[buddydog]

I like reading both of y++ou and I'm no Pollyanna. Retro if you want an idea about what El is talking about, build a wood fire outside and stick a 3/4 inch metal water pipe into the center of the fire near the wood. Now bring a lit match to the other end of the pipe and you will lite a gas flame. The laser cut is the "fire" and the smoke tube is the pipe so you have to hope the fuel air mixture is not close to "stoiciometric" (probably spelled wrong) and that there is no spark or other ignition anywhere in the pipe! I think the laser especially with the air assist on is prime to create combustible gas as the flame is immediately blown out by the air assist leaving what has to be a high amount of combustible gas.

As long as were taking "flyers":
I think I will patent this idea before you guys beat me to it!: Laser beam hits wood in a closed vessel, gas is created, gas is moved to combustion area, power is made! hmmm.

Retro I'll need your machine to clean up what's left over in the exhaust stream.

The mixture from the laser must be extremely on the lean side of stoiciometric because the exhaust fan is pulling so much gas through the machine and that is why we have so few (anyone know of any?) laser explosions like in sawmills or flour mills. I wonder how the mixture would change over time if the "smokefan" stops during a cut and you had a continuous spark inside the case! I want some one else to be there, not me!

[Retroplayer]

I like reading both of y++ou and I'm no Pollyanna. Retro if you want an idea about what El is talking about, build a wood fire outside and stick a 3/4 inch metal water pipe into the center of the fire near the wood. Now bring a lit match to the other end of the pipe and you will lite a gas flame. The laser cut is the "fire" and the smoke tube is the pipe so you have to hope the fuel air mixture is not close to "stoiciometric" (probably spelled wrong) and that there is no spark or other ignition anywhere in the pipe! I think the laser especially with the air assist on is prime to create combustible gas as the flame is immediately blown out by the air assist leaving what has to be a high amount of combustible gas.

As long as were taking "flyers":
I think I will patent this idea before you guys beat me to it!: Laser beam hits wood in a closed vessel, gas is created, gas is moved to combustion area, power is made! hmmm.

Retro I'll need your machine to clean up what's left over in the exhaust stream.

The mixture from the laser must be extremely on the lean side of stoiciometric because the exhaust fan is pulling so much gas through the machine and that is why we have so few (anyone know of any?) laser explosions like in sawmills or flour mills. I wonder how the mixture would change over time if the "smokefan" stops during a cut and you had a continuous spark inside the case! I want some one else to be there, not me!

I do completely understand (now) what El meant about combustible gasses. I really appreciate him(her?) bringing that up because I hadn't thought enough about it. You also point out the fact that you are sucking the gasses through an exhaust system already. A fan motor has brushes. Those brushes cause arcs. So, there is already an ignition source present in the typical exhaust system. Either it is not as huge of a concern as we are discussing or it does exactly what I am talking about in consuming the gasses and rendering them inert.

You also make a great point about the effect of the air assist. You are right, this would probably affect the ability for the laser to consume those gasses. Great point.

Great conversations! I will build up the experiment, show some initial results and then hopefully you two will be around to suggest tests for me.

BTW, Buddy, I see that most of your posts around here have been on the K40 laser and you have been a proponent of it. You might be interested that I have been converting the mechanical parts of this machine to 3D printed parts in the case of needing replacements (and in some cases because the parts are poorly machined and not very accurate in dimensions.) I figured that while I have the machine completely disassembled, it would be a good time to capture all of the dimensions. I will throw these up on thingiverse when I am done.

[Retroplayer]

Alright, let's leave this until I can come back with an experimental setup. I am more than happy to test any suggestions that you have as I believe that will make it as robust as possible. Your skepticism is exceedingly valuable in that sense.


I also appreciate your over-abundance of caution (when you see all the safety features I am fitting into my cutter, I think you will understand that I am also quite cautious.) I can't say I agree to the level that you take it, but let's experiment and find out. There are ways to verify vs. educated guessing. But for one, I disagree that free roaming combustible gasses floating around my workshop (especially a basement where my furnace and water heater are ignition sources) is better than burning it up safely and then filtering it. I can't think of any system in which it is a safe practice to pump combustible gases into an enclosed and occupied area. All systems I am aware of intentionally burn up this gas before releasing it to the air.

[Dean448]

There is too much airflow to do anything but vent to the outside. I'd carefully knock out one glass block. You can always replace the block later. Where I live you can buy air tight aluminum dryer tubing that can stretch 25' and place the laser just about anywhere in the room.


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[buddydog]

There is too much airflow to do anything but vent to the outside. I'd carefully knock out one glass block. You can always replace the block later. Where I live you can buy air tight aluminum dryer tubing that can stretch 25' and place the laser just about anywhere in the room.


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Yes but where is the fun thread in that? :-)

[buddydog]

In my setup I have the fan and water pump and laser all plugged into a switched strip and the strip is turned on and they all start except the laser. After confirming water I turn on the laser with it's power switch. As I start a job I turn on the noisy air assist pump. It reminds me a bit of flying an aircraft. Always do things the exact same way for brain and muscle memory. No one has chimed in with any explosion horror stories? Maybe a non issue.

[Dean448]

Short of putting something flammable in the machine I fail to see how you could have a fire or explosion. The only time I've seen a flame is when the airline got disconnected. The air helps the cutting action and blows any flames out.
I start everything up at once. The only thing that is truly critical is the pump that is monitored by a water switch. If the exhaust or air didn't start you will know it after a while, but it won't damage the tube.


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[BrianJenkins]

Do any of the laser manufacturers provide dedicated inlet (for air coming into the unit) in addition to the outlet?

In terms of venting outside, with a decent size fan, I'll be putting a huge negative pressure effect on the room (and dumping heated/cooled air). I'm curious if I could keep it a closed system? Bring in fresh air from outside and basically push it through the unit?

[buddydog]

Do any of the laser manufacturers provide dedicated inlet (for air coming into the unit) in addition to the outlet?

In terms of venting outside, with a decent size fan, I'll be putting a huge negative pressure effect on the room (and dumping heated/cooled air). I'm curious if I could keep it a closed system? Bring in fresh air from outside and basically push it through the unit?

I hadn't thought of that. We are dumping expensive heated air outside. A closed system using outside air would stop that!