Challenge: Casting Bronze Maker Coins from a 3D Printed Pattern

[@swdweeb]

Just a point of clarity, the basin former came from olfoundryman and smallcnclathes. Coin came out great!

[@PaulsGarage]

Ah didnt know that, gonna pin this comment so everyone can see

[@bigstackD]

Mate that to me was 100% successful awesome coin . Perry made me a design for my own coin and I’m yet to try it as I only have shit casting sand but I do actually have a bag of Titanium dioxide powder and when you ram that up it has the consistency of a tablet so I might give that a go in the near future 👍🏻. I’ll be sure to let you know how bad I screw it up after I do it 🤣🤦🏻‍♂️

[@PaulsGarage]

Give it a shot! I want to see! I've never used titanium dioxide (or anything other than petrobond to be honest). I bet there's a way to improve the sand you have, maybe wood flour or something like that as an additive. A sandcasting book by CW Ammen talks about additives like that, but he also says too many of them will make the sand worse, so i don't know.

[@askquestionstrythings]

@@PaulsGarage yes, adding a "cereal" like wood flour or dextrose should help his sand... also screening the sand a little to get the courser bits out from the play sand should also help.

[@Zillustration]

gotta say... i love watching hot metal being poured into a mold and making something unique and new. there's nothing like it. good work, paulie.

[@PaulsGarage]

Thanks! I agree, it's awesome. It's even more awesome to watch in person, you can feel the searing heat on your face

[@JulianMakes]

Wow I think you did a good job of it. It looks hard to do. It hadn’t occurred to me that thinness makes such a difference. When I eventually finish the foundry I’d love to try one myself. Interesting vid cheers

[@PaulsGarage]

Yeah the thinness causes quicker cooling of the metal. Higher surface area per volume. It's why car radiators have many very thin fins, maximizing surface area per volume of radiator. For this reason the same metal as a sphere will hold heat in better. Far less surface area for the same volume

[@JulianMakes]

@@PaulsGarage i will have to watch out for that cheers. it got so 'sluggish' so quickly! amazing o/

[@1pcfred]

@@PaulsGarage I'm no pro but I believe really thin casting are injection molded? Or maybe centrifugal? Jewelers do centrifugal investment castings. Henry Bessemer claims he cast a rose in iron once. Least he thought he was bragging. Maybe he was just full of it? He never did say how he did it, just that he did. I'm lead to believe it was some kind of lost material method that he did with a real rose as the form. He talks about it in his autobiography. That's a free download on the net. You should read it. The whole book is rather captivating. Googling "henry bessemer autobiography pdf" (without the quotes) turns up links. Then there's them bronze baby shoes. I think they're electroplated? So not really cast at all. They still appear to be solid metal when you handle them. Just food for thought. I briefly leafed through a book that described bronze electroplating once. It was a how to get rich quick scheme book published in the 40s or 50s. Whenever that craze was going on. People selling miners shovels are the ones that always get rich.

[@JulianMakes]

@@1pcfred interesting paul i'll google it

[@1pcfred]

@@JulianMakes Bessemer's biography is a great read.

[@askquestionstrythings]

Those "extremely normal neighbors" lurking in the dark wondering if you are playing with fire lol This is why I'm strongly considering going the electric furnace route. Less for them to see or hear. despite the flaws, it's still a nice result. Got to love these F.A.I.L.(s) First Attempts In Learning. (Quote by A.P.J. Abdul Kalam)

[@PaulsGarage]

Funny you mention that, my new (used) electric kiln can melt aluminum very easily I just learned. Bronze, too, though getting up to pouring temp would be a challenge.

[@TheVirindi]

"The neighbors are extremely 'normal'" - I feel so sorry for them. I wonder what it is like, it sounds like such a sad life :)

[@PaulsGarage]

I know!! They just mow their lawn, go to work, and play baseball in the backyard...like weirdos! Why aren't they melting stuff? It's clearly more productive.

[@bpickerell]

two suggestions for you from my experience (a.k.a. failures) with sand casting. 1: try spraying the mold with a light coating of graphite lubricant and then light quickly light the solvent to bake the graphite in. It will definitely improve the finish and will lock in any lose grains from the pour. 2: you need a longer sprew for something that thin. you want the metal to have momentum so that it fills every nook before it freezes. Maybe even a bigger cup so that you can pour faster.

[@PaulsGarage]

Good tips, i've never heard the graphite lubricant one before. Maybe i could use tin cans to make the top of the sprue and riser taller by a few inches? i've seen people do that.

[@askquestionstrythings]

I suggest watching olfoundryman, or reading the complete casting handbook for an explanation of this small tapered sprue and the pouring basin design that Paul used here. Although swdweeb sent them to Paul, it was olfoundryman who told swdweeb about this sprue and basin design. There are specific reasons why you want to keep the sprue diameter and sprue height low. One of the reasons is related to reducing porosity. Olfoundryman and the complete casting handbook do a much better job explaining the details and the problems that are reduced with this specific design than I can in a short comment.

[@tobhomott]

Thin stuff can drive you crazy trying to get parts to fill sometimes, I feel your pain. Maybe if you had the sprue between the 2 gates instead of at the end of the runner? The one that worked looks great though, very nice. I just built a wooden pouring basin pattern similar to yours, but I'm planning on making a tiny little flask to ram it up in. I always seem to mess up cutting these kind of basins by hand so I end up going back to old habits...

[@PaulsGarage]

I think building the basin works better for me than cutting them in, but using the mold worked the best for sure

[@askquestionstrythings]

I agree, having the sprue in the middle of the coins with shorter runners should help.

[@gramursowanfaborden5820]

hey Paul, look up Mexican Pewter, it's basically a reverse Aluminium Bronze, like 90% aluminium, 5% copper and 5% silica (numbers pulled out of my ass but you get the idea), it's apparently used in Mexico to make fancy silverware as it polishes up to a mirror finish really easily.

[@PaulsGarage]

That's interesting, the alloy looks almost like duralumin with silicon added. Very cool, worth a try. i could just add 5% copper to some cast aluminum probably.

[@Kiber2319]

i really want to know how bad these neighbors really are for you to have to hide the fact you are ultra manly and creative haha

[@JulianMakes]

Hi paul I've finished the foundry! and i'd love to have a go at a bronze maker coin! i'm always up for a 'challenge'. Do you have the file of your coin available to download? great fun video as always i watched it all again lol o/ julian

[@watahyahknow]

i wonder if you can make a "heatingplate " on a rolling cart to put it over the furnace , that way you can heat up the flask while melting the metal . does mean more work as you need to set the flask on the ground before readying the pour need a heating PLATE so you dont set fire to the wood flask , might even make the plate so the flask isnt straight over the hole of the furnace but gets heated from the heat transfer along the plate prolly hide some of the flames from the neighbours too the one coin that came out good eehr came out looking nice wat you could do is running it along a wheel with some buffing compound , it usually blackens/dirties out the deep parts a little and brings out the relief

[@PaulsGarage]

I think you're onto something there. Maybe though I could set this small flask in the pottery kiln on low while I'm melting the metal, get it heated to at least a couple hundred degrees? I got the small one wired up and working already, would he worth the experiment

[@watahyahknow]

@@PaulsGarage could work then again you'll have to reach intoo the hot pottery kiln to take the flask out (if you still want it hot) the wood surround might ignite too could lay the pottery kiln on its side for heating the flask and use sumting alike a pizza paddle to get the flask out without the skin falling of youre arms one thing i dont know for sure about heating the flask in general is if the casting sand might fall a part ruining the object if you heat it up while its still not filled

[@massimoserra4787]

Hi Paul, first of all, I like the maker coin. May be making a smaller mold, half height, the bronze won't cool down so fast into the mold and fill better. Wish you and your family a great christmas time.

[@PaulsGarage]

merry christmas to you, too! That's a good idea about the fill. Mostly my problem was not getting up to proper pouring temperature, and not preheating the mold. I have only preheated a mold a couple times, but when I poured this it was literally freezing outside and the sand was VERY cold. It probably exacerbated the problem...

[@mattm6178]

its satisfying at the end to watch you use your flash superpower to sand 9:29

[@PaulsGarage]

It's the power of too much coffee

[@lancasterfreepress9219]

Paul, Just my 2 cents since I never casted anything but copper and silver... How about hard drive cases from computers. They seem to machine well so they are high in silicone so should cast well for you. I have several hundred laying around myself to try someday. Also the magnets in them are super strong so they might have some other fun uses. Maybe you might have your wife voice over one of the videos. Should be funny hearing her side of your project choices. Slogan for edge of coin... "In Paul we trust" or "Keep Calm and Stay Ginger"

[@PaulsGarage]

Those are great ideas!! Text might be tough, though. I would have to remove an image from one side to make room. I think my printer nossle is 0.4mm diameter, so the text has to be big enough to be made from lines that thickness or greater. The "Paul's Garage" text looks a bit crappy up close because the slicing program cut off all the thin bits of the letters :/

[@lancasterfreepress9219]

@@PaulsGarage On the edge of the coin I was referring to the side edge like this... Something more of a challenge. c8.alamy.com/comp/D9TGGE/british-2-coin-writing-around-the-edge-standing-on-the-shoulder-of-D9TGGE.jpg I can send you a bunch of hard drive cases if you want to try and melt them. Should be easier to cast that way also.

[@ColonelRPG]

What is an Edge? Is it like a Firefox?

[@PaulsGarage]

Sure why not lol

[@Benjamin-du6kr]

I just hope it isn't Shiny.

[@archangel20031]

You need a larger sprue, larger runners, and the runners need to be as short as possible, and you need hotter metal. Try to break the sand into chunks, then crape the burnt petrobond into another container and toss it out.

[@askquestionstrythings]

The complete casting handbook, where this sprue and basin design come from, specifically says to avoid larger sprues as in most cases it only leads to more air entrainment and other problems with the pour. I agree that the runners might have been a little under sized, and definitely too long. But mostly I agree with Paul's initial assessment and you're statement, the metal was too cold and not up to proper pouring temperature.

[@archangel20031]

@@askquestionstrythings Sorry, I meant to imply that if the metal is solidifying before it can fill out the whole pattern, it either needs to be hotter, moving faster, or possess more mass to keep it liquid long enough to fill the whole mold out.

[@Ramuloth]

Out of curiosity, where do you get your petrobond sand from? The stuff is very hard to aquire in Canada.

[@PaulsGarage]

Amazon. There is a company called PMC Supplies, you can order from their website or from their "amazon store". I get my crucibles there, too.

[@thebrodnaxs8304]

Also one called Teton supply.

[@genericaccount9222]

In the garage casting some pewter coins right now actually! Could used this video 10 minutes ago lol

[@jeffreysanborn1005]

Any way to get the file so I could print and use the basin for my casting? I found your files for the tapered sprue, rammer, and surge thingie. Edit: smallcnclathes said he is going to add a link!

[@grandadz_forge]

You make me want to learn casting. I do bullets from lead, but cool stuff with cool metals

[@PaulsGarage]

Casting is awesome, you should totally try it. Lead is way easier to melt than other metals, but aluminum isn't hard to get molten. You just can do it on a stove top.

[@ralphmourik]

Coin came out very nice for a failed-ish pour, i will try coins too in the future... if i every design a cool personal logo... anyone with some 3D modeling/animating skills up for a challenge ? :) btw the voice over work is good, you can keep the rambling to a minimum and make shorter video's, don't do that too often though, sometimes it's hilarious :D

[@PaulsGarage]

Oh I can ramble plenty on the voice over! It was nice not having so much to edit down, though. I've ended up with 3 hours of rambling before, had to cut HEAVY to get to 15 minutes...

[@mindofmadness5593]

I do mine in whatever part of the yard or drive I need [[ant bed pours]] but the neighbors already think I'm weird so no loss. Gives me some thought on how to do the Pirate 'Pieces O Eight' I want to do. I'm mostly blind in one eye-wear a patch so it does not interfere with the other eye, otherwise I close the eye and that looks stupid-don't need any more help looking stupid but little kids think I'm a Pirate and I play along with it. Some Piratey coins would be great to give out. :)

[@AppaTalks]

I will give this a try! Just might take me a few months too :p But I'll do it!!

[@PaulsGarage]

Awesome!

[@AppaTalks]

@@PaulsGarage Video made :D kzbin.info/www/bejne/m6u2n4qvitV2jqc

[@1pcfred]

All of this is why coins are struck and not cast. Drill a hole in a piece of wood (maybe a 2x4 off cut?) and bolt it tight to your angle grinder (you're going to need the right length bolt for all of this to work or the right thickness piece of wood for the bolt you got or washers or something wood should be firmly affixed to grinder though) using one of the threaded handle holes and then hold the wood in your bench vise. Now you have a fixed grinder. Both my 4.5 grinders have a 5/16-18 threaded handle hole in them. I'm not sure if that is a standard or not?. My 7/9 grinders have a different thread in them. They're 1/2-13 so not all angle grinders have the same handle threaded holes in them. I'm too lazy to track down any more angle grinders here to get a bigger sample size than 2 now too. I think the handles are all interchangeable on them though?

[@askquestionstrythings]

The First coins in China were cast (lost wax process). A lot of novelty coins are diecast, more expensive novelty ones are struck. all of the issues Paul ran into with his coin are reasons why sand casting is not a good choice for coins.

[@PaulsGarage]

Exactly! coins are struck for a reason, but I think all those difficulties inherent in casting a coin make this a very telling test. If you don't get it hot enough, or get the gating right, or don't ram the sand properly, you will have failed pours or bad detail or surface finish. You know, all the problems I actually had!

[@1pcfred]

@@PaulsGarage you might not be able to get the detail with sand at all. I'd look into trying some casting with lost wax and plaster. That has the potential to give you the results you're looking for. Sand is good for details down to maybe oh I don't know maybe 3/16s lettering? I haven't seen anything smaller than that ever. I've seen a lot of castings too.

[@texastaterbug5395]

I like that you finally cast some handles for the lid of your furnace. Did you 3-D print a pattern in the shape of vise-grip pliers?

[@PaulsGarage]

Haha no those are still vice grips, but that's a really funny idea!

[@johnmccanntruth]

With the cold temperatures there, wouldn’t that be just one more thing to cause a problem in your casting? Sounds like a good excuse to me anyway... The one looked pretty cool though!

[@PaulsGarage]

Yeah it was really cold. I'm not sure how much it affects things, but I'm sure it causes the metal to freeze faster when the sand is cold

[@christophermanfredo2241]

Awesome attempt man! Perfection takes practice

[@PaulsGarage]

Thanks! I agree, more practice needed

[@Akosyeah]

Cool project. Really liked it

[@PaulsGarage]

Thanks!

[@akwayed1147]

Guys what is the point of that white powder?

[@stamasd8500]

Nice coin! I guess it's worth 1 Paul's Garagf. Yep, final 'e' didn't quite make it. :)

[@PaulsGarage]

Does it become MORE valuable now that there is an error? :D

[@stamasd8500]

@@PaulsGarage Depends. Is that a systematic error or a spurious one?

[@dfross87]

What happened to the last stream? I missed it live (as usual), and it's not in your video list (unlike previous streams).

[@PaulsGarage]

It's in a playlist of streams. I made them unlisted in the "uploads" list, I think they were cluttering the page up. Here's a link to it kzbin.info/www/bejne/bICUnnajZdqjeJI

[@magnuspernemark2339]

How about using gypsum instead of sand? Details should be better.

[@PaulsGarage]

Could be, I've never used gypsum myself

[@1pcfred]

@@PaulsGarage There's a method where folks make lost foam forms and they dip it in thinned out wallboard joint compound. The detail they can achieve is incredible. But you see the foam pattern in their castings. So maybe you can do lost wax and plaster?

[@askquestionstrythings]

Paul's Garage investment type lost wax casting or other thin shell casting processes come with their own set of additional challenges.

[@seanbush5313]

The whistles at high speed 😂

[@PaulsGarage]

As a bearded man I identify with the 7 dwarves whistling while I work

[@franglish9265]

Cool!

[@cagad101]

Where do u buy ur casting sand from?

[@PaulsGarage]

Amazon. There is a company called PMC Supplies, you can order from their website or from their "amazon store". I get my crucibles there, too.

[@martinescult]

necesita la colada mas gruesa y elevar un poco mas la temperatura del metal. saludos

[@edgeeffect]

See... see... see... that's not casting errors... in fact it was made in The Bronze Age and that's... that's... wear patterns from centuries of being buried at some archaeological site somewhere or other.

[@PaulsGarage]

good point! it looks ancient that way!

[@mtnave]

What 3d printer did you use?

[@PaulsGarage]

Prusa i3 mk2S

[@ypop417]

You forgot to put a denomination on that coin LOL

[@PaulsGarage]

Its 5 "Paul Bucks". The conversion is roughly 5,000 PB's per USD

[@StreetMachine18]

I actually prefer the voice over style videos. More concise and still funny

[@PaulsGarage]

Excellent! Good news, then, the next couple are mostly voice over. The problem is my foundry burner and forge burner now use VERY loud blowers for forced air and you can't hear anything other than the burners. The forge burner is a little quieter, but the foundry one literally sounds like a jet engine taking off. It's crazy.

[@badsantaclaus4522]

Paul One out of two not bad nice looking coin

[@PaulsGarage]

Thanks! I agree, the one that worked came out great.

[@franglish9265]

So you casted some currency?

[@PaulsGarage]

Maybe if anyone would accept it as currency lol

[@franglish9265]

@@PaulsGarage I wonder if Zinc would work better...

[@viscash3606]

Check the coins that olfoundryman did after the challenge from swdweeb kzbin.info/www/bejne/r4iXhZqQpLqmgZo

[@PaulsGarage]

cool! added to the list

[@Cyberthuug]

Monsters in the dark.. that was funny

[@PaulsGarage]

There really are monsters in the dark. Maybe not in *that particular dark*, but they do exist!

[@Cyberthuug]

@@PaulsGarage i am thre monster in the dark. But dont worry, i like you so i told all my fellow monsters not to bother you. Now you never have to fear the dark again. Merry Christmas!

[@_topshelf_5845]

HEY!

[@PaulsGarage]

HI!

[@Cyberthuug]

Melting metal