Changing the Chris Crawford Etcher from 24v to 12v. Stopping the burn.

Carl_First_Timer

Carl_First_Timer

Joined
Dec 6, 2010
Messages
1,154
I have searched and searched for info on this and have come up empty.

I have just build the Chris Crawford etcher:
http://chriscrawfordknives.com/#/electro-etching-unit/4535265119

I plugged it in and fried my stencil. So I started the search to figure out why, and have read over and over that 24v is too "hot".

I have read a few fixes for this; dimmer switch; video game push button for mashing away while etching; and changing to 12v; etc...

Which brings me to my question(s):

Which of one/combination of the three above fixes would you guys recommend? If changing to 12v transfomer is one of them, would this http://www.radioshack.com/product/index.jsp?productId=2102700 one work? If not is there one you could recommend?
 
Sure, but you might be able to get an answer looking at the info in that thread.
 
Carl_First_Timer said:
I have searched and searched for info on this and have come up empty.

I have just build the Chris Crawford etcher:
http://chriscrawfordknives.com/#/electro-etching-unit/4535265119

I plugged it in and fried my stencil. So I started the search to figure out why, and have read over and over that 24v is too "hot".

I have read a few fixes for this; dimmer switch; video game push button for mashing away while etching; and changing to 12v; etc...

Which brings me to my question(s):

Which of one/combination of the three above fixes would you guys recommend? If changing to 12v transfomer is one of them, would this http://www.radioshack.com/product/index.jsp?productId=2102700 one work? If not is there one you could recommend?
Click to expand...

I think the 12 volt transformer is the way to go.

However, depending on which transformer you have, it's possible that there are 12 volt leads on that transformer already.

How many wires are there on the output side?
Were there any you had to tape off?
If so measure the AC voltage output from every combo of wires in the output side.
"center tap"
- then I would just use it- no need to buy another transformer.

If not, it makes sense to me to just put in a 12v transformer.


The momentary push button is a nice touch, but all you have to do is pull the hand piece away, same as a switch and no extra finger needed.
 
12345678910 said:
I think the 12 volt transformer is the way to go.

However, depending on which transformer you have, it's possible that there are 12 volt leads on that transformer already.

How many wires are there on the output side?
Were there any you had to tape off?
If so measure the AC voltage output from every combo of wires in the output side.
"center tap"
- then I would just use it- no need to buy another transformer.

If not, it makes sense to me to just put in a 12v transformer.


The momentary push button is a nice touch, but all you have to do is pull the hand piece away, same as a switch and no extra finger needed.
Click to expand...

I'm using the one from Chris' site ( http://www.radioshack.com/product/index.jsp?productId=2102703 ) I have zero experience with electronics wiring other than taking apart my toys as a kid. I am pretty sure all the leads are going somewhere. Not sure why though.
 
Since the circuit is running on 120VAC input, and there is no electronic circuits involved, using a cheap tool speed control will drop the voltage. Use a multimeter to read the output and make a note of the setting that delivers 12 volts. Be sure the meter is set to AC or DC, depending on which output you are reading. The DC voltage will be a bit lower than the AC for the same setting on the speed control.
Here is a cheap control, ebay has lots,too.
http://www.harborfreight.com/router-speed-control-43060.html
 
I built an etcher, but I'm not completely satisfied with the results I get. I was wondering if I may have possibly mis-wired it. I do have a multi-meter (I inherited) and was wondering if it would be suitable to check the output leads for AC/DC and voltage. And, if so, how? I know enough about electricity to almost keep from electrocuting myself, so if this question sounds a little lame, a little slack would be appreciated.

Bob
 
Turn on and set your multi-meter to AC and put it in the correct range (like 30 volts). Set the etcher to the AC output and place the probes on the output terminals. Read the voltage. Remove the probes and switch the multi-meter to DC and set the range again. Turn the etcher to the DC output and read the voltage. If the needle goes the wrong way, reverse the probes.
 
Your transformer (according to what I found on Radio Shack's site) can be wired for either 25.2V or 12.6V.

The two black wires on one side are for 120V input.

You should also have two yellow wires and one black on the other side.

The two yellow wires produce 25.2 volts.

Use one black and one yellow (either of the yellow wires - but not both) produce 12.6 volts. Tape off the other yellow wire so it doesn't touch anything.

You want to go the 12.6 volt way.

Hope this helps.

Robert
 
Robert Dark said:
Your transformer (according to what I found on Radio Shack's site) can be wired for either 25.2V or 12.6V.

The two black wires on one side are for 120V input.

You should also have two yellow wires and one black on the other side.

The two yellow wires produce 25.2 volts.

Use one black and one yellow (either of the yellow wires - but not both) produce 12.6 volts. Tape off the other yellow wire so it doesn't touch anything.

You want to go the 12.6 volt way.

Hope this helps.

Robert
Click to expand...

Wowza! Thanks I'll give it a shot.
 
Robert Dark said:
Your transformer (according to what I found on Radio Shack's site) can be wired for either 25.2V or 12.6V.

The two black wires on one side are for 120V input.

You should also have two yellow wires and one black on the other side.

The two yellow wires produce 25.2 volts.

Use one black and one yellow (either of the yellow wires - but not both) produce 12.6 volts. Tape off the other yellow wire so it doesn't touch anything.

You want to go the 12.6 volt way.

Hope this helps.

Robert
Click to expand...

That's what I was getting at, but I didn't trust the wire colour
 
This may be a little over simplified, however........

Just remember that the transformer output, whether wired for 25.2V or 12.6V is still AC. That is the purpose of the bridge rectifier with the switch. Think of the bridge rectifier as a one-way gate. It allows Alternating Current to pass through, but not "Alternate" and come back.

The purpose of using both AC and DC is to etch your mark with reverse polarity DC and "blacken" your etch using AC (takes a little out and puts a little back).

I built my etcher over 7 years ago and have etched a few hundred blades. Still as good as the day I first plugged it in.

Robert
 
Robert Dark said:
This may be a little over simplified, however........

Just remember that the transformer output, whether wired for 25.2V or 12.6V is still AC. That is the purpose of the bridge rectifier with the switch. Think of the bridge rectifier as a one-way gate. It allows Alternating Current to pass through, but not "Alternate" and come back.

The purpose of using both AC and DC is to etch your mark with reverse polarity DC and "blacken" your etch using AC (takes a little out and puts a little back).

I built my etcher over 7 years ago and have etched a few hundred blades. Still as good as the day I first plugged it in.

Robert
Click to expand...

Did you build one of the Crawford type? How is yours wired? 12V 24V ?
 
Best I can recall, I used the Crawford plans. Mine uses 12V. Bought everything from the local Radio Shack (except for the main power cord). I tend to etch fairly deeply on most of my blades. I want my name to be around long after I'm gone. :)

Robert
 
Carl_First_Timer said:
Did you build one of the Crawford type? How is yours wired? 12V 24V ?
Click to expand...

I used the

instructions and diagrams
http://www.knives.mlogiudice.com/knifeshop/etcher/
http://www.knives.mlogiudice.com/knifeshop/etcher/electro-etcher_circuit.pdf

I understood the schematics much better than the Crawford number 1 to number 2 terminology.

I did a ton of reading and research first, so went directly to 12 volts.


You know, I believe that schematic is made for your same transformer too.
You can likely just follow it.
 
12v is the way to go with what you already have. That transformer will do it, as stated earlier.

16v seems to be ideal though, and can be had as a doorbell transformer.

I played around a LOT with one built out of a Variac, testing voltages, and 15 - 16v always seemed to give the best results in most steels.

My 16v doorbell transformer provides me 15.5v which is perfect.
 
Last edited:
I have had good results with just a power-supply out of an old radio, 120v in and 12v out, nothing fancy but it just works. the out put is 12v 5amp. i get good clean deep etching. i have noticed that the larger the area to be etched the more amps needed. i recently did a large etch and used a 12v car battery charger for the power-supply, worked like a charm.
 
You must log in or register to reply here.
Back
Top