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Al Stewart
05-28-2009, 12:50 PM
Hi All! I have a ULS Versalaser 40 watt with air assist provided by a air brush compressor. I'm thinking of using nitrogen instead. I understand nitrogen will reduce or eliminate charring when cutting wood.

Does it really eliminate the charring??

Will nitrogen eliminate the smoke residue? Not only from vector cutting wood but also acrylic and paper?

Is there a valve you recommend for turning the nitrogen on and off along with the laser beam? I have a relay that turns the compressor on and off and would like to get a valve that could be controlled with the same relay.

Mike Mackenzie
05-28-2009, 3:24 PM
Al,

Yes there is a difference using nitrogen when cutting however the draw back to this is as you are pumping the gas through it is going out the exhaust. So you will use quite a bit of the gas while you are cutting. Having a solenoid in line is smart because it will turn on and off the flow of gas.

It does work well on most materials but in the long run your standard air is probably just as good.

Richard Rumancik
05-28-2009, 4:05 PM
Al - here is an old thread on the use of nitrogen:


http://www.sawmillcreek.org/showthread.php?t=70699&highlight=nitrogen+synrad+gases

Benjamin Maine
05-28-2009, 9:20 PM
Does it really eliminate the charring??

Will nitrogen eliminate the smoke residue? Not only from vector cutting wood but also acrylic and paper?



Burning is more complex than just oxidation. In complete burning of plant material such as wood, the final products are CO2, water, and a tiny bit of ash. However, complete burning is pretty rare because there is not all that much oxygen in air. In fact, air is mostly nitrogen.

In burning, some parts of the flame have more oxygen than others and each type of burning has a name:

zero oxygen - pyrolysis
partial oxygen - gasification
plenty of oxygen - combustion

If you look at a normal camp fire, all three processes take place in different parts of the fire. Heating plant material without oxygen is a very old technique and is how charcoal is made. The final answer is that if plant material such as wood or paper is heated without oxygen, it will turn into charcoal, and volatiles that look like smoke will be given off.

If you use a laser on paper, wood, or plastic even in a nitrogen or argon environment, it can still produce char and smoke.

Benjamin

Rodne Gold
05-29-2009, 1:01 AM
It wont stop charring , it is good when cutting thin substrates such as paper and card and some plastics to stop discolouration , it also stops any flaming.

Jack Harper
05-29-2009, 8:32 AM
It wont stop charring , it is good when cutting thin substrates such as paper and card and some plastics to stop discolouration , it also stops any flaming.

Rodne - Are there any benefits in using the gas when cutting .125 rubber?