stencil material types

Kevin McGovern

Kevin McGovern

Joined
Jul 31, 2015
Messages
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Are there any preferences between the different types of stencil materials for etching? I notice most of the stencils i see other makers using are blue. the ones I got from Tus are brown. One of them is pretty stiff, although I think I overheated it.
 
Kevin, I started with TUS stencils and a cheap etcher and tried different etchants and also ordered the "green stencils" from Marking Methods in Brea , Ca. When I bought a better etcher (personalyzer plus) and changed etchant solution to #94 from IMG in New York then both TUS and the green stencils worked equally well. There are some other popular stencils (the blue ones) that produce good results. My opinion is to stick with your TUS stencils but try a better solution like #94 from IMG. I like to etch at about 20 volts and 3 amps by swiping the felt pad for 4 or 5 seconds on etch (DC) and the same on mark (ac) . Larry
 
I've only used TUS as a hobby maker but couldn't be happier! They was great to work with VERY reasonable and the end product has exceeded my expectations.
 
Larry, have actually measured pulling 3 amps at 20 volts when stenciling? OR - is it just a 3 amp supply? From what I've seen stenciling the currents varies a good bit depending on amount of steel exposed thru the stencil, and this is usually well below an amp.

Ken H>
 
Ken, I cannot be sure of the actual amperage but the Personalyzer Plus unit is rated at 24 volts and 3 amps and I use it at about where the level is about 4/5ths of the way to maximum. Maybe the amperage is less at that setting but the etches look good at 4-5 seconds etch and the same time for mark. I know some knife makers that use etchers rated at 10 amps and 36 volts and their etches take as long as mine but could be deeper. I know more about knife making than electricity though so you are probably correct. Larry

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Power supplies of any type are usually rated for their maximum output. So a 3A, 36V power supply is capable but not necessarily putting out that much current and voltage. Sometimes you'll just see the power rating of the supply listed. Power is just the product of current and voltage. The 3A, 36V supply would have a power rating of 3A X 36V for 108 Watts. If you know the power rating, just divide it by the output voltage to get your maximum possible current.

The power supplies used for etching many times will have an adjustable knob which controls the output voltage. These are referred to as variable D.C. (or A.C.) power supplies. The amount of current that is drawn from the supply depends upon the resistance of the circuit that your hooking up. Current is equal to the adjusted voltage divided by the resistance. So for instance, if our 36V variable power supply were adjusted to say, 15V, and the probe that we hook up had an electrical resistance of 10 ohms, then the current draw from the supply would be 1.5 Amps. Furthermore, under this circumstance, the power supply would be supplying 22.5 Watts of power (remember P = I X V).

Its difficult to predict exactly how much current is going to be drawn by an etching probe because the resistance of the probe cannot easily be measured. Most of all its the resistance of the electrolyte that would be difficult to predict as it would depend upon the specific chemistry as well as the amount of saturation into the pad, and the amount of surface contact with the part being etched. My guess, all things considered would be a resistance of somewhere in the neighborhood of 5 to 20 ohms. I'll be building an etcher out of a piece of carbon block (or perhaps a large motor brush) in the near future, along with a regulated variable power supply and I'll give a full report when its finished along with assembly instructions and schematics.
 
Tony, do you plan to have a voltmeter and ammeter included with your power supply? That is about the only way to measure voltage 'n current. Remember the folks who etched using a car battery? Those would be a 100's amp supply, but the current used would still be the same.

Looking forward to your plans, it sounds like you've got the electrical knowledge to handle the job with no problem.

73 de Ken H> K9FV
 
Ken H> said:
Tony, do you plan to have a voltmeter and ammeter included with your power supply? That is about the only way to measure voltage 'n current. Remember the folks who etched using a car battery? Those would be a 100's amp supply, but the current used would still be the same.

Looking forward to your plans, it sounds like you've got the electrical knowledge to handle the job with no problem.

73 de Ken H> K9FV
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I'd like for folks to be able to affordably build a nice regulated supply. I'm thinking that at this point I would not include meter instruments with the supply for both cost and simplicity. I would recommend that anyone that wanted to monitor the output just go to the nears TSC and buy one of there cheapo digital multimeters. As a matter of fact, I am considering adding a second set of output terminals so that a multimeter could be easily plugged in. I think this would be the best way to handle it for anyone interested in exactly what their supplies are putting out.

I'll be retiring at the end of the next school year from my job as a prof at one of the local colleges here in S.E. Michigan. I've been teaching electronics engineering for over 30 years now having left a job as a robotics system engineer prior to that. I guess you could say I've been around the block once or twice. In any event, as so many other gracious posters on this forum, I'll share as much of my knowledge here as what others will comfortably tolerate. :D I'm just happy that there are areas concerning knife making that I can contribute to. I've gained so much insight from reading what others have posted here.
 
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