Ever wanted to try your hand at wood burning? If you already threw away your first soldering iron—you know the one: plugged straight in to the wall, no temperature control, came with a thick piece of tin foil to rest it on—don’t despair. Pyrography pens don’t cost that much. The variable power supply they plug into, though: that’s another story. Those cost more than they probably should.
[td0g] took the plunge into pyrography a while back, and wanted to build his own controller from an old ATX power supply. Why not? It should be more than capable of doing the job. Even the most heavy-duty pyrography pens only draw 10A, and the 3.3V line showed to be rated for 30A. All [td0g] had to do was add a PWM with a MOSFET and a ‘Tiny85.
The project nearly became Fail of the Week fodder after [td0g] saw huge voltage spikes across the MOSFET. A 47kΩ resistor took care of those, and a heat sink salvaged from the junk bin will prolong the transistor’s life. [td0g] added a push button that cycles through five heat settings, and an LED to show the status. After that, all he had to do was add a male RCA input to connect the pens he already has.
Okay, so you wouldn’t be caught dead dropping money on some fancy power supply for this new hobby. Don’t want to buy pens, either? Roll your own from a plasma arc lighter.
How about a wall-voltage soldering iron plus cheap dimmer control?
How about going solar powered with a $1 magnifying glass.
Or a salvaged fresnel lens out of an old overhead projector for more POWA! Alright, you lose all accuracy, but come on, now you can melt aluminum.
Depends if circular or linear fresnel lens since there are two types I’m aware of. Circular may still be able to designed to be accurate.
That works too… as does using a cheap temperature-controlled iron.
For example:
https://forum.hsbne.org/uploads/default/original/2X/9/94769a0f4e5da69f256954b96000b55aac6b4b1e.jpg
was done with one of these:
https://www.jaycar.com.au/40w-temperature-controlled-soldering-station/p/TS1620
Good question… cimmer controls aren’t really cheap compared to the parts used for this project. Your idea is much simpler (and really, nothing wrong with it), but with this system you can use a variety of fancy wood-burning pens!
I just tried attaching a pyrography wire nib pen to the dimmer switch that was on a soldering iron type burner. I started with the unit off then slowly raised the power i was getting nothing in the way of heat at one point near the max power level I heard a loud pop noise come from the dimmer switch’s innards which made me jump and immediately and instinctively turn the power down fast and at the same time yank the cord from the plug socket all int the same movement. Oh and as always whenever I hear a noise that denotes a possible explosion is to open my eyes as wide as possible in order to allow my eyeballs to absorb whatever the hell is going to be flying towards them. I don’t know what the hell type of safety instinct is built into me that makes me open my eyes like that I’m guessing it’s similar to that other one where in the even of trauma the brain tells the lungs to stop functioning or to overload the body with so much coagulant that the results are death due to self suffocation or organ failure respectively. And I have yet to take the dimmer apart and see what i did to the switch. I am thinking scorching and possible melting of the copper contacts.
The wire on that RCA plug looks much smaller than the 12ga I would expect for 10A – are current/gauge requirements different between DC and AC?
Hmmm? 18 ga would support 10A AC fine… you wouldn’t wire a house like that because of allowances for 50 meter to 100ft runs in conduit, bundled with other conductors, but you don’t need pencil thick cabling for a couple of feet. For DC typically ATX PSUs will be supporting 20A on 18inches to 1 meter of 16 gauge at 12V.
PS, in order to show no favoritism I mixed units deliberately :-P
Except for using only wire gauge. Don’t countries that haven’t landed on the moon mostly use circular mils?
Not circular mils. We enlightened nations use mm2 (cross sectional area in millimeters.)
The truly enlightened use square Assyrian cubits. Download the GNU
unitsprogram, and converting is as easy as:Seriously, get
units, because none of the measurement systems will always be right. Sometimes you care about the cross-section of copper, sometimes you care about the circumference (skin depth effects) and sometimes you care about the diameter b/c you need to wedge it under something.Actually, they use mm².
I don’t understand why he would be seeing the voltage spikes… Could someone enlighten me?
I’ve not messed with ATX PSUs much but probably from inductive kickback when the MOSFET closes.
I meant opens.
Bingo. I’m pretty sure you’re right.
I want to say something like they’re a switching power supply. I should read before I type this as I never really long term memorized to system. Maybe someone can save us time explaining. I know when I modified the one I have for the Honda 1000W gas generator for use with a trolling motor on my john boat and canoe in place of the battery… I recall the voltage being higher to compensate for current draw or something like that. Mine would spike up to ~16V.
My first soldering iron was a wood burning iron. It plugged in the wall and looked like one, but had various tips that fitted over the end. The box even said it could be used for soldering, though no details. It was around the house when I needed it, so I used it. That is likely some of the reason my initial soldering was so bad, though at the time I couldn’t judge. It was soon replaced by a real soldering iron.
Michael
Same for me. I don’t recall the box stating can be used for. I have the red handled ones.
There’s a crossover in Wellers ranges between solder molesters and wood pokers.
I noted on his site that this can almost double as an electrocautery improvised field kit.
I was at first envisioning something more like a soldering iron use also, though the specs are a little different and can still be made to work.
I had no idea the science, art and craft of wood burning or pyrography has advanced. Might be handy for plastic welding too.
I still have my pre-teen wood burner out in the garage I found going through stuff. I forgot I even have as I had another one I was using as a soldering iron for a few I left at my other place I had to vacate.
Seems like lowering the frequency would be more energy efficient I’m thinking if still functionally effective per your requirements.
Neat and way to go!
I remember doing something like this with an off-the-shelf SSR, an old IBM PC/XT power supply and a NE555.
Used the 5V rail, as the 12V rail was crook on this power supply. It worked well until the PSU eventually blew up.
That’s clever. Much the same idea, I opted to use a microcontroller for a simpler control system (one button / one LED / five discrete settings). A 555 would work just as well.
Obviously, the solution is to use a laser engraver.