securing aluminum gas tank

[cowboyup]

I've finished the repairs on my 94 gallon aluminum gas tank. Had the welder put a plug into the small hole on the rear bottom edge. Turns out, this tank is 1/4" aluminum. No wonder it's so heavy. Anyway, I've covered the edges with 2 layers of epoxy and 1 1/2 oz mat. i put 2 thick layers of epoxy on all other surfaces. The tank was originally foamed in place with wooden triangles wedged in between the stringer and tank in several places. the wedges were then screwed into the stringers. Additionally, there were 3 sets of 2x4 (untreated) across the top of the tank. these were also screwed into the stringers. I plan on securing the tank in the same fashion, but i have a foam question. How do I prevent the two part foam from going underneath the tank as its poured in?

 

[Winger Ed.]

Re: securing aluminum gas tank

Put duct tape or that metal foil tape they wrap Air conditioner vents with along the edges you want to keep it out of. Then make a small/shallow pour first.<br /><br />The foam will expand up & outward rather than going under the tank if you offer it even minimal resistance to get under there. Once the first pour sets, you can go ahead with the second pour to really get it all just right. <br /><br />As heavy as that tank is, and then with 6 or so pounds a gallon fuel in it, I wouldn't think it'd take much to secure it. It probably wants to stay where its sitting at anyway.

 

[cowboyup]

Re: securing aluminum gas tank

Thanks for the suggestion Winger. It's a tight fit between the stringer and tank, but i think it'll work. Now, if i could just find that finger stretcher somewhere...

 

[Realgun]

Re: securing aluminum gas tank

Once the first pour sets, you can go ahead with the second pour to really get it all just right. <br />

With 2 part foam this takes about 15 minutes @70 degree F.

 

[ThomWV]

Re: securing aluminum gas tank

Stop.<br /><br />Do not foam a gas tank in place. It is the very worst possible way to secure a tank. It is only done by manufacturer's because its is the very cheapest way to hold them in there. If you do no other thing in returning this boat to life at least go find the proper way to mount a permanent tank witout using foam. I believe Pasco has a full 'How to do it' article on his web page. If he doesn't I suspect at least he will have one of his articles (he is a nationally know Marine Surveyor) on the litany of reasons not to foam in a tank and how it harms the resale value because of heightened safety concerns and maintainence costs.<br /><br />Once again, mount that tank properly, do not foam it in place. I do not care which manufacturers do it or that it is allowed by law - because some laws exist because they were bought and paid for and this is surely one of them.<br /><br />Thom

 

[cowboyup]

Re: securing aluminum gas tank

thanks for all your replies. I am intrigued at the idea of not using foam and saving money and time. I've read Pasco's suggestion on mounting fuel tanks and agree with the concept of airflow and not trapping water in that area, but how in the world could you remove that tank if it's been glued with 5200?

 

[bossee]

Re: securing aluminum gas tank

Hi,<br />My tank in my new boat was placed in foam. This summer the tank came loose bacause I used my boat in larger waves and such. The boat is in for warranty repair now. I do not like the idea to foam in a gas tank. To take the tank out of my boat will be rather difficult I can imagine. I will make sure the dealer will not try to foam in the tank again. Since the tank has to be mounted back a more professional way to fasten a tank must be used but I'm not sure what is best. I have a stainless steel tank. I had to build a temporary plywood frame to hold down my tank so I could use my boat the rest of the season. It took a whole day for me to secure the tank with my temporary solution. Worked great. The problem I have seen is that the tank is larger then the inspection opening. The tank has obviosly been foamed in first then has the floor/inner hull been added and fastened. From factory the hatch was acually fastened with a lot of screws. But I added hinges instead to the hatch so I could easily inspect the gas tank. I'm glad I did since if I had not done this I could not easily have discovered the tank came loose. I open the hatch every time before I go out to sea to make sure all gas houses are in place and gas tank not leaking.<br /><br />

 

[existingmember]

Re: securing aluminum gas tank

Hi. I am just starting a built in gas tank project myself. I was planning on putting it in the floor between the two stringers then covering with ply for the floor. I was going to foam it to make sure it couldn't wiggle under the ply. This is wrong? Any chance you could post the web site with this article. Until now I thought I had it covered. <br /><br /> Thanks.

 

[cowboyup]

Re: securing aluminum gas tank

here's what i read from Pasco about installing aluminum gas tanks. I assume that its also good for stainless as well as plastic tanks too. hope the link works.<br /><br /> http://www.yachtsurvey.com/fueltank.htm <br /><br />Hey Bo,<br /><br />nice job on the "temporary" bracing for your fuel tank. How about doing mine. Looks good enough for the girls i go with.