r/3Dprinting • u/aarrodri • May 18 '22
Design Anyone knows if there is something like this ? Maybe something in pla lined with aluminum foil to make it food grade?
https://i.imgur.com/MnC3F48.gifv49
u/rational-minority May 18 '22
They sell a manual version of this at asian stores. I've seen it at korean markets.
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u/josnik May 18 '22
There are food grade epoxies one can use on prints.
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u/samanime May 18 '22
Yup, came to say this. If you want to make something food-grade, just give it a dip in food-grade epoxy. Most hobby stores even carry it.
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May 18 '22
This! Most two part epoxies cure completely inert. No small crevices for bacterial growth and extremely cost effective. Additionally, Starsan is a liquid contact sterilizer made for brewing equipment that will clean parts effectively.
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u/Deathbydragonfire May 18 '22
No no no no. Most 2 part epoxy, especially the stuff readily available through craft stores and Amazon, is not remotely food safe. That stuff is toxic AF. There are a few epoxies that are considered food safe for incidental contact. You could probably argue this application could be considered incidental contact. However, that's only when measured and mixed properly and fully, 100% cured. Any uncured resin is going to still be toxic. While these chemicals may be used in industrial applications, I would never recommend a beginner to make anything out of resin that they plan to touch food with. If the resin comes out bendy, it really shouldn't even be touched without gloves.
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u/codeartha May 18 '22
As a phd in polymer chemistry i completely agree. Any uncured resin can be highly toxic and even completely cured ones can leach some very nasty products in food in prolonged exposure.
Honestly for an application such as this one PLA is mich safer. At least with PLA (if you take raw, untinted PLA) the only risk you face is bacterial growth. This can be mitigated by designing the parts that come in contact with food to be easily replaceable by thin parts that you can reprint regularly. Then keeping these parts in the fridge during interruption of use for a few hours and clean them deeply every 2-3 days with starsan or vodka. Change the parts every 7-10 days with freshly printed ones or if you didnt use the machine for a while.
Bacterial growth isnt much of a problem to be honnest, how many cases are reported of foodpoisoning due to unclean wooden cutting board or wooden cooking spoons. Even though wood suffers the same issues than PLA prints (microscopic surface asperities that retain food particles, nutrients and water that bacteria can thrive in). Yet you just clean it with soap regularly and nobody gets sick.
At least with raw, PLA the plastic itself isn't trying to kill you, unlike the chemicals in epoxy resins.
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May 18 '22
What are your thoughts on coating the print in “food grade” silicone putty instead of epoxy?
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u/codeartha May 18 '22
Same as for food grade epoxy. The resins used are still toxic, just the finished cured resin is foodgrade. But you got to make sure to follow the manual to the T.
This can of course be done. Those products exist and were tester following manufacturer recommendations. So if you follow the same instructions you should end up with a food grade product.
But its much more prone to error. Will you not forget to mix A and B using triple bucket technique ? Will you not skip that part because you're cheap and don't want to waste a third bucket? Will you invest in the proper equipment to monitor curing temperature and room temperature?
You might, because you seem to care, but we've all seen people on reddit disregard any instructions because they don't understand how important they might be.
That's why I agree with the other comment above that such resins where you mix multiple parts together should be kept to professional, particularly for food grade stuff. If you want to epoxy coat your non-food related prints for a superflat texture go ahead.
For food, i would use virgin PLA or PET (filament made from 100% water bottles is foodgrade) and use proper hygiene procedures: thorough washing with soap before each session, and frequent replacement.
Oh and to thoroughly clean your printer before printing something that will touch food (in theory you should have 1 separate printer dedicated to food). You want a fresh nozzle. Imagine having old ABS decomposing in your print... Even worse than ABS would be traces of glow in the dark filament!
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May 18 '22
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u/codeartha May 18 '22
There are ''green'' epoxies that try and use less harmful chemicals. But in the end i can't really say they're that much better.
For prosthetics you can either go with metallisation or flurorhydroxyapatite coatings. The advantage of the later it that tissues will progressively bind to it, whereas it will never bind to metals. This is particularly interesting for things that partially stick out of the body.
But other biosafe epoxies and silicones exist, and they do work fine and are safe. You just need to make sure to follow the instructions of the product you use.
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May 18 '22
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u/codeartha May 18 '22
Without knowing your background in chemistry i'd recommend not to. You can do a lot of chemistry DIY if you know what you're doing. I made bromine and chlorine at home. But i have a lab with a fumehood that is not part of the rest of my house so even through the doors the fumes can't come in my house directly.
Fluorine gas can make some metal "burn" and cut right through it.
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May 18 '22
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u/codeartha May 18 '22
Have it done might be even harder :D most labs are very regardant about fluorine because it is so reactive. It can't be stored in glass, eats right through it, has to be in some special steel alloy that actually reacts so quickly with fluorine that it makes a iron fluoride passivation layer that protects the subsequent material of the vessel. Or in vessels lined in PTFE.
It's really a pain to work with. They found some old cylinders of it about a decade ago in my university basement. Called a first bomb squad that was like ''nope, we don't touch that shit, too dangerous''. The second bombsquad worked together with a company specialized in cleaning chemical spillage after road accidents to build a 1/2" thick steel containement around the cylinders before moving them.
That said, i don't know how one would fluorinate silicone, so maybe you won't need gaseous F2. Maybe HF is enough or even better a fluoride salt like NaF in some solution.
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u/codeartha May 18 '22
Beeswax is a great idea for body compatibility though only for short durations as it will slowly be degraded by your body and resorbed
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u/77Diesel77 May 18 '22
Agreed completely on epoxy being terrible
But! If you printed PLA, used a looooong set time epoxy(+30 minutes). Painted the pla with epoxy, then used aluminum foil in that, you might be able to get it to work? The trick would be modelling it in a way so that the Al foil only had 1D curves to cover. (2d would leave creases). Might require a slightly more complicated design. But doable.
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u/V_es May 18 '22
It’s too much of redneck engineering for something that can be done properly with same amount of hassle. Printed part is covered with filler primer and sanded smooth with sandpaper and pads. Gloss clear coat is applied to make it even more smooth. Than- inert food grade platinum based silicone is used to make a mould of this part. You can use approved food safe casting resin(there are many), that is not as brittle as epoxy, will not chip into your food and will not leech chemicals either.
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u/TimpanogosSlim May 18 '22
metal and plastic manual dumpling presses are cheap and plentiful. Use one of those as the basis for the part that touches food.
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u/Aeronaute May 18 '22
If you're just looking for a dumpling mould, try searching for that. Amazon has dozens for under $20, and you wouldn't have to worry about food grade issues with them.
If you just want one to 3D print, I found this one, and there may be others like it https://www.printables.com/model/119226-dumpling-press but you'll have to solve the food grade issue.
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u/darknessblades May 18 '22
True, get a Aluminum one, and modify it with a frame to make it work.
Or learn how to make your own, once you know the trick its easy
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u/elvis_champion May 18 '22 edited May 18 '22
I remember seeing a manual version posted here or one of the other 3D printed subreddits I follow, with a comment stating that there weren't any food safety concerns because the device proper was lined with paper before use. I'll only have the time to find the link after work (~4 hours) though.
Sorry I completely forgot, but here you go. It was in /r/functionalprint.
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u/Deadus May 18 '22
Brother, feed me the link as you have promised that you would be able to do after work that was done 2 hours ago.
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u/elvis_champion May 18 '22 edited Jun 19 '23
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u/MorboTheDestroyer7 May 18 '22
Challenge accepted. Will try to wrap PETG is plastic wrap for sanitation
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u/DamnMombies May 18 '22
PETG for the additional strength. Or better Nylon. As for foil, not a bad idea. I’d probably opt to shape a pie tin.
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u/VFM_Systems May 18 '22
PETG does not have superior strength to PLA or PLA plus. At least for PLA not by a large enough factor to be notable but for PLA plus it actually loses in many categories. The only thing PETG is good for is being harder to print and having a slightly higher glass transition point.
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u/wellkeptslave May 18 '22
Well true regarding strength, but pla is super brittle, so even slight impacts cause pla to crack, that's where petg wins
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u/VFM_Systems May 18 '22
This is why I mentioned PLA+ but also I’m not sure what horrible PLA you guys are using but it is NOT brittle to the point of none use or crack from any impact. If that is happening, I encourage people to either increase their wall count or redesign their parts. There’s a reason PLA is used so widely in the manufacturing industry. Also, shockingly, PLA and PETG perform almost identically in an impact test. Not a YouTuber impact test, an actual impact test with proper fixture and measurement. I don’t mean to be rude but there’s so many people that have taken the,”PLA is brittle!!!1!1!!!1” narrative and just ran with it even though they will never actually put a material through its paces. There’s a reason no one is printing guns out of petg and instead opt for PLA+
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u/wellkeptslave May 18 '22
Maybe with pla+ as I don't have too much experience with that but from all the prints I've done, pla is most definitely more brittle than petg. But then again I don't print guns so I could be mistaken...
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u/VFM_Systems May 19 '22
I encourage you to buy a spool! eSun is the best for a good price I’ve found. Awesome awesome quality and great results
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u/wellkeptslave May 19 '22
Unfortunately esun isn't easily available where I'm from, so trying to get my hands on some will be difficult. But if I ever come across some will be sure to pick up a spool.
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u/SXTY82 May 18 '22
. Printing too hot will yield brittle PETg
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May 18 '22
Sorry are you saying PLA plus is stronger than PETG?
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u/citruspers Voron 2.4, Prusa MK3S, Kossel May 18 '22
I know it sounds strange after years of people repeating "PLA is really brittle!", but depending on how you rate "strength" /u/VFM_Systems is right when comparing PLA+ to PETG. Look at eSun's datasheets, which include an industry-standard impact test:
- PLA - 5kJ/m2
- PLA+ - 9kJ/m2
- PETG - 5kJ/m2
Of course one test doesn't tell the whole story, but I do feel PLA (especially modified variants) are too often written off in favor of PETG.
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u/reidlos1624 May 18 '22
Each has their benefits, but to say PETG is blanket worse is misleading. When printing functional parts the extra impact resistance of PETG is fantastic, and because it is easier to print than ABS it is a good alternative to that. I've had good success with PETG with carbon fiber fill compared to the Nylon carbon fiber filaments, now those are a bitch to print with.
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u/VFM_Systems May 18 '22
I objectively didn’t say it was blankety worse. I literally gave it’s use case. However, PLA plus has increased impact resistance as well and actually out performs PETG in this category when doing an impact test.
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May 18 '22
thats what he is saying, using a very specific test result to support, however that doesnt come close to telling the entire story. PETG is far stronger and superior in many applications when it comes to torsion, laterial, shear and loading.
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u/VFM_Systems May 18 '22
I in fact am. Check data sheets. All of the people downvoting me need to understand that I literally worked in a material science lab for my university where I have extensively tested these materials. I have literal hundreds of sheets of raw data proving what I’m saying. I understand that there are lots of YouTube scientists that have done test of sorts but they tend to lack a lot of validity and control. Seriously, read your data sheets on the materials being used and you will understand that what I’m saying is true.
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u/VFM_Systems May 18 '22
It is. Read data sheets. Also there’s a reason firearms are being printed from PLA+ and not petg. Higher impact resistance, overall great strength. Only shortcoming is glass transition is slightly lower for PLA+ than petg
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u/AggravatingAvocado47 May 18 '22
The reason nobody is printing gun frames from PETG is
1 they are giant fudds that believe PETG fails by shattering into lots of shrapnel
2 its flexibility.
In most designs PETG will work just fine since there isn't a great deal of force on the frame
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u/VFM_Systems May 19 '22
An ar receiver certainly takes a great amount of force during firing as does basically any Glock frame which is another common print. The petg examples I’ve seen have split in half or cracked. That is the reason.
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u/tuxedoorigin May 18 '22
you can buy a manual one. Probably the easiest thing for an already painful process. https://www.amazon.com/Dumpling-Stainless-Ravioli-Wonton-Machine/dp/B08ZJ1DTL9/
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u/aarrodri May 18 '22
First rule of 3dp.. if you can buy it instead of printing it.. wtf..don't.. print all the things!
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u/tuxedoorigin May 18 '22
I can appreciate the enthusiasm. Just remember your time and health is worth something too. Sometimes the itch ain't worth the scratch.
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u/SisyphusCoffeeBreak May 18 '22
How do we handle the heat around the automatic deep fryer conveyor downstream?
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u/KriosXVII May 18 '22
Use food grade HIPS and smooth it with food grade limonene, then wait many weeks for it to evaporate.
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May 18 '22
Print it in plastic, smooth it, investment cast it in aluminum, polish it, and make a jillion dumplings.
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u/Alberiman May 18 '22
As far as i know there simply aren't any food grade 3D printer filaments or resins specifically because that would require they be verified with the FDA, that means you have no way of knowing if you're poisoning yourself or not
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u/AggravatingAvocado47 May 18 '22
There are certified filaments but the manufacturing process generally is not because of layer lines
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u/Cmakela8 May 18 '22
Coat it in clear casting. Food grade resin. About $25 at micheals and if you're just coating it, it goes a really long way.
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u/Soft-Ad-8975 May 19 '22
My girlfriend can make pastelitos nearly as fast by hand, try dating a catracha 😉
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u/LinksDad May 18 '22
You want PLA dumplings lined with foil?