Silicone and polyurethane resin beware: I have entered the world of casting!

I'll skip all the introduction, I have moved it to the New Puzzles thread here. Right to the building:

First off, thanks to the.drizzle for pointing me to BRL-CAD. This sort of simple shape project was not hard in that tool, although doing more complicated projects in BRL-CAD does give me pause.
Thanks also to Bradley at PrinTo3D for the parts

First up: Master preparation. I don't have acetone, but I do have milliput. Rubbing some into the grooves of the printed parts and sanding gave me good results. The final part is much closer to the ideal size because I am not sanding to the bottom of the grooves of the filaments. On these I did most of the work with 220 grit, but finished up with 1500 grit, then plain paper for a nice shine:





I have been seeing a lot of puzzles lately that seem to give up on sanding the masters. Stuff with a real grain to it. I can't understand why it isn't worth a bit of prep. I think the results are worth it, my pieces come out of the mold shiny.

If you are wondering what the white and black edge is on the part, that is recovery from a mistake.
I got off to a terrible start by being completely wrong on the measurements. A keychain 3x3x3 is a nice even 10mm per cubie. A keychain 2x2x2 is 12mm per cubie. Don't confuse these two like I did. My wonderful parts came in sized to fit a 10mm cubie, just like I specified them. Oops.
It wouldn't have cost much to print the properly sized up version (120%), but what the heck, I am a builder, right? I have plastic, glue and a file. 2mm is just about 1/16" (1.5mm) and the thickness of the .5mm grey plastic I used to cap my Square-2 corners. This was a huge detour and a lot of work, but I am fairly satisfied with the result. Here you can see the acrylic followed by the grey plastic:


I decided to do a two part squish mold, so the part line is right along one face, making clean up of the part line much simpler (it is on an edge). I "borrowed" some of the idea of Drewseph's method in that I pour a bit of resin into the top to fill the corners before flipping it over and squishing in. I don't bother to wait though, enough seems to hold in to avoid most air bubbles. I had a few (easily fixed by filling) but am getting better and had none on the last half of the puzzle.
It is hard to see from the angle of the picture, but the mold comes up at about 45 degrees from the part line, giving me a nice deep trough for the resin to sit in when I pour.


Finally, my sad little casting station in my garage:

Cold (55F degrees, 30 minute resin hardening times with Alumilite black), cramped and not ideal for the task.
I later moved to a small bathroom once I realized the fumes were not nearly as bad as I had worried about. I could heat that with a space heater and that made the resin much happier.

Enjoy,

Dave

Amazing puzzles Dave, i really like the inverted 2x2x2 it looks real fun to play with.

Very cool puzzles! I'm also surprised that no one had pillowed the 2x2 before.

Too radical for you, huh? OK, be a square (or pillow) like the rest. I gotta be me.

Funny thing is, all my work on this project was for the Inverted cube. The pillowed version was a complete afterthought, more of a "why not?" since I was printing some parts.

Dave

I'm reminded of the statue from Beetle Juice...
Great Job!

The inverted 2x2x2 looks very organic to me. Nice puzzles!

They look flawless! Great, professions work as usual, Dave.

I like the inverted 2x2x2. At first I thought you covered one cubie at a time with milliput and "extruded" the putty by pulling it out with your fingers.

Nice Pillowed 2x2x2. And a great post too.

But Dave, the Inverted 2x2x2 is just plain silly.

Thomas

Now if you place eight rotatable pieces to fully cover all eight spikes,
then you got a 4D8!!!!



Great job David!




Pantazis

Silly? You haven't seen silly. I'll show you silly on my next project. Then you'll look back and think how serious the Inverted 2x2x2 is in comparison.

To quote "Batman Begins" (with some modifications):

"You aren't silly. You're practice!"

Dave

Someone PMd me about the construction of the mold and I thought the answer would be better as a post.

It was a fair bit of work. The theory was to put the one face up, with the cubie cutout down flat. I have never liked mold lines down the center of a face. So I wanted to try to keep them on edges.

I started by taking clay and attaching it to one face of the piece. Then I took a long time trimming away at it until it was just touching that one face, with a line right along the edge (well, it was almost perfect).
This was hard because as I worked with the clay, it got warm and soft, so I kept pushing it out of form.
I had the clay form a pyramid like base to this face, so the part line went about 45 degrees away from each edge, making for a nice trough. I then took a flat bunch of clay and put it on my lego base plate.
The hard part (all over again) was attaching the part and pyramid to the clay base, as fusing them together meant more deformations of the part already attached to the face.
Finally, I used a few lego heads to stick up from the clay as alignment pins. I didn't have room in some areas (and only a few lego heads) so I used a dowel to push down in the other areas.

Eventually I had it attached to the base, and built the lego wall around it, and poured the first half of the silicone. After it set up, I removed the clay and flipped it over. The lego heads round in at the bottom and some were not pushed far enough in the clay, so I trimmed away the overhang (you can see the cut marks).

Next re-build the lego walls and spray some Mann 200 release and I was ready for the second pour. A quick note: This gets all over your part, too. So one of the three faces doesn't cast smooth like I sanded it, but "satin" as Mann describes it. Hrmmmph. I suppose I could have gone through the trouble of trying to wipe off the part without wiping the mold release off of the mold, but I didn't want to risk it. Perhaps in the future I can put down a custom cut mask (just the exposed part), spray, then remove the mask.

The second pour was pretty easy, and once it cured I was done.

This was my first mold, so I am pretty happy it turned out without any big flaw. I went way too conservative on the Inverted piece, that's a lot of wasted rubber around it, but I wanted two in one mold and I needed that size for the pillowed piece. I could have been a bit better on the part line, it isn't perfectly on the edge (it dips towards the corner). But I can get good pieces from it so I consider it a good start.

Dave

Nice work, Dave!

I think the time you spent cleaning up the masters really shows!
And the inverted 2x2 looks great! I thought you were going to call it
the anti-pillow though

One of these days I have to try my hand at casting!

Cheers,
Derek

I think the inverted one makes a very nice stand for the pillowed one, and they both look great, together or apart.

Great work! I am really interested in your next project...


For the master part cleanup, I think the reason that many puzzles are made with minimal cleanup is due to the time involved. For a higher order puzzle this is due to having several copies of each part and filling and sanding 50-100+ master parts is a huge project. This is why alternative methods are getting attention (Polyjet, CNC machining, etc.). In addition to this, some of the puzzles are made from entirely 3D printed parts. They only need to be smooth to work, and polishing every surface is not needed. The bottom line is it is a trade off between quality and time when dealing with FDM master parts.


Back on topic: I am really interested in seeing how they look when stickered; especially the concave surfaces.

Dave, this is fantastic work! It's fun to see this after handling the masters in person and seeing the cubie size difference you had to correct for.
Congratulations. I can't wait to see them stickered.

Wow Dave, awesome work, and as this is your first casting work, I have to say Kudos for making the extra effort!
You are definitely someone who takes pride in your work.

thanks for the response on the mold making. I'm just curious how much rubber this actually took to make?? It seems you had to use quite a bit (that's a lot of mixing :/) I've just barely touched casting stuff so I'm sure I'm in for a big surprise when I realize how much material I actually have to get to make a decent mold :/ lol

The large part of the mold took 150ml (75ml of each part). The second part (the top) was 30ml (15ml of each part).

To get a rough sense of how much volume would be necessary I did a box measurement first: Build your box first, estimating the height you will need. The OOMOO guide (and what I see/read on the forum) recommend at least 1/4" outside your part. This also gives you room for the alignment pins. Then measure the box volume by pouring water into it. It leaked out a bit (much thinner than silicone), but I just needed an estimate.

I actually measured a box intended for just one part. It was a 5x5x5 box in lego measurements, or 125 "Lego" units. I took 100ml of water in a measured cup and poured it in and noted how much remained in the cup when the box was full (10ml). So this box was was about 90ml. So when I went to a box for both parts, I could use this ratio to estimate the box size of the new box (250Lego = 180ml). Since I knew I would be using about 1/4 of the box with the clay and parts, I estimated 150ml for the first pour and about 30ml for the second. There was a bit extra as I never filled all the way up to the 5th Lego layer (*always* have a bit extra) so I used the excess to do a small one part mold for a future project.

I suppose I could have measured the lego blocks and used those to calculate the measurement but direct measuring was quite satisying. My measurement came out ot 0.72ml per Lego unit, but you can probably use 0.75 (3/4)and make the math simple. My measurement was influenced by the raised pips of the lego base, but the low accuracy you need means that is really not important. So for people reading this thread, one of the more useful facts to take away is:

1Lego unit = ~ 3/4ml of silicone
[Edit: a more proper measurement is 0.64ml per block]

Because I combined the Inverted and Pillowed I used more silicone than I should have for the Inverted. But a bit more makes for a solid mold and holds its heat better after warming in the microwave, which is good. So be generous. Silicone isn't cheap, but a little extra isn't a big deal.

I used OOMOO30, and it was pretty sticky messy stuff. The biggest mess was trying to scrape the excess out of the mixing cup. I would tip the cup to pour, and then when I scraped the edges it ran down the mixing stick I was using to scrape. Yuck.

A minor clean up tip (obvious, but perhaps you are as dense as I was): Just leave the excess in the cup. The first pour I spent a bit of time wiping it all out of the cup with a few paper towels. What's going to happen if you just leave it? It solidifies and peels off easily. Duh! Clean up was much simpler the second pour.

Dave

wow!!!!! they are amazing!!! great job omaygod

Wow! I really like the way those look... I'm especially curious to see how the inverted one will look once it's been stickered.

Good job on both of them. It looks like you could really hurt your fingers on the second one though.

That may not be so funny for those who are Diabetics on the forum you may want to remove that post

Perhaps he/she is diabetic?

I go by the notion that everyone should be able to take a jest, but alas I am not a moderator.

It is there decision.

*EDIT*

Forgot to say that I think the inverted is such an interesting and clever idea.

That's some pretty slick casting there, boss. I too think that filling and shaping with 2 part epoxy putty is probably better than even using solvents because the puzzle is more "true" to its original dimensions. But I guess those dimensions depend heavily on how the layers are being deposited.

Just to add to that tip- you can take that leftover oomoo out of the cup, chop it up into little bits, and re-use it as filler for larger molds after you've covered the part. I've recycled many mold leftovers that way. It makes you feel a little less wasteful when making those larger molds.

BTW, I can't wait to see that inverted cube stickered!

I am impatient. I couldn't wait until next month to properly cut stickers, and wanted to see if I could sticker the concave surface of the Inverted 2x2x2, so I cut some stickers by hand (poorly...) to try it out.
*Way* more work than I should have spent for something I will replace, but what the heck.

The stickers work fine, the concave surface isn't very deep.

Since I was just doing a temporary job and using scraps I tried gold and silver instead of yellow and white. I love the gold and silver and they work great on puzzles needing lots of colors, but the gold is too close to the orange so I think I prefer the standard colors. I'll do that when I cut them on the plotter.




Enjoy,

Dave

AAHHHHHH!


Good Job.

May I call it the "Pagoda Cube"?
Pretty please?




Pantazis

Hmmmm.... Perhaps the "Fearsome Pagoda". Yeah, that has a ring to it...

Dave

I couldn't tell. Have you seen my "poorly hand cut" stickers? I can't get it anywhere near your quality!

Why didn't I reply to this earlier? Stupid Jon! Amazing job, Dave. It's funny how every society has even tiny rebellions against popularity. People like pillowed cubes right now, and you made an anti-pillow cube. Now I want to see an inverted 3x3. And 4x4. And 5x5. And every other puzzle that's ever even thought about pillowing itself.

Anyways, Your inverted 2x2 really appeals to me. It looks a little like a virus. If you combine it with your pillowed 2x2, extend the points, and add little knobs at the end, I'll faint. And if you sticker it in all different shades of green, I'll be praying for my life. In other words, PLEASE make a puzzle that slightly resembles this, Dave! Except, you know, with only 8 thick arms.

Why not go all the way and call it "Dave Litwin's Fearsome Pagoda!" (Had to add your last name to match up the syllables)

-Jon

(Edited only because I forgot to add my name. Not because I did something stupid.)

Pillowing a deep cut puzzle is fairly simple because the proportions remain the same. If you try to pillow a non-deep cut puzzle you have to extend the outer layers quite a bit to get the proper inversion, leaving you with non cubic slices, which doesn't appeal to me. You can, with a non-trivial amount of work, make one with proper proportions but that would, in the opinion of some, be exceedingly silly.
Very cool idea. Not soon though, too many other projects to attend to.

Dave

To make an Inverted 3x3, wouldn't it be possible to use a void cube, and put something in the center? Or would it come in the way of the rails?

Good thing you like it. There are plenty of puzzles out there that look like they can kill you. Unfortunately, all of these are sharp. We don't live in the bronze age. Our soldiers don't carry swords as their primary weapons. We need dangerous puzzles that keep up with the times.
Plus, green is my favorite color.

-Jon

I could have been clearer in my comment. If you can't cut in, you have to extend out. A shallow inversion could be done with an existing 3x3x3 mechanism by just cutting down into the centers. But I want a challenge, and the Inversion I am going for is deeper than can be done with the conventional mechanism.
The void cube mechanism can be cut very deep in the absolute center (all the way through!) but the structure of the rails limits you outside of that.

Dave

Sorry for the bump, I wasn't sure this deserved a new thread.

I had lunch with Jason yesterday and had a chance to see his Petaminx (before it gets sold...). I brought an unstickered Inverted 2x2x2 to show, and it turned out to be a great stand for the Petaminx:


Dave

I'd love a pillowed 2x2, but as your last post shows, the inverted one doubles as much more than a fruit stand.

The inverted one has a great, artistic feet to it, too. I can't wait to see it stickered!

EDIT: Has there been a pillowed 3x3 yet?

Thats beastly!

Well, I'm certainly glad you brought this to my attention. I overlooked this thread during my recent sabbatical.

I think you've got a good premise here: transform a simple puzzle into a display stand for a larger puzzle. It's dramatic and thematically-appropriate!

There must be plenty of trivial puzzles that could serve this noble role. I think it would make an excellent "bonus" to sell a custom puzzle with a custom-puzzle-stand made from another puzzle.

Hmmm, seems like the inverted 2x2x2 is actually more practical than previously thought, LOL!

So true!

Smaller puzzles, can indeed be used as stands for bigger ones.
To support this claim, here is the Paragon of Atlantis (or any 9-tile
folding puzzle), which is a PERFECT stand for the Memory Cube.
viewtopic.php?t=6549
(the stability of it, is extremely natural!)




Pantazis

Yet another example.

Great one!
Luckily I can copy this since yesterday

Somehow I just KNEW you were going to mention that.

So Flambore, have you thought about throwing in an inverted 2x2 for the winner of the Petaminx auction?

Umm, that would be Io, not flambore. I don't have one for sale.

Both Jason and Frank will soon have Inverted 2x2x2s, but I am guessing they will not be looking to sell them.
I'll be cutting some stickers tonight (I hope, if the vinyl cutter is really fixed this time) and then post in New Puzzles, which is long overdue for these two puzzles. If this generates some demand, perhaps I'll make a few more for sale or trade.

Dave

Hehe, whoops, I keep getting all you builder people mixed up.

Finally stickered! See pictures in the New Puzzles thread here.

Dave

Time for a minor update. I have built a mold of four of the Inverted 2x2x2 corners. I used the original master and three cast from it. I cleaned up the pieces to remove some of the minor flaws from the original master.

This time I chose to cast them point down. I really wanted to try to keep all mold lines off of any visible surface. The result was successful, with the mold lines all on the inside edge of the piece. It does mean the tip of the piece is prone to having an air bubble, which I remove with a toothpick as I pour.


Here is a picture of the new mold with the pieces on one half to show how I put them in the clay. It took a very long time to get the clay part line just right, and to have it slope down from the piece to form a trough, but it was worth it:

This is a view of the mold right after I take off the top. You can see how the pieces sit in the trough which allows the top to squish in and push out the air (and a bit of resin, but not too much).

Here is a picture of the pieces pulled from the mold. If I am careful and flex the mold a bit it comes out all in one piece, but most often I take it out in parts.

Here is a picture of a piece where I didn't get the bubble out of the tip. I can repair this by dripping a dab of partially hardened resin in it, but the sanding is often not worth it. For one this bad I'll toss it, for one with a more minor bubble I will try to repair it.

Next up is new molds for the Pillowed 2x2x2. I have not poured it yet, but have done the clay. Again this took a long time, and I chose to keep the same configuration as the original. The main factor here was I wanted to hollow out the piece, and that means keeping the hollow part vertical. I only hollowed out two pieces and given their size I decided to mold two at a time:

Here you can see the carefully sculpted clay line to be just along the piece edge and slope down to form a trough in the other half.

Here you can see how the pieces have been hollowed out. It is hard to smooth the inside, but I tried as the smoother it is the easier it will be to demold and the longer the mold will hold up.

Dave

Thanks for posting those pictures, it's cool to see how you set it up.