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Old 03-18-2007, 01:21 PM
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brandvik brandvik is offline
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Join Date: Dec 2006
Location: Texas, USA
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Default Tutorial: Scuba Power for Lindsay Airgraver

Steve asked me to put up this “how to” for anyone who would like to power their Lindsay Airgraver by a scuba tank. I use this power supply because I live in the sticks, off the power grid. I have a good solar power system, but try not to tap into it too deeply. Running an air compressor to engrave is just not a viable option for me. So until Steve builds a solar powered Airgraver…

On the grid or off, there are several reasons you may want to add this mode of power as an additional option.

1. It can be a highly portable system.
2. No power is required which is great if you travel to shows or if your power goes out for an extended time.
3. A standard scuba tank is 80 cubic feet which will run your Airgraver for a long time. It only costs about $5 to fill a scuba tank.
4. It is very easy and inexpensive to accomplish.

Here is a photo of my system. This system has two 100 cubic foot tanks which will keep me engraving for several weeks at a time. It would work the same regardless of the size of the scuba tank you choose to employ.



Basically all you need is;
1. 1 scuba tank
2. 1 diver’s 1st stage regulator
3. A little plumbing

This system should work with any Lindsay Airgraver whether you have the foot pedal or the palm control.

As you can see, I have rigged this system up to my standard Lindsay air regulator.

The plumbing components are shown below all together laid out in the order they go. Sorry for the poor photo, but the detail photos are better.

1. Two hose clamps (shown only in detail photo)
2. One barbed fitting from the end of the hose which ships with the Airgraver.
3. One ˝ inch pneumatic quick connect nipple (female)
4. One ˝ inch pneumatic quick connect receiver (female)
5. One ˝ inch scuba quick connect nipple (male)
This is a quick connect adapter for scuba. It fits into a It is a very common accessory in diving and any dive shop should have them. Divers screw these into an air chuck so they can use their scuba tank to fill a flat tire or whatever else one uses an air chuck for.
6. One quick connect scuba BCD hose.
This is another item every dive shop should have. It is the hose which goes from the regulator 1st stage regulator to the diver’s buoyancy control jacket.
7. One scuba 1st stage regulator.
Most dive shops have a bone yard with several of these. There are two types; piston and diaphragm. Either will work fine. I have tested both types to be sure. These regulators reduce the tank pressure down to a usable pressure of 150 to 200 psi.







Please note that the 150 to 200 psi coming off the 1st stage regulator is considerably higher pressure than your compressor is probably pushing. I have tried two types of 1st stages. One was pushing 180 psi and the other was pushing 200 psi. Both worked fine, but I did have to install hose clamps at both ends of the small hose feeding the Airgraver regulator because the hose popped off the barbed fittings after a while.

Most scuba tanks are designed for a working pressure of 3,000 psi but some are rated at 2,400 psi. For this application though, the important measure of a tank is its cubic foot storage capacity. 80 cubic foot is the most common but there are pony bottles like the black one in the photo below which are as small as 20 cubic foot. (one of these “pony” bottles is just visible in the first photo. It is the smaller black tank)

A 20oz (51 cubic inch) paintball CO2 bottle will last me about 6 hours at the bench, so my 200 cubic foot scuba system should give me 280 hours of bench time. That 280 hours of engraving for $10 worth of air.

Safety Note: 3,000 psi is a lot of kinetic energy, so handle these tanks with care. Never expose them to too much heat (above 130f). They should have a burst disk on the valve which is rated at five thirds the working pressure. So if you did forget and leave a full tank in the truck of your black car in August it won’t blow the lid off, but it will make an awful loud noise when the burst disk blows.

Store these tanks where they are unlikely to get knocked over or beat up. I once saw a high pressure cylinder go right through a wall when it got knocked over hard enough to break the valve neck.

I am searching for the proper high pressure adapters to rig the CO2 regulator for scuba power which will improve the portability of the system. I will post that in the future when I find the right adapter.

Until then, I am using this device to fill my little CO2 bottles from my scuba tank. (Much Cheaper!) http://www.scubamart.com/detail.aspx?ID=338
Safety Note: If you choose to do this also, make sure you monitor the pressure gauge on the fill adapter carefully. Most paintball tank have a working pressure of only 1800 psi.

BTW this "engraving bench" is actually on my front porch. I'm a building a shop but am a ways off from finishing it. The weather is great right now so its nice being outside anyway.

I hope some of you find this useful. Comments and questions are welcome.
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Jim B.
http://www.horseshoeengraver.com
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