In-place Repair of Aluminum Fuel Tank - Moderated Discussion Areas

  ContinuousWave
  Whaler
  Moderated Discussion Areas
  ContinuousWave: Whaler Repairs/Mods
  In-place Repair of Aluminum Fuel Tank

search | FAQ | profile | register | author help

Author Topic:   In-place Repair of Aluminum Fuel Tank

cvyarb posted 09-28-2014 08:09 PM ET (US)
Hi ContinuousWave community. This whole weekend was spent working on the Boston Whaler 27 Full Cabin Whaler Drive boat, and I am pleased to say we covered a ton of ground. I will post pictures and link them here for anyone interested, In the meantime I need some advice. A little background first: after the bad mold was removed from the cockpit area, I pulled the fishing area deck up. It came up in two pieces, one which was very heavy, and I power washed everything and spent a huge amount of time cleaning everything up so there wouldn't be any grime and residue under the decks and in the superstructure of the boat. Next, we drained 170-gallons from the three tanks, 170-gallon main tank and two 70-gallon saddle tanks. We then took the fuel pick-ups off each tank and drained the last bit of fuel, including the crud and grime that had accumulated. There wasn't much in there, and the tank internals looked very clean. But, unfortunately I also ran into a problem.
The 170-gallon tank has one rust spot approximately halfway (maybe more, not sure) through the aluminum. Some people would use it and try to get a year or so out of it, but I'm not going to. It's decommissioned permanently. Replacing it now is not an option.
One saddle tank is totally pristine, and has no problems, whatsoever. The other has a tiny rust spot, maybe one-fifth of the way through the tank. This tank is the one I have a question about.
I have already scraped the small amount of rust away, so that I am down to good aluminum. Obviously the boat won't ever sit again in storage for five years, so there won't be water in there to rust it further, but I would like to treat this spot in some way. Is there some type of epoxy or sealant that I can put on it? I am not going to take the tank out of the boat right now, so this has to be something I can brush on and apply through a hole about 8-inches-big in the top of the tank.
As a side note, I should note that the Yamaha OX66 225's are very low hours and are spotless under the hood. They smoked a lot starting up but, man, it was great to here them run.
Any help you can offer would be greatly appreciated. You guys have been a great resource and I appreciate the help. There are some pictures of this weekend’s work here: http://www.thehulltruth.com/boating-forum/623342-aluminum-tank-repair-question.html

Jeff posted 09-28-2014 09:07 PM ET (US)
http://www.thehulltruth.com/boating-forum/ 623342-aluminum-tank-repair-question.html
jimh posted 09-29-2014 07:01 AM ET (US)
I can't offer any first-hand advice about an epoxy that is resistant to ethanol gasoline. But here are some interesting threads on the topic:
http://www.boatdesign.net/forums/fiberglass-composite-boat-building/ resin-build-ethanol-safe-gasoline-tanks-44720.html
http://www.westsystem.com/ss/wood-epoxy-composite-tank-guidelines/
http://www.egyptian.net/~raymacke/Cbnskif17.htm
http://egyptian.net/%7Eraymacke/Cbnskif27.htm
http://egyptian.net/%7Eraymacke/Cbnskif36.htm
Overall, the inference I make from reading these is only limited success with epoxy and ethanol-gasoline fuel may be possible.
jimh posted 09-29-2014 08:21 AM ET (US)
It may also be possible to draw an inference about the ability of epoxy or other resins to withstand fuel containing gasoline-alcohol mixtures from the experience of a commercial fuel tank manufacturer, Pate Plastics of Miami, Florida. Pate Plastics was successfully manufacturing and selling gasoline fuel tanks made with resin and laminates for decades, but upon the change in gasoline fuels to a mixture of ethanol and gasoline, Pate Plastics ceased manufacture of their tanks. I have to think that Pate Plastics must have explored many possible resins for use in making a fuel tank. Since they stopped manufacturing laminated fuel tanks, it seems a reasonable inference is they must not have found any suitable resin that could withstand ethanol-gasoline fuel.
It may also be possible to draw an inference from the use of laminated fuel tanks in aircraft. In aircraft engines there is an FAA prohibition against use of ethanol-gasoline blended fuels, and only pure gasoline is used as an aircraft fuel. Use of laminated fuel tanks continues in the aircraft industry.
Since laminated fuel tanks are virtually non-existent in marine use but continue in aircraft use, and since the only significant difference is the use of ethanol-gasoline blended fuels in marine tanks, there is a strong suggestion that no good laminating resins have been found which will resist ethanol-gasoline fuels.
jimh posted 09-29-2014 08:37 AM ET (US)
[This thread will be moving to REPAIRS/MODS]
cvyarb posted 09-29-2014 08:51 AM ET (US)
JimH, thanks for your advice and the links to the threads. I read numerous threads on the subject but the opinions vary so much it left me scratching my head and still totally unsure about how to proceed.
I worked in aviation for about 7 years and know about the no ethanol in low lead rule. I didn't know that laminated tanks weren't allowed in aviation. I think your conclusion is correct, and there is a lot of experiential as well as testimonial support for it.
I guess maybe the solution is to just pull the deck each year and keep an eye on it.
Let me throw another question at you if I can. Over on The Hull Truth forum someone mentioned to look out for holes on the bottom of the tank as well; in places where the tank could have been submerged (there was high water in the bilge for about a year). Does anyone have an opinion about whether, if I can check a representative area that was submerged and it is rust free, that that would be a safe assumption about the rest of the tank (for existence of rust holes from the outside of the tank moving inward). As a comparison, the rust holes inside the tank developed over the course of 5 years.
I want to be safe and responsible, but also don't want to overdo it. For me to pull any one of the three tanks means also removing the whole helm area, and then it goes from a big project to a HUGE one.
jimh posted 09-29-2014 11:38 AM ET (US)

quote:
I didn't know that laminated tanks weren't allowed in aviation.
I didn't know that either. I thought exactly the opposite. Where did you get the information that fiberglass or laminated tanks were not allowed in aviation? My research seems to find that aviation was the only place fiberglass fuel tanks were being used.
jimh posted 09-29-2014 11:47 AM ET (US)
[Moved to REPAIRS/MODS for discussion.]
jimh posted 09-29-2014 11:50 AM ET (US)
ASIDE: From the images of the newly cleaned cockpit and engine area, it looks like you did a great job cleaning up the mildew and mold problem that existed on the boat. That was good work.
ASIDE: The Yamaha 225-HP Ox66 engines are very nice two-stroke-power-cycle engines, perhaps the most sophisticated of the older style two-cycle engines with their closed loop fuel injection system and oxygen sensor. You can find some advice about maintaining the Ox66 engine in the archives here.
jimh posted 09-29-2014 12:05 PM ET (US)
The focus of this repair is to find a method of performing the repair while the tanks are in place in the fuel tank cavity of the boat, and, since the tanks are foamed in place, the repair is limited to accessing the tank from the internal tank wall and further complicated by the very limited access to the internal tank area by limited diameter access plates.
I can't offer any first-hand advice on this, nor do I know of any refence I could cite that might offer first-hand advice for how to accomplish the repair. I can only speculate.
It might be workable to accomplish a repair by cutting a large opening in the upper surface of the fuel tank. The dimensions of this cut out would have to be chosen on the basis of affording good access to the internal part of the fuel tank that is to be repaired in-place. The area cut out would then have to be worked in such a way that a newly fabricated cover could be fitted to the tank to re-seal this area. This would probably mean drilling and tapping holes in the tank or using PEM nuts to provide a threaded fastener for the machine screws that would hold the newly fabricated cover for the large opening. Some sort of gasket would be necessary. Grounding would have to be considered.
Through the new large opening, the areas of the tank known to be eroded and thin could be covered with new aluminum plates. These plates could be welded in place. The welding would have to be done cautiously, as the exterior wall of the tank section being welded will likely be in contact with the foam, and, if the tank wall becomes too hot it could melt away the foam.
Whether such an approach is workable, I cannot say. I would be guided by the advice of people experienced in the fabrication of aluminum fuel tanks for boats which are foamed in place.
cvyarb posted 09-29-2014 01:15 PM ET (US)
JimH, thanks for the response.
Thanks for the compliments regarding the clean up. There was a lot of grime/mud whatever under the decks and in the bilge, and it was a big undertaking to get it all out. Totally worth it though.
Regarding the one tank in consideration, I am getting a lot of different advice about repairing the inside of the tank, even from shops that do it. It seems that how the products that would usually do the job react with ethanol is the issue. Everyone is unanimous though that it shouldn't spread further with gas in the tank, and its very light corrosion, so it will be ok until I get a confirmed action plan in place.
Re the aviation fuel tanks, I was responding to what I thought you said. My work was in aviation safety, operations, etc. and I know nothing about fuel tanks, and so I made a mistake.
Some people on THT are saying that I should pull the two saddle tanks to look for corrosion on the bottom and sides, and that if I don't I am asking for trouble. Any thoughts?
I am headed up there now to see how much it will take for me to pull the helm area. I started a thread on pulling Whaler fuel tanks and how difficult it is, if you have the time to offer your advice.
Many thanks.
deepwater posted 09-29-2014 05:52 PM ET (US)
Marine Tex

Hop to:

Contact Us | RETURN to ContinuousWave Top Page

Powered by: Ultimate Bulletin Board, Freeware Version 2000
Purchase our Licensed Version- which adds many more features!
© Infopop Corporation (formerly Madrona Park, Inc.), 1998 - 2000.

Author	Topic: In-place Repair of Aluminum Fuel Tank
cvyarb	posted 09-28-2014 08:09 PM ET (US) Hi ContinuousWave community. This whole weekend was spent working on the Boston Whaler 27 Full Cabin Whaler Drive boat, and I am pleased to say we covered a ton of ground. I will post pictures and link them here for anyone interested, In the meantime I need some advice. A little background first: after the bad mold was removed from the cockpit area, I pulled the fishing area deck up. It came up in two pieces, one which was very heavy, and I power washed everything and spent a huge amount of time cleaning everything up so there wouldn't be any grime and residue under the decks and in the superstructure of the boat. Next, we drained 170-gallons from the three tanks, 170-gallon main tank and two 70-gallon saddle tanks. We then took the fuel pick-ups off each tank and drained the last bit of fuel, including the crud and grime that had accumulated. There wasn't much in there, and the tank internals looked very clean. But, unfortunately I also ran into a problem. The 170-gallon tank has one rust spot approximately halfway (maybe more, not sure) through the aluminum. Some people would use it and try to get a year or so out of it, but I'm not going to. It's decommissioned permanently. Replacing it now is not an option. One saddle tank is totally pristine, and has no problems, whatsoever. The other has a tiny rust spot, maybe one-fifth of the way through the tank. This tank is the one I have a question about. I have already scraped the small amount of rust away, so that I am down to good aluminum. Obviously the boat won't ever sit again in storage for five years, so there won't be water in there to rust it further, but I would like to treat this spot in some way. Is there some type of epoxy or sealant that I can put on it? I am not going to take the tank out of the boat right now, so this has to be something I can brush on and apply through a hole about 8-inches-big in the top of the tank. As a side note, I should note that the Yamaha OX66 225's are very low hours and are spotless under the hood. They smoked a lot starting up but, man, it was great to here them run. Any help you can offer would be greatly appreciated. You guys have been a great resource and I appreciate the help. There are some pictures of this weekend’s work here: http://www.thehulltruth.com/boating-forum/623342-aluminum-tank-repair-question.html
Jeff	posted 09-28-2014 09:07 PM ET (US) http://www.thehulltruth.com/boating-forum/ 623342-aluminum-tank-repair-question.html
jimh	posted 09-29-2014 07:01 AM ET (US) I can't offer any first-hand advice about an epoxy that is resistant to ethanol gasoline. But here are some interesting threads on the topic: http://www.boatdesign.net/forums/fiberglass-composite-boat-building/ resin-build-ethanol-safe-gasoline-tanks-44720.html http://www.westsystem.com/ss/wood-epoxy-composite-tank-guidelines/ http://www.egyptian.net/~raymacke/Cbnskif17.htm http://egyptian.net/%7Eraymacke/Cbnskif27.htm http://egyptian.net/%7Eraymacke/Cbnskif36.htm Overall, the inference I make from reading these is only limited success with epoxy and ethanol-gasoline fuel may be possible.
jimh	posted 09-29-2014 08:21 AM ET (US) It may also be possible to draw an inference about the ability of epoxy or other resins to withstand fuel containing gasoline-alcohol mixtures from the experience of a commercial fuel tank manufacturer, Pate Plastics of Miami, Florida. Pate Plastics was successfully manufacturing and selling gasoline fuel tanks made with resin and laminates for decades, but upon the change in gasoline fuels to a mixture of ethanol and gasoline, Pate Plastics ceased manufacture of their tanks. I have to think that Pate Plastics must have explored many possible resins for use in making a fuel tank. Since they stopped manufacturing laminated fuel tanks, it seems a reasonable inference is they must not have found any suitable resin that could withstand ethanol-gasoline fuel. It may also be possible to draw an inference from the use of laminated fuel tanks in aircraft. In aircraft engines there is an FAA prohibition against use of ethanol-gasoline blended fuels, and only pure gasoline is used as an aircraft fuel. Use of laminated fuel tanks continues in the aircraft industry. Since laminated fuel tanks are virtually non-existent in marine use but continue in aircraft use, and since the only significant difference is the use of ethanol-gasoline blended fuels in marine tanks, there is a strong suggestion that no good laminating resins have been found which will resist ethanol-gasoline fuels.
jimh	posted 09-29-2014 08:37 AM ET (US) [This thread will be moving to REPAIRS/MODS]
cvyarb	posted 09-29-2014 08:51 AM ET (US) JimH, thanks for your advice and the links to the threads. I read numerous threads on the subject but the opinions vary so much it left me scratching my head and still totally unsure about how to proceed. I worked in aviation for about 7 years and know about the no ethanol in low lead rule. I didn't know that laminated tanks weren't allowed in aviation. I think your conclusion is correct, and there is a lot of experiential as well as testimonial support for it. I guess maybe the solution is to just pull the deck each year and keep an eye on it. Let me throw another question at you if I can. Over on The Hull Truth forum someone mentioned to look out for holes on the bottom of the tank as well; in places where the tank could have been submerged (there was high water in the bilge for about a year). Does anyone have an opinion about whether, if I can check a representative area that was submerged and it is rust free, that that would be a safe assumption about the rest of the tank (for existence of rust holes from the outside of the tank moving inward). As a comparison, the rust holes inside the tank developed over the course of 5 years. I want to be safe and responsible, but also don't want to overdo it. For me to pull any one of the three tanks means also removing the whole helm area, and then it goes from a big project to a HUGE one.
jimh	posted 09-29-2014 11:38 AM ET (US) quote: I didn't know that laminated tanks weren't allowed in aviation. I didn't know that either. I thought exactly the opposite. Where did you get the information that fiberglass or laminated tanks were not allowed in aviation? My research seems to find that aviation was the only place fiberglass fuel tanks were being used.
jimh	posted 09-29-2014 11:47 AM ET (US) [Moved to REPAIRS/MODS for discussion.]
jimh	posted 09-29-2014 11:50 AM ET (US) ASIDE: From the images of the newly cleaned cockpit and engine area, it looks like you did a great job cleaning up the mildew and mold problem that existed on the boat. That was good work. ASIDE: The Yamaha 225-HP Ox66 engines are very nice two-stroke-power-cycle engines, perhaps the most sophisticated of the older style two-cycle engines with their closed loop fuel injection system and oxygen sensor. You can find some advice about maintaining the Ox66 engine in the archives here.
jimh	posted 09-29-2014 12:05 PM ET (US) The focus of this repair is to find a method of performing the repair while the tanks are in place in the fuel tank cavity of the boat, and, since the tanks are foamed in place, the repair is limited to accessing the tank from the internal tank wall and further complicated by the very limited access to the internal tank area by limited diameter access plates. I can't offer any first-hand advice on this, nor do I know of any refence I could cite that might offer first-hand advice for how to accomplish the repair. I can only speculate. It might be workable to accomplish a repair by cutting a large opening in the upper surface of the fuel tank. The dimensions of this cut out would have to be chosen on the basis of affording good access to the internal part of the fuel tank that is to be repaired in-place. The area cut out would then have to be worked in such a way that a newly fabricated cover could be fitted to the tank to re-seal this area. This would probably mean drilling and tapping holes in the tank or using PEM nuts to provide a threaded fastener for the machine screws that would hold the newly fabricated cover for the large opening. Some sort of gasket would be necessary. Grounding would have to be considered. Through the new large opening, the areas of the tank known to be eroded and thin could be covered with new aluminum plates. These plates could be welded in place. The welding would have to be done cautiously, as the exterior wall of the tank section being welded will likely be in contact with the foam, and, if the tank wall becomes too hot it could melt away the foam. Whether such an approach is workable, I cannot say. I would be guided by the advice of people experienced in the fabrication of aluminum fuel tanks for boats which are foamed in place.
cvyarb	posted 09-29-2014 01:15 PM ET (US) JimH, thanks for the response. Thanks for the compliments regarding the clean up. There was a lot of grime/mud whatever under the decks and in the bilge, and it was a big undertaking to get it all out. Totally worth it though. Regarding the one tank in consideration, I am getting a lot of different advice about repairing the inside of the tank, even from shops that do it. It seems that how the products that would usually do the job react with ethanol is the issue. Everyone is unanimous though that it shouldn't spread further with gas in the tank, and its very light corrosion, so it will be ok until I get a confirmed action plan in place. Re the aviation fuel tanks, I was responding to what I thought you said. My work was in aviation safety, operations, etc. and I know nothing about fuel tanks, and so I made a mistake. Some people on THT are saying that I should pull the two saddle tanks to look for corrosion on the bottom and sides, and that if I don't I am asking for trouble. Any thoughts? I am headed up there now to see how much it will take for me to pull the helm area. I started a thread on pulling Whaler fuel tanks and how difficult it is, if you have the time to offer your advice. Many thanks.
deepwater	posted 09-29-2014 05:52 PM ET (US) Marine Tex