free 3D flask Pattern

I cast the first couple of parts for a flask from Julians patterns. I found the handles difficult to pull cleanly, felt they are probably a little too thick walled, and shortly afterwards OlFoundryMan started his series.


With all respect to Julians efforts, and I know he put of lot of thought and effort into them, he is also an amatuer like me, and once I watch the OlFoundryman series, lot of the design features he added from a life time of experience made more sense. So my plan (priority 1 on page 3) is to start again casting the OlFoundryMan version.
The link to the STL files come up in the blurb to episode 4a.
Mark

 

My Printer is too small to print some of Oldfoundryman's patterns But I have a set of the 300mm one setup in the slicer and plan on trying them out. I'm honestly going to cast up one or two of OFM and Jullian's designs and give them a test run. See which one works best for me.

 

Here is my design. I prefer loose pins, makes it easy to separate the flasks and gives very positive alignment.

 

loose pins are very good in many instances, long pulls like bells for example ,
but for plaques, I would have more pins in my sand heap then on my flasks, cant keep track of small things around the sand .

Your design is very good also


V/r Ht1

 

So, I am getting enthused about casting aluminum flask components. I'll be making my patterns using traditional wood methods as the components are so simple, my flasks need to be pretty large, and I do not have a 3D printer. I am sure I could find someone to print some components, but I think I can make them in wood rapidly and economically.

Does anyone have experience casting iron in aluminum flasks? I ask as I am concerned that aluminum flasks might be melted by any slopped metal. Is that a fact or does aluminum conduct heat quickly enough to minimize any actual melting of the flask for all but very large spills? And, I guess, if I needed to I could make a simple steel apron to place strategically on the aluminum to shed mild to moderate spills. Generally I our with little or usually no spills. But, I have to be realistic and realize spills will happen on occasion.

I am planning a slightly different design to fit my specific needs. I will not be using long pins for alignment, but instead use the very short pins in the lip of the flask for alignment as my patterns do not require long guidance but rather just good final alignment. And, since my molds are generally too heavy for manual lifting and flipping I will be using horizontal threaded pins in each cope, drag, or cheek component similar to what I use in my wood and welded steel flasks.

Denis

 

Normal Cast Fe spills and splattes are little issues with aluminum flasks ,
Now if you are pouring a couple of hundred pounds of cast Fe and dont get enough sand between your pattern and your flask ( 1 inch Minimum), and have a slow but persistant runout you can FUBAR an aluminum flask

In short use a big enough flask and you should never have an issue

V/r HT1

 

recieved My Flask Pattern parts from 509 Maker They are very well done and fit together well and feel strong and solid
well done and thank you 509 Maker

I borrowed 509Makers pictures also, seems he is a better Photograper then this sand rat!

now as to the design of the parts, so JulianHG's part of this evolution
every section is designed to hold 1.5625 inch of sand
the pin section and it's none pin spacer counterpart are double that, so 3.125 so if you put together two ends and a pin section you get a 6.25 flask

now on the non pin side you can substitute a single rather then the double so the potential flask sizes are

pin side(square flask sizes) ***possible non pin side (rectangle sizes)*
6.25
***7.8125
9.375
***10.9375
12.5
** *14.0625
15.625
** *17.1875
18.75

the pieces are 3.125 tall (Flask Height)

the pieces are .3125 thick
the edge, which will be your flask rim is 1/2 thick
the sand retention is .0937 deep 90° groove

My opinion: based on my work in petorbond , you will get a little farther in green sand ,
1) these are small flasks!!! once you remove the draft, you will have 3 inch tall flasks, that is the smallest you can expect to hold sand, and I have only done that up to 14X14
2) i like the 5/16 thickness, hopefully it will make the flasks light enough to handle well
3) i'm nervious about that 1/2 inch rim, I wish it had been 3/4 all the professional flask I have used had a 1 inch rim reimforced with steel flat bar
4) I'm also concerned about the sand retention, it looks good and I have seen profesional flask done similarly, but a little more aggresively. Olfoundryman's design with the rim in the interior of the flask is superior for holding the sand in place, but does increase the difficulty of ramming up the pattern, and it would not have worked with JulianHG's modular design ( I assume the Modular design allows the use of a much smaller printer)





all that said I have a plan to move forward , im going to cast an end and a side in the 12.5 size
I will then modify those castings into my final pattern by adding a strip of wood or metal to the rim top and bottom, if I extend it into the interior it will help with sand retention, but will effectively shrink the size of the flask , but it's thickness will add height, I would like to get at least 3.5 inches in height , I may increase the agresiveness of the sand retention , which will remove metal from the pattern, lowering the weight

Thoughts???

V/r HT1

P.S. I have made aluminum flasks before, from my own wood pattern I way overbuilt them, and they where too heavy for use

 

at the 20 minute mark of this video, he drops a teaser on how he does it, which I intend to appropriate



V/r HT1

 

Jullian's patterns were designed from the start for 3D printing. He himself says he's an amateur Caster. They printed even on my little Prusa Mini. OldFondryman's were a 3D printing adaptation of a hand made pattern And are a little harder to get to print (can't nest quite as many, need to use rafts because the height to surface is high). The design is based on a lifetime of casting. He also admits they are what he likes. Neither design might be all things to all folks. I haven't gotten to the casting or usage part so I don't have any feedback (and to be honest I'm not qualified to render judgment on). HT I'm looking to you on this as you have the experience with boxes (pro/ homebuilt, good and bad) that most of us here lack.

 

Oh I so remember why casting flasks sucks.
you gotta make flasks big flasks. To get two pieces, a side and end for 12x12. You need a 12x17 flask. A search of my storage I had three flasks that got a trim I actually had and have used 18x18 flasks. Never again. But with a trim I now have 4 flasks I can use to make flasks . I also whipped up another pair of followers

V/r HT1

 

I'll be using my my 12X48's to make 40's for my 36" straight edges and 30 inch squares. I just finished lengthening my my 22's to make them 26's. You are right those are a bear for hand maneuvering. That's why I made my power hoist a while back. 450 pound molds were impossible to use otherwise. Using a hoist is slower than hand flipping, of course, but at least it is possible. I will be making solid flattish lugs on the centers of the end pieces for bolt/pins I use to hoist and flip the molds. For making these aluminum flasks I would think one could use fairly shallow molds to make them lighter. If used with top and bottom boards for flipping the sand should stay put even if they are only a couple inches thick. I use top and bottom boards routinely so I can get away with less sand than otherwise. Also a pain, but makes it doable for me. I have to pour outdoors with the molds not sitting down on a flat surface but usually wedged on corners for leveling. So the bottom board keeps the sand from falling out.

 

I've had a number of dropouts in the past, some of them heartbreaking. A lot of good practices minimize the risk like maintaining your sand, ramming technique, and size and internal features of the flask. But the bottom board is the greatest assurance. I never lift without one. Sometimes I screw it on just to stabilize it while I'm rolling the drag. Lifting and closing my molds are always preceded by a silent prayer.

Pete

 

Yeah, a set of 8 flask parts is a pretty big big project for a hobby caster. I cast so infrequently, that I should probably just accept the wooden ones charring. But Aluminium ones are nice to use.
Mark

 

I tested JulianHG's pattern yesterday, I'm less then excited


on my first attempt I placed the patterns and followers in the drag with the runner, and rammed , though well tucked in and rammed outside to inside , the pattern sections opened up in several places , the worst pictured, this of course is unacceptable you would never be able to get square and true flasks with variable sized sections.


to remedy the pattern falling apart, I descided to permanenty attach the followers to the ramming board, creating a follow board. JulianHG kindly included starter holes in the followers, but in a location that you could not reach while assembling the follow board

here is the second drag, it is quite good looking, but has an ugly issue( see below

the picture does not show it well, but the pattern is slightly lowered into the mold , basically it is banana bowed, what is going on is the follower is a tiny bit too close to the pattern, tiny, like 1/32, this raises up the end of the pattern, since the pattern is not SOLID, it flexed when rammed if I cast it the part will be curved which would make the flasks come out unsquare

OK here is where i'm at,
1) I could loosen up the follower and try to reposition it, the follower would need new holes to make this work with screws, this will always be a bit of a hit and miss. a solid (printed)pattern, or a pattern out of another material would be far less likely to bow this way,
2) i could glue the pattern pieces all together and ease the followers outboard as they would be far les critical with the pattern as one piece
2a) since someone will metion it, yes in a SS or resin sand the extremely soft ram available, might make this entire issue go away
2b) the issue might go away on smaller flask sizes 12.5's have 7 sections only doing 3 sections, you might be ok

Gluing the pieces together really defeats the modular part of this evolution, and way way drives the price up as I would have to have another set printed for a different size flask, this would make the only advantage of the modular design, is those of you with a small printer can make them

i priced the pieces for this on shapeway at near $650 and yes 509 Maker got me a much better deal, or I would not have even tried this evolution, I can Buy 2 Professional 12X12's for that.
I could probably get acceptable flasks out of this pattern, not by ramming it up as a pattern, but using it to cast a master pattern, making any repairs to that pattern and then making flasks ( that was my original intention, and still might happen)

I've had to work with some "ghetto" patterns and core boxes before, this is not the worst I have delt with, but if it is giving me this much trouble I can only think it will REALLY stymie the average hobbiest... a lot of people would not have noticed the banana bow in the mold and would have cast the part and been REALLY frustrated at assembly , when all their flasks are diamond shaped

I'm frustrated and annoyed with this patttern, and at this point would like to try OlFoundryman's , but to me at has an issue, the largest size is 300MM or 11.81 that is smaller then I need, I need 12 or better, I can of course modify the pattern , or add shims at the asssembly of the pieces, a 1/4 inch shim in each corner would get me there... but Olfoundrymans design for sand retention is superior for sure

Has anyone printed or tried Olfoundrymans pattern yet? anyone willing to make me a set at a fair price (shapeways is not fair )
Does anyone have a good pattern for 12X12 flasks ??

V/r HT1

P.S. if i could get one perfect mold, I could use tobho mott's drywall matchplate trick and try to get a master matchplate

 

HT1, What might help separation but probably not bowing and still does not defeat the modularity would be to try nylon-reinforced strapping tape along the length of the pattern maybe covering only 1/2" along each edge both front and back. That would, of course, occlude the contouring of the pattern, but there is plenty of keying to prevent dropout and some could be spared.

I am just starting to cut up Baltic birch slats and fir strips to make wood patterns. I like being able to hold the parts in my hand and look them over and turn them around in my hands to see if they "look right." I have decided there is no way for me to calculate the ideal thicknesses and widths and will just have to do what seems right, cast it, and adjust as needed.

I am thinking I will use the sand I have been using to cast iron which includes coal and see how that works for aluminum. That is unless someone knows this is a terrible idea.

Denis

 

GO thin GO THIN!!!, here is pictures of my first flask Castings , I have a set of these, they are so Heavy, I never use them

here is what is the interior of the Flasks hair over 1/2 inch thick , ( I had access to a planer at the time) so wood any thickness, I wanted 3/4 after shrinkage... What was I thinking???

This is the back, it is the entire Back of the flask sides, it's 1/4, it could have been half as thick

each flask section is a full 3/4 inch thick around the edge, and the edge is beefier then it had to be.

Do everything you can to lose weight

remember the density of soft wood is around 500 kg/m3 , aluminum is 2710 kg/m3 so to get aluminum flask that weight the same as wood flasks, you gotta reduce the volume 5+ times , that is probably not doable, but you can get much closer then I did, Olfoundryman's basic design can get you close.

Start a thread and show us what you come up with


V/r HT1
P.S. I dont think your sand will give you any special issues , Just vent more then normal, and perhaps kick up the head pressure to help fill those thin sections

 

It was laughing at me
I was in the shop working on patterns, it keept taunting me. " you cant cast me!'

like hell, I relocated the follow blocks, added a full gating system, so know its a complete follow board,
" Gonna cast it !" sing along "gonna cast it"




V/r HT1

 

It is good to see these issues. I think you are right, less experienced folks such as myself would have over looked a few of the things you pointed out. Now I can try to be more aware when I go to mold my patterns. For my Julian patterns I am planning to use your 2 and 2b options, I am aiming for a 9.5in flask and I plan to glue everything together and use it as a solid one piece pattern.