Cutting Access Hole in Stainless Steel Diesel Fuel Tank

[Ajay73]

I have a 1980 Catalina 27 with a Universal 5411 diesel engine. I want to cut an access port in the stainless Steel fuel tank. I have good access to make the cut. I will have to drill a starter hole. Can stainless steel be cut with a jigsaw with a bi-metal blade? Has anyone done this kind of modification? What are the problems? I don't think there is an explosion risk in that the tank will be emptied and that it is a diesel fuel tank.

[tommays]

As safe as diesel is cutting into a empty tank that still has some amount of fuel and a bunch of fumes is a high risk job

If you go slow and kept the blades lubed and cool so the SS does not work harden it could be done on a tank that was cleaned OUT

[kd3pc]

the bigger issue, is how to get all the metal shavings out of the tank....if you can stand the cutting long enough..

For small holes in stainless, I have used thick mechanics grease smeared on the top to help hold the shavings. I would at least use that, and a shop vac whilst cutting.

You will need a really good jig saw and top quality blades to cut the stainless, even then it will be time and blade consuming.

Access to good quality sawz-all or shears (air/hydraulic) would be the better choice...

Likely some bad smells and lots of fly back, so wear goggles and old clothes at least

[TQA]

Steam clean the tank THEN then fill it FULL with water.

I would cut it with an angle grinder and suitable disc but a saw will work, albeit slowly and have plenty spare blades..

eg Bosch 2608600701 Cutting Disc, for Stainless Steel, 100mm

DO NOT ATTEMPT TO CUT IT WITHOUT TAKING THE ABOVE PRECAUTIONS - PEOPLE GET HURT OR KILLED EVERY YEAR DOING THIS.

Motor vehicle repair Repair of diesel tanks

[kd3pc]

I assumed a "round" hole, which is all but impossible to cut with a grinder/cut off wheel....but if you can handle a square hole, then TQA's gear will be much quicker.

I have always been "assured" that drilling or small cuts in diesel tanks are safe, and have done quite a few as you are planning...and although you are not torching/brazing....but I would certainly err on his well documented side....and take the thing out, wash and rinse several times, then fill with water and do the cuts...

Or at least have a friend stand by with fire watch...

YMMV

[Boasun]

In almost all shipyards and on commercial vessels, that tank would have to all of the fuel removed and steam cleaned before any modifications is done on it. This is for the safety of the people working on said tank.
You can rent small steam generators and Please use one for your safety along with an explosive meter to ensure that the tank is safe for hot work...And hot work does include drilling and metal saws.

[sawingknots]

although diesel isn't highly combustible,heated fumes are,if you really want to do it safely run a hose from the exhaust of a small engine into the tank for a few minutes and during your cutting,the corbon deoxide and lack of oxygen will prevent an explosion[works on gas tanks too]

[jrd22]

We used to repair truck aluminum diesel fuel tanks using the method that sawingknots suggests. A jigsaw will work, generally the stainless is pretty thin on most tanks I've been around on boats. Good idea using grease to catch the chips.

[ggray]

Can't be too safe.
Worst example --actually, the only bad one I know of -- was in a boat yard where they were cutting on a diesel tank. Plan was to fill tank with nitrogen, but gas company had mistakenly filled a nitrogen bottle with oxygen.
The worker burned to death before they could chop a hole through the hull.
This was 25 years ago, and I still think about it.

[hellosailor]

Boasun, steam gennies may be common in cow country but in the Northeast US you'd have an easier time trying to rent wooden false teeth.

Ajay, an empty tank is now full of vapors and vapors are more explosive than liquid fuel. One trick to making that safer is to dump crushed dry ice into the tank, as the CO2 "melts" it will displace the air and fill the tank with CO2 which doesn't support combustion. You could use CO2, nitrogen, or any inert gas from a welding supply to do the same thing as well. It may be simpler and safer to just remove the tank, clean it out beforehand and afterwards where there's space to work.

The big trick is going to be making sure there are no metal particles of filings in the tank. Putting thick grease on the tool eldge will help that. If you can squeeze in a helper with a vaccum, that also helps. Either way you'll want to wipe out the tank afterwards and really try to chase out those cuttings.