Casting Resin issue?

I'm trying to cast some resin claws for a halloween/convention costume I'm trying to make ( it isn't a Wolverine one .. more a VERY twisted, evil, and blood thirsty Mad Hatter character ) and running into a bit of trouble. I'm following the 5 drops of hardener per 1 oz of resin that is stated on the resin can's instructions. It also says it's supposed to set hard enough to support objects at 40 minutes. I mixed a 2oz batch of resin ( 10 drops of hardener ) and poured it into a rubber latex lined plaster mold that I had sprayed with mold release. I put a bolt down partly into the resin so I can later attach a wire to it and left it alone for about an hour to an hour and a half. I came back to check on it and the bolt was still able to be moved/removed with NO resistance. I figured the mix was bad and threw it out, but noticed it was the consistancy of slime. Did I mess it up and not wait long enough, or did I not add enough hardener or what ? Any suggestions would be great!

Question by Myrr   |  last reply

Floor Filler used for doming casting resin? Answered

I met someone from Germany who had a clear, 2 part floor filling compound, that after mixing, she could pour into a mold and have it turn out like casting resin, Does any body know of the stuff she is talking about?

Question by KyleofAsgard   |  last reply

Acrylic Resin / Polycarbonate Resin: Where can i buy?

I'm trying to find a place where i can buy Acrylic or Polycarbonate Resin to Cast. I'm trying to desgin and build ny own tables, desk, shelfs, and other small projects. 1) Where can i buy the Resin note: i did my research, Tap Plastics and other companys only ofer epoxy or polyester resins for casting 2) i decided acrylic and polycarbonate over other plastics. i would like your opinons 3) What are different types of acrylic and what do i need to watch out for, Im taking a Materials Manufacturing and Processes Class ant my college. Im learning about the chemistry of plastics and find it interesting Im trying to cast on a home level but trying to expand into a small business so comerical and home production tips would be nice But first thing first. I need "Real" Acrylic or Polycarbonate Resin.  Great Quality, it needs to be strong Casting Acrylic/Polyester Resin

Question by jschirm24   |  last reply

How can you make Gopro mounts with resin?

I have an HD Hero 2 and I would like to know how to make mounts with resin and harder.

Question by alspad   |  last reply

Instant setting epoxy, resin, or plastic?

Does anyone know of something that is cheapish and suitable for 3D printing by being extruded from a thin tube, and cures immediately on contact with a dried bit of itself, or exposure to another chemical or something?  It must be practical to put though a tube at low pressure, and again, cure almost instantly once it comes out of the tube.  Traditional 3D extruders will NOT work, as the device needs to be able to distribute to hundreds of tiny tubes at once (I cant cut a plastic filament into 300 pieces lengthwise, if you can, good job!), plus that I would have only about 1/4"-1/8" x 1/4"-1/8" x 6" to fit the device into. 

Question by jduffy54   |  last reply

Covering a stickered laptop with epoxy resin? Answered

Hi! I recently got a new laptop and I covered the top cover with stickers and it looks pretty good if I do say so myself. I didn't want the stickers to peel up or anything so I went on over to the hardware store and bought some Krylon Crystal Clear spray, which is an acrylic lacquer based spray. I sprayed a whole 32 coats on that sucker and it was still paper thin. It's as if I simply made the surface shiny, and the stickers could still easily peel up. So I did a lot of research and I found a lot of things but I figured a 2 part pour on epoxy resin was the best choice. It's thick, self leveling, self doming, and it cures instead of air drying. My goals from the beginning were to eliminate surface texture altogether. I want the end product to be like those table top bars with stuff encased inside within a clear glass-like coating. I have found a lot of stuff, but I have yet to find anyone that has done what I am trying to do, and since it's my new laptop, I have concerns. How durable will the epoxy be? I want to make sure that it will be able to withstand the life of a college student, although I'm a quite careful one at that. Will the epoxy have any trouble bonding and staying bonded to the Krylon spray? It's an acrylic lacquer based coating according to the company. I don't want the shell of epoxy separating from the top of the laptop. I'm worried about bumping the edges and having the epoxy chip off or just separate altogether. That last question is the main and most important one, really. The last thing I want happening is for the epoxy to dry and then separate from the laptop or crack or chip or something. The epoxy I've settled on for now is Envirotex Lite, I'm not sure how much epoxy differs between manufacturers. I've emailed several companies asking lots of questions and I've gotten a lot answered, but these ones have yet to be solved. Thank you so much for reading this and any input or advice would be greatly appreciated!

Question by jcbeaver7   |  last reply

Stator casting and best casting resins ?

I am curious which would be best for casting my 9 coil 3 phase stator ,Cyanate ester resin ,or Polyester resin?I also curious if it would be best to cast all coils together as a whole or would individual castings work better for heat dissipation? The individual picture just for example. Thanks for taking time to help :)

Question by 1RaceFTW   |  last reply

Does araldite glue damages circuit? if yes,what glue or resign you cover your circuits with? Answered

I ones tried covering my circuit with araldite. Eventually it stopped working(as the glue started to slowly malfunction. What glue do Americans use in indestructible like-

Question by Suraj Grewal   |  last reply

DIY method for sorting shredded plastic flakes by resin type?

I've seen thatthe Coca-Cola company is promoting the keep the cap on PETE bottles, and that they use sink/float methods to separate the bottle from the cap after shredding since PET sinks and HDPE floats, now is there a similar (easy/ homebrew) test for other plastics like PP or LDPE, and by the way can 2 & 4 mix on a Melt? looking into doing some layered DIY proyect that involves the DIY Extrution of PET filament and other plastics for experimenting purposes.

Question by AskDaDoc   |  last reply

PDF lock out?

Why isn't the PDF download working? I see the frame next to it with a solid orange border. I click on the PDF and nothing happens. what gives I don't even get asked to join?

Question by doclnemo   |  last reply

Lasers vs LEDs in the deep ultra violet spectrum, and focusing?

I am currently trying to research this topic as I am looking into building a stereolithograph 3D printer. I have been searching for some time now with not a whole lot of answers. This is not my area of expertise so I could use some input. I have found lasers in the range of 256nm wavelength but it is going to cost me an arm and a leg. Even at the price range the UV lasers are only outputting at most 1W of power. I have read that UV curing resin is most reactive in the range of 265nm and that is why I have been searching for something in that ballpark. I have found some companies that manufacture LED in that wavelength but then the problem is going to be trying to focus the light down to a fine enough point. I am trying to design a 3D printer that is in the high resolution range. So, my true question is. Does UV curing resin react best with the 265nm vs the 400nm range as I could just a blu-ray laser. If it is better at the 265nm range, could I possibly be able to focus enough light from a couple of 3W leds down to a small enough point to cure the resin where I want it to be. The other idea is taking a UV laser in the 400nm range and focusing the beam down to get me fine but quick set up time in the resin. Or possibly multiple Lasers

Question by ColtanA   |  last reply

Is it possible from a chlorophyl extract to use its photo-sensitive possibilities, and How?

I·d like to found how to make photo-sensitizer out of chlorophyl extract, or from micro-weeds, or other any organic like plancton, to replace the very toxic technics used in every photo-reproduction work

Question by FeteLeToiMeme   |  last reply

What would be a good ratio of fiberglass resin mix per sq. yd?

I need help on this, I'm wrapping a wood 2x4 frame in 3 yds of fiberglass cloth and some glass tape. I've never worked with it in my life and I don't know how much I should use.

Question by The Ideanator   |  last reply

How much resin/epoxy would be adequate in wrapping a wood frame in fiberglass?

Im using 3yd of 50" wide 10oz fiberglass fabric and some 2" wide glass tape. I've never done any fiberglass work before, and I have no idea how to do it. The resins are expensive and I don't want to buy more or less then I need.-how much resin/epoxy with or without vacuum bagging-where would the most cost effective place be to buy it from All Suggestions Welcome!Update: the part that is going to be fibergalssed is a bike frame made of 2x4sif you dont really know, could you point me it the general direction of the answer?\I have a very limited budget by the way

Question by The Ideanator   |  last reply

what is the reason for crack development in cultured marble block? Answered

What should be the mix of cobalt and resin and catalyst in the marble aggregates ?

Question by ashok -1955   |  last reply

how could i bound polyurethane and silicone ?

Hi I'm trying to make a two part model in polyurethane resin with a thin silicone membrane connecting them so it can expend  and still be maintained by the silicone layer. The problem is that i need to pour the silicone into the model, so i can't make them stick together with some coating or glue. Instead of the silicone i thought about using polyurethane elastomer but it is usually not very elastic and does not age well when frequently teared neither. So i'm searching for a way to pour silicone into polyurethan resin and make it stick. Maybe eventually by putting some fiber on the resin surface while wet so it'll get trapped in the silicone layer while it will catalyze but i doubt it'll resist to the tear strengh for a long term use. Did any of you tried it or found a solution to that problem ?

Question by naomori   |  last reply

can I make a home made LED? Answered

I don´t know if the resins used to make leds are special trated, or very difficult to find the metal of "filaments". But my question is: Is possible to make a home made LED?

Question by pesfan27   |  last reply

what is Rustoleum brand 3603 URT (ultimate repair tape) used for? Answered

Was recently given a roll of ths tape that looks like carbon fiber with a thick adhesive on the back, maybe 3-4 ml in thickness.  It has a removable backing to prevent it from sticking to itself.  The roll itself is about 4" by 6'.  Was wondering if ti cures if exposed to sunlight, or if its meant to be impregnated with resin or not.  The weave of what I assume is carbon fiber is somewhat open, but that adhesive backing would stop complete penetration.  Heat set maybe.  Anyway, anyone have a clue that would be awesome.  Thanks. 

Question by iminthebathroom   |  last reply

I am looking for a way to "cast" wood.

Possibly mixing sawdust with a resin or something like that. There is a product that is called Arbowood that is like this but all natural. I want to be able to pour a "liquid wood" material into a mold. Any Ideas?

Question by ndelta   |  last reply

Making Plastic Cover around USB plug?

I like to know the method of making plastic / PVC cover around USB plugs. The type of resin we have to bye and the method of moulding it to give a good appearance to sockets we prepare? jaytissa

Question by jaytissa   |  last reply

What wattage laser would I need for engraving ABS plastic?

I want to build a laser engraver that can engrave ABS to a high enough depth that the grooves can be filled with resin. How powerful a laser should I get?

Question by JN8   |  last reply

How To Repair A Car Radiator Leak In The Plastic Area? ? ? ? ?

I have a radiator leak that I want to repair instead of replacing the whole radiator. I tried a couple of 2 parts epoxy glues and it won't hold for long. I think the heat just makes it weak. They are small leaks(2) on top of the plastic area. I was thinking maybe trying some fiberglass resin and cloth since I have some leftover from my fibeglass speaker box I've done a while back but not sure if I should go that way. Anyone knows of another way? Anyone had this problem and got a fix? or if there's a website where I can get the top piece to replace it myself please post a link. It's a 2000 dodge neon. Thanks.

Question by PitStoP   |  last reply

My LED circuit suddenly stopped working. Can anyone help?

I set up this really awesome simple circuit for the Chitauri scepter I'm making (so the stone will glow without a visible on/off switch, which will be hidden inside a piece of the scepter), and of course, the instant I tried to install it, it stopped working.  I thought perhaps it shorted out because the resin for the stone didn't set properly, but now I'm not sure.   It's set up like this (going from the power source to the LED, and back). Power source: 9V ON/OFF toggle I pillaged from the battery pack 330 Ohm resistor Blue LED from Radio Shack (max voltage 3.8V) Back to Power source. I've checked everything, and used multiple batteries to double-check.  I even entirely re-did the circuit to make sure that cleaning off the uncured resin didn't mess with anything, and it's still dead in the water.  What did I do wrong?

Question by KateM28   |  last reply

Solar Cells Coating? Answered

Hi Guys! A few weeks ago I found an auction on ebay, bid, and won myself some big old pack of solar cells. Now these panels are wafer thin, no coating or covering. Additionally, I need to put the wire collecting ribbons on myself. The only problem with these is that they are incredibly fragile. What can I coat them with to protect them? Is there any spray or acrylic or resin that you use to protect them? Thanks

Question by transistorguy   |  last reply

Why don't people modify MOT's for high voltage? Answered

Why don't people modify MOT's for high voltage? I just did I left about 3 layers of primary windings, removed the middle coil and the shunts put it back together then submerged it in oil, I also removes a couple of layers of the secondary windings to get rid of the resin so the oil can get in. It worked amazingly I don't understand why people don't do it.

Question by The MadScientist   |  last reply

How hard is epoxy wood filler? Answered

I've asked quite a few questions regarding prop building, as to try and get back to my project. Major issue is the VOC of body filler and fiberglass resin. However, I think I found a soultion to it. I was curious as to how hard epoxy wood filler is once cured. Is it something that (god forbid) if coated onto something, and said something is dropped, will the epoxy be damaged? How hard is it work with (ie, can I heat it up to make it 'thinner')? Thanks in advance! 

Question by DoctorWoo   |  last reply

[Help] Custom sounds for model

I've created a resin cast of a gun (raygun) from a video game (Black ops 2) and as part of making it as authentic as possible I would like to have it emit sounds I've pulled from the game at the press of a button, much like a toy gun. I don't know where to go with the idea from here. I would like something that's relatively easy to hear and not too quite and powered by batteries. If someone could point me in the right direction as far as parts I would need to achieve this I would appreciate it.

Topic by h1web   |  last reply

How UV resistant is wood? Answered

I'm making a USB solar charger intended to last 20 years. It will have no batteries inside, just a voltage reg and a zener diode. The solar cells will be wired together under glass, not epoxy (for better lifespan). I want the frame to be made of wood, but how long will that last in direct sunlight? This solar charger will contain no plastics, polymers, or my only choice for a frame is glass and wood. THANK YOU SO MUCH!! -Nepheron PS. I chose wood because it is very opaque, and I reasoned that it may be fairly UV resistant... But IDK.

Question by nepheron   |  last reply

A question about LEDs? Answered

Hi all first post. Called fairy lights, rain drops, peals, party strings. They come in all different colors, lengths and price points; sold on Amazon and eBay. I cannot find them individually and I can't locate any information on them. My multi-meter needs to be replaced I can't really trust it and I want to cut a string making  different lengths. The transformer that came with 12volt 1amp, will I need to put a resister in line? Their in parallel but I don't know if is the cathode or the anode that has the double wire. Does that matter? It's possible that they are the pico/micro size chips encased in a clear resin. There is approx 300 leds on the string aprox. 4 per ft.

Question by distantansia   |  last reply


Well, okay... I'm not really desperate but I am in (slight) distress-- needing someone to storm the castle of knowledge to save me from pounding my head against the walls of google-search any longer. Looking for some specific LED information. I have looked through several LED-throw-y Instructables but so far I haven't found the information I need. I am mostly electronics-retarded and so if anyone can give me the correct info I would sincerely appreciate the assistance. I just need to know the batteries/battery power/models needed to power smaller than 10mm LEDs. My project involves a very small space-- 1.8mm-3mm-5mm sized LEDs would probably be best-- I would need to know the kind of batteries I would need (least bulky and least number of batteries I could utilize for each size 1.8mm-3mm-5mm) and how many I would need for each single LED to operate effectively. Also-- is there any real concern of a fire hazard with such LEDs housed in an acrylic/urethane and resin container or would the output of the LED be such that I wouldn't have to have concerns of fire (or melting in the case or urethane/acrylic/resin) ? (Sorry if this question seems dumb, but again I stress how electronics-retarded I really am lol). Furthermore, if the LEDs had vellum or translucent paper covering them to diffuse the light-- would this additionally create any fire-hazard? The housing will probably vary between 14mm-20mm  for the LED with the batteries able to sit outside the LED-housing. I appreciate any assistance in getting the information I need and offer many thanks in advance for any helpful replies!

Topic by pneumadragonfly   |  last reply

Any ideas for achieving a Bakelite appearance?

Hey guys. So I'm in love with Bakelite, but not with the price of the raw material. I also want to form my own projects with a Bakelite aesthetic and don't want to deal with shaping such a fragile material. My question is: does anybody know of a recipe for making Bakelite? I also don't have much in the way of workspace or tools, which I'm guessing makes the manufacture of real Bakelite rather difficult. Because of this I'm willing to settle for something that isn't Bakelite but has a similar appearance. Any ideas about how this can be achieved? I've thought of maybe adding sawdust, dye, and finely ground plastic into clear resin, but I'm not sure if that would really look like what I want. What do you guys think?

Question by rozmusway   |  last reply

How to repair a small metal joint? Polaroid SLR 680 camera.

I recently bought a £200 polaroid camera off e-bay for only £20. It was sold cheap due to a break on a hinge. I knew it was something I could fix, or that the camera might work with anyway. I am asking if anyone has any better suggestions for fixing this joint? So far my best plan is to cut out a small metal bridge, and attach it using epoxy resin. I have attached 3 pictures, an overall shot, a close up, and a comparison shot to the other side which is in one piece. They are all high res, so you can click on the images and view them larger for more detail.

Question by gmjhowe   |  last reply

DESPERATE DAMSEL! Need some LEDs assistance...

Well, okay... I'm not really desperate but I am in (slight) distress-- needing someone to storm the castle of knowledge to save me from pounding my head against the walls of google-search any longer. Looking for some specific LED information. I have looked through several LED-throw-y Instructables but so far I haven't found the information I need. I am mostly electronics-retarded and so if anyone can give me the correct info I would sincerely appreciate the assistance. I just need to know the batteries/battery power/models needed to power smaller than 10mm LEDs. My project involves a very small space-- 1.8mm-3mm-5mm sized LEDs would probably be best-- I would need to know the kind of batteries I would need (least bulky and least number of batteries I could utilize for each size 1.8mm-3mm-5mm) and how many I would need for each single LED to operate effectively. Also-- is there any real concern of a fire hazard with such LEDs housed in an acrylic/urethane and resin container or would the output of the LED be such that I wouldn't have to have concerns of fire (or melting in the case or urethane/acrylic/resin) ? (Sorry if this question seems dumb, but again I stress how electronics-retarded I really am lol). Furthermore, if the LEDs had vellum or translucent paper covering them to diffuse the light-- would this additionally create any fire-hazard? The housing will probably vary between 14mm-20mm  for the LED with the batteries able to sit outside the LED-housing. I appreciate any assistance in getting the information I need and offer many thanks in advance for any helpful replies! (posted this in TECH forums as well- apologies if this is like a repost)

Question by pneumadragonfly   |  last reply

what's going on with my LED dimmer circuit? Answered

I'm making a resin block lighting thing for my dorm room, but the lights are too bright to look directly at (and it's meant to be looked at). I decided to make a 555 dimmer circuit, and I used these plans. when I built it, however, the LED stayed off. I couldn't figure out what was going on until I touched the two diodes in the circuit and noticed that the small current leaking through my skin caused the LED to blink slowly. I turned one of the diodes around, and lo and behold, the dimmer worked as expected. so what I want to know is: what was the purpose of the diodes in the original diagram? was the positioning of the diodes just an error in the design? should I run with what I have now (since it works), or do something different?

Question by codongolev   |  last reply

I made a nifty invention that generates light...what do I do with it? Answered

 Ok, I was tinkering around with some  interesting materials today and I invented a strange thing. It's a chunk of greenish resin (impregnated with certain chemicals) about the size of a soda bottle cap. I was shaping it with an electric sander (it had sharp edges), and I noticed it gave off dim green light wherever it was touching the sander. I decide that the friction/heat generated by the sander somehow made it give off light... So I went to a dark room and dropped it in a beaker filled with water I boiled in the microwave. AND IT LIGHTS UP It gives off a pretty bright green light. Not bright enough to read by (unless it's big text), but easily bright enough to navigate a cluttered room. I dunked it in cold water...and the light practically turns off. It seems to get brighter the hotter it gets. I hit it with my torch, and it lit up REAL bright, and then "turned off" (that particular sample doesn't work now :S) What should I do with it? Anyone have ideas for possible applications?

Question by nepheron   |  last reply

Getting rid of humidity inside walls with electricity?

A friend in Europe wants to get rid of the humidity that comes from the ground up into the walls of his old house because of the high hygroscopicity of the building materials (stone and raw bricks), humidity that then goes out to the sides, ruining the plaster and the paint of the walls inside the house. The house is built directly on the ground. Apart from cutting the wall at the base and putting an insulating layer or making holes and pouring synthetic resins to isolate the section, all complicated and expensive procedures, he found an interesting system (called kalibradry, with some copycats around) that fights the capillary action of water by breaking up water dipoles through a magnetic field. Here is a link to the company's explanations on how the thing works : http:// (it is in Italian, but it has lots of pictures plus a simple google translate should do most of the job) and here is the link to the company website:;=en&u;;=it|en The system, to my surprise, seems to be quite effective, so much that it is being used all over Europe (mainly Germany, Austria, Italy), even in valuable historical buildings, such as the Unesco recognised Palazzo del Te in Mantua with frescoes of the Renaissance master Mantegna. I doubt they would allow anything dodgy or dangerous plus I called directly and the museum confirmed they are using the system succesfully and plan on expanding experimantation. I was wondering if anyone could think of a DIY version of the system, since the price for one is around 5000 USD, way above my friend's budget. As a secondary note, there is an even more astonishing system, although much more dodgy, called aquapol that seems to be using electrostatic electricity to deflect water, making it more difficult for water to "climb up" walls this also seems quite effective and is being used in historical buildings as well, but I wonder how it could ever work without an energy source.

Topic by wilson14   |  last reply

GoPro Scuba Cylinder Mount

Hi there, I'm new here. I've recently found an entry-level 3D online modelling software, Tinkercad and have been Tinkering ever since. I'm into scuba diving and I've long wanted to design a GoPro mount for the cylinder to give a 3rd person view of me while I'm swimming about enjoying life underwater. (Think a less-sexy Lara Croft!) I wanted to run it past you guys to see what you think. I've attached 2 screenshots, because as you can see, the mount I've designed is collapsible, to save space in my GoPro bag. I've done the maths (Pythag) so each side is perfectly lengthed to create a right-angled triangle, with the hypotaneuse (long edge) is facing down my body, towards my feet, so that the camera view won't be obstructed. I've used a Pythag triple, so the arms measure 3", 4", 5". This was done for 2 reasons: a) It was easier to desine using these measurements and b) I don't want it sticking too far up from my cylinder so that it doesn't catch on wildlife/coral/divers. As this is my first GoPro mount that I've designed, I've had to go on deimensions I've found online for the actual hinges. I've settled on approx 3mm for each prong as well as the gap in between. I have actually shaved off .25mm from the middle prong of the 3-pronged-hinge, and left the 2-pronged-hinge at 3mm for the gap and prongs. I'm going to get the pieces 3D-printed by a local service I've found on, either in ABS plastic or in resin, though I'll probably go for ABS as it seems to be a bit more hard-wearing, even if it's not so detailed. In terms of mounting it to the tank, I will use 2 headstraps, with the over-the-top strap removed from each one and glue the plastic bits of each of them together, at the correct length of course. I would join them using a seperate piece of plastic and either a hot glue gun, superglue or even some sort of epoxy, whatever lasts longest in prolonged exposure to seawater. I would probably place it nearer the top of the tank, near to where the strap of the BCD jacket goes round it. Does anybody have any advice for me in terms of the design from a functional point of view as well as from whether they think it would actually get a good shot on the camera please? I look forward to your feedback, good or bad!

Topic by JackIsted   |  last reply

Electric Ukelele & Viola, Violin or Octave Violin Build

I am searching for inexpensive means to create aesthetically pleasing electric stringed instruments. I started this project when I started playing viola years after I was forced to quit private lessons. I discovered the F-f-fiddle on which is a super rad 3d printed electric violin but since I do not have access to any 3D printer in the tiny town which I reside in, I sent the files to an online 3D printing business and they quoted me at least $500 just for the Fffiddle body! I didn't even bother to ask for a quote on the electric ukelele which I want to print & build so badly as well. I am interested in this project so that I can possibly help low income public school students in creating their own instruments to inspire them to take up an instrument and show them how much fun it can be to create something by yourself rather than buy. I am especially interested in acrylic plastic/lucite/celluloid, resins, exotic wood, recycled plastics, plastic injection molding, piezo pickups, and any other interesting materials that could be incorporated into these projects. I have been studying luthier tools, supplies, etc, along with design/fabrication of lucite/acrylic stringed instruments, furniture and other home goods. 3D printing/scanning, vintage celluloid guitar finishes, pre amps, recycling plastic bottles, landfill harmonic instruments, leather, pearl inlay, metallic finishes, enameling kilns, metal smithing, hand engraving & everything in between. I have been a mixed media artist for nearly my entire life and my father was a jeweler. I am going to find a way to create some functional and beautiful instruments no matter how long it takes me to narrow down the right combination of materials and how to make them, model them, mold them, dye them, etc! The photos attached are simply inspirational photos which I have collected over the past 6-8 months. Many of them are possibly patented, licensed, etc and I do NOT want to simply RIP OFF any of these photos! Please email me at if you believe you could help me with my low income student instruments program or leads on 3d printing grants for public schools or anything else that may help me on my latest project or contact me directly via my instructables question here. I especially am interested in creating an electric violin which incorporates both classical and contemporary design. Any advice? Could you help?

Question by SVBacklunda   |  last reply

Rewinding a MOT to make a high current supply. Answered

New Question: Ok, I've done a little more research on this, and it seems that MOTs are just pieces of junk basically. Manufacturers design them to go far into saturation because they don't care how much electrical power is wasted, as long as the transformer is cheap to make. The air gap is probably there just so it's easier to cool with a fan. Now I need to bring this thing out of saturation. There are about 90 turns on this primary, which I want to be the secondary at 30 V. So I would have to wind a new primary with 360 turns of thin wire. That's a lot of work, and a lot of wire. Is it worth it? The other option would be to add turns to the existing primary. This seems more reasonable, but just how much would I need to use to bring it out of saturation? Original Question: So, I'm a physicist (in training) and I know the theory behind transformers, but actual transformers are still pretty mysterious to me. I've found quite a few Instructables and other sites related to MOTs, specifically related to making high current power supplies with them. The problem I'm having is that even when the secondary is open, and indeed when the secondary has been completely removed (and the shunts removed), the primary draws upwards of 10A when connected to mains. To me, this is unacceptable. Transformers should draw significant power only when current is drawn from the secondary. I'm trying to figure out why (specifically) it does this. I've got a variac and the transformer only begins drawing more than about 2 amps once the variac is set to about 90V. This seems like non-ideal behavior to me, but what I know about saturation tells me that the amount of steel the core has is more than enough to stave off saturation at open secondary, but I could be wrong. The only thing I can think of is that the primary coil has about a 1cm air gap on either side of the core. Since the efficiency is related to the magnetic flux, and I'm guessing the area of the air gap is roughly 1/5 of the area of the core, this could cause significant inefficiency. Here's what I want: I want to make a ~30V (possibly with multiple taps) high current supply out of this MOT that draws less than 1 amp when the secondary is open. I tried connecting the mains to the secondary before I removed that and I got about 5 volts on the primary, but I need more than that, and the windings were so saturated with resin I had to just remove the entire secondary. I'm thinking about winding a new primary (using the old primary as the new secondary) with something like 18 gauge wire that would give me 30V. Would this work? What I really need to know is why the existing primary is drawing 10 amps. That's just ridiculous. If I can solve that then the problem is easy. Update: There is a difference between resistive and reactive current, and I know that reactive current actually draws net zero power because it's 90 degrees out of phase with the source voltage. Capacitive and inductive loads do this apparently. Is this the reason for the massive current draw? If so, I might be able to minimize the current draw from the mains line by putting a matched capacitor in parallel with the primary. But this wouldn't stop the transformer from heating up.

Question by laserjocky   |  last reply