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geekhack Projects => Making Stuff Together! => Topic started by: djfunh8r on Wed, 04 October 2017, 12:09:06
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I’ve been working with these materials for a few weeks. I have no background in this, nor sculpting at all. These are my notes on various materials and techniques gleaned from the internet and trial and error.
Sculpting:
- Air-sculpt: not a fan. Consisency of overworked taffy, and not great for fine details.
- Super sculpey firm: works well, can be softened with Vaseline, etc., remains pliable until baked. I also use this for general purpose adhesive and other minor applications. I don’t bake the sculpts, but the synth could probably handle it fine. I mentioned I'm not good at sculpting.
- Milliput Superfine White – This is better than the air-sculpt junk. Two parts combined and tries hard within a few hours. It really gets annoyingly into your fingers, but you can use water to thin it out and make it more workable. It dries very hard, and will stick to the Synth. Because it dries hard, I like that you can sand it.
Mold Making- Materials
- Smooth On oomoo 30 (https://www.smooth-on.com/products/oomoo-30/) – stir like crazy, cures faster if left in warmer environment
- Legos for outside structure
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- $ynth - The Synth is being used here. I have seen other Synth users leave a lego dot outside the Synth, resulting in a mold where the Synth is more placed “into” the mold. I place the legos right at the edge, which results in a mold with open corners so you can see the Synth is fully inserted.
- Issues
- De-Molding
Making sure the sprues form on the mold will make de-molding way easier. On my first few, I just mashed some clay in there. I ended up scratching the hell out of a Synth removing caps because it was really difficult to separate the sprue components from the top of the cap in order to free the piece. For follow-up attempts I left the base of the Synth clean, and then inserted wooden sticks until they reached the base of the sculpt. Then I flush cut the sticks and place some clay on the bottom to secure in place. This resulted in very clean results, and because the wooden sticks end up with some “shoulder,” they are easier to push through with a non-metal tool and free the cap from the Synth.
- Floating $ynth
Another issue I encountered was the Synth floating within the Oomoo, which resulted in an un-level mold and a pain to extract from within a big brick of silicon. Going forward I used clay to fill the bottom of the mold and press in the Synth.
- Floating Sculpt
A further issue when using keycaps to mold blanks or as a sculpt base is the potential for separation of the sculpt from the Synth during molding. I had one piece separate resulting in a huge cap with a stem sticking way out the bottom. Modeling clay seems to work relatively well holding the sculpt on, but if you have used mold release on the cap before, it may have issues clinging.
Casting
- Materials
- Smoothcast general – Below is a table of all the different varieties. They vary in hardness, color, pot life, and cure time. I shake while in bottles for at least 30 seconds, stir each component while in cups. after mixing together thoroughly, I try to high-pour into another cup to get as many bubbles out as possible. I pour into the corner of the mold when possible and try to flow it into the mold. I’ve used a large variety at this point. The trial size bottles go pretty far considering the size of finished pieces. I have ordered from Amazon in the US as well as directly from Smooth On. Both suppliers sent products that still worked (these apparently have relatively short shelf life). One part is usually very thick and one is thinner. Generally I mix the color into the thinner bit and mix initially in the thicker cup, as I figure less volume will be lost to the sides of the cup. In very small quantities adding too much color messes with the cure and won’t set up properly. I mix the combined components at least 60 seconds prior to the high pour into the final cup prior to pouring.
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- Smoothcast 300 - (https://www.smooth-on.com/products/smooth-cast-300/) – forgiving, quick cure, white, takes color well.
- Smoothcast 320 – best results so far, quick hard cure, takes color well
- Smoothcast 325 (https://www.smooth-on.com/products/smooth-cast-325/) – clear, but I’ve had a ton of issues with hardness even after waiting out cure time. I wind up having to leave these on the mold for over at least 90 mins before hard enough to remove without damaging, particularly stem area.
- smoothcast 326 - (https://www.smooth-on.com/products/smooth-cast-326/) – better cure hardness than 325, longer cure time, but may be shorter overall given the additional post-cure time required for the 325.
- Smoothast 305 - (https://www.smooth-on.com/products/smooth-cast-305/) – cures white, longer pot life and cure time. May have fewer bubbles due to lower viscosity.
- Epoxacast 690 - (https://www.smooth-on.com/products/epoxacast-690/) Reserved.
- Smooth-on Universal Mold Release - (https://www.smooth-on.com/product-line/universal-mold-release/)– great stuff, super slick and never have any issues with release on resin. Smooth On recommends a different mold release for working with silicon. I had a mold of a maneki neko that I ruined because the mold release totally failed to separate the silicon mold from the poured silicon. This stuff doesn’t smell awful, but creates a pretty decent cloud of mold release vapor that results in super slick floors and other surfaces. If you can do the spraying outside or in a sink, you'll have a safer time.
- Michael’s-bought mold release – I’ll try to get a name, but this is one of the only mold releases sold at my local Michaels store. Pump spray bottle. This stuff works reasonably well, but nowhere near as effective as the aerosol from Smooth On.
- Easy Cast – very long cure time, dries very hard and clear, exceedingly difficult to remove from the Synth in my experience, but I was not using the Smooth On mold release.
- Smooth On SO-Strong Colorants (https://www.smooth-on.com/product-line/strong/)- Sampler pack of a few colors. These work well in very small amounts for the volume of resin used.
- Smoothing, Shine, Etc
- Alcohol – brushed on with soft brush to uncured Sculpey. Seemed to help a little, but it reacts somewhat to the Sculpey, making it harder and changes how it responds to tools, etc. Using water on a brush with curing milliput worked as well.
- Acetone vapor bath – largely ineffective. Looked like it had some results, but ended up messing with the structural integrity of the polymer (test pieces started disintegrating along unseen pour lines).
- Future Floor Polish - Difficult to work with using a brush or dipping, ended up with tons of puddles, etc. Bought a cheapo airbrush from aliexpress to assist. Better results with multiple ligher coats, but results still not spectactular. You can achieve a slightly textured surface with a light dry coat that kinda resembles the finish on at least the PMK DSA Dolch set I’m looking at. I am waiting on a bottle of Simple Green to try the suggested mix through the airbrush. Overall, working on smoothing the sculpt as much as possible and using proper mold release ends up with more satisfactory shine and finish than post-casting means. I’d like to try tinting this to see if any aging or other interesting effects are possible. It seems to be a fairly resilient finish, but I’m unsure how it would respond if the key were used extensively (e.g., a blank). Oh also this stuff smells really good.
[attach=1]
- Bubbles - Obviously more prevalent in the transparent resins, but also causes issues with opaque. I tried a few things to mitigate, but I think a pressure pot will be the most effective solution. The longer cure time Smoothcast resins also generally resulted in fewer bubbles, possibly due to the higher viscosity retained longer. Bubbles can also look cool, but getting them in thin walls or at the stem is an issue.
- Phone vibration- To eliminate bubbles in the mold and casting I attempted to place the molds onto a vibrating cell phone. This seemed to result in more surface bubbles escaping vs a stationary mold, but I would expect the effect is minimal. You also have to worry about getting goop on your phone. I typically placed the molds onto a 6x6” lego platform.
- Subwoofer vibration - I attempted to use my free-standing floor subwoofer generating a sine wave between 40-100hz to remove bubbles. The woofer didn’t vibrate much unless at high volume, which made living sortof like a never-ending ominous scene in Paramormal Activity. It was determined to be potentially effective but wildly irritating and was outlawed by popular vote.
- Hand-Sander - I purchased a cheap orbital hand-sander from Amazon. It has one speed (SAND), but if you plug it into a dimmer you can achieve varying speeds. I still have to devise a mount for this, but the vibration was more in line with what I was looking for. Potentially in combination with a pressure chamber this could be effective.
Stuff so far:
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Next steps:
- get better sculpts
- pressure pot
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Super informative, and some great colors you've got from your resins. More googley eyes!!!
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Nice work, so did you ever get that pressure pot? If so, what brand did you use? Also, I'm not sure if you last pics used a pressure pot or not, but they look really solid, very clean.
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Nice work, so did you ever get that pressure pot? If so, what brand did you use? Also, I'm not sure if you last pics used a pressure pot or not, but they look really solid, very clean.
No pressure pot. The pics above are the first real test batch. Even without the pot I think they turned out relatively good, and had probably about 10% that came out with a wacky stem or a bubble in the stem. I'd like to get one, but the money and storage costs are pretty high. I think vacuum setups are less expensive, but I've read less effective for the resin casting.
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cone king prototype: [attach=1]
stackable stem proof-of-concept: [attach=2]
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cone king prototype: (Attachment Link)
stackable stem proof-of-concept: (Attachment Link)
Hey that Cone King is tight. Nice idea. If you aren't using pressure or vacuum set ups. Are you using low visc resins and rubbers? What was your final method of getting bubbles out? I was having to poke the bubble with a needle, I thought about using a blow dryer, but my both my current medias are quick setting (mold is high visc), so I feel like they'd be more likely to trap bubbles. I've tried tapping and lightly banging the mold on a surface.
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cone king prototype: (Attachment Link)
stackable stem proof-of-concept: (Attachment Link)
Hey that Cone King is tight. Nice idea. If you aren't using pressure or vacuum set ups. Are you using low visc resins and rubbers? What was your final method of getting bubbles out? I was having to poke the bubble with a needle, I thought about using a blow dryer, but my both my current medias are quick setting (mold is high visc), so I feel like they'd be more likely to trap bubbles. I've tried tapping and lightly banging the mold on a surface.
I am still not using any vacuum or pressure system, though I'd like to at some point.
The molds I'm making with Oomoo and casting with the various Smoothcast resins in the OP. I have given up on using the phone vibration for bubbles at this point, as results were not exceptional and this crap gets everywhere. These resins have various pot life and the longer cure time resins seem to result in fewer bubbles generally. Because the molds are upside down to utilize the Synth, most of the bubbles wind up towards the bottom of the sculpt and underside of the cap. Opaque resins you can't really see most of the bubbles; ones on the surface appear like pits mostly. I like working with smoothcast 320 the most so far. 325 is transparent but I really hate it due to how gummy it seems and it has more bubbles than the translucent slower-cure 326.
Other things to maybe try:
- use a brush, dropper, etc. to fill weird areas
- do a high-pour of your mixed resin into another vessel to try and get as many bubbles out before pouring into mold
- slight overfill prior to inserting $ynth, then pressing $ynth in firmly to make sure resin gets squished into problem areas
Hair dryer/heat gun had minimal effect on my castings, but all exposed areas when using the $ynth get sanded or clipped off anyway.
placing smoothcast 326 into an oven at around 165(F) to cure resulted in more bubbles throughout the piece, with a bunch of foamy, bubbly excess
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Great post and I share many of the same experiences. I am demolding one of my first synth casts of just a basic key this evening. A question I have is about hardening the clay on sclulpted masters. Sculpey you can cure in the oven but I am concerned that the keys I have may melt. How are you hardening the final master so you can preserve them properly? I have cast molds from clay in the past and was able to maintain the clay sculpture for later molds.
Again, thank you!
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Sculpey you can cure in the oven but I am concerned that the keys I have may melt
I sculpt on PBT keys so I don't have to worry about them when I pop 'em in the oven to let the Sculpey harden.
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Great post and I share many of the same experiences. I am demolding one of my first synth casts of just a basic key this evening. A question I have is about hardening the clay on sclulpted masters. Sculpey you can cure in the oven but I am concerned that the keys I have may melt. How are you hardening the final master so you can preserve them properly? I have cast molds from clay in the past and was able to maintain the clay sculpture for later molds.
Again, thank you!
I have not recovered a clay master to date. I used milliput extra fine for the DSAhh basic sculpt, which cures hard in couple hours, and I'd recommend trying it out as an alternative to super sculpey. All unbaked masters of course get smashed.
With the $ynth, you are left with a clay master with a relatively thin base wall due to the pretty generous tolerances of the $ynth mold, even if you bake it. I am completely fed up with using the multi-purpose smooth-on mold release for this purpose, and will be purchasing some of Smooth On's silicon-specific mold releases very soon (with GID and fluorescent dyes!). I have had awful recent experiences with the Oomoo silicon sticking to the $ynth and master. Vaseline releases far better, but brush application is visible in the mold. I'll update with info on the silicon specific mold-release as I have it.
To attempt to preserve the original as much as possible, I set aside the second resin casting. The first resin casting tends to pull tiny remaining slivers of clay from the mold. I'd like to attempt to create a two-part mold of multiple identical caps using a similar method and without relying on the $ynth, but I haven't yielded a sculpt worth doing this for yet. Blanks would be a good candidate.
PBT plastic has a melting point of 433(F)
ABS plastic has a melting point of 221(F)
Super sculpey calls for baking at 275(F)
I am not a chemist. The ABS melting point is approx 50(f) higher than super sculpey baking recommended temperature. You can clearly use a PBT cap with no problems, though. Practically, for making blanks, you will need the blank to stick to the clay and to the $ynth. It may stick better without baking while the clay is tacky. You can google around for "parbaked" super sculpey, but you may be able to fully cure at 220 for a longer time.
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I love the thorough approach you're taking! Stackable artisan is a shower thought I had but never pursued, glad to see it happening here! That cone is bonkers too!
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Thank you for the responses guys, I have completed a few keys this last week and finally getting closer to the results I am aiming for. I notice I can't get a stem that is worth anything without the synth and overpour. Current issues is the blank I have used has thin walls so my keys come out with wall damage. I have been using easy cast but plan to try some other resins at the beginning of next month (headed to vacation in a week).
A question I have about casting stems, is it possible to get a decent stem from a oomoo 30 mold? I feel like I just can't get a decent stem from them. I am also tempted to cast keys and 3D print stems and affix them with super glue?
I am going to get a pressure pot setup and small oven as well soon.
I have also considered making materials in bars and just using a CNC and bench Sanders to cut keys from ingots of material.
Thank you again guys you all rock for providing such detailed info! Really inspiring.
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Cone king 0.2 and some extra scoops:
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These would look better more rounded and attached looking. Having some issues getting top stem coming out with bubbles, but squeezing the mold and trying to force the air out of the stem seems to work okay. Clearance issues though with trying to get a round shape near the base of the cap. Will revise again. Also got fluorescent dyes from Smooth-On and a tub of blue GID powder, which is pretty easy to use and glows fairly bright (expensive though).
Still no pressure pot, and as we head into winter my work space is shrinking significantly.
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Again, great colors you're getting! Sweet stuff!
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I've been making a weird sculpt face most nights this week to try and learn some stuff.
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[attach=1][attach=2]
I'm now using a pressure pot system, which makes everything exponentially easier. There are a lot of new products coming out (l2k, other 3d printed systems) that make making things less painful.
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Congrats on moving up to pressure! Exciting times for sure =D
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Wow nice to see progresses! Followed you on instagram and am liking your work and colours!
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What I really want to see is someone cast alphabet soup noodles into clear resin!
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I remember making a post similar to this one. That was a long time ago, but the important part is looking back you'll know where you started.
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I remember making a post similar to this one. That was a long time ago, but the important part is looking back you'll know where you started.
The trail of information here, in #casting, and everywhere else has been super helpful, so I've been reluctant to go back and edit the early posts, though some of the work is pretty embarrassing.
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I remember making a post similar to this one. That was a long time ago, but the important part is looking back you'll know where you started.
The trail of information here, in #casting, and everywhere else has been super helpful, so I've been reluctant to go back and edit the early posts, though some of the work is pretty embarrassing.
Not at all. I feel like your earlier written work was your observations. Albeit you have some outdated information to your process at least others have a reference of understanding at such an early stage.
Rubbing resin together in the woods for warmth.
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Now using Mold Star 30 and Smooth-On 326 exclusively for the most part. The large sizes are a better deal than the trial sizes. My personal solution to the large containers is to use smaller pump bottles for the resin. Part B seems to be ok. I'm a few weeks and 2 refills through on the part A bottle, and the pump is starting to have some issues. I would imagine introducing the pump material to part A causes some kind of issue, but workflow has improved.
Flash Shiner Nail Buffers are great for finishing casts, but a little expensive. Mold degradation (loss of glossy finish in my case) with Mold Star 30 seems higher than with Oomoo, but it is a better material imo. Evaluating other mold release products to ease the pain.
resin-party.com (http://resin-party.com) is where I'll be updating more frequently and to post small batch things.
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Great progress! You are getting some awesome colors.
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Great progress! You are getting some awesome colors.
Thank you! For pearlescent effects, PearlEX is a great set. I've also been having good luck with very cheap nail glitter and powders from aliexpress.
I've started using Releasys78 mold release that I purchased from HWS and really prefer it to Universal, which is pretty greasy. Using the Synth 3.0 is turning out to be very easy and pleasant to use.
Initial casts of a new thing:
(https://i.imgur.com/jhq4BQs.jpg)
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Picked up a second Synth 3.0 Mold Box so that I can create molds for the top and bottom simultaneously. To make a butt, it takes under 15ml of silicone, and around 20-30 for a top half. Working with these small amounts + not having to make a lego mold box every time makes the process much faster and cleaner. I can currently pour 1x butt, 1x top, and however many casts using 326 resin before leaving for work, which are cured by the time I get home, and the same before bed which are ready for demolding in the morning.
Worked with Monster Clay for the first time to create a new sculpt. At first it did not want to adhere to the synth 3.0 base, but eventually it got very stuck and issues with the clay peeling away from the base went away. The hardness was nice to work with, but I'm not sure I prefer it to polymer clay. Maybe a combination of the two could be used?
New friends:
(https://i.imgur.com/6MjXmm6.jpg)
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You have made great progress, great
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Thanks for this just started getting into building keyboard and casting caps and this was a good source of information about casting.