Foam
 

What density of foam is used for foam installation of a fuel tank.

I am aware of all of the pros/cons of foam, just trying to figure out what type is used for this job.

Thanks!

Re: Foam
 

i've poured both 2 & 4 lb/cf foam and the foam I pulled out of my boat around the tank sure felt like 2 lb/cf.

Re: Foam
 

I believe 4lb is what was recommended to me by the supplier.

Re: Foam
 

does your tank have flanges on it? why foam? if you do foam, put a thin layer of pvc board between the foam and tank so no moisture can transfer.
just my 2 cents.

Re: Foam
 

if,you properly chemically etch primed the aluminum,and coated it in interprotect,the proper thickness-10mils,then,aluminum is completley isolated from any and all moisture contact - no need for a barrier between the tank and the foam...

Re: Foam
 

Why add foam in the first place?

Re: Foam
 

The foam debate will rage on forever. My old tank was foamed in for 34 years and it would still be going if the baffles hadn't broke. The guy that built my boat still does it the same way. I will be dead in 34 years, my new tank will likely be fine.

Re: Foam
 

I understand all that but, what's the real advantage? If properly mounted and coated why add foam? Or anything else? I'm in the middle of resto on my 23' and have elected to not foam it at all.

Re: Foam
 

I won't have any flotation foam in my 25 Seafari either. But I will have three bilge pumps with a combined capacity of 4800 GPH and a high water alarm buzzer tied to the float switch on the second backup pump.

As for foamed in tanks, been there, done that on crevice corrosion. For an untreated foamed in aluminum tank, failure may take a while, but I think it's inevitable.
Dave

Re: Foam
 

I smeared mine with coal tar epoxy and will be screwing them in, with NO foam. I also plan to leave an inch or so between them. I am hoping that as the condensation builds up on the outside the air flow will allow them to breath a little bit.

Re: Foam
 

I foamed between the stringers except the tank....
To me it is cheap insurance if the boat were to flip,
you will not sink!
You could put in 50 bilge pumps, but will still sink
if turned over!!
Just my 2¢ worth.. :)

See ya. Ken

Re: Foam
 

The simple answer is its the way the tank was designed to be installed in my particular boat. There is nothing to really tie the tank into that will survive the kind of beating a Nor Cal boat like mine will be subjected to.

My hull will be pounding into a NW swell that averages about 8 feet, with 2 feet of chop on top of that. I would rather replace it in 25 years, then have it come dislodged or be sweating a mechanical connection every time my boat is taking a beating.

Re: Foam
 

I welded 4" long pieces of 1 1/2" x 1/4" angle about every 8" around the top perimeter of the the tank and epoxy - glassed them to the sides of the tank coffin. Don't know if yours has a tank coffin, but if it does, its a method to think about. My tank will not move! If the tank ever has to be removed I'll just grind the glass; I hope so anyway [img]/forum/images/graemlins/tongue.gif[/img]

Re: Foam
 

Well foam makes sense then. But why not coat the tank with coal tar epoxy or epoxy barrier coat before foaming it in? My first boat was a 17' Seasquirt. It had an aluminum tank that wasn't foamed in, but it sat on a flat deck in the bilge that regularly got wet. The tank failed due to crevice corrosion when the boat was about 10 years old. Sean, if you don't have another 30 years left in ya, you don't want to be digging that foam out ten years from now. ;) :D

Ain't it funny how you ask a simple question around here and we all pile on with unsolicited opinions? :eek:

Re: Foam
 

I will be coating it, foaming it, and then glassing over the foam and tabbing the tank to the stringers. There will be a drain on top of each corner of the tank that will take any water that bypasses the hatch into the bilge.

I will likely drown ab diving well before this set up rots.

Re: Foam
 

What happens if the batteries go dead....the three bilge pumps producing 4800 gph with back-up alarms wont do you much good...If the foam is installed properly it should not be a problem ...although after looking at Blue Herons progress on the 25 and his attention to detail he probably knows best...

Re: Foam
 

That's why I love this site. All the different opinions makes one think of other options. Hundreds of heads are better than one! :cool:

Re: Foam
 

Keep in mind that water bypassing the hatch will be measured in teaspoons not gallons, but regardless there is no consequnece. My bilge can be flooded and the boat will be fine.

In fact it is fairly common for the bilge on my model of boat to be converted to a live well for the commercial live halibut fishery. My boat used to be commercial boat as well, but the bilge was never converted.

Re: Foam
 

Point well taken....I was not aware of that....Thanks

Re: Foam
 

No worries...Radons are weird.