sealant removal from a blind fuel tank

[cajid]

i am facing a problem where the sealant has blocked some of the internal vent holes inside a blind metallic fuel tank. The tank has only inlet and outlet connections available for access. Can anyone suggest some solution how to get rid of sealant from this area.
thanks

 

[FieldTeam]

How big are the inlet/outlet?
Is the sealant loose that has floated into the holes or excess that has sealed the holes?

High pressure air or water can be used to blow out loose sealant. Modify a piece of tubing to direct and blast the sealant out.

An Aquamiser can be used to get rid of the tough stuff.

http://www.aquamiser.com/

All depends on the available access.

 

[cajid]

The holes are very small about half inch in dia while the metalic tank is inside the walls of the wings. The sealant has blocked the holes inside the wings. water o high pressure air is not working in it. There is no access as its a blind tank from all sides, except the available ports of fuel inlet and fuel outlet connections. Any other suggestions.

 

[eng3000]

Do you know which composition/manufacturer of sealant it its?

Has this been incorrectly applied (recently?) or has it migrated there though creep or being dislodged?

If practical and safe, you might like to try softening it first with a solvent before trying again with air or water.

For a lot of common aircraft sealants MEK (methyl ethyl ketone,) does the trick.

 

[WKTaylor]

cajid... very odd tank that has no access for maintenance.

Unfortunately, the only safe option may be structural disassy to remove the tank; open it up (cut a hole) to remove the sealant; patch-repair it; then reinstall and accomplish structural reassembly as needed.

I once worked a case where a fighter wing was contaminated with powder fire extinguishing agent (long/sad story). Wing was removed and sent to depot for tear-down and clean-up. It was the ONLY safe way to decontaminate it.

Hmmm... PERHAPS a flexible borescope with surgical implements/attachments could cut-out and retrieve the sealant, in-pieces.

Regards, Wil Taylor

 

[DavidLeyman]

Is not MEK an illegal substance in many countries now? I am thinking about COSHH legislation and its equivalent elsewhere.
Turco might do it but it is a bit of a long shot.
Practically speaking I go with WKTaylor. That is undoubtedly my route though this problem.
Dry powder? Tank? You have me on edge - there is a story here that you must tell!

 

[thruthefence]

Buy it any of the "big box" home improvement stores everyday.

 

[DavidLeyman]

thruthefence: Ye Gods. Really? Are you living in third world country, perhaps?

 

[thruthefence]

Not Yet, but we are shuffling towards that status as we speak.

 

[kontiki99]

Maybe try something like a small plummers snake.

 

[floch]

Hi,

"Sorry, I'm not a god in english"

I'm agree with wktaylor

May be with a endoscopic material.Endoscopic could allow to access in a blocked vent hole by inlet and outlet connections.
You can local manufacture a little knife or attach a scapel or razor blade.
I already use this method.

Have you an endoscopic equipment?

Regards

"Le capitalisme, c'est l'exploitation de l'homme par l'homme ! Le syndicalisme, c'est le contraire !"
Coluche

 

[thruthefence]

I'm not trying to be disrespectful here, but PRC, or proseal is extremely tenacious. The idea that it can be removed with an exacto blade on the end of an endoscope is not going to happen.

 

[DavidLeyman]

I'm with thruthefence on this. There is also a teensy worry about what happens to the shaved off bits. Can we guarantee that they are all out?

Et aussi, je ne suis pas un Dieu en Francais, malhereusement

 

[DavidLeyman]

In retrospect I have a niggle in the back of my head that says 'scratched surfaces'. Granted that the case in point may be stainless steel but if the practice of flailing about with sharp blades becomes endemic then the surface finish of the structure could be impaired. Scraping sealant off is one thing but restoring surface protection is another quite apart from the potential for setting up fatigue points in the metal directly and indirectly (through corrosion). See wktaylor above (both responses).

 

[edmeister]

I have a problem here.

If sealant is being used - then this tank should be a riveted tank. Unrivet - clean & reassemble.

If it is a 'one-piece' welded tank - then there should be no sealant in the interior.

Once a solvent such as MEK loosens up a section of sealant - any of the adjacent sealant will not be reliable - and in time leak. Given that only a single out-port exists - there is more reason why it should be opened up & a clean job performed. Using borescopes; non-explosion proof light sources & microsurgery inside a fuel tank also seems silly.

Recommend - cut a typ 8" circular hole on the top surface - perform task - obtain a Engineered repair to install a internal nutplate ring /gasket & lid.
- If this is a tank is from a fairly old aircraft & dissembly is not an option - you will require the access to reseal all the leaky joints anyhow ..

 

[pirko]

Dear Cajid there are two ways,
You can Dry ice with pressure air. This is Standard striping technology for aerospace painting.
Second look and try this striper.

http://www.aerospace.chemetall.com/pdf/tds-nsolvfn-05-02-17.pdf

Good luck. Libor