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No bake foundry process

sgpl

Plastic
Joined
Aug 26, 2021
Hey everyone,

We make many different types of Cast Iron parts (8,000+) and have been facing tremendous problems in the casting qualities we receive.
Due to the variety of parts we make, we continue to use sand moulded (hand moulded) castings, which due to their variance apparently make it more difficult to machine our jobs.
I have come to learn about the No bake casting process, which has a higher tolerance in castings produced, and also quality of castings with lesser defects.
Can someone enlighten me in depth on the no bake casting process (in other words, if I wanted to set up or create a project report on setting up a no bake foundry) what equipment would be required to get started.

Thank you!
 
The one that's been around a long time is the sodium silicate and CO2. Often used for cores.

I visited a production foundry some years ago that said they used a binder that sounded like some variety of epoxy that was mixed with the sand and used immediately. In their process the sand was blown or flung into the boxes so I think they weren't hand ramming. I expect cost is the major consideration.
 
I've used green sand, sodium silicate and Pep Set 8000. The later being a no bake two part resin + catalyst that gets mixed with sand and cures. I've only done prototypes from aluminum (no cast iron). From my experience not a big jump going from green sand to Pep Set, the later actually being easier to ram, less delicate to handle, and having a better surface finish

From my limited knowledge you may be able to use the same patterns you are using with green sand or petrobond sand but you may need a a different release agent for the patterns, I've used Zip Sick with Pep Set and it works really well. You'll need a mixer to mix the sand with the resin. I have mixed by hand with ok results for very small batch one offs but even that is a lot of work and not recommended. You're doing higher volume so I think mixing is the biggest thing to sorted out. Since you have a limited amount of time to work with it until the binder sets so you'll need to figure out what batch sizes you'll want. The other thing to consider is what to do with the sand when its used. Not sure if it can be reclaimed or considerations when disposing of it vs green sand.
 
Hey everyone,

We make many different types of Cast Iron parts (8,000+) and have been facing tremendous problems in the casting qualities we receive.
...
Can someone enlighten me in depth on the no bake casting process (in other words, if I wanted to set up or create a project report on setting up a no bake foundry) what equipment would be required to get started.
Where in the world are you? Please update your user profile such that your location appears under the colored disk to the left.
 
Am I wrong in thinking there is a big jump from hobby casting to industrial scale casting, with not much in between?

As compared to machining where there is a long slope from benchtop 12x36 lathe to an Index multispindle, with lots of us falling somewhere on the spectrum in the middle (old Mazak, new Citizen, Haas, etc).

It just doesn't seem like casting is small-mid size shop friendly. Like if Goldenfab wanted to go from making one prototype at a time to batches of several hundred, is that doable?
 
Am I wrong in thinking there is a big jump from hobby casting to industrial scale casting, with not much in between?

As compared to machining where there is a long slope from benchtop 12x36 lathe to an Index multispindle, with lots of us falling somewhere on the spectrum in the middle (old Mazak, new Citizen, Haas, etc).

It just doesn't seem like casting is small-mid size shop friendly. Like if Goldenfab wanted to go from making one prototype at a time to batches of several hundred, is that doable?

You probably have a point. I don't know since I've only done small scale one offs.
 
Goldenfab - Where did you obtain a small qty of pep-set? I used to buy a 5 gallon pail of each side from my local foundry in MN. haven't been able to find it in less than 55 gal drums anywhere since then and have gone back to co2 & soduim silicate for our prototype castings we do in aluminum
 
Goldenfab - Where did you obtain a small qty of pep-set? I used to buy a 5 gallon pail of each side from my local foundry in MN. haven't been able to find it in less than 55 gal drums anywhere since then and have gone back to co2 & soduim silicate for our prototype castings we do in aluminum
Out of curiosity, have you tried propanyl carbonate to catalyze sodium silicate? I use it routinely and find it easier to wait the 2-3 hours from mixing and mold packing to stripping than it is is to shoot CO2 into the mold. The PC guarantees uniform and complete setting of the silicate. Shooting in CO2 is nice because it is instantatneous, but sometimes a bit of a guessing game with deep molds. If you are using a vacuum to draw the CO2 throught the silicate, that is anothjer matter. I have also hurried the propanyl carbonate mix along by packing the mold (or core) and then hitting it with CO2. The PC makles the mix more sensitive to CO2.

Denis
 
I was able to get a sample size from a foundry supply business in Phoenix called Porter Warner. I think it was one gallon of each parts A and B plus a small bottle of catalyst. I've bought a few foundry related things from them and just drove down to pick them up. This was some years ago.


I tried sodium silicate but Pep Set was easier with shakeout when it came to core cavities (complex cylinder head water jackets). I also had more issues with sodium silicate sticking to my patterns.
 
Yeah, there is a foundry or two over there that is pushing tons of cast iron castings for drillable down hole tools for the oilfields around the world being done over there in India. And it's not just the oilfield, almost every industry out there is resourcing their products from India today over that of China. We are seeing stuff being pulled from China and going to India at a alarming rate. I can see them improving on things like castings to stay competitive over there.
 
Out of curiosity, have you tried propanyl carbonate to catalyze sodium silicate? I use it routinely and find it easier to wait the 2-3 hours from mixing and mold packing to stripping than it is is to shoot CO2 into the mold. The PC guarantees uniform and complete setting of the silicate. Shooting in CO2 is nice because it is instantatneous, but sometimes a bit of a guessing game with deep molds. If you are using a vacuum to draw the CO2 throught the silicate, that is anothjer matter. I have also hurried the propanyl carbonate mix along by packing the mold (or core) and then hitting it with CO2. The PC makles the mix more sensitive to CO2.

Denis
Alcahol works also to instantly harden waterglass
Inject with alcahol and let the alcahol evaporate Burn off the last bit if need be
For a backyard foundry with smaller cores it can be usefull
 
Interesting thread! I wonder about reuse of the base sand after it's had these binders "fired" by the cast itself. If anyone has concrete (sorta pun) info on that please pipe up.
 
Interesting thread! I wonder about reuse of the base sand after it's had these binders "fired" by the cast itself. If anyone has concrete (sorta pun) info on that please pipe up.
from my reading (just sitting on the sidelines) they burn it out in an oven/furnace. But I would like to hear from "Them that's doing".
 
Interesting thread! I wonder about reuse of the base sand after it's had these binders "fired" by the cast itself. If anyone has concrete (sorta pun) info on that please pipe up.

You need special reclaiming equipment to re-use sand mixed with pep-set, It's a 2 part system that is some sort of polurethane (I think) the sand is harder than concrete and you get a really nice surface. It would need to be crushed and pulverized and then screened I would think. You have to use Zip-slip (alot like silver anti-sieze) to coat your pattern so the pep-set won't stick to your pattern. Also you usually build a cope and drag side box separate, with one side of the pattern being in each box, rather than using a matchplate. There are registration cones you use to assure accurate alignment once the halves are assembled.
 

Not too much ... here's a guy who doesn't know anything, looking for superficial knowledge about casting, and then he's going to write a report. That oughta work well.

Want to see some video of making 500 lb investment cast stainless steel valves from ... not India ?

You realize, they've tried this shit before and it didn't work ? And won't work this time either ? What did HD decide to do ?

Yeah, leave. I wonder how much they lost on that world-beater scheme.

Somebody should hide the damn "how to run your company" business magazines in the dentist office. Too many upper-level pointyheads read those things.
 








 
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