Binge, thank you for creating this inspirational and extremely helpful thread! I have taken the plunge and started casting keycaps and used materials recommended by you with great(ish) results. You have great suggestions, and the pics you post are great! Especially helpful for me are the silicone mold pics.
Now, I am ready to take the next step and I was wondering, in your opinion, what is more important piece of equipment, a Vacuum degassing chamber, or a Pressure Pot? I plan to get both eventually but I was wondering your opinion on which one helps the most with eliminating bubbles?
Both are used for different purposes. Casting under pressure reduces formation of extra gasses in the mold and vacuum degassing removes existing gasses from the mix. Consider how each of those techniques align with your goals and choose what works for you.
I chose pressure first and it allowed me to get started. If you still don't feel informed enough please do more research on why the machines are used in the process. They target different problem areas in the process of resin casting.
Thanks, I think im going to go with the vacuum chamber first as I am not only casting keycaps but I have another project that I am doing in conjunction that requires very soft (45D) urethane in a larger mold that would benefit more from pre-pour degausing more then a pressure pot im thinking. The larger mold end result casts dont really matter if there are bubbles in it. That and the vacuum chambers are much more readily available.
As for pressure pots, I found a decent one on the artmolds website I think im going to get in a few months. What I really need is a hint as to where to get an air pump that does both vacuum and compress in one unit. Any hints? :D
Also, and you don't have to answer this if you dont want. Are your current end-product keycaps both degaussed and pressurized?
Beware the artmolds pressure chamber I would recommend what I always recommend, but I think you should take this convo over to my 'Let's talk shop...' thread.
https://geekhack.org/index.php?topic=70967.0
From the Capcraft Hub:Binge, thank you for creating this inspirational and extremely helpful thread! I have taken the plunge and started casting keycaps and used materials recommended by you with great(ish) results. You have great suggestions, and the pics you post are great! Especially helpful for me are the silicone mold pics.
Now, I am ready to take the next step and I was wondering, in your opinion, what is more important piece of equipment, a Vacuum degassing chamber, or a Pressure Pot? I plan to get both eventually but I was wondering your opinion on which one helps the most with eliminating bubbles?
Both are used for different purposes. Casting under pressure reduces formation of extra gasses in the mold and vacuum degassing removes existing gasses from the mix. Consider how each of those techniques align with your goals and choose what works for you.
I chose pressure first and it allowed me to get started. If you still don't feel informed enough please do more research on why the machines are used in the process. They target different problem areas in the process of resin casting.
Thanks, I think im going to go with the vacuum chamber first as I am not only casting keycaps but I have another project that I am doing in conjunction that requires very soft (45D) urethane in a larger mold that would benefit more from pre-pour degausing more then a pressure pot im thinking. The larger mold end result casts dont really matter if there are bubbles in it. That and the vacuum chambers are much more readily available.
As for pressure pots, I found a decent one on the artmolds website I think im going to get in a few months. What I really need is a hint as to where to get an air pump that does both vacuum and compress in one unit. Any hints? :D
Also, and you don't have to answer this if you dont want. Are your current end-product keycaps both degaussed and pressurized?
Beware the artmolds pressure chamber I would recommend what I always recommend, but I think you should take this convo over to my 'Let's talk shop...' thread.
https://geekhack.org/index.php?topic=70967.0
Is the artmolds pot no good?
the ASME standard for building pressure vessels is a process certification that signifies that the manufacturer followed best practices in welds, material sourcing (EXTREMELY IMPORTANT), rolling or forming, and of course, that the design was certified by the standards body.
the sum total of this is that the asme certified pressure vessel construction is the absolute minimum that an engineer designing a critical pressure/vacuum system will require in production. here is why: when a pressure vessel explodes, people die.
SO! there are plenty of tanks out there that invite you to fill them with pressurized gases or fluids. many of them are ok on their first few uses, or ok for the first month after production, but after repeated cycles of expansion and contraction, and potentially oxidization at weak points in the vessel, they will eventually let go. if you're lucky (for example, a contractor's compressor tank), the vessel will pop a few leaks and the end result will just be the compressor's motor locking up from overwork.
if you're unlucky, the vessel will basically become a grenade; it will explode and high velocity steel shrapnel will fire off in all directions. you will probably not see any evidence that the unlucky case is going to happen. often, this will happen while the vessel is pressurized (and not during a release or pressurization cycle). once a large enough piece of tank fires off, the resulting stress on the hull will disintegrate it.
so anyway, my rule of thumb is that for typical cast and mold applications with the materials that people here use, a 40-50psi cure pressure is pretty standard. to hold 40-60psi for the duration of a cast (30-60mins), i source at least 100psi asme rated pots. also, because these pots tend to sit at pressure for long periods of time, i only source stainless pots. finally, i don't source anything that could even possibly have chinese "steel" in it (the chinese metal market is an absolute mess).
finally, all seals, gaskets, and fittings are fluorinated, period. silicone cures give offgas caustic nasty stuff. a seal failing will have a similar effect to the catastrophic explosion above (possibly worse, actually).
so that's the pot! a lot of people ask about compressors and hosing (OH MY GOD SO IMPORTANT) as well. but yes, the pot? don't screw around. your life is not worth the hundred or so dollars separating a high quality certified pot from something that has a non-trivial chance of killing you.
oh, i should mention that vacuum pots are not things you should be screwing around with either. i have seen far too many acrylic topped soup pots that i can to recall. hey remember pressure pots turn into small grenades when they explode? turns out that vacuum pots do the same thing when they implode!
so that's the pot! a lot of people ask about compressors and hosing (OH MY GOD SO IMPORTANT) as well. but yes, the pot? don't screw around. your life is not worth the hundred or so dollars separating a high quality certified pot from something that has a non-trivial chance of killing you.
so that's the pot! a lot of people ask about compressors and hosing (OH MY GOD SO IMPORTANT) as well. but yes, the pot? don't screw around. your life is not worth the hundred or so dollars separating a high quality certified pot from something that has a non-trivial chance of killing you.
mkawa's post is right on the money but I think this needs to be emphasized. A pressure chamber is only a few steps away from a bomb.
would not recommend. the mechanism of action is going to be something like a viscosity decreasing agent that will change the composition of your casting material. in complex multipart multi-rx materials, that could result in unpredictable cure schedules and worse, non-uniformity of cure (the whole point of thorough mixing..)
would not recommend. the mechanism of action is going to be something like a viscosity decreasing agent that will change the composition of your casting material. in complex multipart multi-rx materials, that could result in unpredictable cure schedules and worse, non-uniformity of cure (the whole point of thorough mixing..)
Surfactants typically affect the surface energy of the substrate (which may have a slight effect on viscosity). The specific surfactant he listed seems to be designed for this application, so I don't see much harm in trying it. In fact, if I ever tried my hand at casting I was going to test some surfactants too.
Also, they are actually pretty common in industry (especially in inks, which yes, are resins in a lot of cases), though the application is indeed quite different.
Your concerns are certainly valid and something to be keeping an eye out for, but if you can't figure it out just revert back to he original recipe. No harm in trying.
Ah, ok. Good to know
would not recommend. the mechanism of action is going to be something like a viscosity decreasing agent that will change the composition of your casting material. in complex multipart multi-rx materials, that could result in unpredictable cure schedules and worse, non-uniformity of cure (the whole point of thorough mixing..)
Surfactants typically affect the surface energy of the substrate (which may have a slight effect on viscosity). The specific surfactant he listed seems to be designed for this application, so I don't see much harm in trying it. In fact, if I ever tried my hand at casting I was going to test some surfactants too.
Also, they are actually pretty common in industry (especially in inks, which yes, are resins in a lot of cases), though the application is indeed quite different.
Your concerns are certainly valid and something to be keeping an eye out for, but if you can't figure it out just revert back to he original recipe. No harm in trying.Ah, ok. Good to know
Thank you both. I ordered some AF-4. I will post my results with varying ratios of resin:surfactant.
IDK of anyone on this forum that's tried a combination of surfactant + (ultrasonic) vibration degas but I think it might be a good training-wheels degassing method for newb-casters who aren't ready for pressure.
My question is about bubbles. Many new cap makers have little bubbles when they first start out. I understand pressure is a good way to get rid of this, but as someone who has done traditional metal casting, this seems a little daunting to take on at first.
Can you use a shake table or some sort of non-disruptive agitation to rid yourself of bubbles? Or is resin not viscous enough. Thanks guys!
My question is about bubbles. Many new cap makers have little bubbles when they first start out. I understand pressure is a good way to get rid of this, but as someone who has done traditional metal casting, this seems a little daunting to take on at first.So many different kinds of resin... all with different viscosities and surface tensions. The surfactant would help bubbles escape. As to agitation the standard methods of degassing are far more effective because they cause less kinetic energy conversion to heat. Most people seldom consider the catalysts cause a thermal reaction which can be enhanced with kinetic forces. Vibrating tables will cause your thermoset reactions to catalyze more quickly. They are much better suited for silicone degasing on a budget. Ultrasonic is more superior for silicone and resins, but the cost for a large unit can be equal to the industrial casting aids, pressure/vac chambers, in which we dabble.
Can you use a shake table or some sort of non-disruptive agitation to rid yourself of bubbles? Or is resin not viscous enough. Thanks guys!
My question is about bubbles. Many new cap makers have little bubbles when they first start out. I understand pressure is a good way to get rid of this, but as someone who has done traditional metal casting, this seems a little daunting to take on at first.So many different kinds of resin... all with different viscosities and surface tensions. The surfactant would help bubbles escape. As to agitation the standard methods of degassing are far more effective because they cause less kinetic energy conversion to heat. Most people seldom consider the catalysts cause a thermal reaction which can be enhanced with kinetic forces. Vibrating tables will cause your thermoset reactions to catalyze more quickly. They are much better suited for silicone degasing on a budget. Ultrasonic is more superior for silicone and resins, but the cost for a large unit can be equal to the industrial casting aids, pressure/vac chambers, in which we dabble.
Can you use a shake table or some sort of non-disruptive agitation to rid yourself of bubbles? Or is resin not viscous enough. Thanks guys!
Yep entirely custom ☺My question is about bubbles. Many new cap makers have little bubbles when they first start out. I understand pressure is a good way to get rid of this, but as someone who has done traditional metal casting, this seems a little daunting to take on at first.So many different kinds of resin... all with different viscosities and surface tensions. The surfactant would help bubbles escape. As to agitation the standard methods of degassing are far more effective because they cause less kinetic energy conversion to heat. Most people seldom consider the catalysts cause a thermal reaction which can be enhanced with kinetic forces. Vibrating tables will cause your thermoset reactions to catalyze more quickly. They are much better suited for silicone degasing on a budget. Ultrasonic is more superior for silicone and resins, but the cost for a large unit can be equal to the industrial casting aids, pressure/vac chambers, in which we dabble.
Can you use a shake table or some sort of non-disruptive agitation to rid yourself of bubbles? Or is resin not viscous enough. Thanks guys!
What's your vac/pressure setup btw? Is it mkawa's custom?
Will someone please yell at me and get me to not buy this crap (http://www.ebay.com/itm/1-QT-Glass-Vac-Purge-Chamber-Stabilizer-With-SlickVacSeal-Silicone-Kit-/121699249500?hash=item1c55d72d5c:g:q5cAAOSwcwhVQxG9)? My rationality is starting to go out the window
What do you generally use as your casting resin? Do you personally use aluminum molds or silicone. Have been talking to a buddy with a degree in industrial design who has experience with casting stuff. He seemed intrigued by the subculture lol
Will someone please yell at me and get me to not buy this crap (http://www.ebay.com/itm/1-QT-Glass-Vac-Purge-Chamber-Stabilizer-With-SlickVacSeal-Silicone-Kit-/121699249500?hash=item1c55d72d5c:g:q5cAAOSwcwhVQxG9)? My rationality is starting to go out the window
Please don't buy that stuff.... that's an accident waiting to happen.What do you generally use as your casting resin? Do you personally use aluminum molds or silicone. Have been talking to a buddy with a degree in industrial design who has experience with casting stuff. He seemed intrigued by the subculture lol
I don't want to share this kind of information because you will not benefit from me telling you to buy a product. You will benefit from reading about casting and talking to your chemical manufacturer of choice about their products.
Will someone please yell at me and get me to not buy this crap (http://www.ebay.com/itm/1-QT-Glass-Vac-Purge-Chamber-Stabilizer-With-SlickVacSeal-Silicone-Kit-/121699249500?hash=item1c55d72d5c:g:q5cAAOSwcwhVQxG9)? My rationality is starting to go out the window
Please don't buy that stuff.... that's an accident waiting to happen.What do you generally use as your casting resin? Do you personally use aluminum molds or silicone. Have been talking to a buddy with a degree in industrial design who has experience with casting stuff. He seemed intrigued by the subculture lol
I don't want to share this kind of information because you will not benefit from me telling you to buy a product. You will benefit from reading about casting and talking to your chemical manufacturer of choice about their products.
Just to play devil's advocate, wouldn't a vacuum chamber that fails just sort of collapse?
Will someone please yell at me and get me to not buy this crap (http://www.ebay.com/itm/1-QT-Glass-Vac-Purge-Chamber-Stabilizer-With-SlickVacSeal-Silicone-Kit-/121699249500?hash=item1c55d72d5c:g:q5cAAOSwcwhVQxG9)? My rationality is starting to go out the window
Please don't buy that stuff.... that's an accident waiting to happen.What do you generally use as your casting resin? Do you personally use aluminum molds or silicone. Have been talking to a buddy with a degree in industrial design who has experience with casting stuff. He seemed intrigued by the subculture lol
I don't want to share this kind of information because you will not benefit from me telling you to buy a product. You will benefit from reading about casting and talking to your chemical manufacturer of choice about their products.
Will someone please yell at me and get me to not buy this crap (http://www.ebay.com/itm/1-QT-Glass-Vac-Purge-Chamber-Stabilizer-With-SlickVacSeal-Silicone-Kit-/121699249500?hash=item1c55d72d5c:g:q5cAAOSwcwhVQxG9)? My rationality is starting to go out the window
Please don't buy that stuff.... that's an accident waiting to happen.What do you generally use as your casting resin? Do you personally use aluminum molds or silicone. Have been talking to a buddy with a degree in industrial design who has experience with casting stuff. He seemed intrigued by the subculture lol
I don't want to share this kind of information because you will not benefit from me telling you to buy a product. You will benefit from reading about casting and talking to your chemical manufacturer of choice about their products.
I was just looking for more generics. Not brand X compound Y. But I understand. Like I said I don't have much knowledge in the area, but have a friend that does. The artisan keycap subculture came up and he was just wondering how people were going about it.
Will someone please yell at me and get me to not buy this crap (http://www.ebay.com/itm/1-QT-Glass-Vac-Purge-Chamber-Stabilizer-With-SlickVacSeal-Silicone-Kit-/121699249500?hash=item1c55d72d5c:g:q5cAAOSwcwhVQxG9)? My rationality is starting to go out the window
Please don't buy that stuff.... that's an accident waiting to happen.What do you generally use as your casting resin? Do you personally use aluminum molds or silicone. Have been talking to a buddy with a degree in industrial design who has experience with casting stuff. He seemed intrigued by the subculture lol
I don't want to share this kind of information because you will not benefit from me telling you to buy a product. You will benefit from reading about casting and talking to your chemical manufacturer of choice about their products.
I was just looking for more generics. Not brand X compound Y. But I understand. Like I said I don't have much knowledge in the area, but have a friend that does. The artisan keycap subculture came up and he was just wondering how people were going about it.
Will someone please yell at me and get me to not buy this crap (http://www.ebay.com/itm/1-QT-Glass-Vac-Purge-Chamber-Stabilizer-With-SlickVacSeal-Silicone-Kit-/121699249500?hash=item1c55d72d5c:g:q5cAAOSwcwhVQxG9)? My rationality is starting to go out the window
Please don't buy that stuff.... that's an accident waiting to happen.What do you generally use as your casting resin? Do you personally use aluminum molds or silicone. Have been talking to a buddy with a degree in industrial design who has experience with casting stuff. He seemed intrigued by the subculture lol
I don't want to share this kind of information because you will not benefit from me telling you to buy a product. You will benefit from reading about casting and talking to your chemical manufacturer of choice about their products.
I was just looking for more generics. Not brand X compound Y. But I understand. Like I said I don't have much knowledge in the area, but have a friend that does. The artisan keycap subculture came up and he was just wondering how people were going about it.
A silicone that can reproduce fine detail and has a decent tear strength. A resin that has a long enough pot life to degas and accepts colorant well.
From there its all about experimenting with what works well for the equipment you have, the conditions you will be working in, and the look you want in the end result. Like Binge said, talking to the manufacturer is a fantastic way to get some idea of what is in your ballpark.
I am fortunate enough to have a brick and mortar to go to and show what went wrong to (they even hold events for new products and are willing to do classes for people who want to get into the hobby).
What do you generally use as your casting resin? Do you personally use aluminum molds or silicone. Have been talking to a buddy with a degree in industrial design who has experience with casting stuff. He seemed intrigued by the subculture lol
I don't want to share this kind of information because you will not benefit from me telling you to buy a product. You will benefit from reading about casting and talking to your chemical manufacturer of choice about their products.
What do you generally use as your casting resin? Do you personally use aluminum molds or silicone. Have been talking to a buddy with a degree in industrial design who has experience with casting stuff. He seemed intrigued by the subculture lol
I don't want to share this kind of information because you will not benefit from me telling you to buy a product. You will benefit from reading about casting and talking to your chemical manufacturer of choice about their products.
I've been looking around for quite a while for improvement of my current resin, but still haven't found any good manufacturers that ship to Sweden/ Europe... Do you know of/ could you recommend any? Been reading through the thread, really usefull information coming from experienced artisans! Thank you very much for sharing, it really helps a lot!
What do you generally use as your casting resin? Do you personally use aluminum molds or silicone. Have been talking to a buddy with a degree in industrial design who has experience with casting stuff. He seemed intrigued by the subculture lol
I don't want to share this kind of information because you will not benefit from me telling you to buy a product. You will benefit from reading about casting and talking to your chemical manufacturer of choice about their products.
I've been looking around for quite a while for improvement of my current resin, but still haven't found any good manufacturers that ship to Sweden/ Europe... Do you know of/ could you recommend any? Been reading through the thread, really usefull information coming from experienced artisans! Thank you very much for sharing, it really helps a lot!
What is the issue with your resin? I doubt the resin is the issue. It is probably environmental during the cure.
I want to expand on the ASME standard for pressure vessels. What this means in factual terms is that the welders involved in making the pressure vessel have ASME certification. The facility manufacturing the vessels must also have ISO and ASME certifications. Finally a comprehensive visual and usually x-ray inspection is performed for every finished unit. It is not a guarantee that the unit will not fail. However, it is about the best that we have available. Finally, The vast majority of of ASME certified vessels are made in the USA with traceable sources of steel. I emphasize this because steel and aluminum sourced from overseas is often very high in impurities. These impurities can lead to catastrophic failure despite a sound vessel design.
What do you generally use as your casting resin? Do you personally use aluminum molds or silicone. Have been talking to a buddy with a degree in industrial design who has experience with casting stuff. He seemed intrigued by the subculture lol
I don't want to share this kind of information because you will not benefit from me telling you to buy a product. You will benefit from reading about casting and talking to your chemical manufacturer of choice about their products.
I've been looking around for quite a while for improvement of my current resin, but still haven't found any good manufacturers that ship to Sweden/ Europe... Do you know of/ could you recommend any? Been reading through the thread, really usefull information coming from experienced artisans! Thank you very much for sharing, it really helps a lot!
What is the issue with your resin? I doubt the resin is the issue. It is probably environmental during the cure.
I've been trying out many different methods to inprove my casting; mainly to reduce bubbles/ improve details. The problem I've been having is that the caps, as many have pointed out, have the texture and looks of "candy". I've seen several other artisans having this look while beginning making caps, such as katzenkinder in his first sales. I've very recently invested in new sculpting materials which greatly improves the texture/ details of the caps; I haven't made any molds using these though. I will see how this looks soon, but I doubt it will fix this specific problem, as the same texture still applies to for example blanks. I am aware that I have merely begun making caps, and that I'm miles away fron most other artisans, but I still need to know if this specific look is due to me doing things wrong or due to the resin itself! Do you have any suggestions on how to fix this specific problem?
What do you generally use as your casting resin? Do you personally use aluminum molds or silicone. Have been talking to a buddy with a degree in industrial design who has experience with casting stuff. He seemed intrigued by the subculture lol
I don't want to share this kind of information because you will not benefit from me telling you to buy a product. You will benefit from reading about casting and talking to your chemical manufacturer of choice about their products.
I've been looking around for quite a while for improvement of my current resin, but still haven't found any good manufacturers that ship to Sweden/ Europe... Do you know of/ could you recommend any? Been reading through the thread, really usefull information coming from experienced artisans! Thank you very much for sharing, it really helps a lot!
What is the issue with your resin? I doubt the resin is the issue. It is probably environmental during the cure.
I've been trying out many different methods to inprove my casting; mainly to reduce bubbles/ improve details. The problem I've been having is that the caps, as many have pointed out, have the texture and looks of "candy". I've seen several other artisans having this look while beginning making caps, such as katzenkinder in his first sales. I've very recently invested in new sculpting materials which greatly improves the texture/ details of the caps; I haven't made any molds using these though. I will see how this looks soon, but I doubt it will fix this specific problem, as the same texture still applies to for example blanks. I am aware that I have merely begun making caps, and that I'm miles away fron most other artisans, but I still need to know if this specific look is due to me doing things wrong or due to the resin itself! Do you have any suggestions on how to fix this specific problem?
It's likely due to the colorants you are using. If you use colors which resemble the opacity and color candy the keys will look like candy. I am very careful with what I use to color my keys. You will have to source a good polymeric colorant supplier like Milliken Chemical and see to whom they distribute in your country. This goes back to my earlier comments about talking with your chemical supplier. They will have much better resources than any of the artisans on GH due to their knowledge of the product they are making/selling. They need to make things that people will use, so a lot of times they have to answer questions like the ones you are bringing here.
As for what's on topic... bubble management and details can be improved with the right shop tools for your chosen RTV/platinum cure silicones and resins.
My question is about bubbles. Many new cap makers have little bubbles when they first start out. I understand pressure is a good way to get rid of this, but as someone who has done traditional metal casting, this seems a little daunting to take on at first.So many different kinds of resin... all with different viscosities and surface tensions. The surfactant would help bubbles escape. As to agitation the standard methods of degassing are far more effective because they cause less kinetic energy conversion to heat. Most people seldom consider the catalysts cause a thermal reaction which can be enhanced with kinetic forces. Vibrating tables will cause your thermoset reactions to catalyze more quickly. They are much better suited for silicone degasing on a budget. Ultrasonic is more superior for silicone and resins, but the cost for a large unit can be equal to the industrial casting aids, pressure/vac chambers, in which we dabble.
Can you use a shake table or some sort of non-disruptive agitation to rid yourself of bubbles? Or is resin not viscous enough. Thanks guys!
My question is about bubbles. Many new cap makers have little bubbles when they first start out. I understand pressure is a good way to get rid of this, but as someone who has done traditional metal casting, this seems a little daunting to take on at first.
Can you use a shake table or some sort of non-disruptive agitation to rid yourself of bubbles? Or is resin not viscous enough. Thanks guys!
I think Binge is right. I've tried almost every method to stop it. I'm just gonna have to either get pressure (or vac) or just accept the bubbles.
This only applies to clear resin. If you have bubbles with white resin your problem is just in the way you cast generally (mixing the resin too violently, usually)
My question is about bubbles. Many new cap makers have little bubbles when they first start out. I understand pressure is a good way to get rid of this, but as someone who has done traditional metal casting, this seems a little daunting to take on at first.
Can you use a shake table or some sort of non-disruptive agitation to rid yourself of bubbles? Or is resin not viscous enough. Thanks guys!
I think Binge is right. I've tried almost every method to stop it. I'm just gonna have to either get pressure (or vac) or just accept the bubbles.
This only applies to clear resin. If you have bubbles with white resin your problem is just in the way you cast generally (mixing the resin too violently, usually)
The only time I've used a vac chamber was to remove butane from something that is not legal in all states. ^-^
How does this work with casting?