Economical PCP fill tank

[cpt_sfc]

?? please , I called the US wt/measure  office and the NAFTA book people # are on the internet and you can get them from your fed, rep's office. From both office's The us standard is 15 years on HPA tanks, Same tanks in the EU are 30 years. , they could not say why. They have only had one documented fail at a fire dept. when a firefighter left his tank setting in paint solvent for 4 days in back of PU solvent spilled. Carbon fiber tank., then filled it to 4500 and put it in the truck. During that week it failed.  I do not know what would cause a modern tank fail if made of steel or alum. Any thoughts!!!

[ztirffritz]

This was my solution:
http://www.airgunnation.com/topic/ebay-air-tank-project-is-complete/

Tank: http://www.ebay.com/itm/371107005440?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
     Last time I checked there were still 280+ tanks available for purchase.
Gauge:
Hose:
Fittings: http://airhog.com/A13_Quick_Connect.html
HiydroTest (by mail if you can find nothing local): http://www.hydrotester.com/index.htm
Mesh Wrap: http://www.mcmaster.com/#4764t6/=y72mdm
Handle/Strap:

Total Cost: $393 for a 65.5cf tank with 7 years remaining on it.  In 7 years buy another used tank for about $100 and get another 5-10 years out of it.  Leave the mesh and straps out of the list above and save about $35.  Find a cheaper hydrotest option and save another $30.

I will say, if you have the money, I recommend buying a complete package from Joe or AirHog as you'll get all new, and tried and true components.  My setup works and I trust it, but I'm the only data point.  Joe has many many more years of experience in this field than just about any of us.  AirHog too has a wealth of knowledge to draw from.

[Case Stuffer]

?? please , I called the US wt/measure  office and the NAFTA book people # are on the internet and you can get them from your fed, rep's office. From both office's The us standard is 15 years on HPA tanks, Same tanks in the EU are 30 years. , they could not say why. They have only had one documented fail at a fire dept. when a firefighter left his tank setting in paint solvent for 4 days in back of PU solvent spilled. Carbon fiber tank., then filled it to 4500 and put it in the truck. During that week it failed.  I do not know what would cause a modern tank fail if made of steel or alum. Any thoughts!!!

FYI CF tanks are in fact made from alum. and then they are wrapped in cf.. This enables the use of thinner alum. and the cf wrap provides additional strength.


Snip from an offical testing / investion

The other major category of visual inspection failures consists
of those induced by hydrostatic testing—including cylinder stem thread galling due to improper
removal and reinstallation of the cylinder valve fitting, and to interior cylinder surface contamination
or corrosion caused by improper drying of the cylinders after hydrostatic testing.

Full report

http://www.phmsa.dot.gov/pv_obj_cache/pv_obj_id_DD40218680269DDB4602688C3BFA523D45C70900/filename/FINAL-Report-SCBA_Cylinder_Life_Extension_Study_09202012.pdf

SCBA Cylinder Life-Extension Study, Final Report (A ugust 2012) The  U.S.  Department  of  Transportation  (DOT)  in  the Code  of  Federal  Regulation  (CFR)  49, Section  180.205  mandates  maintenance  requirements  f or  SCBA  cylinders.  Glass  fiber-reinforced plastic   (GFRP)   and   carbon   fiber-reinforced   plastic (CFRP)   SCBA   cylinder   maintenance requirements  were  established  in  the  early  1990s  ba sed  on  cylinder  manufacturer  input.  At  that time,  there  was  extensive  experience  with  aluminum- alloy  tanks  but  very  little  knowledge  of  the long-term durability and strength characteristics o f fiberglass or carbon fiber. A lower limit on the service life of composite-wrapped cylinders was est ablished at 15 years based on limited studies on the  durability  of  fiberglass  observed  in  testing  fo r  NASA  aerospace  applications.  The  15-year cylinder  life  is  also  linked  to  cylinder  cycle  test ing  (fill-and-empty  cycles)  at  the  time  of manufacture,  when  two  percent  (2%)  of  all  cylinders   manufactured  are  cycled  10,000  times (corresponding  to  about  one  cycle  per  working  day  f or  40  years),  then  subjected  to  a  number  of strength  tests.  Cylinder  manufacturers  submitted  th at  this  testing  established  a  threshold  level  of acceptable  safety  that  can  be  reasonably  expected  o ver  a  15-year  service  life  (regardless  of  the working gas).

So test were equal to 40 years of  5 days a week full fills and empties and 2% failed so it was decided that 15 years was a Safe Life Span.

No consideration given to not being used  five  cycles a week or not being completely emptied and refilled each time.


52 wks a year X  5 fill cycles a week X 40 years   equals 10400 cycles  At this point 2% failed after being subjected to  stress testing.
52 wks. per year X5 fill cycles a week for 15 yrs. =3,900  fill cycles.

( How many years would it take you as an air-gunner  to  fill or have  your SCBA type tank filled 3,900 times?   My Guppy gets filled / topped off every week to  ten days , once a week for 3,900 fills equals  75 years ! ) 

My 3 month old Guppy cf tank gets filled once  a week to ten days  not 5 times a week and it only gets used down to 2,600 to 3,000 . A partical fill as from 2,500 to 4,500 does not age / wear / stress a cf tank as much as a complete  zero to 4,500 cycles does. Metal fatique in a cf tank is caused mostly  by contraction and expansion.

I have a 15 year old SCOTT SCBA 60 min. 87 cf  cf tank which as pulled from service 10 years ago thus was only used for 5 years and shows hardly any sign of useage. This one has been setting  in my shop for  two months at 4,500 PSI and I expect this one to last longer than I am able to shoot airguns.