plastic gas tank

[seagenie1]

I am replacing my gas tank that sits bellow deck because of pitting issues. I am thinking about a plastic tank does anyone have any pros or cons about them. Also I am curious to know what the 3% expansion rate is on a 109 gallon tank. It is 33 inches wide by 67 inches long and 15 inches tall. The area between the stringers is 34 inches wide and about 20 inches tall and 68 inches long.

 

[1970 Chieftain V]

Re: plastic gas tank

Before you pitch the tank you might want to look at this stuff.

http://www.kbs-coatings.com/Tank-Sealers_c_7-1-0.html

I did my two 12 gallon tanks with them no leaks yet.

Jason

 

[dingbat]

Re: plastic gas tank

The biggest disadvantage of plastic in larger tanks is that they don't have baffles in them. You'll end up with 50 gallons of fuel sloshing around under the floor. Plastic tanks have also been known to permeate over time. I can't say for sure if that?s the case anymore but it's something to think about.

Personally, I perfer metal storage containers. The metal tank will buy you a bit of time should a fire break out. The plastic will just melt and your done.

 

[seagenie1]

Re: plastic gas tank

btt

 

[5150abf]

Re: plastic gas tank

Cabellas has tanks from Moeller I think in a bunch of different shapes and sizes.

 

[Woodnaut]

Re: plastic gas tank

Sooner or later, for better or for worse, like it or not, there is a good chance that we might all be looking at running E85 in our boats. 10% ethanol is already standard in many parts of the country, such as where I live in the greater Houston area. Some blends are even as high as 20%. When choosing a tank material, it might be good to keep in mind the probability of having ethanol blends stored in it.

 

[jay_merrill]

Re: plastic gas tank

I have a pair of 12 gallon plastic tanks that have been used for about ten years. They were once used as external, main tanks and now serve as removable aux tanks for my current boat. Both are still perfectly usable and about the only noticeable change in them is that the red color has faded on the top of each, due to sun exposure.

The previous comment about safety of internally installed plastic tanks is interesting. I can see pros and cons of both types. I agree that plastic is going to have a lower melt point than aluminum, which is not good from the standpoint of having a bunch of fuel escape, and become fuel for the fire. On the other hand, a container that is somewhat resistent to heat (aluminum will eventually melt too), may just serve as an ignition source for fuel vapors in a partially filled tank, with the end result being an explosion. This one sort of sounds like a "damned if you do, damned if you don't" scenario.

I guess I would do some homework on this before settling on one type or the other. You might want to visit your local fire department for some advice. In addition to their own expertise, they could also get into NFPA publications to see what they might have to say about fuel tank materials.

 

[seagenie1]

Re: plastic gas tank

btt

 

[seagenie1]

Re: plastic gas tank

does anyone know how much they will expand and how much clearance I need. This tank also has baffles in it.

 

[JoeCrow]

Re: plastic gas tank

Before you pitch the tank you might want to look at this stuff.

http://www.kbs-coatings.com/Tank-Sealers_c_7-1-0.html

I did my two 12 gallon tanks with them no leaks yet.

Jason

This stuff sounds to good to be true,
did the tanks need to be removed to use it?
How was it applied?

 

[Joe_the_boatman]

Re: plastic gas tank

This stuff sounds to good to be true,
did the tanks need to be removed to use it?
How was it applied?

Tank sealers are used a lot on motorcycles.
I restore vintage bikes on the side (got 8 under my belt that I've completely disassembled and rebuilt), and though I've heard of many people who are happy using tank sealers, I'll never use them.

I tried once, followed directions exactly and was very cautious since the stuff is $40/kit and I didn't want to waste it. The muriatic acid in the kit (used to remove the tank's rust) ended up making the existing pin holes into real holes. It made other areas very thin, so much that it'd be dangerous to use. I rinsed it out (per the directions), dried (w/ a blow gun) and then put the sealer in. It looked nice, but still leaked, and in some areas, was peeling off.

After that incident, I use electrolysis to remove the rust and scale, rinse, then etch w/ phosphoric acid. I then swish around a gas/oil mix inside to prevent any flash rusting, and then seal it up for storage until the rest of the bike's done.

This applies to steel tanks of course, not aluminum.

The tanks should be removed if you want the whole interior coated, not just the bottom. Also, if it pools in the bottom, it might not set up properly due to being so thick.

For what it's worth, my boat came w/ a nice 20-gal Mirax steel tank w/ level sender & gauge. When I redid my boat, I replaced it with 2 orange poly tanks. Although the Mirax didn't leak, it just looked like trouble w/ all its surface rust.

 

[Fishinmagician]

Re: plastic gas tank

i have 1 plastic tank and one metal, i just added the plastic one and im very happy with it. i never thought of the fire thing that was posted above i really cant think of advantages or disadvantages except that eventually the metal would deteriate over time..... unfortunatly, plastic is forever.

 

[mthieme]

Re: plastic gas tank

My Searay has a plastic replacement tank although only 26 gallons. It's been in there 20 years or so. I had it out last year to do some work behind it. It still looked new. No issues.

 

[1970 Chieftain V]

Re: plastic gas tank

This stuff sounds to good to be true,
did the tanks need to be removed to use it?
How was it applied?

Unlike Joey I haven't had any trouble with the KBS coatings. I followed the directions and they have held up fine. I had pin holes in the bottom that I repaired with epoxy putty.

Yes the tanks need to be removed to do it right.
You pour it into the tank and rotate the tanks around the different sides until they are all coated.

Jason