SoCal Jet Boats

Tech Talk => Engine Mechanical / Electrical => Topic started by: 1972Challenger on July 09, 2011, 11:12:10 PM

Title: leaking gas tanks
Post by: 1972Challenger on July 09, 2011, 11:12:10 PM
its official... my boat leaks gas.... and it comes a day before i go to the lake...

soo now i am lost... does anyone know about gas tanks... i have built in poly tanks and there is a seam that the gas is leaking out of.... so i think i gotta replace the tanks....  :banghead: :banghead: :banghead: :banghead: great timing....

i need help, ideas, guidence,... anything can help right now....

thanx
Title: Re: leaking gas tanks
Post by: ka0tyk on July 09, 2011, 11:23:51 PM
only advice is to hop in someone elses boat until the tanks are replaced with aluminum tanks.  leaking gas is not something you want to chance just for a weekend. 
Title: Re: leaking gas tanks
Post by: IRRebel on July 09, 2011, 11:28:57 PM
its official... my boat leaks gas.... and it comes a day before i go to the lake...

soo now i am lost... does anyone know about gas tanks... i have built in poly tanks and there is a seam that the gas is leaking out of.... so i think i gotta replace the tanks....  :banghead: :banghead: :banghead: :banghead: great timing....

i need help, ideas, guidence,... anything can help right now....

thanx
Do NOT take this lightly...........If they leak now, and there's foam under the floors soaking up that fuel that's PROBABLY been leaking for some time............well.......here's my first hand account of being stoopid about that..........No one's life and well-being is worth a lake/river trip........ ;)

(http://i673.photobucket.com/albums/vv95/Irrebel/Beisemeyer/BiesemeyerBurning.jpg)

Ray

FWIW, I'd be pulling the whle boat apart, removing floors, foam, then replacing everything including the tanks.........
Title: Re: leaking gas tanks
Post by: Nixonnow on July 09, 2011, 11:32:01 PM
its official... my boat leaks gas.... and it comes a day before i go to the lake...

soo now i am lost... does anyone know about gas tanks... i have built in poly tanks and there is a seam that the gas is leaking out of.... so i think i gotta replace the tanks....  :banghead: :banghead: :banghead: :banghead: great timing....

i need help, ideas, guidence,... anything can help right now....

thanx

i just went through this. i had the fiberglass tanks in my boat. i finally bit the bullet and ripped them out and put aluminum tanks in that i found on craigslist. i tried to patch the fiberglass tanks i had but they just kept leaking. so i wouldnt try and fix/patch them. its like putting a band-aid on a broken leg. the only fix is to get rid of the tanks and replacing them with aluminum or ss tanks. seriously man. a water leak is one thing but a gas leak is just down right dangerous. when mine were leaking, the only thing i could think about was seeing those pictures of boats that burn down to the water line. its scary as hell bro. you dont want to be spending your whole weekend worrying if your boat is gonna catch on fire. just for piece of mind man. makes you feel alot better. keep your eyes out for alum/ss tanks on craigslist/ebay. or buy em brand new, they are spendy brand new. but seriously im telling you this from experience. get rid of your tanks.
Title: Re: leaking gas tanks
Post by: GT Jets on July 10, 2011, 08:56:04 AM
Listen to all these guys.

I have some aluminum bullet tanks if you are interested, but need to get some specifics before we know they would even work....

Get some aluminum tanks built. Do not even think about repairing what you have.

GT
Title: Re: leaking gas tanks
Post by: 1972Challenger on July 10, 2011, 12:22:10 PM
Thanks for all the info. And i am replacing them. I gotta get measurements   Today im goin to empty and tear the out. Then see wat the next step is. Can i build tanks and pjt a fuel gauge in them?? Or how does that work
Title: Re: leaking gas tanks
Post by: ka0tyk on July 10, 2011, 12:38:22 PM
Thanks for all the info. And i am replacing them. I gotta get measurements   Today im goin to empty and tear the out. Then see wat the next step is. Can i build tanks and pjt a fuel gauge in them?? Or how does that work

you can probably use your existing senders in your fiberglass tanks if they're going to be made direct replacements.  just drill the hole in the alum tanks where the deepest part will be and mount em up with something to seal em, fuel safe silicone, etc.   if your senders are nasty now is a good time to get new ones.

http://www.cpperformance.com/c-499-fuel-tank-gauge-senders.aspx (http://www.cpperformance.com/c-499-fuel-tank-gauge-senders.aspx)


if your fuel fills are right above dont forget to ground them to the tank.  sparks + fumes = boom.
Title: Re: leaking gas tanks
Post by: Colesifer on July 10, 2011, 01:02:44 PM
my buddy has some VERY nice Russell SS tanks im sure he would be willing to let go of..give him a call 928-607-7221
Title: Re: leaking gas tanks
Post by: 1972Challenger on July 11, 2011, 10:51:59 AM
my dad and i were taking a look at the tanks and se decided this... we are goin to cut out the old tanks, and make new alum ones for my boat... i work in a sheet metal shop so im goin to draw and program them up, get them welded by a buddy, and hope that they turn out lookin good...  :banghead: :banghead:
Title: Re: leaking gas tanks
Post by: fordfan on July 11, 2011, 02:22:07 PM
My buddy made tanks out of two 8" rolls of aluminum and just welded end camps on them! Then welded aluminum angle for mounting them to fiberglassed 2x4s. and weldded bungs for pickups and fuel fills on the tank.
Title: Re: leaking gas tanks
Post by: wizard612 on July 11, 2011, 04:49:40 PM
See my post on "rusty bow tank" another story to remember when dealing with fuel in the bilge.
Title: Re: leaking gas tanks
Post by: 1972Challenger on July 14, 2011, 07:08:23 AM
i got a question.. people have been tellin my dad and i conflicting information.. so i thought i would ask all u guys since u know alot about boats...

wats batter for fuel tanks.. ss or alum????
and in wat gauge of material??
Title: Re: leaking gas tanks
Post by: wizard612 on July 14, 2011, 08:04:57 AM
SS IMO is best but is pricey and just a bit heavier. Alum is ok but I would not want to get near salt water. The exterior of the tank is important too. Aluminum tanks like a moon tank look great but need more TLC to keep looking nice. My old float had SS saddle tanks about 7 gal each (circle boat) and cleanup was a quick swipe with a soapy rag, never got a scratch never oxidized.  A lot of guys on their river rides would have tanks made from anything covered in carpeting, I never liked that because you could not inspect very well and it made a good wick for your floating molitof cocktail.
Title: Re: leaking gas tanks
Post by: 1972Challenger on July 14, 2011, 08:57:10 AM
im def not goin to cover them with carpet... if im makin custom tanks i want people to see them...
and IMO? is that like the style of SS.. like 306 or something??
Title: Re: leaking gas tanks
Post by: ka0tyk on July 14, 2011, 10:36:53 AM
im def not goin to cover them with carpet... if im makin custom tanks i want people to see them...
and IMO? is that like the style of SS.. like 306 or something??

if you go SS, use 316.  corosion resistant.  best for marine applications. 
Title: Re: leaking gas tanks
Post by: 1972Challenger on July 14, 2011, 02:07:24 PM
wat guage tho?? like 18 gauge or thicker
Title: leaking gas tanks
Post by: sandeggo on July 15, 2011, 06:59:41 AM
I used 1/8" 5052 aluminum. Shouldn't corrode through in my life time
Title: Re: leaking gas tanks
Post by: 1972Challenger on July 15, 2011, 09:40:43 AM
1/8?? thats heavy isnt it?? i mean i know its alum, but its thick
Title: leaking gas tanks
Post by: sandeggo on July 15, 2011, 11:00:02 AM
The tanks have a lot of vibration and flexing, I've had to repair thinner tanks
Title: Re: leaking gas tanks
Post by: ka0tyk on July 15, 2011, 02:07:42 PM
pretty sure my tanks arent that thick....

just call IMCO and act like they're lookin for some tanks and ask what gauge they make theirs out of and what ####?  if its good enough for imco its good enough for you.  =)
Title: Re: leaking gas tanks
Post by: 1972Challenger on July 15, 2011, 02:09:51 PM
IMCO???
Title: Re: leaking gas tanks
Post by: ka0tyk on July 15, 2011, 02:13:50 PM
they custom make alum and SS tanks, exhaust, drives, etc.... 

http://www.imcomarine.com/cal_store/fuel-tanks-1.html (http://www.imcomarine.com/cal_store/fuel-tanks-1.html)
Title: Re: leaking gas tanks
Post by: 1972Challenger on July 15, 2011, 03:03:43 PM
ok thanks

what i have been thinkin is takin 1/8'' alum tubing, welding caps on them and ext...

i thnk that sound good.... and clean wehn i polish them up
Title: leaking gas tanks
Post by: sandeggo on July 15, 2011, 04:19:41 PM
Imco said 1/8" 5052 lol
Title: Re: leaking gas tanks
Post by: ka0tyk on July 15, 2011, 04:20:32 PM
Imco said 1/8" 5052 lol

 ;D
Title: Re: leaking gas tanks
Post by: 1972Challenger on July 20, 2011, 07:32:24 AM
ok so im now in the process of buyin my materials and i got a few easey quesions for u guys..

how do you fiberglass.??
and where do u buy the stuff at..

im going to be putting in 3 wood mounts in my boat and i want to fiber glass them in. then i want to mount the tank to those.... in 3 spots
Title: Re: leaking gas tanks
Post by: 75 fantasy on July 20, 2011, 08:09:06 AM
when i did my sub-floor i got the all the materials from westmarine less wood. they also had a nice how-to fiberglass book. most chain auto part stores sell glass kits and you can get how-to info off the net. glass work wasn't as hard as i thought it was going to be.  :thumbup:
Title: Re: leaking gas tanks
Post by: 1972Challenger on July 20, 2011, 09:55:42 AM
ok cool.. ill check the marine store near me
Title: leaking gas tanks
Post by: sandeggo on July 21, 2011, 05:58:33 AM
Make sure you space any wood away from the boat itself, if you glass wood directly to the boat with a tight fit you'll be dealing with stress cracks
Title: Re: leaking gas tanks
Post by: 1972Challenger on July 21, 2011, 11:19:01 AM
so i cant glass wood to the boat??? like wat i was goin to do is put 3 pieces of wood to hold down my tanks and i want goin to fiber glass them to the floor and the side of the boat...
Title: Re: leaking gas tanks
Post by: ka0tyk on July 21, 2011, 11:46:30 AM
so i cant glass wood to the boat??? like wat i was goin to do is put 3 pieces of wood to hold down my tanks and i want goin to fiber glass them to the floor and the side of the boat...


build up some small blocks to keep the tank off the floor and level. sand the area with like 80 grit to rough it up, put some resin down, then the block, and then a little run of some mat around that and resin to coat.   id personally put some rubber on top of those so there isnt tank to metal...  but thats just me.   then u can either get flanges to the gunnel, or just fiberglass something to hold em to a gunnel. 

(http://www.riverdavesplace.com/forums/attachment.php?attachmentid=156891&stc=1&d=1311051042)
Title: Re: leaking gas tanks
Post by: 1972Challenger on July 21, 2011, 02:06:40 PM
how many coats or resin and the matting do i need??
Title: Re: leaking gas tanks
Post by: 1972Challenger on July 21, 2011, 02:11:17 PM
this is my idea for my tanks....

attatched is a pdf of the tanks
Title: leaking gas tanks
Post by: sandeggo on July 21, 2011, 03:08:53 PM
so i cant glass wood to the boat??? like wat i was goin to do is put 3 pieces of wood to hold down my tanks and i want goin to fiber glass them to the floor and the side of the boat...
Yes you can, you gotta space it about a good 1/8". Set it with spacers, glass in between the spacers and let it set up. Then pull the spacers out and glass until your heart desires. It's called tabbing. If you are only doing blocks only on the floor and not the floor and gunnel then don't worry about it. You need to tab things that attach at more than one surface
Title: Re: leaking gas tanks
Post by: 1972Challenger on July 21, 2011, 03:25:31 PM
Yes you can, you gotta space it about a good 1/8". Set it with spacers, glass in between the spacers and let it set up. Then pull the spacers out and glass until your heart desires. It's called tabbing. If you are only doing blocks only on the floor and not the floor and gunnel then don't worry about it. You need to tab things that attach at more than one surface

what do u mean i need to tab things that attatch to more then one surface??

are u talkin about the tank? or fiberglass??




Title: leaking gas tanks
Post by: sandeggo on July 21, 2011, 10:09:53 PM
Like if you were glassing a bulkhead in. It touches the floor and the inside of the gunnels.
Title: Re: leaking gas tanks
Post by: ka0tyk on July 22, 2011, 12:02:20 AM
what do u mean i need to tab things that attatch to more then one surface??

are u talkin about the tank? or fiberglass??

what he basically means is that you use a strip of glass mat.  and lay it out so theres an overlap onto the new piece and what you're trying to stick it to. 

for example:

(http://www.fiberglassrv.com/forums/attachment.php?attachmentid=27749&thumb=1&d=1280150138)

theres like 4" on the stringer part, and 4" on the floor.  both sides. 
Title: Re: leaking gas tanks
Post by: IRRebel on July 22, 2011, 12:39:19 AM
what he basically means is that you use a strip of glass mat.  and lay it out so theres an overlap onto the new piece and what you're trying to stick it to. 

for example:

(http://www.fiberglassrv.com/forums/attachment.php?attachmentid=27749&thumb=1&d=1280150138)

theres like 4" on the stringer part, and 4" on the floor.  both sides.

Exactly how I was reading it as well. Glass in the wood mounts, then simply mount or secure the tanks to those. Haven't done it.......yet, going to happen here quick, but I plan on three layers glassing the wood mounting points in. cloth, then mat, then cloth again.  spreading out a little further each layer.

Reason being, say an 11 gallon tank holds 72 lbs of fuel, plus the tank. A Half or partially full tank, sloshing around, can emit quite a bit more force than that, so I am working on a side load capability of 150 lbs or more.

You're on the right track! You cannot over secure them.

Ray
Title: leaking gas tanks
Post by: sandeggo on July 22, 2011, 04:15:53 AM
Ok not the greatest pic but here's my tank mounts, see how they attach at the floor and at the side of the boat. There is a 1/8" airspace between the wood and the existing fiberglass of the boat. If the wood touches it will spider crack the outside of the boat. It's the same on the bulkhead and the same reason that the bulkhead and side supports don't touch the underside of the deck. It allows it all to flex. Derek and ray are right, you want to roll out some mat under the piece so that it sticks out on either side parallel with the joint, then glass the 90 degree sides. On mine I used about 4 layers of heavy mat and a finish layer of cloth. One other thing I did that seemed to help is I routered or sanded a little bevel on the wood piece which allowed the resin and mat to "flow" better.
(http://i15.photobucket.com/albums/a376/00s-ten00/69%20schiada/85829252.jpg)
(http://i15.photobucket.com/albums/a376/00s-ten00/69%20schiada/9d8444b6.jpg)
Sorry these are the best I've got
Title: Re: leaking gas tanks
Post by: 1972Challenger on July 22, 2011, 07:04:44 AM
thanks for all the info...

the way im mounting them is with 3 2x4s pcs, about 5'' long, on the boat... the old tanks that were in there were built in tanks, and there is a step of glass in the boat for the old tanks. so what i was goin to do is put the pieces of wood on that, glass them down, and bolt up my tanks to that....
Title: leaking gas tanks
Post by: sandeggo on July 22, 2011, 10:56:12 AM
Sweet
Title: Re: leaking gas tanks
Post by: 1972Challenger on July 31, 2011, 10:18:07 PM
ok so i went to buy the fiber glass and the guy asked me what kind do i want..??

sooo what kind do i want??

i mean what is used in boats?

thanks
Title: leaking gas tanks
Post by: sandeggo on August 01, 2011, 04:29:33 AM
I'm no glass guy but the way I understand is mat is where the strength is, and cloth is for smooth finishing
Title: Re: leaking gas tanks
Post by: ka0tyk on August 01, 2011, 11:06:07 AM
I'm no glass guy but the way I understand is mat is where the strength is, and cloth is for smooth finishing

i used a biaxial cloth with a mat backing.  i dont remember the oz in the mat, but it wasnt too thick.  i used some epoxy and radius'ed all of my 90* corners.  fiberglass doesnt do a 90* corner very well... 

covered the area with poly resin, layed down my fiberglass, poked it into little nooks and crannies, took my brush and saturated it until it was somewhat translucent.  then took a roller and rolled out the excess resin and air bubbles. 


you could pick the boat up by my seat frames...