airgraver power supply

[monk]

i'm soon to get me an airgraver. they can be powered by air compressors. in the portable mode, why must one use co2 ? could one not use a tank of compressed air for small jobs ? or does the co2 simply deliver more engraving time ?

[Ray Cover]

Monk,

The 20oz co2 tanks will hold up to 800 lbs of pressure and will last me about 8 hrs with general use.

I don't think you can get the same kind of pressure or amount of air in an air tank.

The CO2 is compressed enough that it is in liquid form in the cyninders by time if turns to gas and comes out of the valve it has supplied a much greater volume of "air" than one would ever get a conventional portable air tank to hold using atmospheric air.

Ray

[Steve Ellsworth]

ray its about a hundred to one ratio tank size wize
best bet would be to get a large tank and fill it with nitrous from dental supply and run the exhaust into a mask. that ay engraving would be just as much fun as going to the dentist, maybe more

[KurtB]

Just a thought - I enjoy Scuba, and there are a huge variety of Scuba tanks that all hold upwards of 3,000 PSI of air. These range in size from a unit called a "Spare Air" right up to an 80 cubic foot standard cylinder. The Spare Air units are especially intriguing - think of a James Bond underwater escape scene. They are about the same size as a can of WD-40, and are refilled from a standard 80 cf cyclinder with an adapter. Without a lot of experience, my best guess is that a small scuba tank known as a pony bottle would run these tools for days and days, and it'd be portable and cheap. Of course you'd need some sort of adapter/regulator to go with them.

[Danny C]

Yup - SCUBA and the E-Tank would work fine - the "regular" 1st stage regulator reduces it down to a useable pressure, but an adapter is needed to go from the air hose to a standard regulator to regulate it further. (a palm control at 200psi would be something to behold! - please take pictures!)

If the hose connects to the regulator with a standard hose fitting, then you are all set. Remove the Standard hose and attach a regular hose fitting and attach a hose to that.

As a matter of fact, I looked into using an E-Tank to fill up my Jeep tires, and the shop "did" have an adapter to hose.

The worse case is to take the hose to a "hose shop" and they can cut off the end and install a hose fitting to pipe adapter with a high pressure fitting. When that is done you can connect it directly to a regulator.

The CRITERIA is that the maximum pressure that the "1st stage regulator" allows to the mask is at or below the inlet pressure for the "use" regulator. This is usually not a problem as the "working outlet pressure" is around 150psi above ambient. (so 200psi or less working regulator is ok).

Check with a dive shop to be sure of standard atmospheric outlet pressure of a regulator. They would also have the adapter (or could get it).

[brandvik]

Hi Monk,

The fact that the Palmcontrol is so efficient when it come to air consumption and the fact that it is proven to be adaptable to so many portable sources is exactly what drew me to it. (That and its shear beauty, of course)

I live off-grid and depend solely on solar power or generator if the sun doesn’t shine for a few days. So having a compressor kick in every few minutes sucking up my meager power supplies is just not an option for me.

Regarding the SCUBA tank idea, Kurt and Danny are both correct in that this is a viable option. I taught recreational and technical diving for 10 years and owned a dive shop for 8 of those years. There are essentially only two types of 1st stage regulators; piston and diaphragm. The delivery pressure can be altered to a degree on most but generally speaking 150 to 200 psi is the operating range.

One other important point to mention is this. Reputable dive shops go to great lengths and expense to filter their air of contaminants such as oil, fumes or water. This is because it is a real safety concern. While a few ppm of Carbon Monoxide in the mix may not be a big deal at the surface, it is increased at a rate directly proportional to the density of the air breathed. So a diver breathes in 5 times as much of the bad stuff at a depth of 130 feet. (5 Atmospheres of pressure) So you can bet the air in a SCUBA tank will be much cleaner than any off the shelf compressor can deliver thus keeping your PalmControl nice a clean and dry.

I will be receiving my Palmcontrol airgraver soon and right now I am in the process of experimenting with just such a SCUBA powered setup using an old regulator and a dual tank rig I used to use for cave diving. The dual tank rig holds 200 cf of air which I calculate will last for weeks of use. I am hoping to arrive at a quick connect coupler solution to address the hose issues already mentioned. I will post more information for anyone interested once I have worked the kinks out.

[KurtB]

Jim, if you pursue this, I'd love to hear more details. I cannot imagine that it would be hard at all to adapt the Scuba's first stage output at 150 to 200 PSI to a simple and standard industrial regulator with a 1/4" pipe taper output, from thence to the Lindsay tool. Your point on the dryness and cleanliness of the air is spot on, and something that I hadn't thought of. You'd need absolutely no filtration at all - the air out of that tank will be pure, sweet, and bone dry.

A safe, used 80 cf scuba cylinder can be had really cheaply off of eBay and other similar sources. I can think of only one drawback - some shops simply will refuse to refill a cylinder for you unless you can show them your certified diver card. Maybe if you describe the setup, and paint on the cylinder something like "SHOP USE ONLY, NOT FOR DIVING" they'd fill it for you.

One last option, not cheap but possible... I'm sure plenty of people are set up with some sort of welding outfit in their shops. Those big bottles of Argon would run this tool for a LONG time!

[brandvik]

Will do, Kurt. :thumbsup: I talked with SL a while back about this and he didn't see any reason from an engineering standpoint not to pursue this.

At my shop, we would fill tanks occassionally for non-diving applications. I remember one guy who used a scuba tank to start his airplane engine. (Don't ask me exactly how that worked!) We just required a boiler-plate, written statement to be signed and witnessed for non-divers with no certification stating that it was to only be used for non life support purposes.

One word of caution to those non-divers who may be considering this. Federal law requires a current (within 5 years) hydrostatic certification on high pressure cylinders such as is used for scuba. So before you buy a used tank at a pawn shop or garage sale, understand that no one will fill it without a current hydrostatic test. Some shops also require an annual visual inspection of the interior of the tank, which they will do at the dive shop.

The hydro date will be stamped just below the neck in the mm-yy format. Hydros can run $30 or $40 dollars and there is always the chance that a tank might fail the test. (In which case the testing station will drill a big hole in the side of it converting it to a large paper weight.)

[Big-Un]

I would not use argon in any closed shop, too dangerous. Instead, the nitrogen bottles are relatively cheap and are dry. We used nitrogen to keep a blanket of dry air in the high voltage transformers in the transmission/distribution substation in order to eliminate any moisture in the system. Any moisture in a 500KVA transformer is disasterous and unhealthy for anyone nearby.

[KurtB]

Originally Posted by Big-Un

I would not use argon in any closed shop, too dangerous. Instead, the nitrogen bottles are relatively cheap and are dry.

Bigun, I don't disagree that Nitrogen would work, but there is nothing dangerous with Argon in a chemical sense. It is an inert gas. Like Nitrogen, it can displace oxygen and cause asphyxiation, but the quantities must be huge, and the ventilation non-existant, for there to be any danger. Guys are using CO2 for engraving; same deal. The airgravers simply don't process enough gas for this to be an issue, IMO.

I tossed out the Argon as an option for shops where a lot of welding takes place. In many shops like this, there are 1 or dozens of huge 3,000 PSI bottles, and overhead manifolds, to support welding ops. It'd be easy to tap an Argon regulator to run an airgraver, or rotary tool.

[Tim C]

I picked up the high pressure tank used in paintball guns (called "Markers").
It is made of carbon fiber and has a 3000 psi rating, for this you need a good two stage regulator. I haven't found the right one yet to get the pressure down to about 300 psi so the second stage can be connected.
Diving regulators might work if you can find the regulators for a "Hooka" set up.
For you folks in the midwest areas of the country, a Hooka is a diving set-up that uses a long hose and an air supply on the boat/raft. Either a compressor or air tank is used to feed air to the diver.
Because the diver doesn't carry the tank, it is easier for him/her to stay down longer and get into those little holes the lobster like to hide in.
If you find a two stage regulator that will do the job, please post make and model.
Thanks,
Tim

[Big-Un]

You are correct in saying argon displaces oxygen. My fear is, since argon is heavier than air, it collects at the lower levels and therefore could accumulate if there is no ventilation. When working on construction sites, it has accumulated in small depressions and ditches and was deadly on one job I know of. The worker went into the ditch, beant over and immediately collapsed. His buddy jumped in to rescue him and was killed immediately also. I fear argon for that main reason. It could happen in a small shop that is not properly ventilated, and that tends to mess up a potentially fine day.