air assist question

[Dee Gallo]

I just got a new Mini today (yay me, thank you very much) to help the Dinosaur with its work. This has Air Assist which is new to me. I saw posts where people recommended airbrush compressors providing about 20 psi. I paint with an airbrush and use a co2 tank, which gives me clean dry (and SILENT) air to paint with. Can I hook this up to my air assist if I need it? Or is this asking for trouble? Another question: do you use this feature all the time or only when you see or smell smoke or something? My Eclipse has an integrated fan which has never given me even a whiff from anything, even leather. Thanks for any comments.

[Larry Bratton]

I just got a new Mini today (yay me, thank you very much) to help the Dinosaur with its work. This has Air Assist which is new to me. I saw posts where people recommended airbrush compressors providing about 20 psi. I paint with an airbrush and use a co2 tank, which gives me clean dry (and SILENT) air to paint with. Can I hook this up to my air assist if I need it? Or is this asking for trouble? Another question: do you use this feature all the time or only when you see or smell smoke or something? My Eclipse has an integrated fan which has never given me even a whiff from anything, even leather. Thanks for any comments.
Dee:
Air assist is used primarily when vector cutting. It keeps down flaming of material etc. I do not suggest using any kind of air in your laser (not even canned air to clean with, as it contains propellants) other than what Epilog recommends. You could possibly void your warranty also. The compressors like the ones used for air brushing is what I have hooked up to my Epilog EXT.

[Scott Shepherd]

I also think it has a selenoid on it, so even if it's on, then it won't call for the majority of the air until it signals a vector cut. I could be wrong, but I think that's how it works. It might be sending out some air, but I don't think it calls for all the air until it's vector cutting.

[Joe Pelonio]

There is indeed a solenoid, so that if you were using a tank of CO2 it will run out into the room until the laser is actually cutting, it's diverted inside the machine until called for. I too use an airbrush compressor at 25 lbs but go to a real compressor at times for more pressure as needed for some materials.

[Robert Ray]

I would offer to suggest a Gast or Thomas diaphragm pump rated for continuous duty.

Examples are Thomas model #107CAB18A or a Gast model #DOA-P135-AA.

I use the Thomas myself, and it does not get hot, even after running 16 hours nonstop. I purchased mine used off ebay from someone who used it for a few years as an aquarium compressor at a pet store running several large tanks.

I have ran mine for 5 years now without incident, but what happened is the airbrush compressor that they sold me with my laser would only run for an hour or so, then over-temp and shut off. It is a great airbrush compressor, but lousy for air assist.

After that happened I spent a few weeks researching continuous duty air pumps and read great things about Thomas pumps. I work at a company who uses Gast pumps continuous duty to get vacuum, so I was familiar with them too, but discovered their diaphragm pumps also double as a both vacuum or pressure. So do the Thomas diaphragm pumps. Gast pumps get warmer than Thomas pumps, but both are more than suitable. As an added bonus, you can use these pumps as a vacuum pump in case you need one for a project, just remember the pressure side becomes an exhaust in this case.

When I got my Thomas, I ran it all day, and it was not hot to the touch, so I decided to purchase a spare, in case the used one ever went out. I found a surplus one on ebay for $50 brand new, and have never needed to use it, because the old one keeps running great.

Now about the air assist; I have the Laserpro machines, and the air flows constantly, however my friend has the Epilog Mini 24, and his air assist is controlled by the software drivers, and has a solenoid which shuts it off. It has been raining a lot here, and when the humidity is high, and the valve shut, the pump is compressing air, which causes condensation in the lines. Water has sprayed out on his material when the air assist solenoid turns on. As a solution, a moisture trap must be used and bled off regularly. You can get them from Harbor Freight cheap.

Well that's all I know about air assist pumps, but I hope it helps.:)

-Robert

[Richard Rumancik]

. . .It has been raining a lot here, and when the humidity is high, and the valve shut, the pump is compressing air, which causes condensation in the lines. Water has sprayed out on his material when the air assist solenoid turns on. As a solution, a moisture trap must be used and bled off regularly.

The LaserPro is even more sensitive to water in the line, as the air is fed directly below the lens. With the LaserPro, you don't want to run the risk of getting water (or oil) on the lens when you are cutting. Other lasers that have a separate "tube" for air assist are perhaps less vulnerable to moisture. But the moisture trap is really a good idea for any compressor.

[Dee Gallo]

Thanks to all of you for the info - much more helpful than my manual! I think I have a clear understanding now of what I need to get and how to use it.

I would just like to to repeat what I've read so many times on this site: Your donation to SMC will reward you over and over!

-dee

[Brian Robison]

Hi Dee,
My Mini 18 doesn't have a solenoid but it's a very early model.I remember calling Epilog and saying how nice it would be to have one. I never use the combination raster vector. I know I'll forget to turn on the little compressor.
I've been using a Harbor Freight air brush one for several years and it seems to do fine. If I were a big shop I'd use a regular compressor with a regulator. Sometimes it would be nice to have more air than the little compressor can supply.

[Dan Hintz]

For Black Friday this past year I picked up a 35-gallon compressor from Sears... anyone think 90-psi is good for anything? ;):D

[Mike Hood]

The LaserPro is even more sensitive to water in the line, as the air is fed directly below the lens. With the LaserPro, you don't want to run the risk of getting water (or oil) on the lens when you are cutting. Other lasers that have a separate "tube" for air assist are perhaps less vulnerable to moisture. But the moisture trap is really a good idea for any compressor.

My LaserPro (Explorer II) has an air tube for air assist. I don't do anything special for the air I use in assist... just shop air. I also installed a MAC valve and wired it to a plug and let the switched compressor outlet open and close it. Works like a charm.

[Richard Rumancik]

Mike, I should have said Mercury not LaserPro. I see that the Explorer has a tube which seems to point straight down adjacent to the lens. On the GCC website it is hard to see the details of the carriage construction. I looked at the Spirit and it seems to have the Mercury type connection but it's not clear.

I think the Mercury system is actually a good idea, in that it pressurizes the area below the lens so smoke and particles will be less inclined to go up onto the lens. The other advantage of air from the lens nozzle is that it has the potential of blowing air straight down into the kerf to expel material better. (I am not thrilled about the small elbow they use on the side of the carriage, however, as it contributes to high pressure loss. If you crank up the air, it makes quite a bit of noise.)

Industrial lasers tend to use this system and they pay a lot of attention to nozzle shape, size, air velocity, etc. For laser engravers I don't think that as much analysis goes into the design of the air assist.

[Marc Myer]

So is there an optimum air pressure for vector cutting?
I use a big compressor for vectoring but have a small airbrush compressor as well. Would the 20psi small compressor be a better all-around solution?

I normally use about 30 psi, but the air assist blows smoke down onto the cut and stains the edges of the material. Does that mean the pressure is too high, or is there a benefit to the higher pressure that offsets the discoloration?

[Sandra Force]

I use air assist all of the time and have found the the need varies by material. Wood likes mid to high psi and so does polycarbonate, abs and most thicker heavy materials. Thinner stuff and lightweight materials including laserlites, paper, filon, 1/16 laminate I use much less air down to 15 psi. I run even raster work with at least 3-5 psi to keep the lens clean. My air comes into the focus tube directly under the lens and that makes it absolutleyy necessary to have a water filter in line. I run with a 90 psi compressor as recommended by Kern. I also have a secondary air filter just before the tube with a small in line air filter to pull any that might be left in the line. Be sure and check the filters regularly and drain the water tap.

[Roy Brewer]

I just got a new Mini ...This has Air Assist ...Dee,

Let me explain that your Mini has a solenoid that is, from the factory, set for a "tankless" air compressor. Hence, it blows by the air assist channel unless the solenoid is "engaged"(as instructed by the firmware settings). If it didn't do this, then often the Gast/Thomas/airbrush type compress would overwork and even not be able to start if turned off then back on quickly because of the pressure in the line. Also, the hissing sound annoys many people.

However, in just a few minutes, the solenoid can be (and should be)reversed if you are going to use a tank type airsource. Check with your sales rep or tech support to confirm. Most are irritated that Epilog doesn't have a document to explain this, but it is too simple for a document; dismount, change the in to the out and the out to the in, remount and you're done.

Nothing wrong with using inert gas for your air assist. CO2 fine, Nitrogen is cheaper and more available in our area; many use it when they want the absolute least amount of oxidation.

[Dee Gallo]

Thanks Roy, I will contact my rep and see what he says about this. I would really prefer to use inert gas since it's clean, dry and quiet.

- dee

[Joe Pelonio]

Dee,

Let me explain that your Mini has a solenoid that is, from the factory, set for a "tankless" air compressor. Hence, it blows by the air assist channel unless the solenoid is "engaged"(as instructed by the firmware settings). If it didn't do this, then often the Gast/Thomas/airbrush type compress would overwork and even not be able to start if turned off then back on quickly because of the pressure in the line. Also, the hissing sound annoys many people.


Roy, what's the problem with using a tank-type compressor? I normally use the air brush pump but when I do need more pressure my real compressor will only come on about 2-3 seconds every minute or two, always works fine that way.

[Larry Bratton]

For Black Friday this past year I picked up a 35-gallon compressor from Sears... anyone think 90-psi is good for anything? ;):D
Yep..sandblasting.

[Richard Rumancik]

. . . . CO2 fine, Hydrogen is cheaper and more available in our area; many use it when they want the absolute least amount of oxidation.

Roy, you didn't really mean to say hydrogen, did you? Nitrogen maybe?

edit: correct that to Nitrogen: RB

[Mike Hood]

Nothing wrong with using inert gas for your air assist. CO2 fine, Hydrogen is cheaper and more available in our area; many use it when they want the absolute least amount of oxidation.

You're nuts if you think HYDROGEN is the gas you wanna run through anything near a flame... :eek:

I think you were thinking of Nitrogen? (correction-use Nitrogen--RB)

[Roy Brewer]

Roy, what's the problem with using a tank-type compressor? Joe,
No problem at all using a tank compressor. And if you flip back & forth, I'd not recommend inverting your solenoid. To many people the noise of the air "blowing by" the solenoid when not in use is annoying.

[Roy Brewer]

You're nuts if you think HYDROGEN is the gas you wanna run through anything near a flame... Mike & Richard,
Ouch! What was I thinking, Mike Null, can you change that in the post to Nitrogen.
Now who would believe I have a degree in chemistry? 1). That degree is 42 years old now, and 2) maybe that's why I was never successful in that line of work(?).

[David Ford]

I have just taken delivery of a new Camtech L-20 25W machine and have been searching this forum for tips and tricks on setting it up. One question I have is regarding air compressors. The manual for my machine lists the following air compressor specs:
- 25 gallon capacity (minimum)
- oil-free or oil-less
- 10 to 12 SCFM minimum output
That sounds like overkill to me but I admit to being a newbie to this game. Would the Thomas model# 107CAB18A (described below) setup with aquarium hose be suitable for my needs? I do have an inline water/oil filter that came with the machine.
Thanks in advance for any advice offered. I will be submitting a donation to Sawmill Creek asap, easily one of the best investments for my fledgling business.

Cheers,
Dave Ford
Kootenay Laser Design Inc.
Trail, B.C.
Canada






I would offer to suggest a Gast or Thomas
diaphragm pump rated for continuous duty.

Examples are Thomas model #107CAB18A or a Gast model #DOA-P135-AA.

I use the Thomas myself, and it does not get hot, even after running 16 hours nonstop. I purchased mine used off ebay from someone who used it for a few years as an aquarium compressor at a pet store running several large tanks.

I have ran mine for 5 years now without incident, but what happened is the airbrush compressor that they sold me with my laser would only run for an hour or so, then over-temp and shut off. It is a great airbrush compressor, but lousy for air assist.

After that happened I spent a few weeks researching continuous duty air pumps and read great things about Thomas pumps. I work at a company who uses Gast pumps continuous duty to get vacuum, so I was familiar with them too, but discovered their diaphragm pumps also double as a both vacuum or pressure. So do the Thomas diaphragm pumps. Gast pumps get warmer than Thomas pumps, but both are more than suitable. As an added bonus, you can use these pumps as a vacuum pump in case you need one for a project, just remember the pressure side becomes an exhaust in this case.

When I got my Thomas, I ran it all day, and it was not hot to the touch, so I decided to purchase a spare, in case the used one ever went out. I found a surplus one on ebay for $50 brand new, and have never needed to use it, because the old one keeps running great.

Now about the air assist; I have the Laserpro machines, and the air flows constantly, however my friend has the Epilog Mini 24, and his air assist is controlled by the software drivers, and has a solenoid which shuts it off. It has been raining a lot here, and when the humidity is high, and the valve shut, the pump is compressing air, which causes condensation in the lines. Water has sprayed out on his material when the air assist solenoid turns on. As a solution, a moisture trap must be used and bled off regularly. You can get them from Harbor Freight cheap.

Well that's all I know about air assist pumps, but I hope it helps.:)

-Robert