I Have To Do Something With All of These Crayons!

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The Worst Way to Make Candles

I Like To Make Stuff

[smartereveryday]

Dude... as a child that candle store you worked at blew my mind.

[Riku]

Mechanical design engineer here with some relevant at-work experience in mold-based manufacturing via thermoplastic injection molding, RIM and metal casting. Here's a couple of pointers to help in similar projects in the future:
1. Make the TPU gasket into a narrow sealing band just on the mold cavity border instead of a full layer on the parting line plane: the clamping forces needed for proper sealing without flash will be drastically lower. Make the TPU seal protrude from the parting line plane about 30% of the seal's thickness (think of it as an O-ring gasket on a flat flange connection), so when the hard mold faces seat, the TPU is adequately compressed, without deforming the mold halves.
It's also beneficial to use a seal cross section geometry that is, depending on your application, either a right angle triangle where the vertical side is parallel to the cavity wall or an isosceles triangle, if you're making a generic seal for an enclosure for things like outdoor or underwater housings for electronics. The thin point will compress more easily, compensating for more surface defects and non-planarity in the mold surfaces.
(side note: a similar pointed cross section geometry in the perimeter wall is used when designing parts for ultrasonic welding in thermoplastic assemblies, as the thin tip will focus the energy and therefore initiate the weld pool more easily, than a wide contact patch)
2. as you're already using additive manufacturing for the mold, you might as well incorporate the mold alignment registration features directly into the print. Most preferably a non-tolerance sensitive 2 DoF limiting shepe that registers in X & Y, clamping surfaces bottoming out registers in Z. A rectangular truncated pyramid, with corresponding drafts of about 5deg works well.
3. Along with the previous note for additive manufacturing:
by selecting a suitable infill, you can pre impregnate the mold with water to act as a heat sink due to water's high thermal capacity. Alternatively you can make only the inner mold cavity surface a solid shell, while leaving the rest of the mold open (tree supports in the clamping direction work well for this, as long as you start with a thick enough raft layer to distribute the clamping pressure). This way you can drop the mold in a container of cold water before pouring the wax, and the thinner shell (lets say 3..5 mm thick) will allow the heat to dissipate more easily into the water, while the vast amount of the mold's structure stays cool and rigid. If you have access to suitable fittings to make a coolant flow system, you could also incorporate a flowing coolant jacket around the mold cavity, just like in an IC engine around the cylinders, allowing for high thermal dissipation without fumbling with open containers of water but rather just a tap and some tubing.
4. for clean casts that don't have a shrink suction divot develop in the pour opening, you'd probably be well of having a bit of a spout in the mold for ease of pour. You can then just cut off the spout for a repeatable flat bottom for your casts.

Br. Long time casual viewer from Finland


edit: corrected multiple mistakes in spelling & grammar - probably didn't get them all 😅

[LTGormanLV-]

Us librarians love donated crayons! We melt them down and put them into silicon molds of letters. The bigger crayons are now easier for little hands to hold and color with 😀 Enjoying your channel!! 😊

[rickypacheco]

This is prime Bob. Learning adapting and taking us along in the ride. Very inventive.

[anthonyalfano]

My favorite part about this channel is how real you keep it. You show the trail and error. It’s a good reminder that not everything works every time and not to let it discourage you

[rtslord]

"it might look terrible but we won't know until we try it" is probably my favorite Bob saying/mantra yet 🤣

[dPrintCreator]

The reason I love your channel so much is that you don't only show all the perfect successes. You also show all the things you try, that fail, like we all experience.
Love it, please keep going on.

[ddutton]

if I remember right, the fancy candle places also have a water dip to help cool the exterior and let it build up without overheating.

[rrddaatube]

3D printed mould for giant crayons please! Melt down your remaining crayons and create giant versions of them.

[louschillaci]

This is the most hillarious episode ever. AND .... I am never doing this myself. Thanks for always being the GUINEA PIG. Keep 'em coming, I'm hooked!

[ccarruth]

Hi Bob! it's Christina from the Rock and Roll Race! I think we worked at the same Candle Company. I worked at all three locations. We had to learn from the River Street location but they had kiosks in both malls. I worked during the Christmas season about 30 years ago too! I remember working with Heather Grooms and Jennifer Kleinpeter. All of my candle were never full price. I couldn't master the technique fully to move past the reject shelf.

[mrxmry]

How hot was your wax? Was it just above melting point or was it considerably hotter than that?

[JonBaldry]

11 out of 10 for perseverance!! That said, I bet I'm not the only onw who shouted at the screen as soon as I saw you going to pour that wax into the plastic cup LOL!!

[abasecurrent]

Somewhere, a Crayon maker woke up. ”I felt a great disturbance, as if hundreds of voices suddenly cried out in terror and were suddenly merged in to one.”

[Ceira]

For consideration: Since the crayon wax is softer, maybe it could be used as a dip to make the outer layer rather than the core.

[jarrodsmith]

I love the "it might not work" comment Bob makes. So relatable! Trial and error are how we learn.

[juneritchie]

Thanks for sharing the journey! I always benefit from your 'stick-to-it" process (and when to "give-it-up"). My latest art installation could have failed without that type of inspiration. 👏👏

[nevet]

Charmander laying down with his tail up would be a cool candle

[Homesteadactivities]

We tried doing the same thing! But obviously the crayons aren’t best for candles, soooo we actually made fire starters out of the old crayons because they are actually flammable. So we melted them all down and made molds for fire starters and we can use them on future camping trips.

[nathanhiggins]

I love that most of your content is about experimenting and trying new things. Seeing what works and what doesn't but you always learn something.