CO2/Air F.A.Q. Look here first

[ironpanther]

Ok so I have had alot of questions recently regarding air setups so here is my official "quit asking me I told you in a stickied thread" thread. ÂÂ*;D

First off for all paintball guns you have to have some source of compressed air for them to operate. ÂÂ*This is a list of types of air, pros and cons to each, and their applications.

CO2
AKA Carbon Dioxide
Stored in a liquid/gas equilibrium which at room temperature(76 degrees F) is roughly 800 psi. ÂÂ*CO2 requires alot of heat energy to vaporize due to it's boiling point being near 32 F. ÂÂ*This means that if you shoot CO2 you will have COLD liquid moving through your marker at some point and whatever marker you are shooting will not be able to chrono consistently due to the liquid having to boil off and severely fluctuating the input pressures to your gun. ÂÂ*This does hell on seals and temperature sensitive metals(brass). ÂÂ*Many mechanical guns can operate smoothly enough on CO2 and the cost is definitely cheaper in the short term. ÂÂ*One way of getting the most out of your CO2 and not having to worry soo much about liquid CO2 running through your gun is to get a Anti-siphon tube installed. ÂÂ*This effectively gives your CO2 tank a snorkel inside the tank that goes from the valve to the high point of your tank when it is screwed into your gun and held normally. ÂÂ*The tube makes it much harder for liquid CO2 to get into the valve and gun but does not completely prevent it. ÂÂ*Also a cheap and effective upgrade to any CO2 tank. ÂÂ*One thing to keep in mind when getting an anti siphon tube installed is that the tube will be bent to be pointing upwards when the tank is completely screwed into a certain ASA. ÂÂ*If you use the wrong ASA and the threads start in different places you may end up having a tube that only sucks up liquid CO2 and not only starves your gun but turns it into a popsicle with a trigger if you try and play with it at all.
CO2 comes in 8, 12, and 16 gram disposable one time use cartridges, 4 oz disposable cartridges and refillable tanks can be found in 1.8, 3, 4, 7, 9, 12, 14, 16, 20, and 24 oz sizes. ÂÂ*Reffillable tanks up to 12 oz only require a visual check for hydrostatic condition but above that volume the filler should check to make sure the tank is inside it's hydro testing certification period. ÂÂ*I will cover how to read a hydro stamp or label later in this thread. Per DOT regulations older tanks that use a Schrade type valve(similar to mountain bike tire valves, can be IDed by the small ball headed valve pin) can no longer be used and must have the valve replaced. ÂÂ*Also all refillable CO2 tanks must be equipped with an over pressure burst disk rated at 1800 or 3000 psi to prevent the actual tank from becoming a bomb due to overpressurizing (keep the tank out of direct heat when not in use). ÂÂ*The most common thing I found people do with CO2 tanks that blew their burst disk was they would get them filled in the morning, put them in a car, do errands all morning, and come back in the afternoon wondering why there tank was empty when they pulled it out of their hot car to play.
CO2 is not suggested for ANY gun that uses a solenoid to operate a pnuematic ram. ÂÂ*If you find you have one of these guns but can't afford a high pressure air tank ussually a field will have tanks to rent or you can bum one from a friend till you get your own. ÂÂ*DO NOT try and use the CO2 even if you have an anti siphon. ÂÂ*It will ussually cause leaks and void your warranty.

[ironpanther]

__________________________________________________ __

High Pressure AIR
AKA N2, HPA, Air

HPA is just as the name suggests normal air stored at high pressure. Seeing as the mixture of air we breath is both inert and has a very low boiling point(below -100 F even when pressurerized) the air in the tank does not require the heat CO2 does because it never has to boil off from a liquid. This results in the air being alot more stable and much less affected by atmospheric temperature changes. Also seeing as HPA is pressurized to 3000+ psi and seeing as no gun can use that kind of pressure all HPA tanks are regulated down thus providing a very consistent input pressure to your gun no matter how fast you fire. Due to this stability and abscence of liquid HPA is the best air source availbe right now for any gun and sometimes the only air source that will not void your warranty. HPA tanks are made of either steel or carbon fiber wrapped aluminum. Either way because of the potential for explosion DOT mandates that steel tanks must be hydrostaticly tested(hydroed) every five years and depending on the manufacture and max pressure of carbon fiber tanks they must be hydroed every three or five years. If a tnka is outside it's hydro date any perosn filling should not fillt hat tnak unless it has a new hydro stamp that indicates it has past a test recent enough to certify it is safe for fill. All Carbon fiber tanks no matter of they can pass hydro or not are required to be destroyed or recycled after 15 years of use. At this point hydrostatic testing cannot gaurantee three or five more years of use due to the possibility of sun damage to the resin and carbon used to wrap the tank and also possibly undetectable hairline cracks that may cause the wrapping to give way at any time.
HPA tanks come in two variations regardign regulation. Preset and adjustable. Preset tanks come in 850, 800, 450, 400 psi outputs and are reffered to as either high(850, 800) or low(450, 400) pressure output. Though certain guns are designed to operate best on low pressure output tanks(angel speed) for general purposes I recomend to anybody getting a tank that they just get a high pressure output because it is the most versatile. (continued on next post)

[ironpanther]

(erg! I had a whole post about adjustable tanks but I just lost it because it was too long and I didn't have it on my clipboard.)


HPA tanks come in 3000, 4500, and 5000 psi storage capacities. ÂÂ*This just signifies that that is the DOT's set limit for that kind of bottle and if you want the bottle to last you shouldn't fill beyond that pressure.
The size of an HPA tank is measured in cubic inches or liters deoending on which side of the pond your from. ÂÂ*Many times you will see a bottle stamp that says 88 cu 4500 psi / .9 L 304 BAR(I didn't actually check the conversion it's justa n example). ÂÂ*This is just so that those who are familiar with the metric measurements will be just as able to read the stamp as those of us who use the imperial system. ÂÂ*HPA tanks for paintball guns come in 45, 47, 48, 62, 70, 71, 72, 80, 88, 91, 112, 114 cubic inch volumes and the bottle style can be calssified as stubby, peanut, long, or regular. ÂÂ*Stubby bottles are a little wider than regular bottles but still resemble a regular bottle otherwise. ÂÂ*Peanut bottles are ussually wider than they are long or pretty much near spherical. ÂÂ*Long bottles are just that slimemr and longer, a relic of the days when woods ball tourney fields were an acre or more and playing tight meant not standing out in the open. ÂÂ*regular size bottles are any bottle that is the same width as a 68 cubic inch standard bottle and only varies in length.

__________________________________________________ __

Hydrostatic testing
AKA Hydro

Hydrostatic testing is the standardized tests that are used to determine if a bottle designed to store extreme pressures(100+psi) will be able to safely continue to be regularly used to store those pressures for a certain amount of time. the test involves measuring how much a bottle flexes by placing the bottle in a special tank, pressurizing it, and measuring how much water is displaced by the pressurized bottle relative to the same bottle, in the water, devoid of pressure. ÂÂ*For HPA and CO2 bottles used in paintball the hydro periods are anywhere from 3-5 years and if a bottle doesn't pass hydro and cannot be repaired it will be destroyed so it isn't a bomb waiting to be used. ÂÂ*All bottles that are designated as requiring regular hydro testing will have a stamp in the metal or label specificly stating the last month and yeat that the bottle passed hydro testing and most HPA bottlse will also have a note on the label that says if the hydro is every three or five years. ÂÂ*The hydro stamp can be located because it will always by to numbers separated by a symbol(ussually the manufacturer's or hydrotester's). ÂÂ*A hydro date reads month then year hydroed and can either be for example 3 ~ 02 or 03 ~ 2002 which both signify that it last passed hydro testing in march of 2002 and if it is a three year bottle will be up for hydro on the first of march in 2005. ÂÂ*NEVER FILL A BOTTLE OUT OF HYDRO!!! ÂÂ*Almost ever accident involving an exploded tank involved either a tamppered with burst disk or an out of hydro bottle. ÂÂ*Almost every case of exploding bottles has resulted in death and all at least resulting in lost limbs.

I have one last thing to add to this post that I posted a couple days ago and if you have any other questions AFTER reading this thread go ahead and post them in this thread.

[ironpanther]

(this was coppied from a earlier post asking about incomplete fills. IF you can wade through it and learn somethign from it then i can tell you right now college is easier. ;D ;) )

quick thermodynamics lesson. when you pressurize air it releases kinetic energy. That energy is now lost as heat for the most part and only a small amount can be captured and recycled. When the air expands it requires energy which is most abundant in the form of heat. When a tank especially as large as a scuba is being filled the air goes from pressurized to expanded and back in a very short amount of time. In that time it takes heat energy at the source of the pressureized air and releases heat energy in the tank that is being filled because the air has to be repressurized. Anyways the larger the tank the more energy released in the initial fill which is translated into heat energy that is then temporarilly stored in the walls of the tank. As the heat dissapates the pressureized air has less energy to maintain the pressure and thus decreases in pressure until it reaches an equilibrium. A slow fill allows the heat energy released to dissapate evenly and thus not heat up the walls of the tank and create an inacurate pressure reading due to excessive heat.

simplified: heat is created by molecules colliding together(friction) add more molecules = more collisions
each molecule has an equilibrium where is won't release anymore heat
thus the more molecules you pack into a small area quickly the more heat will be generated at the same time.
Heat excites molecules but cannot be stored at that level and wil dissipate after a while(thermal conductivity)(why steel tanks get hotter than carbon fiber tanks if filled to the same pressure at the same fill rate)
the more excited molecules are the more pressure they exert on each other.
therefore air molecules surrounded by heat will exert more pressure then the same amount of molecules at a lower temperature.(after a fill the tank has the same amount of air in it it is just at a lower state of excitement)

ok so that was a long thermodynamics lesson but if you made it through the whole thing and understand what I said your doing really good.

[NORCALBALLIN]

ironpanther=my hero!!!

Peace, Dean
Team Loki

[Got_Paint]

Hey great write up, good to see the record straight.

I remember talking to Glenn Palmer and he told me that CO2 cannot be a liquid under 550 PSI, so that would be a good thing to add once I confirm and make sure thats accurate.

[ironpanther]

550 sounds a little low but yes please if craig is reading this let us all know.

[gang_a_change]

make a matrix thread pplleeaasee

[ironpanther]

a matrix thread would be very huge from the start, I have been thinking about it for a while but find that www.matrixowner.com already has just about every matrix question answered and you can talk directly with dave from toxic, dave from dye, ethan from free flow, flops from tadoa and even lee of leertech the original designer of the matrix.

[Got_Paint]

550 PSI is needed to keep CO2 at a liquid state, so I was pretty close.

[IMAGINE_A_SPYDER04]

Hey ill just sorta ask my air question in here to keep things neat and not cluttered.

Ok for xmas i was thinkin of gettin air. But i know very very very little about air. I read this thread but doesnt rly make that much sense to me. I know air is more consistint ant thats about it. So i was wondering wat air setup is should get for my spyder imagine 2k4. Wat would i need to get and im lookin fora carbon fiber wrapped tank. And list the prices of different things. Try to keep it around 400 if at all possible. Under or a little over.


Thanks alot

[NORcal]

hey an air system is only like 100-150 bucks, and just get a high pressure tank. a 68/3000 will work perfect on any gun. u might be needing a reg for yur gun too. hope this helped.

[IMAGINE_A_SPYDER04]

ya i sorta figured i needed a high pressure tank but its the reg part that im lost on. Dont the tanks come with regs on them. Or would that not be enough. Thanks for the help guys

[ironpanther]

you know I had a huge post about the actual reg part of the tank but I lost it when posting this whole thing. Pretty much though it said that for best versatility and weight a carbon fiber, screw in 4500 psi tank is the best for your money. Yes the regs come on the tank and I would suggest a crossifre or ACI tank for a screw in. Otherwise I would suggest the MacDev tank if you want an adjustable tank.

[IMAGINE_A_SPYDER04]

So ur sayin the regs on a 4500 tanks would be enough reg for my gun. (imagine 2k4) And about how much does a 4500 CF crossfire or ACI tank go for.

Dont want my gun to break or anything so the regs on the tank would do fine cuz there arnt any on my gun.

[ironpanther]

the tanks can be bought in the range of 160 -250 used to new.

[IMAGINE_A_SPYDER04]

ok thanks

And the reg on the tank will be enough to reg the air cuz thats the only reg that will b on my gun.

And is the 4500 tank that much bigger than the 3000 tank. Heard that the 4500 tank is monsterous on the end of u gun compared to a 3000

[ironpanther]

I replied to your PM. whoever your friends are that are telling you some of this stuff need to shut up before they hurt themselves. They obviously don't know what they are talking about and your best choice would be ask these questions to a shop manager or here.

[NORcal]

Hey i'm just wondering, whats up with those gay stickers/hydro dates on co2 tanks? back when i shot co2 we didnt need one... do u HAVE to have one for it to be filled, or is only for certain tanks? How much do u have to pay/do to get one?

[ironpanther]

if a CO2 tank has a hydro sticker on it it must be airly new. All CO2 tanks have the hydro date or class of tank stamped into the metal near the collar at the top of the tank. If your tank doean't have a sticker don't worry about it as long as it is stamped some where on the bottle.

[Got_Paint]

Tanks under 2 inches in diameter are exempt from hydro.

This applies to 4, 3.5, and the old KP style 10 ouncers, as well as 13 and 22 ci HPA tanks.

[ironpanther]

remember though any CO2 tank with the old Schrade valve is no longer fillable per DOT regulations. The valve can not be the same kind of valves you see on a bicycle tire.

[shockerguy04]

Hey great thread, but i have a question that escaped lol. I was at this paintball proshop here in reno, who asked not to be named, and the guy working the counter had for sale a 48ci 3000psi PMI pure energy nitro tank. It had a 2009 hydro and a couple faint scratches, so i knew that it was new. He only wanted $20 for it. I said whats the catch, cuz they retail for like 90. He told me that the bottle had been dropped, and the ASA got dented, so it wont thread into a gun. I bought it cuz i figured i could get a new one for like 40, and it would make a great backup tank for my woodsballing. The thing that im wondering is can i just replace the part with the pin valve that threads into the gun, or do i have to replace the whole thing with the fill nipple and gauge on it too? I know i have to have it changed by a pro, but the guy said that if i got a new ASA, the shop has a torque machine that is certified for putting them on. Also, regardless of which part i have to get, do u have an idea where i could get one?

[ironpanther]

yes please don't name the shop. they have no idea what they are talking about. You can replace the threaded piece alone and all you need to do is contact pmi and get the replacement piece from them. It is a simple screw on piece but I would still suggest having the change done by an airsmith.

[shockerguy04]

hey thanx a ton man. i just figured for 20 bucks it was worth buying and seeing if i couldnt change the top piece, cuz i could always use it as a window brick if nothing else lol. jk.

[Got_Paint]

By "Schrade valve" do you mean old thermo valves from the early 90's comonly known as cali air?

[ironpanther]

I believe your thinking of the valves used on the first CA tanks which were actually manual on off turn valves. No I am not talkign abotu those. I am talking about the valve that is standard on the kind of bike tube you can buy at wallmart. The pin is about 1/32 of an inch in diameter with a ball head and the whole valve assemble is about half an inch long and is threaded into the rest of the assembly. About two years ago DOT said that you could no longer fill these types of valves beyond 60 PSI when it came to liquid/gas bottles.

[Got_Paint]

Ok now I remember those.


Yes thermo's are the manual turn off one's in the early 90's.

[IMAGINE_A_SPYDER04]

Sorry to bug u again about the air questions ive been having.
But i was just lookin around and on 1 of the ACI tanks it said

ACI Bulldog 4500 tank with 800psi preset regulator in both 45ci and 68 ci.

So is preset at 800psi good for a 2k4 imagine or preset is no good. And does the shot count per tank differ from a 45ci to 68ci and so on?

[ironpanther]

good and yes volume(ci:cubic inches) of the tank affects overall shots per fill.

[Got_Paint]

The general rule of thumb is

10 shots per CI at 3000 psi
15 shots per CI at 4500 psi

so....

45 CI at 4500=675 shots
68 CI at 4500=1020 shots

Remember though this number will change depending on the gun and how it is setup.

[ironpanther]

dude I dont' know where you came up with that rule but its a little too general. if you look at the volumes your shot count off a 45 cubic inch tank will be roughly 60 percent of the number of shots you will get off of a 68 cubic inch tnak.

[Got_Paint]

Well a 45 is almost exactly 2/3 the volume of a 68, so you would get that number.

Yes the rule is general, but I just use it as a rough shot expectancy.

[IMAGINE_A_SPYDER04]

so how many shots would i about get out of a 45/4500 with my 2k4 imagine stock. Cuz i may need to go for the 68 just for shot count and play it safe and not run out in the middle of a game

[ironpanther]

your goign to have to borrow somebody else's tank and see how many shots you get off of it to really know. each gun is different in its efficiency.

[impulseDUDE]

wat should i get for my impulse a 68/3000 or 45/4500 wat well get the most shots...and high pressure tank or low pressure tank?

[Got_Paint]

I did some math, and they will yield the same amount of shots.

[impulseDUDE]

and how much is that?

[Got_Paint]

It's hard to say every gun is different, but they have the same amount of air in each tank. It's how air effecient your marker is.

I'd say somewhere between 500-700 shots

[impulseDUDE]

o my marker is an impuse....

[Pvilleplayer]

we already chatted by 68/4500.

go to the pro shop at nfinite, andy hooked my gun up, i love it now.

[Alden]

a good addon to this thread would be tanks and their recharge rates.

[lic2q]

i read earlier that a broken/dented thread can be replace and an airsmith is recommended to replace the thread. how about the fill nipple? will that be done at a paintball shop or an air smith? thanks

[ironpanther]

Alden though it would be a good add on the sad part s that manufacturers are deceptive about their recharge rates and the only people who know them for real are the people who engineered the reg and then flow tested it. A simple guideline to tanks is this. Crossfire is the best. PMI, Empire, WDP all use the same screw in reg on their bottles so your paying for brand name. ACI makes great regs and bottles but the stainless steel reg makes it very heavy these days. WGP and Empire use the same adjustable reg. Evil scions are Armageddon regs. Dye makes their regs in house and the quality is getting better but price is prohibitive. Maxflows are manufactured by SP but are poorly designed and fail too easily to be a top reg with the selction you have these days.

[ironpanther]

Snotshooter your gauge is faulty woudl be my first guess. Also if you are running that much pressure right to your valve of course you are going to have a hard time gettting much air because your hammer will be hard pressed to hold the valve open.
Break in is a real thing. Springs need to be flexed a few thousand times before they become really consistent. Orings need to wear just little before they become uniform all the way around in the seal seat. And reg seats need to be comrpessed ALOT before they stop compressing a little more and just seal. SO yes break in is true but no your tank should put out 850 +- 15psi if it is an 850 psi output tank. The easy way to test this is get something like a remote line on off and a Good quality(none of these little mini gauges I'm talking snap on, mac tools, or a gauge manufacturer's 0-1200 psi gauges) and screw the gauge in place of the hose. Now screw in your bottle and slowly turn on the on off valve till the bottle valve starts to open(I say slowly because going fast will slam the gauge which is exactly what kills the mini gauges). Once the valve is open and assuming you don't have air leaking all over the place you should be able to get an accurate reading of the tank reg output on the gauge.

[ironpanther]

Lic2q fill nipples are easy to do and a trained airsmith should be able to do it in about five minutes as long as he as a replacement nipple. As far as the threads on the tank are concerned there are two things. IF the threads holding your reg into your bottle have been damaged the whole thing is trash. DO not use it because the strength of the threads has been compromised and a hydrostatic test will not show a weak spot in the threads. If the threads that screw your reg into your ASA has been damaged you ave two options. IF the damage is minimal it is possible with the right dye a trained airsmith/machinist can recut the threads. For safety reasons though I would suggest just replacing the regulator. I know ACI offers their tank regs without bottles for around eighty bucks and if you called aroudn you might find a manufacturer willing to tade your damaged reg for a fixed one at a lower price. This gaurantees that the regulator threads are within manufacturer's specifications and may include a limited warranty.

[lic2q]

thanks for the info. my tank won't fill that's why i think the fill nipple is broken. actually it does fill but at a extremely slow rate. the lady over at sport chalet checked it and told me it seems as if there is some sort of restriction/obstruction the prevented a quick fill. the fill nipple was taken out and and found nothing would obstruct the pin size air hole. any suggestions? replace the whole fill nipple, just the internal, or just the fill nipple o-ring?

[ironpanther]

pin size air hole? that is your restriction right there. There is ussually a 3/16th inch or so hole that has a plunger with an oring. The plunger goes down and opens the hole when pressure is aplied to it from the fill side and goes u and seals when the fills side pressure is relieved. A pin sized hole doesn't sound like a fill nipple.

[lic2q]

sorry for not being clear. the pin size hole is on the reg. the fill nipple is not restricted as we took it out, clean it, the plunger, and the o-ring. the o-ring was then lube with n2 crease and the reg looks fine. the tank just won't fill. ??? thanks

[ironpanther]

Oh man you royal screwed up now. NEVER GREASE OR OIL THE FILL ORING! USE NO OIL! The common misconception that you should oil or grease your fill nipple oring if it is leaking is not only wrong but dangerous. I am seriously not kidding. When you compress air it heats up. Common knowledge. When you increase the pressure around flammable material it's spontanious combustion temperature goes down. Atomization is used with flamable liquids so they will burn faster. So you have just made a aerosol oil/grease sprayer out of your fill nipple and are spraying into a extremely high pressure and heated container. Starting to get the picture. Let me spell it out for you. B O M B! Please if you have a leak in your fill nipple replace the oring or the whole unit.
A pin sized hole on the reg could be over pressure vent or maybe you are looking at the vent on a blown burst disc.

[lic2q]

thanks for the lesson and a lesson learned.
i will either replace the o-ring and throughly clean the fill nipple or replace the fill nipple completely. thanks.
i don't know what to do without this great site. sacpaintball.com is the best.

[xCHiLLX]

good accurate information. thanks for the help.

[dini8]

very insigghtfull and educational you answered all my questions

[stupiddogg]

Adding a great post from the internet on DOT CODES, Hydro info etc


As it comes up every so often and was stickied on MCB I figured I would repost the info over here.

HPA tanks

There are blanket rules, and exceptions for the the blanket rules. First, the blanket rules.
1 - All fiber-wrapped tanks are to be hydrotested every 3 years, unless the manufacturer specifically indicates ON THE BOTTLE that hydrotesting is due at 5 years. All fiber-wrapped tanks have a maximum lifespan of 15 years, no exceptions.
2 - All steel and aluminum HPA tanks are to be tested every 5 years, with an unlimited lifespan. The only exception to this rule is for steel tanks stamped 3HT, which must be tested every 3 years and have a 24 year lifespan.

CO2 tanks

Again, first the blanket rule.
1 - All CO2 tanks (including those manufactured from chrome-moly alloy) must be hydrotested every 5 years, with unlimited lifespan. The only exception is for tanks under 2 inches in diameter and less than 2 feet in length, these are exempt from testing. NOTE - Chrome-Moly tanks are NOT exempt from testing!! There is a wide belief in the paintball industry that they are exempt, they are not, unless they fall under the 2 inch diameter rule. The 2 inch/2 foot rule will apply mostly to 9-ounce tanks.

Exceptions

There are some "E" codes stamped on some fiber-wrapped HPA bottles. Many people believe that if their bottle is stamped with an "E" code it means they are exempt from testing, this is not true. It means that bottle falls under an exemption from the blanket rule in some specification, but that exemption may or may not address the hydrotest date. Here are the only listed "E" codes for fiber-wrapped tanks on the DOT site, and how they will affect your bottle.

E-07277 - manufacterer SCI, to be tested every 3 years, 15 year service life. This exemption deals with the manufacturing process, not the hydrotest schedule.

E-09634 - manufacturer Luxfer, to be tested every 3 years, 15 year service life. This exemption deals with the manufacturing process, not the hydrotest schedule.

E-10915 - manufacturer Luxfer, may be changed to 5-year schedule, this will be explained below.

E-10945, manufacturer SCI, may be changed to 5-year schedulue, as explained below

E-11005, manufacturer Careton Tech, to be tested every 3 years, 15 year service life. This exemption deals with the manufacturing process, not the hydrotest schedule.

E-11194, manufacturer Careton Tech, may be changed to 5 year schedule, as explained below

E-12479, manufacturer Luxfer, to be tested every 3 years, 15 year service life. This exemption deals with the manufacturing process, not the hydrotest schedule.

On some Scott CO2 bottles E-8096: exempts these bottles from ever needing to be tested, for their service life of 15 years. These are for 16 ounce chrome-moly tanks, the exemption will expire on October 31, 2005. After that date, if the exemption is not renewed by the manufacturer, they will have to be hydroed.


5-year test schedule exemption explained - All these bottles still have a maximum service life of 15 years from original manufacture. These bottles were originally manufactured under a 3-year retest schedule, but the manufacturer was allowed by the DOT to move them to a 5-year retest schedule, provided they have been tested/manufactured after a certain date, as applied below.

For exemption code E-10915, if the last test date was before May 11, 2001 then your bottle is still on the 3-year cycle and must be tested every 3 years. If it shows a test date after May 11, 2001 then your bottle is now on a 5-year test schedule.

For exemption codes E-10945 and E-11194, your bottle is on a 3-year test schedule if the last test occurred before July 1, 2001. If your bottle has been tested after that date, you are now on a 5-year test schedule.

[/end Thread theft mode]

Also at the bottum of the same thread there was a amindum about a set of fualty tanks so I snaged that too.

It reads......

http://hazmat.dot.gov/regs/notices/sa/70fr-47273.htm

High pressure DOT exemption cylinders made and/or distributed
by Global Composites International, Inc. (GCI), Ontario, CA

PHMSA and the OIG have evidence that suggests GCI manufactured, marked, certified, and sold an undetermined number of high-pressure DOT exemption carbon fiber filament cylinders when the cylinders had not been manufactured in accordance with the Hazardous Materials Regulations (HMR), DOT-E 12695

DOT recommends that any person possessing a cylinder manufactured by Global Composites International, Inc. (GCI) and marked with exemption number DOT-E 12695 take the cylinder to a qualified refilling station and have the pressure relieved from the cylinder. The cylinder is no longer authorized for use. Refilling stations and cylinder requalification facilities are advised that DOT-E 12695 has been suspended and these cylinders may not be refilled or requalified for service.
_________________

This part was a follow up post to my post (above) on the MCB thread.

NOTE:

For the 2x2 rule to take effect, the tank ALSO NEEDS a special DOT exemption.

These exemptions did not start until around 1990, so usually, 7oz tanks before 1990 are NOT exempt, but tanks AFTER 1990 are.

The code for catalina is DOT-E7737
Not sure about other brands.


Hope this helps everyone!