Make your own Woodburner

Re: Make your own Woodburner

Fred in NC

>I am not sure I like computer supplies for this. They are switching power supplies. The voltage and current cannot be controlled without an outside circuit.

Re: Make your own Woodburner

John Trant (Baltimore/DC area)

>I made one of these but it did not work well for me. The heatsink (for the MOSFET) got VERY hot but the pyrographic pen only got warm. I put a meter on the circuit so I know everything was wired up correctly and the output is correctly regulated by the potentiometer. It is likely that I purchased one or more components with the wrong specifications even though I had my EE friend help me with the shopping. A list of components with RadioShack part numbers would have been helpful. After spending $20 on components to build my failed device, I ended up purchasing a DetailMaster.

John

Re: Make your own Woodburner

Pascal Oudet

>Ben, I did, since it's my web-page ;-)

it works very well for me, I use it for branding patterns. Most of the time the potentiometer is set close to mimimum, I have plenty of margin power-wise. Last thing I've done is fully branding the inside of a 6" bowl and it worked perfectly.

Fred, I'm not sure to understand why you feel switching psu are not appropriate. voltage is very precisely regulated internally, so you can't (simply) adjust the voltage, but it's the same if you purchase a non-switching psu.

John, sorry to hear that your circuit didn't work. the most important point for the mosfet is to have a low Rds-on

(that's a parameter which is given in the component specification. ideally the transistor is a kind of on/off switch, but when ON it still has a small resistance, which will cause it to dissipate power. something in the 10 milli-ohms range would be good). if you indicate me the reference of the component you have I can check if it is suitable or not. in a future update of the page I can give more precise components reference.

Pascal

Re: Make your own Woodburner

John Trant (Baltimore/WashDC)

>Thanks for the info. I think you found my problem. The MOSFET I have is 20W max power (drain) with timing of 20 ns on and a resistance of 0.6 ohms (on). I am sure the reason that the heatsink was so hot is due to the high resistance of the MOSFET. Is that also the reason why the burner did not heat up? The MOSFET is from RadioShack (276-2072) "IRF510 Power MOSFET Transistor, N-channel, 60 volt"

TIA

John

(remove 2 for email)

Re: Make your own Woodburner

Pascal Oudet

>yes, I checked the spec and 0.6 ohms is way too much.

a tip is in the 0.2 ohms range. (roughly, it's hard to measure such small resistance). it means you dissipate 3 times more power in your mosfet than in the tip: you would have better success using the heatsink to burn the wood. might give interesting patterns ;-)

with the potentiometer at max position, you would deliver ~8W to the tip, and 23 to the mosfet. that's why your tip doesn't heat enough.

I've checked radio-shack website, and found they have no other N-MOSFET than the IRF510 (I'm disappointed, I thought they had a bigger catalogue). I don't know the US market for online vendors of electronic components, so can't recommend any, but any good supplier should have a suitable mosfet. if you give me some URLs I can have a look.

Pascal

Re: Make your own Woodburner

John Trant (Baltimore/DC area)

>Well it all makes since now. The heat sink burned my fingers but the tip was only warm. Thanks Pascal for the info. I will look around for another supplier.

John

Re: Make your own Woodburner

walta100

>Is this the one you are looking for

Re: Make your own Woodburner *LINK*

walta100

>Is this the one you are looking for


MCM

Re: Make your own Woodburner

John Trant (Baltimore/WashDC)

>The page doesn't provide enough information but it worth a call to them for help.

Thanks,

John

Try Digikey.com

Fred in NC

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