3D Printing metal casting flasks (Modular flasks PART4) pattern changes & Second greensand casting

[@JulianMakes]

Just a little reminder that my email address is in my channels 'about' tab. Please feel free to send me pics/diagrams if you want, i have trouble with long technical worded sentances to describe this stuff sometimes, mainly becasue i'm not really an engineer so the words dont mean the same to me as they do you guys. Also i'm still only an amateur caster bloke in a shed at the end of the day! Also thank you so much for all your continued help/support/advice, it's greatly appreciated. It seems that the large majority of you are enjoying this deep dive into these different designs and seeing how the differences affect the outcomes, so i will continue to delve deeper! thank you to you all, i'm having loads of fun with it (although my printer is exhausted at this point - as is Nikki from the noise of the thing - it's beneath out bedroom!)

[@ARTYCOATY]

I was surprised! You are full of talent!

[@RaspyOB174]

Can't wait to see 4 put together and the future improvements. Good job man! Seeing the troubleshooting really helps beginners like me put together sound designs. You're a BADASS!

[@JulianMakes]

RaspyOB174 thanks raspy!!!

[@swdweeb]

Looks like it could double as a child's boat 1:17 ;-) Cheering right along side you 12:31. Kinda OCD 22:06 ;-) I'm so glad you're bringing us along to participate in the ride. The evolution and learning is great. Thank you. Oh, and Perry can be an idiot, careful what you listen too ;-)

[@JulianMakes]

thanks buddy! i'm not sure it's always one step forward! but it sure is fun. i've just ordered my THIRD (yes third!) 2.3kg spool of PLA!!! i''ll show a lot of failed patterns in the next one. It seems reducing the ribs to nothing is problematic :)

[@ChatterontheWire]

More white powder floating around in this video than most coke parties in the 80's! enjoying the process, keep it up and good luck with all of the iterations!

[@JulianMakes]

lol narcos eat your heart out! cheers chatter!

[@robinson-foundry]

Wow, those are fantastic castings! The warping is an interesting problem. I Imagine it could be really problematic with longer pieces. Keep it up!

[@JulianMakes]

thanks Seth! yes i agree and i'm going to get to the bottom of it :)

[@3DTOPO]

To eliminate the defects from shrinkage, either make all of the walls the same thickness, or you need to add risers to feed the thicker areas as it solidifies. I strongly recommend to brush up on "directional solidification", but in short, thin areas that solidify first will draw molten metal away from the thicker areas that solidify last. Therefore, when uneven thicknesses are cast, one needs to use risers (that stay molten longer than the thickest sections) to feed the areas that the other thinner sections steal metal away from. It's a fairly simple concept, and once you have a understanding of it, you can tell where there will be defects if risers aren't used just by looking at a pattern.

[@raschellesherwood6347]

Shrinkage will always go to the thickest part in a changing thickness cast. Feeders,feeders,feeders. Aluminum shrinks it a rule. If the only think feeding the quiet large shrinkage that aluminum is known for.is the sprue and those 2 tiny gates.. the amount of shrinkage in one of those pieces isn't even equal to your gating and runner system. And that's just one of the parts. I use a feeder around at least 3 times to volume of my part I'm making. A part I make weighs. 187 grams and the feeder I use is the diameter of a aerosol paint can and around 55mm high. The feeder ends up being about 530g. Over kill I know but I have zero shrinkage and can cast perfect flat 15mm thick plate . Which I sometimes use as a match plate when I get very busy.. :) but again mate bloody great idea and great job. Congrats

[@Angus_McGyver]

I would like to see another casting with the same patterns, but adding feeders near the thick sections to see if that gets rid of the shrinkage.

[@JulianMakes]

your wish is my command tinkers! i hope to do just that, that will answer it once and for all (i hope! :)

[@huddsman69]

Dont know bloody why?, but somehow I got very emotional about this pour!!

[@RotarySMP]

Nice work. As others have said the change is the issue. Rather thn feeding thicker sections, thin them out. Once you get the pattern to feed well, with predictable results, if there is any remaining curvature, you could just compensate by adjusting the angle slightly from 45°. Have you considered putting a shallow divet in the bolt flange, as a drill center. You will want all holes located quite accurately to ensure interchangablity.

[@charles1379]

Julian, I recommend that the thickness of the inside wall should be as narrow as possible and the ribs be of the same thickness . this will minimise the bowing/bend on cooling. the deeper the ribs the less will be the tendency to bow. the thicker the base the greater the shrinkage. try reducing the dovetail rib height but keeping the longitudinal ribs higher.

[@danharold3087]

Just found your channel. LIKE IT. Keep in mind there will always be shrinkage. You only see it when the solidifying metal has no source of liquid metal to make it up. If we do a good job of plumbing the mold the shrinkage we see will end up in feeders and other bits we cut away. I expect you know this but don't skimp on the feeders because they need to solidify after feeding the last part(s) of the casting to solidify.

[@JulianMakes]

Dan Harold thank you Dan! That is very kind. Good advice, I’m going to do some feeding in the next test casting, I’ll be interested in what changes occur :)

[@garygenerous8982]

FWIW I would love to see you keep iterating this to as close to perfection as possible. And for you to bring us along for the ride of course ;P but realistically this version is probably 90% of the way there so stopping now likely wouldn’t cause any failures.

[@JulianMakes]

thank you so much Gary, it seems lots of peeps agree with you so i'm going to take my time and explore all avenues. yeah you are right i can fall back to this one if all else fails :)

Reading through the comments the general consensus would be feeders for the thicker parts, and that was my first thought. Having said that, I don't think the slight warp in the facing surface would be very detrimental. They look quite useable to me ! They would be pretty unique castings if a little bit of fettling was not required. Would love to see a completed flask and how well the mating surface between them fit up. That is an important detail, leakage from those surface would be less than desirable.

[@luckygen1001]

How can it be possible for you to fill up a green sand mold without a vent? Every metal caster on youtube will tell you a vent is needed otherwise the mold will not fill up. You must be the most talented metal caster on youtube

[@JulianMakes]

Haha nice one lucky! Cheers :)

[@tobhomott]

That's awesome! That little bit of shrink and warp shouldn't stop them from being usable flask sides, FWIW I always have to shim my wooden flasks a bit to get them to close up perfectly flat and square. But if you want to avoid that shrink, I think you're right, you could lose the vertical ribs, or try to make them the same thickness as the back plate and the horizontal ribs, or pour a little cooler, any of those might do the trick. Maybe even molding it ribs up in the cope instead, who knows, it might help with that warping somehow. Can't wait to see 8 sides bolted and pinned together!

[@JulianMakes]

great ideas Tobho, do you think moulding it 'upside down' would make much difference? i'd never even considered it. i guess it would mean the main flat plate would cool first?? i'm having difficulty getting my head round it? what do you think? i think adding a feeder would be prudent near the middle (at least) too perhaps. cheers mate o/

[@tobhomott]

@@JulianMakes ok, you got me, I have no idea if molding it the other way up would make any difference, I just always try to think of different ways to make molds is all, plus it would be fun to watch! :)

[@charles1379]

also should have some risers where the runner enters the cavity. have these waide 30mm diameter and this will reduce the shrinkage of the cross ribs at this point.

[@frugalberry]

Love it Julian!! I think the pattern you have right now is perfectly workable. My only question is... have you thought about the line-up pins/battons between cope and drag? How do you see them fitting into the design? I'm guessing you have already thought of it, but haven't seen anything in your videos about it. Blessings!!

[@askquestionstrythings]

Love the improvements, It looks like you got the ridge for the pouring basing much closer to 10 mm off the bottom, That turned into a much better pour. those middle "vertical" ribs on the side without the alignment pin "handles" are way too beefy, thin those out so they are equal with the other rib thicknesses; that will reduce the shrinkage in that area and likely the bend... At some point adding a riser/feeder will be needed to deal with shrinkage. Commercial casting flasks made of cast metal also have ribs. Look at the Freemont flasks. The outside edges of their flasks are thicker than the ribs, I would say their ribs are about 1/2 or maybe 1/4th the thickness of the outside edges (top, bottom, left, right, and corners). fine tuning with a sander to get the flasks to meet up perfectly is totally acceptable and somewhat expected (you would mill those meeting faces flat and to the right angle in a commercial production anyway).

[@JulianMakes]

thanks Ask, that is very kind. Yes that thicker sectioned module (on the side with ho handles) was intended to be thicker - so we can add handles to it later, but you are correct i'm certain about the shrinkage causeing the bow. So i will reduce that module side walls by a further 2mm (still thicker than all the rest but still wide enough for M6 bolts i think :) oooh i'll have a look at those flasks in a sec thanks. yeah i'm realising some finishing is going to be required, i just hope to keep it to basic machines (sanders etc mainly because i only have a sander!) cheers o/

[@thoughtnox]

The less height you have, the more they will warp. You can indeed make the dovetails much smaller, also have the ribs thatcarry the dovetails thinner by at least 1/3. If you also make the closed surface that warps the most thinner, maybe only 3mm thick. Also add some more feeding. If you're filling the cavity from the middle (which is a good idea), put some risers onto the angled surface, increase your general gating system diameter. It looks much too small for a part this size. Since you can remelt all of it, there is no loss, making the gating system the full height of the part and 4cm wide. Also putting the patterns closer to each other would help making them cool down slower. You need to make the part cool down slower in order to get rid of the warping. The warping however is not really a big deal, i would machine the parts afterwards anyway. But if one can get around machinig this surface because it does not warp at all... its still a large time-saver.

[@JointerMark]

Those look like some great castings! Are your PLA patterns flat and angled at 45 degrees? Maybe the casting is reflecting the mold? WOuld feeders at the ends of the thicker ribs allow the feeders to shrink instead of the casting? Thank you Julian for posting this very interesting series!

[@JulianMakes]

the patterns are flat. perfectly flat, even when stuck togther. it's a weird one. i'm sure heat/shrinkage management is the answer, and so far i've done none of that. I will feed the thick parts next time and see if that helps :) and you are very welcome, i'm really enjoying all the interaction with you guys, i'm learning loads and i'm being forced to think it totally different directions its really fun! cheers :)

[@JointerMark]

These could also double as icecube trays when you aren't casting with them:-)

[@JulianMakes]

hahaha i'll be needing a few gin'n'tonics once this is done!

[@ChatterontheWire]

My wife made the same comment on one of these iterations too!

[@abrahamd2k]

Watched your other videos and think you are doing good. About your bending issue... Have you considered the forces of punding the sand down may have something to do with the bends? Since your using a modules system where the modules join and being plastic may just be enough to have a noticeable bend occur. I have never seen any bending through casting like that. but I am new to casting too so it may exist. Also, your ribs cool down 1st so to keep it cooling evenly it may be better to make them short and stubby or same thickness as the face/wall. And also I thinking your 45 degree ends are too long. You should only need 16 to 20 mm surface contact with two fasteners per corner. Nut and bolt or machine thread screws. I will soon design my flasks but not modular because there is only average only 3 to 4 sizes anybody will ever need.

[@Angus_McGyver]

Do you really need the 45 degree wings on the ends to extend out past the plane of the sides? If not you could flip them over the other way in the flask and not have to cope down.

[@JulianMakes]

Hi tinkers i know you know what you are talking about, but i dont really understand what you mean (being a noob). wouldnt that just be the same but just casting it 'upside down'? r do you mean get rid of all 45's altogether? if you can do me a pic, i've pinned a comment to the top here with details on my email address, cheers o/

[@dr.rumack7668]

Do you know how you are going to achieve a good mating surface between cope and drag yet? (please go down that rabbit hole even further)

[@JulianMakes]

not really dr rumack! i've not thought about it. Will do! :)

[@wolfmeisterschmid6269]

I going to give you a great opportunity to tell me I am an idiot here, but... why do you not cast each section from aluminum or at least the one with handles by squaring off the sides (as much as possible when casting) and then bolting them together. this way you can make different size flasks on the fly, from just one part. and with thru holes on the ends going both ways you can bolt them to make corners also. this is a poor description I know but I find it hard to explain without pictures! LOL!

[@JulianMakes]

Wolfmeister i dont think your an idiot at all, i just immediatly went with 45 degrees so all corners could be the same, but perhaps 90's would be great. but there is the issue with draft, i cant think of a way to have draft on the required edges and it also have 90 flat corners (which is why i just went straight to 45's). but if you can come up with something let me know, a pic would help me understand it if you do come up with something. Yeah me too words just can't convey the same as a picture! fyi my 'about' tab on my channel, has my email address if you want to email me a pic. cheers o/

[@raschellesherwood6347]

Pouring cooler if possible. Removing some ribs. And maybe try adding in a small machining allowance to address the bowing. Ie bowing your mold slightly in the opposite direction. And another thing to look at is the 2 most inner ribs towards the centre are much fatter than the other ribs.. hence why your shrinkage is so pronounced there. Feed the parts man. There hungry :) lol you can tell me to bugger off at any time too if ya like . Lol

[@JulianMakes]

thanks Raschelle, yes those two fatter columns/ribs def shrunk like crazy, they are intentionally bigger though (a module for putting on a custome handle later) but i'll be shrinking them a tad more i think. Also i will def feed them in future, it'll be interesting to see it that cures the bow alltoegher...

[@stoneomountain2390]

You're ignoring a small detail, Perry used angle iron for his flask, while you are effectively using channel. Much less and catching capability. Don't worry about a bit of warping on the face, all that really matters is your 45° faces being right. At this size, you can get away with tiny ribs, so go for it. I estimate that when you get to more than 75cm length, 20 width, you'll need the bigger ribs, but by then the angle faces will be too weak to be bolted and hold their square. As an extra, you might want to consider drilling holes 0.5 to 1mm into you handles to blow air into to release the pattern, that should result in less nipping when you pull the pattern. I do love the nut/bolt idea, that shows a desire for many future flasks to be made If you feel like more challenges, some folks do vertical casting, so maybe a module with a hole in it as well? You know, for the sake of exhaustiveness,😁 Cheers

[@JulianMakes]

thanks Stone'o yes you are correct. Also i think a little air will clear most of the fallen sand without too much bother. Oooh good idea, i've never actually done a vertical casting, are those the flasks i've seen wth the little funnels on the side? i'm not sure i could do the funnel but a hole with slopey side would be doable. i'll add it to the list of things to do once the approx side design is sorted. cheers :)

[@stoneomountain2390]

@@JulianMakes I think you just have to make a hole the size of a can diameter for that side casting method. That way the cope doesn't get much damage with a pour. The small hole through the handle I mention is to enable release from the sand, so you don't have a repeat of your previous video. It sort of feels you misunderstood what I meant.

[@JulianMakes]

@@stoneomountain2390 quite probable mate! ok cheers, do you mean the size of a regualr coca cola type can? I think any air release holes might be metter drilled? what sort of diameter for the air release ones?

[@stoneomountain2390]

@@JulianMakes I was thinking the size of a can of Heinz, it's something that seems to be a universal size. And it'll keep its shape with both ends removed. As to the release blow holes a 1mm hole should be fine, you basically just need a small burst to break the vacuum at the deepest contact areas. I'm not sure what you mean by metter drilling, but if you meant "miter" I doubt you'll need to make skew holes, square to the face will do, with a toothpick ( there's your ideal drill size!) to fill the hole while tamping the sand. Then just pull the toothpick with a needle nose plier, and you'll probably need to make the hole on the face side a size that your pneumatic nozzle can push into.

[@JulianMakes]

Stone o'Mountain sorry stupid autocorrect, I should have typed ‘better drilling’, as in that could be done after with a drill. I’ll def make a open hole module, I’ve made some good progress today, all will be revealed soon!