Tutorial: Scuba Power for Lindsay Airgraver

[brandvik]

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 ½ inch pneumatic quick connect nipple (female)
4. One ½ inch pneumatic quick connect receiver (female)
5. One ½ 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.

[KurtB]

Excellent writeup, Jim, thank you for sharing with us. It really is amazing just how much air a scuba tank holds, and given the low air consumption of Steve's tools, this is a really viable way of foregoing a compressor, and creating some portability to boot.

Do you know offhand what the female thread is on the scuba first stage? On my own system there are multiple female thread ports, some high pressure, some low, and IIRC the industry standardized these threads some time ago, so you can swap mouthpieces + hoses, buoyancy compensating devices, and other air powered goodies, between systems. I'll take a look and see.

Neat setup!

[brandvik]

Originally Posted by KurtB

Do you know offhand what the female thread is on the scuba first stage? On my own system there are multiple female thread ports, some high pressure, some low,

Kurt, no I don't but the only port which is different (which is a larger diameter the others) is the high pressure port which is used for the pressure gauge. This port will probably almost certainly be marked with "HP" to indicate High Pressure (actual tank pressure). This is the whole reason the ports are sized different - to prevent someone from accidentaly running high pressure to a second stage or to a BCD. All the other ports expel what the dive industry refers to as "intermediate pressure" which is the 150 to 200 psi mentioned. Then the diver's second stage regulator delivers his air at whatever the ambient pressure is for the given depth. In our case the second stage is the engraver's adjustable regulator.

[Danny C]

What is an educated guess at the cost of this setup? That is for us that don't have anything at all and have to go buy 100%?

[brandvik]

Danny, I just went to Leasure Pro to check prices since I have been out of the business for almost a decade now. I used to hate these guys when I was competing with them. They are about the cheapest around. I found the following were the cheapest they had. I shopped their site as if I were going to be buying for myself from scatch.

Here's what I came up with.
80 CF tank. $149.95
The larger tanks like mine are expensive and as heavy as the dickens. I wouldn't go any smaller than 80 since most dive shops charge the same to fill a tank no matter its size.

Regulator $124.95 This one comes with the second stage regulator as which you will remove. (Just need a cresent wrench.) and replace with the quick connect hose.

Quick connect hose $19.95

Quick connect nipple $19.95 I would check your local dive shop for this as this sounds high to me.

I would check with your local dive shop regardless as they may have old stuff in their rental fleet that they would sell cheap. Plus you will need to make contact with them anyway since they will be the folks who will fill your tank(s).

The only cost I had for my setup was about $6 for the pneumatic quick connectors (Home Depot) and the hose clamps $2.00 (Napa Autoparts).

So the grand total if you were to buy everything brand new would be. $323.80.

Hope this helps. just let me know if anything is unclear.

[Danny C]

Thanks for the detail breakdown. That's about the same as a decent compressor and 1/3 the cost of a silentair. It would be a lot easier to fill than a full size Oxy tank (or equivalent) filled with nitrogen (that sucker should last about a month! Plus you have to have a place to put it.)

[Steve Lindsay]

Jim, Thank you so much for posting this info! Steve

[mckeenh]

Excellent info guys. I think this would be ideal for a show as there would be no noise to deal with. I also saw the tank mounted on a small hand truck in another post which would make it super simple to take any size tank to a show.

Neil

[airamp]

HI,

A Scuba tank is a very nice setup.

I am setting up a welding tank 80cf or 120cf tank. It is filled with compressed air or Nitrogen (your choice).
(DO NOT FILL TANKS WITH OXYGEN BIG BANG FACTOR).

I use one of these filled with compressed air for a breathing system when working with epoxy construction (airplane).

Note: To Filling scuba tanks at a dive shop you have to be certified to dive or they will not fill them up.
Scuba fills have moisture in the air so you do not dry out, can really mess up tools but better than compressors without a dryer system. (you still need a trap in the line). (round bottoms)

Welding tanks for a breathing system (compressed air) no problem if you tell them you need it for a compressed air system or what you are doing. (flat bottoms)

Nitrogen is no problem at all and no questions BEST CHOICE (for your health compared to CO2 and filling ease) since it in the highest percentage of the air on earth.

(you do not change the air around you when working, can make your lines go off)

Air Composition


The sea-level composition of air (in percent by volume at the temperature of 15°C and the pressure of 101325 Pa) is given below.


Name Symbol Percent by Volume
Nitrogen N2 78.084 %

Oxygen O2 20.9476 %

Argon Ar 0.934 %

Carbon Dioxide CO2 0.0314 %

Neon Ne 0.001818 %

Methane CH4 0.0002 %

Helium He 0.000524 %

Krypton Kr 0.000114 %

Hydrogen H2 0.00005 %

Xenon Xe 0.0000087 %




Note:The gas from a welding shop is MUCH DRYER than the scuba tanks filled at a dive shop so no trap and better for tools.

I have a welding regulator on it (they are 2 stage) to get the pressure to whatever you need for the airgraver manifold. (welding Oxygen regulator works great).

Gas has different fittings but these regulator fitting's can be changed.

The difference is cost. You can find tanks (40-240cu ft) at the welding supply house used for moderate prices or go on your local craigs list and pick them up for 50-100. and regulators (oxygen) (if you don't have spare welding equiptment).

All standard welding fittings.

Here is the link for the greatest buy sell link you will ever need and it is local in your area. Listing is free, yes free and they call and pick up the stuff you have for sale local.... You can get anything also CHEAP including scuba gear.

http://geo.craigslist.org/iso/us

YOU WILL BE AMAZED... WHAT YOU WILL FIND..

Remember to chain your tanks to a bench or wall. even small co2 tanks have 600 psi and the big boys (scuba and welding are at 2800psi) yes they do go though walls, cars, or anything that gets in there way if you hit the valve VERY HARD (very rare). Welding tanks have screw on steel caps to protect the valve use them when transporting tanks.

regards,
Dr. Mike

[Sam]

Airamp, you have it backwards about the moisture in scuba air. Moisture is removed from scuba air for a couple of reasons. The main reason is because when a normal air compressor is in use the high pressure air coming out the end has a oil and water mixed in. It doesn't become breathing air until it goes through the filtering system which removes the oil/water. A oil and water mixture doesn't work too well in your lungs. Too much oil/water can also make your regulators freeze up in cold water and corrode your tanks. if your getting that much moisture the dive store isn't changing his filters on a regular basis. the only dive shops that wouldn't remove a large amount of moisture would be one the runs a rix oilless compressor in a warmer climate.

[airamp]

Hi Sam,

I think you misunderstand. I did not say there was gobbs of oil and water in scuba air. It is filled with a special compressor and yes it is filtered. It is a good product and yes it does have trace amounts of moisture and oil and the quality can vary as you stated.

It is a safe product for the use, never said it wasn't.

I do know the equipment dive shops use, but it does not compare to the Major gas supply houses (welding supply companies) make available.

Welding gas supply houses distribute these gasses for the major producers like Airgas co.

The fill costs much less, is more convenient (no restrictions) and is highest quality compressed gases you can get breathable or not.

Also the tanks are easily exchanged for the cost of the fill. Even though you own the tank they are so common that they just exchange them. Almost like the propane tanks for you grill.

Not so with scuba tanks.

Tanks stay current (no hydro testing of expired tanks since you are getting a good tested tank at each exchange).

Shops will even exchange out of date tanks for a slight or no fee over the fill price.

They want your business and you still get a fully tested current tank no wait time.

Not so with scuba tanks.

If a scuba tank is needs hydro testing you will pay for the testing on your tank and if it fails you they cut it in half..(no exchanges). The testing can take days if not longer.

In other words welding tanks are the best investment and nitrogen is the best gas to use.

You can buy a tank from craigs list (big ones up to 240cf (largest a normal business can own by law) and exchange it for a 120 or 80 (maybe 2 60cf) full.

Welding companys need these tanks and are always willing to deal with you to make you happy and get your business.

Order of impritys from most to least in the compressed gases is:

Compressors, compressors with drying systems, scuba, welding gases including compressed air, and nitrogen and medical gases.


Scuba very good set up.

It is just more practical and cost efficent to use welding tank set up in my opinion. Preferable with nitrogen (most common gas).


ps: co2 is liquid in the tank and tanks are filled as such.
It is endothermic (uses heat to change to gas) if too much is drawn out of the tank makes for very cold gas.

It can freeze up a tool.

CO2 will not be a problem with the airgraver since it does not use large enough volumes of air (co2) to get cold or freeze.

I wouldn't use co2 with other units power gravers that use much more air pressure and volume.


I still like welding tanks and nitrogen as a quiet safe source.

Dr.Mike

[Gail]

So, Airamp, you are saying that I could use a Nitrogen tank the same as I would use a CO2 tank? Are there any cost/other differences?
Thanks,
gailm

[airamp]

Hi Gail,

Yes you could use Nitrogen (80% of composition of out air) check out the other posts of air composition.

Tanks are cheaper and exchangable at a welding shop, current hydro testes so no added costs for testing a outdated tank. You can get any used tank bring it to a welding shop and they will exchange it for the tank you want with the gas you want. (try for a green or oxygen tank or a gray nitrogen or argon or argon/co2 mix tank common for gas, tig or mig welding) (NO Acetylene tanks)

Used tanks are easy to get (local craig's listed link posted).

No specal fitting. A welding regulator (oxygen) will work just fine also easy to get used. uses 1/4 inch or 3/8 standard brass fittings. (all are 2 stage 2800 to adjustable usable pressures).

The tanks have flat bottoms and steel valve protectors for transport for to and fro to the welding shop.

Down side they are steel and a bit heavy.

Mike

[Sam]

airamp, sorry about the confusion. I see what you are talking about. One other thing for your argument. Welding supply stores are everywhere. Dive stores usually aren't, especially if you live in a rural area.

[airamp]

Hi Sam,

Yes they are and there are alot of used tanks all over your local area.

Did anybody check out the link to craig's list?

Mike

[SVD]

If anyone doubts you on what a tank can do they need to go to the Discovery Channel's website and check out the Mythbuster's episode where they tested it. Full size tank with the valve knocked off went through a cinder block wall like it was tissue paper.

And those of you working in basements should take his advice on N2 vs. CO2 - stuff'll build up on you if you're working in a 'pit'.

[airamp]

Hi SVD,

Yes that is correct. N2 will not hert you at all. Co2 confined will give you hypoxia.

Can you post how you are putting up thumbnails?

airamp

[SVD]

Click the 'Go Advanced' button, then on that page hit one that says "Manage Attachments" - that lets you upload the image to the forum (and shows the thumbnail).

[airamp]

Hi,

Thanks for the help. I have been trying to figure that out.

Will give it a try and maybe even start a thread.

regards,
Mike

[PS_Bond]

Originally Posted by airamp

N2 will not hert you at all. Co2 confined will give you hypoxia.

Both are hypoxic - neither of them will support life. Both require adequate ventilation...

I'm not entirely convinced by the claim that welding gases are less contaminated than the air (or nitrox, or O2) in my dive cylinders; it's commonly accepted in the UK at least that welding O2 isn't a good solution.

However, very little of that has anything to do with running an airgraver off it, and all the theory is good

I would steer well clear of using O2 on it however - pure O2 is very, very dangerous if you don't know what you're doing with it; the stuff will support combustion in the strangest ways. Drop wire wool into O2 and it'll go up without any obvious ignition source.

[airamp]

Hi Ps bond,

Yes

NO O2 to Run any tools.

The reference is for the TANK only.

As explained in earlier posts you do not want to run anything on O2.

The tank is what you want so you can exchange it for a N2 or co2 if you like.

Go to your local welding or gas supply house and ask of the purity of the gas than compare it to your diving shops prity. I think you will then see the difference.

N2 is 80% of our atmosphare. It is not toxic at all. adding a little at your work space will not bother you or hert you at all.

co2 is only 0.0314 % adding a little to your close quarters work space will have a effect is the point.

regards,
Mike

[SVD]

The advantage of N2 over CO2 is that CO2 is heavy and will pool. Open a CO2 cylinder in a basement and you can get the air to unhealthy levels pretty easily.

N2 isn't going to keep you alive either, but since air is 70% N2 it won't collect in the low spots. If you have no ventilation then you can probably hurt yourself releasing it into the room but I think the CO2 levels (from you breathing) will get to you first. Most people that suffocate in an enclosed space die from CO2 buildup before the O2 levels can drop low enough to kill them.

On a semi-related note I'm going to start another thread on picture posting showing two ways to do the thumbnail thing.

[airamp]

Steve,

Yes thanks for the added explanation.

The thumbnail thing thread is a good idea.

Saves HD space and looks real nice.

Mike

[SVD]

Just posted the new thread. Check it out and see if it works for you.

BTW, I generate my web-sized images (and thumbnails) with a utility called 'PhotoCleaner' - http://www.photocleaner.com

Nice little bit of shareware.

[PS_Bond]

I'm not sure if this should be tagged onto this thread, or one of the CO2 threads...

Over this side of the pond, I've been having a lot of trouble finding a paintball site willing & able to fill 20Oz CO2 cylinders. Part of this is down to (hopefully) unfounded liability worries, the other part is that a lot of paintballers seem to have switched to high pressure air. With a bit of digging, it turns out that the HPA cylinders are 232 bar rated cylinders with a single stage fixed regulator on the end, allowing them to act as a direct replacement for a 20Oz CO2 bottle. Refilling is done from dive cylinders or banks (although I suppose you could use a stirrup pump...!).

So... One 2nd hand paintball HPA cylinder and one charging station (from EBay) and I have both portability and easy recharge, so I won't need to lug my compressor around.

The other option I looked at was renting a CO2 cylinder & decanting from that - for the amount of time I need the portability, it really wasn't viable.

[PS_Bond]

Oh - and while mooching around, I found an adaptor for Sodastream cylinders (to 20Oz) too: http://www.palmer-pursuit.com/cart/i...roducts_id=909

Pity shipping here is twice the cost of the adaptor...

[SVD]

What you need now is a second 2nd hand HPA paintball cylinder - that way you can have your backup cylinder ready to go - especially usefull for trips where you might not be able to get the one you have now recharged right away.

[CJ Allan]

Lots of good info here.......
and very useful, as I'm about to put together a tour, and my daughter just got certified as a scuba diver........
I can use her tank(s) ..........

[SVD]

This thread had me asking about HPA at the paintball shop but it wound up being cheaper (for me) to stick with CO2.

But if you already have scuba tanks around...

[Sam]

Brandvik, i didn't notice it before..nice tanks. those scuba pro 95's are great. I still have a bunch of them in the garage, not sure if i could lug a set of doubles around anymore though. Is that a scubapro MKII reg? Thats what i am using on mine. I had them set up to use with my drysuit/ argon setup..

[Omar Haltam]

Great Post Jim Thanks
i am a scuba Diver as well and this was a very interesting post to read. I am considering a setup at a small Kiosk in the Mall and i think this would do the trick.

Thanks again, Omar

[HARDTIMES MC]

Look like lp 95's and a bail out bottle, ypu must not live in Fl! i have some out of hydro 80's that i could rig up... my steel tanks get used weekly, as i'm always underwater grocery shopping!cheers!