I have called almost every shop here is town and they do not pressure test tanks. Has anyone made their own contraption to do this? I do not want to seal up the deck without testing it.
Yeah, I had the same problem finding someone to test a heat exchanger, so I did it myself. I put rubber plumbing caps w/ hose clamps on the outlets, plugged the drains, and tee'd a schrader valve and gauge into one of the plugs. I pressurized it to 15PSI and held it overnight. No problemo.
if this is a fuel tank the max is 3 PSI. You can make a device to fit in and plug the fill with a tube through it for the air hose. Plug the vent. Even duct tape will hold. Us vice grips or a clamp to clamp the fuel line. Pressurize for 15 minutes if it holds for 15 minutes its OK
Pressure testing brings up all types of liability issues.
Air compresses so five psi of compressed air is not the same as 5 psi of the fluid pressure. Air becomes very volatile even at very small pressures. Tanks should to be hydrostatically tested.
Could you use a cooling system pressure tester available at most auto stores? They are hand pumped and test low pressure for leaks in your radiator/hoses/cooling system. Have to have a way to plug the inlet, vent and outlet.
A cooling system pressure tester is way to much pressure (I think they are in the 12-15 psi range?). As Peter said, about 3PSI is the MAXIMUM you would want to use. More than that and you can due real damage to the tank. -- Think about it for a second. As an example, just a small tank with one side of say 12"x24" has 288 square inches in that 12x24 surface. Multiply that by the 3PSI (pounds per square inch), and you have 864 pounds pushing on that tank wall surface. the pressures build up FAST even at low PSI. If you used a cooling system pressure tester on that same 12x24 tank you would have 4320 POUNDS of force (at 15PSI) on that tank wall.
As stated above, "tanks should be hydrostaticly tested" is compleatly correct. I spent allot of time in the Navy running a hydo testing facility and tanks should not be pnuematically tested one because air compresses, water does not and 2 you will ballon your tank possibly ruptureing it or cracking the welds and altering it's shape. The process is the same for both types of testing, just use water instead of air and get an appropriate gage attached inline between your pump and the tank. Also, make sure you have compleatly filled the tank with water and eliminate all air pockets.
I may need to be corrected, but I'm thinking that hydrostatic testing isn't necessarily proper either. The effect on the tank is the same for both air testing and hydrostatic testing, the stored energy has just been removed with hydrostatic testing (which makes it much safer). So any hydrostatic testing would still need to be done at the 2 - 3 psi range.
I may need to be corrected, but I'm thinking that hydrostatic testing isn't necessarily proper either. The effect on the tank is the same for both air testing and hydrostatic testing, the stored energy has just been removed with hydrostatic testing (which makes it much safer). So any hydrostatic testing would still need to be done at the 2 - 3 psi range.
Yep.
We are talking 2 or 3 psi, not 3500psi tanks of welding gases that would expand 10,000 times upon rupture.
And don't just fill it with water to check for leaks either, you need the 2 or 3 psi as gasoline will leak thru cracks and holes where as water will not if tested statically.
so the answer is...fill with gasoline and look for leaks?
I'm guessing that a vented tank won't build up any pressure (above the weight of liquid) anyway.
Testing with water means you then have to drain and dry it.
If the bilge is dry, you could lay out newspaper or sprinkle chalk dust I suppose.
Of course if you find a leak you have to be ready to evacuate the tank.
If it were out of the boat, couldn't you seal it except the fill port, and fill with a garden hose, and be careful of rupture? Is that too much pressure?
You could fill with water and then just the 2 or 3 psi of water. The water alone (without psi) might not leak but under a couple of psi it will leak where gas will leak.
Sprinkle the outside with baking soda and leaks will show up easier. Then use a rag and the baking soda to clean the spot prior to repairing.
Or just use 2 or 3 psi of air and find the leaks with soapy water.
The USCG standard for fuel tank testing is 3 psi MAX. Normally tanks are tested empty and then a soapy solution is sprayed on all fittings and gaskets to look for leaks. Do Not use any thing with ammonia in it! Go to any place that sells propane or propane supplies ( a camping world will do) and get a bottle of leak testing solution. This is a simple test. It is not complicated or hard to do. Frankly I am very surprised that your marine shops say they don't do it because most do!
You can actually put 3psi on a tank with a bicycle pump. You don't need an air compressor.
Here is an excerpt from This Old Boat, by Don Casey : " If your deck fill is similar to the one on my boat, a 1 1/4 inch threaded PVC Plumbing plug will thread into it. Drill a hole in the plug and insert a standard tire valve. Clamp short lengths of fuel hose to the outlet an vent fittings. Then squeeze these hose airtight with a clamp or Vice-Grip pliers. Half a dozen pumps from a bicycle pump should put the tank under light pressure. Never put more than 3 pounds of pressure in the tank. If the tank holds pressure overnight it is leak free."
Since the tank is installed. clamp the out let hose with vice grips or a clamp. The vent can be plugged just by wrapping it tightly with duct tape. I don't think you need to wait overnight. If it holds pressure for 15 minutes it's ok.
