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DrRadium

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  • Reusing Silicone Molds & Saving Money

    If you have mold release on your molds, you can remove it by washing the silicone to be reused with mineral spirits or acetone. I usually use each sequentially followed by dish soap (usually dawn) and water when I want things really clean, as it needs to be here. Keep in mind the life of these molds may be shorter due to the old mold material separating from the new siicone over time. This could probability be prevented by using a silicone primer.

    Or you can use a very stretchy silicone like dragon skin. I don't recommend doing this is you are reusing old molds as done here. That just encourages delamination between new and old silicone.

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  • Make Different Colored Smoke Bombs

    This doesn't work regardless of whether you use oil crayons or wax crayons like crayola. The mix burns at too high a temperature to vaporize the colorant before it burns. There is no potassium nitrate based formula that will make colored smoke. Potassium nitrate and sugar will make a nice grey/white smoke though. To make colored smoke you need to use solvent dyes for color and a potassium chlorate-sugar mix cooled by the addition of magnesium carbonate and sodium bicarbonate. Solvent dyes decompose at a higher temp than the water soluble food coloring dyes. here are two references on making themhttps://hackaday.com/2018/11/10/making-colored-smo...and Don't waste your time with any formulas not based on chlorates and be aware that even some of these won't work well if the dye isn't...

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    This doesn't work regardless of whether you use oil crayons or wax crayons like crayola. The mix burns at too high a temperature to vaporize the colorant before it burns. There is no potassium nitrate based formula that will make colored smoke. Potassium nitrate and sugar will make a nice grey/white smoke though. To make colored smoke you need to use solvent dyes for color and a potassium chlorate-sugar mix cooled by the addition of magnesium carbonate and sodium bicarbonate. Solvent dyes decompose at a higher temp than the water soluble food coloring dyes. here are two references on making themhttps://hackaday.com/2018/11/10/making-colored-smo...and Don't waste your time with any formulas not based on chlorates and be aware that even some of these won't work well if the dye isn't right.

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  • Werewolf Stilts, Digitigrade Legs.

    I made these for my daughter's wendigo costume. I deviated a little from the plans in three places. First, I didn't use the t-nuts placed in metal to provide surfaces to thread bolts into. I already knew how to use a tap to thread holes, so that is what I did. Second, I used different cable hardware. Specifically I used wire rope clips in place of sleeves and thimbles where the cable loops around at the thigh attachment point. A bolt bushing spacer was used to allow the thimble to rotate freely. As an aside, plasma cutters work great to cut cable. Leaves it with a nice blunt melted end. Third, I modified the feet substantially. Based on ideas gathered from a variety of feet on digigrade stilt designs, I made a foot that curved up at front and back, attached at 2 points to the ...

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    I made these for my daughter's wendigo costume. I deviated a little from the plans in three places. First, I didn't use the t-nuts placed in metal to provide surfaces to thread bolts into. I already knew how to use a tap to thread holes, so that is what I did. Second, I used different cable hardware. Specifically I used wire rope clips in place of sleeves and thimbles where the cable loops around at the thigh attachment point. A bolt bushing spacer was used to allow the thimble to rotate freely. As an aside, plasma cutters work great to cut cable. Leaves it with a nice blunt melted end. Third, I modified the feet substantially. Based on ideas gathered from a variety of feet on digigrade stilt designs, I made a foot that curved up at front and back, attached at 2 points to the leg, had a traction pattern on the bottom, and was encased in a rubber shoe made from simpact 60A urethane rubber from smooth-on. I had to made this in steel as I don't really have the capacity to bend thick plate aluminum . Also I'm more confident of my MIG welding abilities in steel than aluminum. I'll make a set for myself soon.

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  • Rotational Casting Machine

    I eventually ended up dumping the belt altogether. Even with T2.5 steel reinforced belts, they would slowly stretch and eventually come off or break, usually in the middle of a casting run. So I switched to a chain and bevel gear system, and also changed the PVC tubing to schedule 40 aluminum pipe for improved rigidity. In place of the I used a #40 roller chain. The stationary pulley was removed and saved for later. Others may wish to move it to the outer side of the base as a guide for the axle. I didn't need it because I had already put in a bearing here, In place of the original stationary pulley, attached a stationary sprocket I made by welding sprocket to a piece of plate steel with a hole cut in it for the now aluminum pipe. On the outer moving frame, I used a 1/2" alu...

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    I eventually ended up dumping the belt altogether. Even with T2.5 steel reinforced belts, they would slowly stretch and eventually come off or break, usually in the middle of a casting run. So I switched to a chain and bevel gear system, and also changed the PVC tubing to schedule 40 aluminum pipe for improved rigidity. In place of the I used a #40 roller chain. The stationary pulley was removed and saved for later. Others may wish to move it to the outer side of the base as a guide for the axle. I didn't need it because I had already put in a bearing here, In place of the original stationary pulley, attached a stationary sprocket I made by welding sprocket to a piece of plate steel with a hole cut in it for the now aluminum pipe. On the outer moving frame, I used a 1/2" aluminum tube with a sprocket attached at one end and the small bevel gear of a set I printed in nylon at the the other. I removed the rotational pulley, and replaced it with the previous stationary pulley to act as a guide and spacer but the axle was extended when I replaced the PVC with aluminum. The other larger bevel gear was attached to this axle. To guide the 1/2" tube, low profile base mounted bearings were used. I published the bevel gears at https://www.thingiverse.com/thing:3161163. Mine ware printed in taulman bridge nylon. I found that it was important to replaced both belts, and not try to rely on just one as the bevel gears tended to slip with large molds if only one gear set was working. I've included pictures to help in visualizing.

    I think I solved the problem by changing to a bevel gear system and chain/sprocket. See my comments from today on step 14. It uses bevel gears that are printed in Taulman bridge nylon. The bevel gears have held up for just shy of a year without any problems. They've been a big improvement over using T2.5 belts, which were in a big improvement over G2 belts. Only issue is that it does require making a stationary sprocket. I did this by welding but it should be possible by soldering with a simple propane torch using stay-bride silver solder.

    I put support beams on mine and have been using mold straps with much easier changes and placement than the original sandwitch. Thanks!

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  • Werewolf Stilts, Digitigrade Legs.

    I know I'm trying to practice necromancy here, but I'd love to know more about how you mad the feet of your stilts. I'm making these right now, and I'd love to improve the feet.

    I'm building these stilts right now and really like the feet you have on them. Any chance you could say how you made them and some insight as to how they are attached (2 bolts or one, do then pivot, what is on the bottom of the feet and how is this attached?)

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  • Werewolf Stilts, Digitigrade Legs.

    Do you have URLs for some pictures of your modifications. How did they work out?

    I'm interested in your modifications and how they worked out.

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  • Arduino: Controlling Servo With PS2 Controller (Program With Visuino)

    Does the Visuino programming solve the problem of debouncing button presses from the PS2 controller? The Cytron shield has worked great for me, but the button input bounces are a problem. You press the button once and the arduino may think its been preset several times quickl. I was never able to get any debounce library to work with the Cytron shield inputs and cytron support didn't seem to have any idea what was even meant by debouncing button input.

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  • DrRadium commented on SusanLand's instructable Fix a Dented Democracy
    Fix a Dented Democracy

    I did this when I was an undergrad and it was a lot of fun. Also, if you're concerned about voter intimidation or voter fraud, this is the place to be to help make sure neither happens. This is a good place to start and links to information about each state's requirements: https://www.eac.gov/voters/become-a-poll-worker/

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  • Rotational Casting Machine

    I changed the system used to hold the mold to the one you used. But before aI did, I ran with the original one that used 2 pieces of 2ftx2ft plywood and 3/8" bolts and spun a mold weighing over 6kg, not counting the resin. The motor I described spun it just fine at 15rpm. After I switched the mold support to the system you used, I spun again. Unfortunately a heavy 10ft section of 6" PVC pipe that I was using to build a dust evacuation system had fallen in its way and the rotocaster had to try to lift it to continue moving. I rushed in to get the pipe moved but the motor had almost done it by itself and as still moving when i was able to help lift off the pipe. It finished the run without a problem. Since then I haven't been too worried about the motor's capacities!

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  • Seaming and Patching Silicone Puppets

    Seriously, I hope you will enter the casting competitionhttps://www.instructables.com/contest/casting/This would certainly qualify.

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      • Seaming and Patching Silicone Puppets
  • Seaming and Patching Silicone Puppets

    Thank you very much for posting this! I developed by own method for removing flashing and sprues from solid silicone objects after trying to find one (this wasn't published yet). Even the makers of the silicone had no idea how to finish silicone objects. The method I eventually developed used vibratory polishing with ceramic and then porcelain media to produce a glossy finish after removing silicone with a power sanding method. But the information you supply should help the sanding portion quite a lot. I was already using aluminum oxide, but didn't know not to use silicon carbide. Also I was using keeping the silicone taut at the point being sanded to avoid catching. I suspect that petroleum jelly will help this part of the method be more successful!I hope you will consider enter...

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    Thank you very much for posting this! I developed by own method for removing flashing and sprues from solid silicone objects after trying to find one (this wasn't published yet). Even the makers of the silicone had no idea how to finish silicone objects. The method I eventually developed used vibratory polishing with ceramic and then porcelain media to produce a glossy finish after removing silicone with a power sanding method. But the information you supply should help the sanding portion quite a lot. I was already using aluminum oxide, but didn't know not to use silicon carbide. Also I was using keeping the silicone taut at the point being sanded to avoid catching. I suspect that petroleum jelly will help this part of the method be more successful!I hope you will consider entering the casting competition. I thought about it myself but it would require too much work in too little free time to go back to make all the pictures of SFW objects to do so. But anyone who has tried to remove seams or imperfections from silicone rubber will appreciate your work.

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  • Rotational Casting Machine

    Screws and bolts work great on the PVC. That's how I attached mine to the PVC as well. The video didn't upload properly so I uploaded it to YouTube. Here is the URL https://youtu.be/Z7vuvAVYPHc

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  • Rotational Casting Machine

    Another solution to the problem of the crank is to motorize it. I've wanted to do this for a while but only recently found a inexpensive motor that worked. I found one on eBay that seems to gave enough torque (12VDC, 15rpm, 1.5A 18W with 40Kg cm torque [= 3.92 N m torque]). Pictures of how it is attached and a video of it moving are shown.

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  • Rotational Casting Machine

    To attach a handle I made an adapter. A PVC tubing cap and coupling are used with some tubing to make an adaptor. A 3/8" hole is drilled and tapped in the PVC cap and the threaded rod screwed into it. The rod is then stabilized by pouring smooth-cast urethane resin into the adaptor and letting it cure. A 3/8" coupling nut has 1/4" holes drilled and tapped on every other side near one end of the nut. Set screws are used in these to hold a hex rod for adapting to a drill, or to the hex wrench used for garbage disposals as a crank handle. The other end is slipped onto the PVC pipe that this the outer rotational axis and help in place with coarse drywall screws. It isn't pretty but it works.

    I'm interested in how you attach molds. I am using a cassette made from plywood but it is clumsy and takes forever to change molds.

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  • How to Make an Electric Foundry for Metal Casting

    Oh and one comment to anyone making this or any other design with a solid state relay. As I discovered, they don't completely turn off power, they just cut current to a trickle but at the same voltage. So even when the pid controller has the relay turned off you can still be shocked. Not to a fatal degree, just an alarming one.

    Thanks for the instructable and the you tube post on this. I built a slightly larger square one along with steel tube crucibles. It works quite well but I find that the heating wire tends to slip out of the channels after a short time. This tends to result in the heating wire sagging and making contact with other sagging wire. At best this creates wire breaks at worst complete heating wire meltdown. Because the wire gets quite brittle pushing it back i to the grooves also tends to produce breaks. Have you had problems with this and if so, how did you address them?I have seen one build that suggests leaving a lip to keep this from happening but I've found it less than trivial to do this so I was hoping for simpler solution.

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  • PLA 3D Prints Smoothing Research Project

    Xtc3d is an epoxy resin. It does work well though I have had occasional problems with it wetting some areas. Cleaning well with soap and water as well as mineral spirits helps prevent this problem. Also it isn't good for spot fills. Kind of all or nothing.

    I've used a heat gun to help smooth really rough spots. Doesn't make things really smooth. Works better for places where the print quality is poor.

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  • Mold Making: Glove Molds and Mother Molds

    Another thing to note is that typically this cut is made in s zig-zag pattern in order to help align the mold.

    You mention in regards to casting silicone:"If your'e going to make silicone parts you either need to find a silicone sealant or go with a soft urethane mold."Many cast silicone projects require body safe materials, and that means platinum silicones (aka addition cure silicones). These have problems curing when in contact with some materials including most urethane rubbers. Usually platinum silicone rubber molds are used along with a suitable mold release to prevent the silicone being cast from sticking to the mold One that works very well is Mann Ease-release 200

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  • Making & Soldering an ESP-07 Breakout Board

    When I've done it, I've used a larger diameter solder. That way you aren't really feeding the solder in, All that you need is the tiny bit at the end of the held strand of solder. Alternatively, heat what you are applying solder to, move the iron to the solder feeding the solder onto the tip of the iron, then back to where you are applying solder. Keeping in mind the distances involved need to be in the single digit millimeter range.

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  • Making & Soldering an ESP-07 Breakout Board

    "If you other hard is hold the forearm of the soldering hand, how did you hold the solder in place?" The third hand tool. Which also hold the pieces being soldered.

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  • Controlling simple LED Bar Graph with Arduino

    Unfortunately I do not. I picked them up from Vetco and they didn't provide any data But I check the website and they have it there: https://vetco.net/products/12-led-bar-graph-module)I searched the provided supplier code without success. But the online Vetco info shows a picture with the LED lit by 6V with a 40 ohm resistor, so I'm guessing that is adequate.

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  • Controlling simple LED Bar Graph with Arduino

    Any suggestions as to correct resistor value for a 12LED graph?

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  • World's easiest silicone mold.

    The one part silicone that cures with moisture sticks to things, which is why it is used as a caulk. But cured two part silicones (tin or platinum) won't stick to any nonporous surface except the same type of silicone. While mold release will prolong the mold life; it is really only critical when casting silicone of the same type. Note that tin silicone inhibits cure of platinum silicones.

    Actually, you don't have to glaze it. SuperSeal from Smooth-on seals porous surfaces and is specifically made for this purpose. It comes off with warm water.https://www.smooth-on.com/product-line/superseal/

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  • Cheap and Easy Lab Agitator / Shaker (Great for PCBs too!)

    For the author or anyone else who made one: how long did the motor last in continuous use?

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  • Make A Candle From Cheese

    I have used these as campfire starters on many occasions, and they work great. You don't even need to make the candle. The "handy cheese opening mechanism" works well enough to get the wax melting on on the tinder, where the tinder now starts to get coated and acts like a wick. I've always taken them with me when camping. Despite what the package says, in my experience, the wax wrapped cheese stays just fine for at least 5 days at moderate pacific northwest temperatures. Maybe not so much at higher temps but check out the comment from INSAYN regarding his babybel longevity experiments at: http://www.expeditionportal.com/forum/archive/ind...Specifically: "BabyBel Cheese Round Singles in wax coating (An assortment of flavors) I tested one of these by placing in the ...

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    I have used these as campfire starters on many occasions, and they work great. You don't even need to make the candle. The "handy cheese opening mechanism" works well enough to get the wax melting on on the tinder, where the tinder now starts to get coated and acts like a wick. I've always taken them with me when camping. Despite what the package says, in my experience, the wax wrapped cheese stays just fine for at least 5 days at moderate pacific northwest temperatures. Maybe not so much at higher temps but check out the comment from INSAYN regarding his babybel longevity experiments at: http://www.expeditionportal.com/forum/archive/ind...Specifically: "BabyBel Cheese Round Singles in wax coating (An assortment of flavors) I tested one of these by placing in the window sill facing South for nearly 3 weeks. House is usually 67º-70ºF and the window sill saw upwards of 85ºF. After sitting there all that time, I tried it and found no issue with the flavor, texture, or usefulness in eating or cooking with." Not all that surprising. Cheese was made as a way of storing milk before refrigeration. And this use really is a very practical survival technique as being able to start fires in survival situations can be critical.

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