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Posted: Sun May 06, 2012 10:29 pm
by captainmaniac
Is it Saturday again?

Posted: Sun May 06, 2012 10:31 pm
by jefflaw35
no not at all, man wants to paint his tank. why tell him no, tell him how! IMO

Posted: Sun May 06, 2012 10:41 pm
by jefflaw35
k9th wrote:I just replaced my tanks with aluminum tanks two years ago. The manufacturer offered to porcelain coat them which, I understand, is a standard option for aluminum tanks. I did not add the porcelain coating as I do not believe the tanks need to be painted or coated.

Just my 2c.
yea i agree, really no need IMO, if you wanna paint them, well thats easy!

Posted: Sun May 06, 2012 10:53 pm
by gettaway
SRD,

will you post pictures of the old tanks coming out and the new going in? I really had a hard time trying to decide as to whether or not to replace mine when the engines were out, the existing tanks are solid but ... I just didnt have the budget to do it all at the time.

anyways it would be interesing to see the process.

Posted: Sun May 06, 2012 10:55 pm
by Big D
I think it's important to know why you want to paint them; is it for looks or longevity?

Posted: Sun May 06, 2012 11:05 pm
by jefflaw35
wouldnt think it matters. Its aluminum/ in a boat. what do you prefer?. aluminium look? or blue, pink, white, black. its a fuel tank thats not going to rot like the old ones did! IMO think Ill even let my kids carve there names in my paint like concrete a slab when its done, we"ll see how well it holds up 20 years from now!

Posted: Mon May 07, 2012 1:14 pm
by prowlersfish
Aluminum fuel tanks need to be installed correctly and designed right .for them to have along life . I have seen some poorly installed tanks leak in a few years . poor design or the wrong type of aluminum can cause issues also . even the best don't last forever . seen many topaz 28s have fuel tank failure , after about 10 years .

some info ,

http://www.marinesurvey.com/yacht/fueltank.htm

Posted: Mon May 07, 2012 7:49 pm
by davidsmith
Make sure you have a good ground on your tanks when you finish painting them so you dont create any electrolysis and so your sending units work. The only drawback I see is it could mask any corosion due to electrolysis.

Posted: Mon May 07, 2012 9:26 pm
by Big D
prowlersfish wrote:....Aluminum fuel tanks need to be installed correctly and designed right .for them to have along life...
100% correct. Ever see the bottom of an ALUMINUM tank thats been sitting on water for a while? Here's a good one you'd appreciate Paul and Tony; Carver aft cabin with the aft tank buried under the swim platform, no way to see under the tank without cutting out the platform and lifting out the tank so better be sure it is the tank that's leaking right? Pressure tested to 15 psi and left it for the weekend. Not a single pound dropped all that time. Brought it up to 17 psi and that's when the leak was confirmed. Cut the swim platform, pulled the tank, and the bottom of the tank was full of pin holes. The tank looked brand new otherwise. While out, I experimented and found that while sitting on water, the film of water was enough to prevent a pressure drop. Off the water, she would leak at 5 psi :?

The moral is, aluminum doesn't guarantee you anything.

Posted: Mon May 07, 2012 9:35 pm
by jefflaw35
good thing about aluminum corosion, or at least what I have seen and delt with, is that through paint it draws up a white ring first. then it forms a cloud. On white it looks yellowish kinda like nicotene stains. so dark or light paint I would be happy with. I agree with david smith. BUT how many of use can see the bottom side of our tanks? we will never know with out pulling them for inspection. Anything can fail, good or bad quality. IMO Paint done correctly helps. You cant just paint it and toss it aside as a non-service item tho. Im learning every part of a boat needs to be looked at from time to time!

Posted: Mon May 07, 2012 9:42 pm
by jefflaw35
Big D wrote:
prowlersfish wrote:....Aluminum fuel tanks need to be installed correctly and designed right .for them to have along life...
100% correct. Ever see the bottom of an ALUMINUM tank thats been sitting on water for a while? Here's a good one you'd appreciate Paul and Tony; Carver aft cabin with the aft tank buried under the swim platform, no way to see under the tank without cutting out the platform and lifting out the tank so better be sure it is the tank that's leaking right? Pressure tested to 15 psi and left it for the weekend. Not a single pound dropped all that time. Brought it up to 17 psi and that's when the leak was confirmed. Cut the swim platform, pulled the tank, and the bottom of the tank was full of pin holes. The tank looked brand new otherwise. While out, I experimented and found that while sitting on water, the film of water was enough to prevent a pressure drop. Off the water, she would leak at 5 psi :?

The moral is, aluminum doesn't guarantee you anything.
agreed sorry D, I was typing when you posted. I should take back my aluminum last forever and say it lives longer. bottom of tanks worry me. cant see them.

Posted: Tue May 08, 2012 9:56 pm
by Paul
Marine tank manufacturers offer epoxy coatings on their aluminum fuel tanks to prevent corrosion. I didn't think this was necessary when I had my new tank built so I left the shinny finish, except for the bottom where it sits on the mounting rack. Coating the mounting area is important since moisture can get trapped there and cause corrosion. The following spring I found light oxidization on the aluminum tank in a few spots due to condensation over the winter.

I cleaned up the aluminum tank and coated the rest of it just as I had done the bottom with Interlux Interprotect. This prime is a 2 part epoxy that is formulated to stick to aluminum and works as a barrier coat against moisture. It's been 6 or 7 years now and the tank still looks like the day it was coated.

I did allot of research when I designed and built this tank and I can say with no hesitation that an epoxy barrier coat is definitely the way to go.

In the picture below you can see the coated aluminum tank next to the generator.

Image

Hope this helps,

Posted: Tue May 08, 2012 10:09 pm
by Big D
Paul wrote:Marine tank manufacturers offer epoxy coatings on their aluminum fuel tanks to prevent corrosion. I didn't think this was necessary when I had my new tank built so I left the shinny finish, except for the bottom where it sits on the mounting rack. Coating the mounting area is important since moisture can get trapped there and cause corrosion. The following spring I found light oxidization on the aluminum tank in a few spots due to condensation over the winter.

I cleaned up the aluminum tank and coated the rest of it just as I had done the bottom with Interlux Interprotect. This prime is a 2 part epoxy that is formulated to stick to aluminum and works as a barrier coat against moisture. It's been 6 or 7 years now and the tank still looks like the day it was coated.

I did allot of research when I designed and built this tank and I can say with no hesitation that an epoxy barrier coat is definitely the way to go.

Hope this helps,
+1 Paul

Posted: Wed May 09, 2012 4:45 am
by alexander38
Good ideal Paul, and real world test....