy as it would be inserting into the potato anyway.

Next up is the Potato! Rather than using OOMOO 30 again, I decided to go for the cheaper but very effective option of using Rebound 25 for the potato.
 This brush on silicone doesn’t require any vacuum chamber either, and only takes about 4 thin layers to get a good negative of your object. I started with a lump of clay, and  built it up to roughly the halfway mark of such an awkward shape. The little nodules I made in the clay using a screwdriver are a key for when you’re putting the the mold back together so your mold doesn’t end up not aligning properly.

The first layer goes on nice and thinly as you can see in the picture here, making sure you get a good even coat all over, and after an hour a thicker layer can be
added and so on until you have 4 to 5 layers of silicone on that side. I added silicone thickener to one layer so that I could build up some support around the edges and where the lumps cause undercuts. Once all the layers were on I left the top half over night to cure
fully so it didn’t warp or anything if I took it off too early. The next morning when I was sure everything was completely cured I put a shell of plaster over this side of the mold, this acts as a supporting shell to help the mold keep its shape while the material you’re casting is curing. When that was completely dry, I flipped it over, removed all the clay and cleaned the surface. Once a coating of release agent and sealer was put on I basically repeated the whole thing again to get the other side. Make sure you leave a gap between the plaster layers though because they will want to fuse together.

Pro Tip: Release agent will stop the two sides of your silicone mold sticking together and help with the de-molding process too if it’s a tricky shape!
Once everything was cured and the plaster was completely dry, it was time to remove the original potato and make a new one. I cleaned out the inside of the mold and mixed equal parts A and B of Smooth Cast 305 and pored this into the bottom of the mold. Then I closed the mold and tied it shut with some straps with metal fasteners and rotated in every direction possible to make sure the entire inside of the mold was covered. I did this for about 15 mins, and then left the plastic cure for another 15. It should be noted if you’re doing this, and you’re not a whiz at mold making, or maybe if you are a whiz, chances are you might not get it perfectly sealed up, either way, always wear gloves in case some resin decides to leak out the sides onto your hands.
Oh! and make sure you remove any resin trying to fuse the two plaster sides together when it’s still soft because if you don’t you’ll have a nasty job on your hands if it cures fully.  The first pull brought with it all the excess dirt and bits I couldn’t see out of the mold so I kept that one as spare and basically did the same thing again only with a little more resin to get the potato I was going to use. The next step will be cleaning this up and giving it a bit of a sand before I carve the eye hole and give it some colour!

Better get to it!


PotatOS Project Part 2

[PART 1]

[Sorry for the lack of pics in this post! Completely forgot to take pictures of the electronics on their own except for the bad one of the sound board! Hope you enjoy the rest of the post!]

Now where was I…

Last time I was talking about priming the potato and getting it all the one colour. That worked a treat, there were a few imperfections and raised lumps I hadn’t noticed that I got sanded down. I did not, however, want the potato to be perfectly smooth. It’s very tricky to do natural organic random dents and knicks in a man made potato, but I decided while I didn’t want massive lumps, bumps and chunks I didn’t want it to be pristine. If it was pristine, it’d look extremely fake. I’m being graded on this project as if I was making a prototype for a collectors piece or collectors toy so it’s allowed look plastic but not too plastic. Little hard to explain I guess but I don’t want it covered in dirt like it was just picked out of the ground either!

Anywho, I got my potato primed and sanded a few times until I was happy. I had ordered some Smooth-On OOMOO 30 silicone from Kaupo.de and that is when disaster struck. The original plan was to do a two part block mold of the potato, and then slush cast it so I had a hollow version to fit the electronics into. It seems I didn’t order enough for one side, let alone two and I didn’t trust my instincts and poured anyway. The silicone didn’t even come close to enough, and it was an extreme waste! I had removed a lot of the negitive space by packing in some extra clay, but then the mold walls ended up a bit too thin.

Pro Tip: Trust your instinct and don’t mold when you’re extra tired!

Now while the silicone didn’t work out, and when I pulled the potato from half the mold it was a little too transparent to make a plaster jacket for, I have to say OOMOO 30 is really nice stuff. It’s advertised as a silicone that is so fluid that it doesn’t need a degassing chamber, it does it all itself!  there was not an air bubble in sight on the inside of that mold! I was really impressed. Most of the Smooth-On range is just mixed 1:1 by volume which is dead handy! OOMOO 30 cures in 6 hours, but there’s an OOMOO 25 that curse in just 75 minutes for those than need their mold pronto. I don’t think I’ll be trying that one for a while, it only has a mixing time of 15 minutes and I’d hate for it to start curing while I work. I’ll get better at mixing quickly, then we’ll see.

The potato was resting in a chunk of clay because I was doing a two part mold, this was packed in to about halfway around and then silicone is poured ontop. Ideally when that cures, I flip it over, remove the clay, clean the silicone and add some release agent before doing the second half. That didn’t happen so I had to pull the potato from the lump of clay it was resting it because I was terrified the damp would do damage to the model. I’m not sure how well primer takes to sitting in moist clay for a long period, but I’m certainly not going to test it now.

So, while I wait for more silicone to arrive, I decided to give the electronics a shot!  Shane kept me company while I was working on these as he had a little more soldering experience than me. I also find I work well in the company of others, especially other people that I can bounce ideas and questions off. Even if the person doesn’t know the answer, just hearing it out loud or saying it can be enough for your brain to turn around and tell you you’re being silly, or say, well why not give it a shot?

As I said in PART 1, I was never good at electronics in school. We learnt a fair bit in physics, but because I was relatively good at the nuclear physics end, that usually got me through exams ok. We don’t learn electronics in college unless we teach ourselves so this was going to be an exercise in that. It is probably due to my lack on knowledge that plan A didn’t work out to well, so plan B was implemented. If anyone out there reading this has any ideas or sugestions on the electronics they’d like to toss my way feel free to add it to the comments below.

After a lot of trial and error
and way to much money (shall definitely be investigating seriously cheap online electronic stores next time) I have a soundboard that has 2 push buttons for the outside of the potato (one for the red dot on her eye – and one for the small one on her computer chip) that are wired to the soundboard. It’ll be more like a toy or collectors item this way – push button A for phrase 1 and push button B for phase 2. The soundboard has a little mic in it so I can record directly from my laptop and runs on a 6V battery. I also got a speaker from an audio kit because the soundboard didn’t have it’s own. I’ll have to make a plastic tube for it to help with the accoustics but it seems to work rather well. there’ll be 2-3 LEDs around her eye and everything will have an off switch too.
Oh speaking of her eye, there was a bit of a Health and Safety issue in the college still so instead of laser cutting out 3 discs of 5mm MDF and one of 1.5-2mm, I had my dadteach me how to use his router and cut out my own. This was a little awkward because the eye piece is only 65mm in diameter, and the router much prefers to cut big things.  We made a template that was about 60mm in diameter by using a hole saw drill bit. This was because the guard on the router that edges it around the template, would add an extra 8mm or so to the diameter. After the circles were all cut out, I was able to glue them together and sand them back down, nice and evenly, to 65mm using what was basically a vertical lathe constructed from a drill press, a drill, and a metal bar with my circles clamped down the end.


Once the 3 larger discs were sanded I filed down
 the grove in the eye piece that goes across the lower circles. It’s about 1mm deep and 1mm across. My squared needle file was the perfect size for it. I then added the smaller upper circle that was also cut using a hole saw drill bit, and filed a little hole where the red button is going to go. This’ll be cast and slush molded so it’s hollow enough to fit various electronics underneath. Because it was still a little rough on the edges I added some red putty smooth it out before priming.

I gave the eye a quick sanding with very fine paper to get any small blemishes out, and re-primed so it had a perfectly smooth finish. The very centre was still a bit lumpy from the glue I used to attach the smaller disc, but because that was going to be removed from the final cast, it didn’t bother me so much. The next post will show how I molded this eye piece and the main potato.

[PART 2.5]

PotatOS Project Part 1


        4th year in my course consists of 2 projects and 1 thesis. The 2 projects are called the “Initial Project” and the “Final Project”. The Inital Project can be anything you want, so long as it fits into a 1 foot cubed clear perspex box. Due to the fact it’s in a 1ft cubed space it’ll need to be about 10″ cubed to make it fit nicely and look presentable rather than squished up against the sides. The project is allowed be connected to your final project, and even be part of it so, for example, if you were doing a stop motion animation, you could make your character and a prop or two to put inside the box. Then, when the Final Project comes around you’ll already have a bit done.

I dont know if my Initial Project will be directly connected to my Final Project or not, but I decided to make PotatOS from the Valve game Portal 2. For those of you who dont know PotatOS is a version of the main antagonist of the Portal series, GLaDOS. She has been confined to a potato as punishment and you end up carrying her around the game in potato form for quiet some time. The following picture is of the in game model and I aim to make a real life version as close to this as possible. All going according to plan, she’ll have LEDs and a voice by the end of it. Which is an excellent exercise for me in electronics as I was never very good at it in school!

        The first step was to make the actual potato. One of my main reasons for making PotatOS was I wanted to make a really accurate version. Most of the versions I could find online were attached to real potatoes or they’d just cast a large potato instead. I decided to sculpt mine instead, and try make it as close to the in game potato shape as possible. I also wanted to make sure I added in the roots which I consider a rather obvious feature that a lot of people leave out.

I started by drawing a series of outlines of PotatOS. These were done by taking screen caps of the front, back, side, top and bottom of the model in 3ds Max which Shane helped me rip from the game using 3D Ripper DX. This is a very useful tool which I’d certainly love to use again, but it is trick to get the model out without it becoming skewed in some way. This is where Shane came in, he’s like the computer whisperer!


Before going on to making actual PotatOS, while I had the 3D model I decided to print out and make a Pepakura version so I’d get a proper sense of the shape. There’s a big difference between looking at a 3D model on the computer and actually holding one in your hands, so having a prototype was extremely handy for the first part of the project.

After I’d finished the outlines, I printed out a copy of  the front, side and back. Turns out I didn’t really need the bottom and top. After some enlarging and size tweaking I managed  to get them printing so each one was aout 18cm tall. Now, that may sound huge, and I thought it too, but PotatOS is actually quiet a large model, more of a sweet PotatOS really. I glued these outlines to some scrap card so I could use them as templates.

In 1st year we made fake fruit as part of a replication module. This was done by drawing a front, back and 2 side views of the fruit, lining them up, and sticking them to a cube of foam so when you passed the foam through a hot wire cutter you had a template to move around. I was using the same basic idea for PotatOS except I was carving her out rather than cutting her out with a hot wire. A friend of mine had a lot of scraps left over from making some Daft Punk helmets so I stuck a few pieces together so I had a block big enough. This saved me buying a massive sheet of insulation foam I just didn’t need! 

I carved the initial big chunks away with a knife and as you can probably see in the previous picture I had a big thick black outline so i’d only carve close out the outside of the black like and then use a sanding block and 250 grit sandpaper to start rounding it down into the right shape. It might be hard to see in the initial image but PotatOS has a few lumps and bumps on her close to her eye, and then there’s also the dents and holes for the roots but I decided to sand those bits away and add them back in at a later date. 

After I had her completely rounded down, it was then time to protect the foam from priming and painting. If you spray an aerosol paint or primer onto any form of polystyrene you’re going to end up with a very molten sticky puddle on your hands. First off I cover her gradually in a thin layer of Isopon which is a car body filler and the European version of 3M’s Bondo that most prop tutorials seem to mention online. By the looks of things though, Bondo seems to be a bit more gooey and smooth in comparison to Isopon. Anyway, once the Isopon was dry, I then built the bumps back up with Milliput and modeled the root holes and eyes in the potato.
 Then began sanding the whole thing back down again, so I had a nice smooth finish. Unfortunately Isopon has a tendancy to get little pin holes and dents in it so my lecturer suggested I try 3M Red Acryl Glazing Putty, which apparently goes on after Isopon. The putty filled in all the deep sandpaper scratches left over from the lower grades and all the pin holes and dents were filled in.

This needed to be built up in a thin layer first though, so it required more sanding to get back to the surface. The picture here is off a section I’d managed to sand back, as you can see there are some red streaks where scratches have been filled in.
 This is completely sanded back now, and after sealing some patches of exposed foam with a bit of acrylic and making a few changes to the bumps and root hold I put in the wrong place, I’ve started priming with grey car primer. This will take a few coats becuase once everything goes the one shade, it’ll be very easy to see every detail so i’ll be sanding it back again.

Pro Tip: Grey is the best colour for photographing detail, that’s one of the reasons Super Sculpey firm is grey.

That’s all for now! I better get back to priming and sanding!

[PART 2]
[PART 2.5]