Building And Sealing Tanks With Clecoes?

[Spike]

Don't touch it. The moisture content in there should be very low with using them as fuel tanks, etc.

[bullojm1]

I have been searching for threads re this subject without luck, and so I figured this was as good a place as any to start a discussion.

I am trying to decide what (if any) 'finish' should be applied to the internally (fuel exposed) surfaces of the fuel tanks.

I am assuming the faying/bonded surfaces are thoroughly cleaned and ruffed up in order to acheive a good bond and therefore the Alclad is completely removed. So the question for the bonding surfaces, should they be etched and alodined or what??

Additionally, there are areas that will not get coated with Pro-Seal resulting in exposed 'raw' aluminum and so what is the recommended approach here?

Tim Cook
Chino, CA
RV-7A

Tim,

One of my only regrets about something I wish I had done on my build was Alodine the insides of my tank. Especially since I had a gallon of the stuff. Now, 99.9% of RV's out there don't have any protection on the interiors of the tank and I haven't heard many complaints about corrosion. I say if you already have Alodine and AlumiPrep, go for it. If not, don't lose any sleep.

[dons]

I didn't do anything to mine. I do admit to being careful about what I scuffed and then covering most of the scuffed area with sealant.

[airguy]

I did alodine my main tanks, more so as a hedged bet against the possibility of E-10 induced corrosion than anything else. I do plan on running E10 in my airplane, and the additional corrosion potential is small but very real (and completely over-hyped). It was a simple, easy thing to do to eliminate that issue.

[BSwayze]

Any reason why you couldn't pour some alodine in a finished tank, slosh it around, and thoroughly rinse it out when it's finished?

[bullojm1]

Bruce,

I don't know how well alodine "sticks" to alclad (no scuffed) aluminum. Also, the datasheets for Alodone call for using Alumiprep first. Knowing that, I do not know how either of those chemicals would react to the proseal in place.

I would say don't worry about it. Alclad is a really tough corrosion resistor. If you become super paranoid down the road, I say do it right and build a new set of tanks Alodined.

[BSwayze]

I hadn't thought about the prep work and the alodine, Mike. You're right. I'm not worried about it at all, really. I'll just do like thousands of other RV builders before me and leave the alclad alone.

[TomNativeNewYorker]

Bruce,

I don't know how well alodine "sticks" to alclad (no scuffed) aluminum. Also, the datasheets for Alodone call for using Alumiprep first. Knowing that, I do not know how either of those chemicals would react to the proseal in place.

Alodine does not do well on aluminum that hasnt been thoroughly cleaned and given a break free surface.



Alodine shouldnt be much of a problem from what I have seen over the years with brief contact with cured sealant.

Some components I have worked, it was common SOP to fill dents with sealant and sand smooth to make the surface entirely aerodynamically smooth. After the surfaces were sanded, I would prep and alodine all the surfaces.

[cook_ts]

Wouldn't it be cool to ask a question and have everyone agree?? HAH!

Thanks for all the options. I choose to use my normal 'pre-prime' process. Quick wash with Dawn followed by thorough AlPrep33 scrub, followed by Alodine 1201.