i have to ask,why do you even need to cut another hole in a fuctional fuel tank,don't you already have a filler,vent,fuel level indicator and supply to the engine hole?

 

its not involved at all,and after he has removed it he still needs to cut the hole and someone is right diesel isn't that cumbustable but i wouldn't take that chance,rinsing out with water won't prevent an explosion,comepletely filling with water would but then how to comepletely remove the water,i'm not all that sure about steam cleaning either, i just don't see how removing the tank is going to be of any partcular benefit

 

The guy just hasn't gotten any good advice yet.

OK, so you take an empty coffee can and tack it down (couple drops crazy glue or hot wax) to the fuel tank where you want the access hole to be. Now carefully make ONE wrap of detonex or other light primer cord around the base of the can where it meets the fuel tank. Fill the fuel tank and coffee can both with water.

Following normal safety procedures, detonate the primer cord.

Voila, neat hole in side of tank, no grindings or metal filings to worry about. Polish or paint as necessary. This is a ten minute, nothing more.

 

nah just use a torch right after you get lots of life insurence,if your boat survives someother sailor will enjoy it

 

Well, my apologies to everyone. Tank is aluminum, not stainless steel. I will still take it out to clean it and take a look for any corrosion. The tank has been sitting on plywood for its 31 year life so I'm sure there has been a lot of trapped moisture between the bottom and the plywood. Everything I read on aluminum tanks is that they have a life of 15-20 years. Tank is .090" aluminum. The one quote I received for a replacement is .125 inch aluminum.

 

.090 tanks were one of those things they did for a short amount of time and there life was much less than the .125 tanks

FWIW my 1970 Cal just got its third tank in 2011

 

Aluminum is a soft metal and non sparking. Cutting is easy. The dry ice tablets are a good idea though, I'll have to remember that.

 

We cut holes in Stainless electrical panels and tanks all the time. Big holes, lots of cutting just using a jigsaw. You want one with variable speed, AND blade oscillation.

Blade oscillation on a jigsaw is an unbelievable improvement when cutting stainless and even plastics. With oscillation the blade cuts on the upstroke and clears the cut on the downstroke so the teeth don't drag, or kick the saw back up. Ussually the middle of three oscillation settings works best on stainless.

On our Bosch saws we use a coarse tooth blade, distance between teeth should be slightly less than the material thickness so that at least two teeth are in contact at all times, but not many more. Fine teeth take lots more power. Fine teeth pack with chips then break off. Coarse blades have more set, making a wider kerf and it is easier to cut a curve.

Set the speed slow, use a little lubricant, a wax stick lube works very well. Hold the saw firmly and keep moving forward. If you have it all right it will work like a nibbler, producing thick relatively cool chips. We cut about 4 to 5 feet of cut with a single blade.

You know the most powerful non nuclear bomb in the US arsenal is a fuel air bomb, that detonates a cloud of kerosene vapor. All these tricks to clean the tank MIGHT work, but a tank full of water leaves no space for any fuel and air to combine, so its safe even if the tank contained gasoline. If the tank is completely full the water will cool your blade too, and the tank will be heavy and much quieter too. Your ears will appreciate the difference!

One of my coworkers was an airplane mechanic. He was first on scene and found two guys knocked out cold by an aluminum airplane tank they had carefully washed out!

Gary H. Lucas

 

You know the most powerful non nuclear bomb in the US arsenal is a fuel air bomb, that detonates a cloud of kerosene vapor. All these tricks to clean the tank MIGHT work, but a tank full of water leaves no space for any fuel and air to combine, so its safe even if the tank contained gasoline. If the tank is completely full the water will cool your blade too, and the tank will be heavy and much quieter too. Your ears will appreciate the difference!

Gary H. Lucas

Gary, this is just fear-mongering and bad information. Lets look at the facts:

Fuel air bombs don't use kerosene, they use ethylene oxide. Even if they did use kerosene, we're talking about diesel here. Fuel air bombs rely on a complex system to create a POWDER of explosive in the air at a specific concentration. From the Fedaration of American Scientists: CBU-72 / BLU-73/B Fuel/Air Explosive (FAE) - Dumb Bombs

#2 diesel fuel is not even considered flammable on it's MSDS, it is combustable. http://www.marathonpetroleum.com/brand//content/documents/mpc/msds/0281MAR019.pdf

It's flash point is 130-190F. (reference the link above) For those that need a brush up on what "flash point means" read below.

"Flash point This is the minimum temperature at which the vapor above a liquid fuel will first support a combustion transient or "flash". The flash point is measured by a standardized test using a small quantity (50 cc) of liquid that is slowly heated (about 1 deg C/minute) until a flash is observed when an open flame is dipped down into a covered vapor space. The legal description of flammable is used for all liquids with a flash point less than 100 deg C, and the term combustible is used for liquids with a flash point in excess of 100 deg C." EDL

Now to apply it to the case at hand. Diesel will support a transient flash if a flame is applied to diesel that is heated to 150F. (I've done this trying to re-light a stove). Diesel will not explode, flash, or even burn if a spark is applied to a tank that has been drained and has water sloshing around in it. What about every boat's bilge? It is essentially a very weak diesel solution ( <1% by volume much as a tank would be). Nobody is taking extra precautions "just in case" there.

As long as you don't use an oxy-acetylene torch to cut into a full tank, you're really not at risk. Again, the MSDS lists diesel as combustable, (#2 on a scale of 0-4) it's not even called flammable.

Medsailor

 

The 3 best times of a Boat Owners Life

My Company, Power and Sail Boat Repair does a lot of Fuel Tank Issues in
Eastern North Carolina.

I've found after cutting an access area, wiping out the tank and putting back a suitable cover plate you'll find it leaking shortly afterwards due to the fact
you've cleaned out the crud from the bottom that was keeping it from corroding thru ( or you accelerated the process ).

The 3 Best times of a Boat Owners Life:

You buy a Boat

You sell a Boat

You have a Brand New Fuel Tank that doesn't Leak
and has nothing in it but Fresh Fuel !

 

FWIW, I recently had my Catalina 36's fuel tank cleaned out in place. The guy drained the fuel, removed the sender unit to provide ventilation, cut two large square access holes (one on each side of the baffle), drilled and installed a 1/4" plug/cap so I can check fuel with a dipstick, hand cleaned and polished the inside of the tank, fastened two SS plates over the access holes, added 5 gals fuel...DONE. Took about 5 hours with a helper. He's been doing this daily since 1979, he's still alive.

Mike