Step 11: Etching Conductive Cloth for Soft Circuits

Pic14 shows a ribbon cable made of etched conductive cloth (Veilsheild). LEDs could be glued on it to make a light ribbon. Clean and sharp conductive traces like this are possible using the method described  below.

For the robot pumpkin head circuit I wanted to etch a very simple pattern as I was going to be trying several new techniques to glue and laminate the circuit.

The problem has always been to find an inexpensive, simple way to get a resist that is removable but will etch sharp high resolution conductive traces. I experimented with all kinds of tapes but they were either not waterproof enough or they had so much adhesion they peeled off the conductive coating on the fabric.

I finally tried clear vinyl shelf liner. It is just sticky enough to keep out the ferric chloride etchant, but not so sticky that it wont come off cleanly. the conductive cloth is placed on a piece of shelf liner with its sticky side up. this seals the back side. Another piece of liner is cut with a sharp x-acto knife to remove vinyl wherever the circuit needs to be etched. The conductive cloth is then sandwiched between the two layers of shelf liner. See pic15.

The cut traces are then burnished with a Popsicle stick to make sure the edges are adhered well to the cloth. It is then dipped into ferric chloride etchant for five minutes at room temperature. As soon as it looks well etched, it is removed and immediately submerged in a bucket of water and swished around. Remove it from the water and then rinse it some more to be sure all the etchant in the fibers is removed. the shelf liner can then be slowly peeled off and the cloth left to dry. Pic16 is the final cloth circuit board.

I have been experimenting with etching conductive cloth for several years. For some of the results see here: http://www.instructables.com/id/Conductive-Fabric-Make-Flexible-Circuits-Using-An/

<p>Great stuff. I used it make a rubberized casing for some electronics. </p><p>I found it was pretty sticky to work with while wet, so my hand molding tended to leave the rubberization on the finished product looking pretty lumpy.</p><p>does anyone have any good suggestions for applying an even coating of it on a surface such as a metal housing?</p>
<p>Wow - great post! Thanks! <br>Question: Do you have a feel for how well this would survive over time inside a dishwasher? (I need to do basket repair)</p>
Already my first attempt was a full success - thanks a lot ?
<p>Great! I think about modelling a stop-motion-puppet... Oogoo could work over an armature ... Thank you!</p>
<p>This is, in a word, awesome. One more cool thing to do with corn starch. I can't wait to try it. I might go poor(er) buying tubes of silicone caulk, but I have simply got to try it. Thanks! :-)</p>
<p>On hackaday (see below) one person said they used bleach instead of corn starch. </p><p>Does anyone know if this is a good or bad idea? </p><p>Other than the normal dangers of working with bleach <br>(fumes, chemical burns, staining your clothes, etc.)<br>would this create toxic fumes or result in a more toxic plastic, <br>or have any different properties that might be useful <br>(such as more or less flexible, bendable or rigid, etc.)?</p><p>Much appreciated... </p><p><a href="http://hackaday.com/2010/10/11/oogoo-a-home-made-sugru-substitute/" rel="nofollow">http://hackaday.com/2010/10/11/oogoo-a-home-made-s...</a></p><p>&gt;&gt; Bob C. says: October 12, 2011 at 1:14 am</p><p>&gt;&gt; ...</p><p>&gt;&gt; I just made some of this stuff and used regular household bleach </p><p>&gt;&gt; instead of corn starch and a few drops of acrylic paint. </p><p>&gt;&gt; 2 drops of bleach for every full trigger pull of GE Silicone I, </p><p>&gt;&gt; it worked GREAT&hellip;</p><p>&gt; </p><p>&gt; Jerry Carter says:</p><p>&gt; August 28, 2013 at 11:04 am</p><p>&gt; Thanks for the alternate recipe! Sounds like bleach would </p><p>&gt; mix more readily than corn starch as well<br></p>
<p>I can't comment on the chemistry, but given a choice, I would go with the corn starch, for exactly the reasons you listed. I'd rather work with something I know is safe and non toxic and not going to harm me or the environment. </p><p>The only way to know if the bleach makes a difference, for better or worse, would be to try it. I have to disagree with the comment that it would mix more readily though. In such a small amount, it would be difficult to get it mixed evenly, especially when you can't see it. And 2 drops for every trigger pull is not really an exact measurement. How big of a drop? What happens if you get 3 drops instead of 2? Can the ratio be adjusted, as it can with the corn starch?</p><p>If you have tried it with the bleach, it would be interesting to know what the results were. </p>
<p>can someone explain why the silicone 2 will not work for this? It seems to be more easily avaliable to me, but I don't quite understand why it's different</p>
<p>I don't understand the chemistry, but Silicone II cures differently. It is a rapid cure caulk, and for some reason doesn't work well by adding other materials to introduce moisture into the caulk (which makes Silicone I caulk cure all the way through).</p>
<p>I was able to find the sil I caulk type after a couple stores, been a lot of fun expitimenting with this stuff!</p>
<p>Hello,</p><p>I am having trouble with the drying process. First off, I mix the cornstarch and caulk in a container until it is fully mixed. I continue to mix it, then I use my hands to start to shape it. At this point, the oogoo is very sticky and the consistency is not as thick as clay. I finish shaping it and it resembles clay and has a matte finish. It does degenerate when I push on it. I let it go for about 2 hours, and it still degenerates! It is not rubber at all! I used a 1:1 ratio. I was thinking one issue might be that I am working in a humid environment. I mix and shape the oogoo outside, but after about 5 minutes outside I take the oogoo inside for it to &quot;harden&quot;. PLEASE HELP!!!!</p>
<p>Make sure you are not using the &quot;Silicone II&quot; caulk. This is a quick-curing caulk that does not work well when you include additives like cornstarch. Instead , get the &quot;Silicone I&quot; caulk. It's cheaper too!</p>
<p>Are you sure you are using 100% silicone caulk? I tried it with some sealant we had and it wouldn't harden at all but that proved not to be the right caulk. With the 100% silicone there is a really strong acetic acid smell and that has worked every time for me.</p>
I see that you are having some trouble, and I am too. I tried something this morning though. I suggest before putting the Oogoo on the plastic molds, rub them in something that's liquidy and never dries, like vegetable oil. I'm sure that this will work. Just don't wash the oil off until after you take the oogoo out of the mold.
Of course, this only for plastic molds. I'm afraid I can't help with anything else.
<p>if your mix seems to act more like vaseline than putty it may be because the caulk you are using is too old. I learned that there is a shelf life on silicone caulk the hard way. recaulking the bathroom was no fun but at least the internets let me know that it wasn't a skill fail but a materials fail.</p>
<p>Regarding coloring the plastic, the last time I was at Home Depot, I looked in the paint department and could not find any linseed oil based paint.</p><p>Can anyone recommend where to find this, either online or at a national chain, and if so, a specific brand or product?</p><p>How would food dye, candy dye (which I think is oil-based), standard (ie non-linseed oil-based) oil paint (for example the kind in tubes they sell at an art store), or acrylic paint work in lieu of linseed oil based paint?</p><p>I would want a coloring agent that</p><p>1. is non-toxic &amp; safe for regular handling, kids, etc. (which is probably why they specify linseed oil based paint?),</p><p>2. will not stain things when wet (which I suspect something water-based like food coloring or acrylic paint might do?)</p><p>3. is not too hard to find or expensive (a nice to have, the above two requirements are the most important)</p><p>Any info appreciated!</p>
<p>Fine arts supply stores. I use Dick Blick and Utrecht Art, but there are many. </p>
<p>I've found that Alkyd (fast drying) oil paint, works very well.</p>
<p>Artist's paints for painting on canvas are linseed oil based. Michael's stores carry them as well as most independent art stores. Just a few drops is all you need.</p>
<p>apple-o, as far as I know, most oil paints are linseed oil based.</p>
<p>Not sure why that post is blank...?</p><p>Here ya go:</p><p>Has anyone figured out what to add to make oogoo harder, like Sugru? Maybe another additive, or simply the &quot;golden ratio&quot; of cornstarch to silicone etc.? The end product is great, but Sugru seems to be a little tougher, stronger once fully set. Thnx!</p>
<p>Maybe this is of some use?:</p><p>'The formulation of sugru contains 30% silicone caulk (polysiloxane) 20-50% talc, and the remaining additives including:<a href="https://en.m.wikipedia.org/wiki/Oxime" rel="nofollow" title="Oxime">methyltris</a> (methylethylketoxime) <a href="https://en.m.wikipedia.org/wiki/Silane" rel="nofollow" title="Silane">silane</a>, &gamma;-aminopropyltriethoxysilane, and dioctyltin dilaurate.'</p><p>~ <a href="https://en.m.wikipedia.org/wiki/Sugru" rel="nofollow">https://en.m.wikipedia.org/wiki/Sugru</a></p>
For sealing caulk tubes, I find sticking a large nail in the end of the tube works really well. Cheap, and reuseable, as long as you haven't cut the opening too large.
Hello, <br> For those that would like a pourable version ...use 1-1-1 parts of <br>100% silicon caulk (white or clear) <br>Corn starch <br>Naptha or paint thinner....Naptha will set faster but costs is a little more. <br> <br>I use this ratio to create molds to pour my fishing lures...like soft rubber worms..etc....it will stand heat up to 500 degrees. <br> <br>Mix very well....NO LUMPS.....this ratio will start to set in 40 min...and be fully cured in 4-5 hrs....I let mine set for 24 hrs before i put them in full use.
<p>How does the rubber compare to the putty version's?</p>
<p>I made some yesterday and managed to hang some pot lids up with it.</p><p>You can seal the caulk tube by removing the nozzle and laying some cling film/saran wrap over the hole, then screw the nozzle back on again to hold it there. Poke out the stuff stuck in the nozzle if there is any , so it can still be used.</p>
<p>I just seal the cartridge tube with a little of the silicone sealant, screw the nozzle back on, then put it back in the fridge.</p>
<p>Probably the preparing temperature and moisture are important, gelatinizing the starch could make sense!</p><p>Found an old Patent:</p><p><a href="http://www.google.com/patents/US4495226" rel="nofollow">http://www.google.com/patents/US4495226</a></p><p>Method for preparing silicone-treated starch </p><p>US 4495226 A </p><p>A method for treating starch with organosiloxane polymers is described in which the organosiloxane polymer is contacted with starch in an aqueous dispersion at a temperature of from 60&deg; C. to 98&deg; C. for a period of at least 60 seconds. Starch treated by this method can be useful as glue, a binder, a filler, or a coating. Starch treated with aminoalkyl- or epoxyalkyl- substituted polydimethylsiloxane is especially useful as a water repellent sizing for substrates such as paper and textiles.</p>
<p>I found you here:</p><p><a href="http://hackaday.com/2010/10/11/oogoo-a-home-made-sugru-substitute/" rel="nofollow">http://hackaday.com/2010/10/11/oogoo-a-home-made-s...</a></p><p>and besides the high price of Sugru this is the annoying point:</p><p>&quot;but one can&rsquo;t (yet!) just drop in on any local hardware store to buy a quick fix&quot;</p><p>So, good idea to test and probably improve!</p><p>:-)</p>
<p>Oogoo sounds funny</p>
<p>Wonderful instructable with must-have knowledge for the diy-selfer!</p>
<p> <br> <br>Excellent <br> information on your blog, thank you for taking the time to share with us. <br> Amazing insight you have on this, it's nice to find a website that details so <br> much information about different artists.</p><p><a href="http://www.monacopropertylistings.com" rel="nofollow">appartamenti a monaco</a></p>
<p>I am aware that it has been done many times, but I am wondering how well oogoo performs as a cord reinforcement. My old laptop cord has finally reached the end of its extended life (I have already rebuilt it once using super glue, heat shrink, and modable epoxy, and I nearly destroyed it in the process). Instead of waiting for my new-soon-to-be-heavily-used cord to wear out, I intend to reinforce it ahead of time. I have several questions:</p><p>1) Will the oogoo stick to both the cord and power brick?</p><p>2) The brick will be moved around a lot, will the oogoo wear down significantly over time?</p><p>3) I tend to be very fidgety. Can cured oogoo be easily shredded (and make a wonderful mess a the community college)?</p><p>4) Will the oogoo become hard enough to actually protect the cord?</p>
<p>Oogoo sticks to metal and plastic, but not real strongly. The more surface area it is in contact with the better it will stick. If there are rough surfaces or irregular surfaces that it can wrap around, it will stick better.</p><p>When rubbed it does not wear down easily.</p><p>It does not shred easily, but it can be sliced by sharp objects.</p><p>It will be hard enough to protect well if you can attach it well enough to not slide around.</p>
I have made this for a couple of projects. I thank you very much for the instructable. I have been using two plastic spoons and a shallow Tupperware container to mix it in and I really am happy with the re usability/ ease-of-cleanup those items give me. I simply let them dry and in a day or two peel all the silicon bits off and they are ready for the next project.
<p>Do you believe that the cornstarch contributes to the fast curing? Do you know of any other higher temperature tolerant fillers a person might use for say, casting pewter or eutectic alloys?</p>
Hello there mikey 77.. Im just wondering, if i put lets say about 2 to 1 cornstarch to silicone by volume, will the silicone absorb all the cornstarch? And i want to know if it is heat safe? Thanks for the great idea dude..
<p>hello can this method be used to make large molds for beeswax candles? I ve a ceramic ganesha I'd like to mold</p>
<p>Yes, it works well for molds for beeswax and other materials.</p><p>Test the Oogoo on the the object you are casting with a small patch of Oogoo.</p><p>See how well it sticks and how easily it peels off.</p><p>If it sticks too well to a porous object, you can spray the object with spray lacquer, as a mold release.</p><p>Apply the Oogoo, let it set up and then you can cast the beeswax.</p>
<p>Do you think adding epoxy to the mix would help it to be more rigid when it cures? It would be cool to be able to vary that based on how much you mix in. </p>
Is oogoo safe to use with foods? I.e. If you made a spatula or as the lid to a jar similar to the one you made. Also is it safe if a child got its hands on it and put it in their mouth?
<p>As I have said several times before, Oogoo is not food safe. So, you can add it to the list of things people, and especially children, should not put in their mouth.</p><p>If you want food safe silicone, you could try sorta-clear 40 silicone which is available from Smooth-On.</p>
If I'm using pure silicone aquarium sealant (which says that it is food/pet safe when fully cured) and food-grade corn starch, is there any reason that the final product wouldn't be food safe?
<p>Most likely, it would be food safe, but the only way to know for sure would be to run some tests.</p><p>One test you could try would be to do a test with the minimum of corn starch. Mix a batch of 3 or 4 to 1 of silicone to corn starch by volume. After it has cured, bury it in moist dirt for a week or two. look at it under a microscope for any signs of discoloration or mold. I have done this test with regular silicone caulk and found no evidence of mold after several weeks.</p><p>In my experiments most of the corn starch is internally embedded with very little on the surface of the cured Oogoo. You could try boiling the set up Oogoo in boiling water for ten minutes to dissolve any surface corn starch that could feed mold or bacteria.</p><p>That said, I would suspect aquarium sealant, if it smells like vinegar while curing, would be quite safe for storage of dry materials like coffee or powdered milk.</p><p>Hot liquid foods and moist foods might require further testing.</p>
<p>Oogoo catalyzed by corn starch vs soapy water bath? The latter being the less messy and easier method is now gingerly haning off my laptop as I type. I have been following the oogoo process for awhile now and happen to come across the soap/water bath rendering and decided to make the water immersion version since it a more &quot;pure&quot; rendering. I've taken a few photos and I'll update with the cured form as well. </p>
<p>Hey there! I tried making Oogoo just recently and it worked great but I was wondering about something. Is there a way to make Oogoo bond to surfaces by itself like Sugru could? Also, if I use less corn starch, would that help make the surface more repellent to sweat? I'm planning on making a mouse grip and would love to make this workout! Thanks and great instructable! :D</p>
<p>As I mentioned in the instructable, Oogoo does not bond as well to some plastics as Sugru does. You can try putting a thin coating of superglue or a thin coating of pure silicone caulk on the surface. Let it set up overnight and then apply the Oogoo.</p><p>If that does not work you can try for a mechanical connection. Use whatever glue will work on your surface to glue fabric or thin plastic mesh onto the surface. Once dry you can add the Oogoo.</p><p>I have not had any trouble with sweat on Oogoo. Clean it occasionally with soapy water and it should work fine.</p>

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Bio: I believe that the purpose of life is to learn how to do our best and not give in to the weaker way.
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