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Contamination? on Fuel Tank Ribs

TASEsq

Well Known Member
Patron
My fuel tank ribs (2024-T3 ALCLAD) seem to have some kind of contamination on the surface - it doesn’t come off with acetone. These have been sitting on a shelf in a dry room (50-60% humidity). The leading edge ribs were sitting right next to these and didn’t have any contamination.

Has anyone else seen this before?

I think I’m going to have to use Alumiprep and a scotchbrite pad and clean these before I begin assembly - but not so hard to remove all the Alclad.
 

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Had similar

Many of the ribs in my kit, which is a mid '90s 6A, had a similar looking 'bloom' which I assumed was related to the hydroforming process, and I didn't worry especially about it, and treated everything the same (except inside the tanks) with degreaser, scotchbrite and then zinc chromate primer.
 
Looks like they got handled with hot sweaty hands at some point and put away, resulting in light surface corrosion.
 
Leading edge and main ribs are manufactured from soft “O” material that has been heat treated prior to them being Hydro formed. That is why these parts don’t come with blue vinyl on them. The heat treating process does leave a different coloration to the material when compared to other parts. It is also somewhat variable and can look slightly different from one batch to another.
What I see in your photos is totally normal and doesn’t require any special preparation.
 
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Thanks Scott,

That’s good to hear. Appreciate your reply. Hope you guys are safe re the bushfires.

Out of interest, is there any issue with using the Alumiprep and a scotchbrite on the fuel tank ribs? Or would this open the ribs up to corrosion later (as they can’t be primed)? I’ve been scuffing the mating surfaces where the proseal will go but I was wondering if etching would be better.
 
Thanks Scott,

That’s good to hear. Appreciate your reply. Hope you guys are safe re the bushfires.

Out of interest, is there any issue with using the Alumiprep and a scotchbrite on the fuel tank ribs? Or would this open the ribs up to corrosion later (as they can’t be primed)? I’ve been scuffing the mating surfaces where the proseal will go but I was wondering if etching would be better.

I can't think of any benefit to using an etching chemical on the tank parts if no conversion coating was going to be used as well.
Mechanically abrading the mating surfaces where sealant will be used is a better method and the rest of the surface on the parts is fine to use as is even if it does look a little off when compared to non-heat treated parts.

Thanks for the sentiment regarding the fires. We have a lot of employees that have been evacuated from their homes for days now, and many others that were under be ready for immediate evacuation. One that knows his home is gone (brand new employee at Van's) and at least a couple more that probably don't know for certain if their homes are still there. For the rest of us in the immediate area, we have just had to endure smoke and ash fall bad enough that many of us are running residential air cleaners around the clock in our homes (mine are home engineered using box fans and low micron furnace filters).
Weather has taken a major turn for the better with even some rain in the forecast for next week so hopefully some improving air quality and relief for our Fire Fighters will be here soon.
 
Thanks for the sentiment regarding the fires.

My state went through the same thing at the start of the year, and while I wasn’t affected, had friends who lost houses and one whose deck was burned before the air tanker hit it. It’s a selective beast - in one street 4 houses taken but one left untouched. Whole towns here surrounded and residents pushed to the beach - to be evacuated eventually via navy ship. 2020 - what a ******* year.

Maybe I shouldn’t be tackling fuel tanks this year - leave them until 2021.

Copy your advice - I’ll scuff the mating surfaces only for now, then another light scuff and acetone clean before glooping them up. Thanks for taking the time to respond with everything going on at your end.
 
Weather has taken a major turn for the better with even some rain in the forecast for next week so hopefully some improving air quality and relief for our Fire Fighters will be here soon.

That’s great news! Best wishes to everyone affected.
 
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