Why are sharpie pens acid resistance? Answered

What's the chemical compound of the sharpie to make it acid resistance? Such as for PCB etching.

Question by nfarrow   |  last reply


How can I get tin metal, or some other metal resistive to oxidation, to fall out of a ionic salt in solution?

Is there a simple chemical reaction that leads to a pure metal precipitate?

Question by T3h_Muffinator   |  last reply


aluminum powder is conduct electricity??? Answered

 Dear All...  Please help me to know aluminum powder is conduct electricity ???  Because I have bough ALUMINUM metal POWDER  99.7% Lab Chemical 425 mesh µ35 on EBAY. for making conduct electricity paste But when measured with my digital meter at 20 meg ohm  with 1mm distant I don't see  any resistant .Thank you in advance for your time.                                                                Best regards                 HAPPY NEW YEAR  

Question by lam   |  last reply


Needle valve on the cheap?

I need a needle valve or similar to adjust some pressure with more or less precision. Problems I am facing with commercial solutions at the moment: Needs to withstand about 300psi max pressure, must survive contionous exposure to concentrated ammonia vapour. I already wasted too much money on stainless steel valves claiming to be chemical proof and capable of 6000psi only to find out they use seals that turn to goo in the ammonia vapour and fail. And since the stuff is not really healthy, not easy to get, I would prefer something safer. Real problem is also that the thing should be able to allow for good flow rates when opened fully. Modes of operation: During the active cycle ammonia vapour needs to pass through an opening as big as possible while after that the flow must be shut off. The reverse cycle needs to be adjustable from closed to fully open with great detail to control the flow rate. Current ways to compensate: With a ball valves and extra piping I could seperate the two cycles so I won't have to bother with tiny openings but I would prefer to use only a single connection. With a bypass around the needle valve this could be accomplished better but still looks ugly. Materials out of the question: Copper, brass, normal seals based on rubber, nitrile or similar. Questions: I know fully sealed in.line valves exist for LPG system and similar. Are any of these magnetic valves available for the use with ammonia? And if so: Can they be operated with a neodymium magnet instead of the coil? Even stainless steel valves rated for chemical use and high pressure fail quickly on the seals. Is there anything available that does not use soft seals but for example aluminium instead? Thinking spray pump here... One way ball valve systems like used in simple spray pumps are a great thing. With some aluminium tubing I was able to make a simple valve that with some more attention to detail might even work. But of course there no other way of moving the ball then to use a magnet and with sufficient back pressure even neodymium ones fail to get the ball in the open position and keep it there. Now getting this combine with a needle... If, instead of the ball, a magnet in a teflon shell is used on a spindle I could spin a magnet around the outside to turn the valve with great precision. Has anyone already designed such a thing or would I have to start from scratch here?

Question by Downunder35m   |  last reply


Get into PCB creation? Answered

Well I just realized over the past few weeks that I really need to start getting onto the PCB bandwagon and start manufacturing my own stuff...  So... I need materials and instructions on how to make my own PCBs... I have copper boards already (sourcing them is not a problem...), and i am pretty good at designing boards in EAGLE (I find it fun), but I need a method of etching them.... I have tried many toner methods and they never work how I like, I always get some pretty big mistakes and etching them sucks...  I have heard of photo resist methods, and it sounds wonderful because it has a pretty good accuracy and can go down to some pretty fine wiring... My only problem is that you have to get presensitized boards (Expensive!), as well as other chemicals... As for etching, I think I am fine, I have used a vinegar/salt/something combo and it works pretty well, just takes a while to etch.. I have some muratic acid but that stuff is nasty so I have never really tried that.. Anybody have any non-toner PCB creation process that is pretty inexpensive? (I am in high school and have a limited budget already...)

Question by astroboy907   |  last reply


What's the difference between an electric boiler and an electrolyzer?

Backstory: I don't understand how they create steam without hydrogen and oxygen. I've been researching the prior art on electric boilers. This involves the type that passes the current through the water. Here's one of many examples: Electric Boiler There are also jet flow boilers which seem to do the same thing. I thought it might be the ac current instead of dc which allows the creation of steam without the dissociation of the water molecules. I've actually been trying to create steam this way. But this has been driving me crazy. I started experimenting with a AA. I start small. Safety first. :-) Then a AA with a disposable camera circuit. It will charge up a cap to 319 Volts. Then I jumped to 9V, 12V car battery, 120VAC, then rectified 120VAC with a bridge rectifier. So far, I've just used regular tap water. My meter reads open circuit.  I've tried a couple different electrode materials for the 12V in the 2 gallon container: plated screws, aluminum plates, spark plug. The only thing I can think of is to decrease the size of the container, dramatically. Even then, I would still have the problem of dissociation. I've been told to throw in some chemicals to decrease the resistance. But that's how to get more hydrogen production as well, from what I've read.  I would think it should go something like this: As I increase the power, heat would rise, proportionally, till it starts becoming a vapor. As I continue to increase the amount of power, the moisture of the gas decreases as the hydrogen and oxygen content increases. That's not what happens. Production starts almost immediately, with very little heat. No steam. I'm going to try decreasing the chamber next, but I still think I'm going to be getting hydrogen and oxygen, just with a higher moisture content as the water starts to heat up.

Question by Vorenus   |  last reply