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

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 😅

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!! 😊

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

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

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.

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.

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

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.

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

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!

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.

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. 👏👏

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

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

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.

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.

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

This is great for people who want to work on mold making for epoxy but aren't ready to commit to the expense of epoxy. Another great video showcasing the process of learning. Thanks Bob!

I’ve been thinking about doing a specific candle shape using 3d prints and silicone for over a year. And here you gave me the blueprint on how to do it! Thanks Bob!

We used to dig holes in the sand (while at the beach) and put a little piece of driftwood next to the hole for our candles. We mixed paraffin wax and crayons and filled the hole with wax. The wax would mix with the sand on the outside, but there would still be pure wax in the middle. Another cool technique is to pour wax into a container filled with ice cubes with one color. Then dump all the water out of the container and fill the voids left by the ice with a different color.

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.”

I really enjoy that you show the process not just the “win”

Try making water cooled molds. The gaskets are water tight so it should be easy to add internal channels and pump water trough them. It also might solve the heat issue.

Got a couple of recommendations, from a decade plus of 3D printing... 1. Thicker walls on the mold. They will stand up to heat better, and will be less likely to deform. 2. Make the outside of the mold a square box. It will help with clamping. Use the registration pins to keep the parts from sliding on each other. 3: Don't use PLA (or even PETG for that matter) for molds. Use something that can take heat, like ABS or ASA. PLA/PETG are good for cold molding, like concrete or low-temp resins.

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

Maybe FusionForMakers needs a second 'chapter' specifically on mold making

Just a thought/idea, if you designed some passage ways through your 3d print and then blew some compressed air through it when pouring the hot wax it may be enough to get the heat away so as not to distort the 3d print. And should help speed up the time to cool the wax also. Or another idea would be to 3d print a mould with an open infill that you could fill with water and freeze.

I have no idea what you were talking about about 90% of the time... But, YAYYYYYY, CANDLES! Cheers!

This was insanely relatable video, I feel like all of my recent projects required just as much problem solving and testing as this did. Very cool to see your process to reach your end goal!

I work in an aluminum foundry, and watching this is very interesting to me, In short, everything you covered in this video about molding and designing patterns, is the same process the we preform to create our patterns

That star mold could make some tree tops. Just use green wax and use a wood sticks in the middle.

23:08 - That was an awesome shot of the hardening wax.

Just wanted to mention that I'm loving these videos where you talk through the project and your thought process

I saw “candle” and thought “wow he’s really playing it safe” This has been one of the best videos I’ve seen to showcase iterative design.

From my experience of making candles: 1) If you try to create a layer of wax onto an existing candle by dipping it in, the liquid wax has to be as cool as possible - a good indicator is, that at the top around the edge the wax already starts solidifying. 2) The candle has to be relatively cold - I did it outdoor when it was cool/cold, but putting it into the fridge or freezer between the dips might have a similar effect. 3) Most cheap candles sold in Europe have a white core and the colour on the outside is just a thin layer, probably made by dipping it into intensely coloured wax. If you cut off the outer layer you can re-melt the core and get white wax, if you don't the candle still gets quite intensely dyed, especially if you use burned out candles. So if you have white wax, probably adding some crayons will dye it, but keep the other, desireable properties of the wax. 4) If you pour wax that is too hot, your mold will melt. 5) If you use a pot with a spout, it won't make such a mess

Bob - I’m always amazed at your 3D printing skills. I just recently got into the hobby and starting in on Fusion 360 in large part to watching you. Thanks for your inspiration!

When I've made candles in the past I've had a tub of cold water (maybe ice I dont remember) to harden each layer as I am dipping multiple times. Its probably better to cool the surface off as much as possible to make it harder for the next wax bath to melt the last layer.

I’m reminded of a hack that was a way to “recycle” crayons. (I never tried it.) It required putting small pieces of similarly colored crayons in different cups of a cupcake pan and then putting the pan into the oven until the crayons melted. After the wax solidified again, it could be popped out of the pan and used as a crayon, with the added bonus of the different shades of the same basic color in different areas of the crayon. Interestingly enough, there is also a survival hack that uses a crayon, in the paper sleeve, as a candle. (I haven’t tried this one, either.) The paper sleeve, loosened and slid up just a little bit past the wax at the pointed end of a new crayon, can be lit with a lighter and will act as a wick, using the wax inside as the candle. I’ll have to look both of these hare brained ideas up online. I enjoyed this video, and it is very thought provoking.

☕ cool beans ☕

I ate a lot of those 😂

I think a step you were missing when dipping it in a new color was immediately dunking it in cold water to harden the layer before dunking it back in. Unless you did that off camera and I didn't catch it. All of these experiments were amazing though and really helped you see through the process! 👍

Nice video,For Silicone pouring. I learnt to make a chimney (filling sprout) next to the object that is connected to the bottom of the mold. That way you can fill the mold bottom up via the chimney lessening the air bubbles. Worked like a charm when i cast a silicone gasket in the past.

I've been looking for a way to make custom molds for my mother's homemade soap and this gave me so many ideas so thank you

Need to reduce your temps ahead of time. Freeze the prints to help prevent them from softening. Same with the wax, use the absolute minimum temperature for dunking, and make sure the wax you're dunking is nice and cool beforehand.

It's encouraging to see the failures. Too often people expect stuff to work first time when in reality engineering is often an iterative process working towards the final working solution.

Rather than trying to clamp the sides together, why not make the mold have a perfectly square outer shape, the 3d print a hollow box that is open on the top and bottom that yo slide the mold into. if you make all the molds have a standard outer size, you would only need one outer sleeve unless you wanted to pour more than one candle at a time. Plus the increased mass may help with heat dissipation.

really cool to see you experimenting and learning throughout a video!

It's been a long time ago but I remember watching a show how they built up multiple layers on candles and if I remember right, after each 'dip' they then dipped the candles into cold water to help it solidify quickly preventing it from sort of running, and since it was cold for the next dip I think it prevented it from partially melting when dipped.

Fun video! Surely someone somewhere has created a 3d printer that prints candles!

I have missed this Bob. Bring him out to play more often!

7:06 would've been the perfect opportunity for an Alton Brown "camera in the fridge" moment

10:18 Mmmmmm, forbidden Mac n' Cheese!

They say play is the work of a child. Lucky for you play is your work also, and we’re just living vicariously through you!

Part of the reason that Crayon wax is so crumbly is because it is very pigment dense... You really do not need that many crayons to transfer the color to standard paraffin wax. We used to do up to three crayons per cup of paraffin. You can go a bit higher but you face more of the crumbly texture and fewer gives a bit lighter color density. You already figured out and demonstrated many of the little "issues" that crop up in mold making, especially multi part molds and yes, 3D printing can help prototype a LOT faster. Finally, thicker candles will take a LOT longer to harden... especially when encased in an insulator like plastic... you should also setup to do five or six perimeters to resist deformation and then you can drop infill to a minimum (like 10%) for structure.

you shoulda had an ice bath next to your wax dips so you can quick-chill the layers of wax buildup between each dip. It helps a ton.

I just kept thinking about the dandelion girl, watching all the dandelion crayons get melted ahhh!!!

For dip candles you have to cool them between each round. Usually in just cold water to keep them from melting like the blue/orange one did.

This video was worth it just to learn that Crayola recycles crayons and markers :D I never knew that and am VERY glad I do now!

You should try using candle wax for the candles but try coloring the candle wax with a small piece of candle. I've made a large pillar candle where I only used a 1/4 of a crayon to something like 4 cups of candle wax and it's amazing how much the color stays true to the crayon. In other words try just using a small amount of candle grated to color a large amount of candle wax. I never did figure out how much wax you could dye with a single crayon. Great fun video. Thanks!

Thank you for making your Fusion360 course discounted. I don't have a job right now and money it tight, but I love making things with my 3D printer and Laser cutter. I have some DIY projects and always wanted to learn. I hope to sign up today or ASAP. Thanks!!! P.S. I relate to the Bloopers, When I am trying to record stuff for my channel and as soon as I hit record.... there's that awkward silence I know that I look like a deer caught in the headlights and then all I can say is !!!! Dang, why does that happen LOL???

How about using Slush Casting technique to layer your colours instead of dipping. You could also refrigerate the layers in between pours (and hope not to have expansion cracking). You could also do the outer layer with regular candle wax and use the crayons as 'infill'.

Love the instant transmission sound effect

You can use a bucket of cold water to dunk in between layers. It helps the wax set. And use candle wax... maybe some crayons to color it.

You could use an immersion circulator (like what is used for sous vide cooking) to get your wax just above melting temp, so it hardens as it contacts air

There's actually a large cran recycling program that donates them. I didn't know that Crayola was taking them back to

The PETG / TPU combo is smart thinking!

I love how you pivoted and kept on going. Great job as always👍 I think you can use a double boiler for this. It might make it a bit safer to work with and cool down faster.

Love the new glasses Bob 😉

Really cool T-shirt right there! Now back to the video

I remember making a candle with my mom using crayons to color the candle wax maybe like 15-20% crayons. Our mold was a cardboard milk carton. First we filled it with ice then poured the wax into it was really interesting looking with all of the cavities from the ice melting. But the smell of the crayons burning was intense.

If the heat of the of the candle wax can dissipate, the wax itself will become the gasket. I made candle molds out of just regular printer paper and painters tape. The initial wax will seep through the paper, but as it cools rapidly is solidifies it becomes a barrier.

I've always used a double boiler with wax. (You can sit a pan with wax in it on a trivet in another pan filled with water.)

A couple ideas. You could try ABS type filament instead of PETG and try acetone vapor polishing to get really smooth walls in the mold, not sure if it would have a negative impact on TPU. Also when making the silicone mold you can use the same pin idea on the 3d printed part so it's exactly center and help ensure the wick hole ends up where you want it in the final candle

Good mold ideas, definitely will come handy in my own projects :)

I admire your persistence. Such a complex process to end up with a Crayola turd-candle 🤪. Enjoyed the journey though.

23:02 Hearing a William Benckert track in an ILTMS video makes me miss Now in the 90s channel even more! Great track choice.

You have to dip the candle in wax and then immediately into cold water to harden each layer quickly so it doesn't melt the wax underneath.

3d printing components with gaskets has so many potential applications for both prototyping and for repairs.

This was an interesting video. I think the last 3d printed mold missed only couple of things for it to be more usable: 1. it seems your initial idea of splitting the mold into two (or more) parts that lock together is better for removing the cast material, even thought it will most likely leave a seam 2. mold would be better if you used a filament that's slightly more temperature resistant so that it doesn't deform during pouring. Something like ASA would be a bit better compared to PETG. Of course just keep in mind that ASA is harder to print compared to PETG and it's a bit more expensive than PETG, but should be more doable compared to even more expensive and temperature resistant materials

I like how you used red and blue for the original gameboy Pokémon games. Also snorlax is awesome. lol

When I was a child, 40 years ago, I remember we used to dip the candle in water after each wax dip, to avoid the melt-trough.

One soloution to the melting plastic mold could be to print a water cooled mold.

Bob: uses low poly snorlax for his candles Porygon: am I a joke to you?

I believe they dip the candles in ice water between wax dips to solidify the layers and prevent the melting issues

In a billion years I will never make a candle BUT (yes big but there lol) the process you went through was top notch and I learned a TON from that... fails and all... oh and the bloopers, top shelf.

You can use a few pieces of crayons to dye your candle wax instead of water based food coloring. It works great!! ❤

This is the only candle making video I have watched in all my years on this planet. And it will probably be the only one (unless you make another)

When I was young I used to make candles....only they were boring square using a milk carton for a mold. But if you let some extra wax almost set, you can froth it up with a fork & make frosting for your candle.

Guy did a great table with wax crayons melted into a river and covered with epoxy. Might be a little complicated, but looked great when it was finished :))))

19:15 I think you should drop dies before you pour the wax into your mold, so that more color stay on the surface of the candle. The reason why it came out all blurry is because when hot wax meets the cold mold it freezes and creates a thin layer of clear noncolored wax.

Loved the video! Really documents the whole try an try again aspect of projects!

you can use this idea to make personal pulls for drawers, choke handle like on a bike. just the first things that come to mind

Bob, I really love how you just waxed your way into this video! 👍👍

4:18 alignment pin should be in the split model option. if it's in the Orca slicer option, I'm pretty sure it's there in the Prusa slicer option

Maybe try putting the candle into the fridge to lower its core temp and then try dipping to build up layers

On the big blue star mold, have you tried Roto-casting?, the first layer to help cool down the mold before pouring the rest of the wax.

I don't care about candles at all but this was way more interesting than I thought

Insightful Bob on the bench is back

I know magnets dosent work that well when heated but instead of clamps could you use magnets for the molds? :-)