Fuel tank sealant removal machine

[isaacpr7]

This is what it looks like with regular fittings in operation.

[Marauder]

  On 4/4/2015 at 12:16 AM, isaacpr7 said:

This is what it looks like with regular fittings in operation.

If you put wheels on it you could sell it as an under vehicle washing system!

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[22 others]

How will the stripper come out of the wing without it running all over the paint?  It seems that the underside of the wing needs some sort of dam or spout to make the stripper drip out into the bucket underneath.

[isaacpr7]

There will be a threaded attachment installed in place of the fuel drain valve. Someone else mentioned several postings back that when the sealant gets thin enough, the solvent can start to seep out of the bottom access panels. That is something I will figure out when I return from my deployment because I am short on time. Any suggestions will be greatly appreciated. And remember, I am trying to keep it simple.

[ryoder]

I had my tanks stripped and resealed for 1900. That was the total for both tanks. I wonder how much a machine would reduce this amount?

[isaacpr7]

If someone is actually doing this for that much I would not hesitate to have them do it for me for that price. In materials alone there is about 600 dollars after you buy the stripper, type A sealant, type B sealant, access panel sealant, and sealant protective layer. Your source might have the hookup in materials but the labor to do it by hand is insane from what I've heard. I've been quoted between 80 and 100 hours of labor. Most of it is stripping by hand but with this machine you can let it cycle on its own and come back 6 hours later when it's complete. I can see how some shops might have access to machines such as the one I'm building and still charging customers as if they did it by hand but they are still good honest people out there

[ryoder]

The shop used polygone and then removed what was leftover by hand.

[isaacpr7]

  On 4/5/2015 at 12:45 PM, ryoder said:

The shop used polygone and then removed what was leftover by hand.

What state is the shop located? I might be better off going that route when I get back if they still charge the same fee.

[carl]

Ryan,

It doesn't matter what state its in to me , I could fly it there and drop it off.

 

carl

[Belso]

Hi,I live in Australia where not one shop wants to redo tanks plus labour is $100.00 per hr.I own a F model with leaking tanks and decided to do the job myself.I bought a magnetic driven  chemical pump since any other will dissolve the seals with Polygone.After some trials and disasters with all the mentioned problems in this blog ,which is normal in R&D,came up with the commercial available garden sprinkler and replaced the plastic fittings with non dissolvable plastic fittings plus bearings to make it run smooth.Had to ad some more holes in the arms to make it propel better,I made 2 sprinklers to fit in the tanks from below,leave the top hatches on to prevent leaking,under neath I built a mobile tray,that covers the 3 tanks plus a bit more,that collects the liquid and filters out the course material,then before the pump I have a fine filter which is highly required since stuff gets past.Ihave cleaned both wing tanks with great success without hardly any manual work.If any one is interested I can supply pictures and working of the rig.GOOD LUCK

[carusoam]

Belso,

Your description of success in a far from Texas place is inspiring.  Your pictures will be appreciated by many, I think.

Best regards,

-a-

[cliffy]

Pictures please! 

[TargetDriver]

Anyone still following this chain?  Sure would like to see those pictures.

I'm building a flush system now for the K model I just bought. Left tank is the worst, right tank has one small weep.  It doesn't look like anyone on MS has mentioned resealing or doing their tanks in some time.  I've found the sealant but haven't figured out how much to buy (per tank). I'm going with 3 gal of PolyGone for the stripper. I opted for rotary nozzles for my system with more flow than pressure to keep atomization down and wet-flow up. 

The intent is to make it somewhat smaller and crate the system and for it to be shippable...just in case someone else wants to use it.

[1524J]

I've stripped and resealed a tank. Building a recirculating system may take more time than stripping by hand unless your planning on using the system multiple times. I just can't imagine that you still won't need several hours of hand work even after using a recirculating system as you've got to clean every nook and cranny. After my experience, I think a syringe system that allows you to push the sealant under pressure would be the ticket. Forcing the sealant into every crevice and seam. You inventive types come up with that and I'd pay to rent! 

[N201MKTurbo]

  On 3/15/2016 at 12:39 AM, 1524J said:

II've stripped and resealed a tank. Building a recirculating system may take more time than stripping by hand unless your planning on using the system multiple times. I just can't imagine that you still won't need several hours of hand work even after using a recirculating system as you've got to clean every nook and cranny. After my experience, I think a syringe system that allows you to push the sealant under pressure would be the ticket. Forcing the sealant into every crevice and seam. You inventive types come up with that and I'd pay to rent! 

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I have one of these:

http://www.aircraftspruce.com/catalog/topages/sealantgun1.php

Put a sealant cartridge in after mixing, push the button and a nice little bead comes out.

[TargetDriver]

24J,  After studying the resealing procedures I think I'm going to use a technique we use in the field on military target fuel tanks (Composite) if there's a leak. .. I know I have to be very careful to prevent any over-pressure due to the structure but we would slosh or paste a tank (that had seams) and then apply no more than 3-5 psi for about 20 min. This forces the still-semi liquid sealant into the same cracks that fuel would be trying to seep into. We don't leave the pressure on too long so not to force it completely through any possible seep ports. 

I have yet to figure out how much of each type of sealant to get though for a tank. I'm only going to do the left tank completely as the right one only has one small seep showing. After filling it completely and letting it set for two weeks, the left tank has dropped 4-5 gallons. Hard to believe really.

 

 

 

 

[1524J]

  On 3/15/2016 at 4:15 AM, N201MKTurbo said:

I have one of these:

http://www.aircraftspruce.com/catalog/topages/sealantgun1.php

Put a sealant cartridge in after mixing, push the button and a nice little bead comes out.

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Well......I obviously need to get out and do more research. If that's been around for more than five years I'm gonna kick myself. I tried to put my sealant in a big syringe and it worked on seams that were easy to reach.....not so much on the hard to reach places. Have you used it? I still need to strip and reseal the left tank but if I wait long enough I'll probably need to do the right side again. Now would probably be a good time since I just replaced my shock discs. Just really hard to get the motivatied.....

[1524J]

  On 3/15/2016 at 4:24 AM, TargetDriver said:

24J,  After studying the resealing procedures I think I'm going to use a technique we use in the field on military target fuel tanks (Composite) if there's a leak. .. I know I have to be very careful to prevent any over-pressure due to the structure but we would slosh or paste a tank (that had seams) and then apply no more than 3-5 psi for about 20 min. This forces the still-semi liquid sealant into the same cracks that fuel would be trying to seep into. We don't leave the pressure on too long so not to force it completely through any possible seep ports. 

I have yet to figure out how much of each type of sealant to get though for a tank. I'm only going to do the left tank completely as the right one only has one small seep showing. After filling it completely and letting it set for two weeks, the left tank has dropped 4-5 gallons. Hard to believe really.

 

   That would probably work on a patch job. Not sure it would work on a complete strip and reseal.That's essentially what Don Maxwell does to find leaks (except he uses soap and a vacuum) but then they patch with sealant. You've got to be very careful with your Mooney fuel tanks that you don't seal or cover the holes that allow the fuel to flow between the bay's. Also take extra care to seal the screen on your pickup tube before you start. Be meticulous in your inspection before sealing up your access panels. I've got a good relationship with my A&P/IA and only tackle jobs that I'm very comfortable completing. Mostly the labor intensive ones that don't require a great deal of experience in knowing what your looking for. He still makes me show him the service manual and explain what I'm going to do to make sure I "get it." An example......I was in the shop a couple of days ago and Pete hands me a crankshaft and said "can you believe the wear on this after 15 minutes of running?" Not knowing what wear on a crankshaft is supposed to look like I told him "wow, that really looks bad!" Then fessed up and told him I didn't have a clue what "wear" he was talking about. Being the kind A&P he proceeded to explain, but you get my point. I'm sure with your military background (Thanks for your service!) you have a great deal more experience than I do but I always follow Clint's council......:)

 

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[TargetDriver]

24J,

You're very welcome and it's still an honor to support the warfighter effort when I can. Ya gotta love Clint !

I see what you mean about the light pressure may not be enough to force so many areas into those crevices. The tanks we're doing that on are carbon composite and can take much more pressure if need be, whereas our aluminum skin structure could not.  It'll be a real time call when I see the consistency of the sealant and how it all flows. I may do a quick 3 psi test piece to check it.  I've met an A&P/IA at my new airport that allows me some of the same freedoms thankfully. Having built several planes, race cars, etc. helps with my knowledge base,  but he wants to see my work which I'll gladly do to get his blessing.  I like a challenge and as much as everyone curses the fuel tank reseal, I'm looking forward to doing it. I'm kind of dense that way... tell me I can't do it or no one does that because...  I'm all over it just to prove I can do it. 

Had to laugh about your crankshaft wear story... I work with a company of aerospace engineers and use that all the time... I call it the "old person nod". They'll go off in some other language of engineereese and I'll just nod, smile and say...yeaaaa... no clue what they're saying sometimes. Ha ha.

Turbo,

Have you used that air gun yet?  Do you use a long nozzle and leave the gun out of the tank or do you actually get the gun in the tank and use a hard nozzle. How is it for maneuvering it around in the tank if you do?  I  like that idea.  I've seen the 6 oz kits. Do those "kit" tubes just fit in that gun and mix as its leaving the nozzle or do you mix externally and load a disposable tube?    At work we sometimes use a ClickBond structural adhesive that comes in a dual tube with a plastic nozzle that has "zig zag path" molded into it. One squeeze and they both mix as they go down the tube.. exits as mixed and ready to lay.  It's fantastic for gluing nutplates in position.

[MARZ]

  On 3/15/2016 at 4:02 PM, 1524J said:

  On 3/15/2016 at 4:24 AM, TargetDriver said:

24J,  After studying the resealing procedures I think I'm going to use a technique we use in the field on military target fuel tanks (Composite) if there's a leak. .. I know I have to be very careful to prevent any over-pressure due to the structure but we would slosh or paste a tank (that had seams) and then apply no more than 3-5 psi for about 20 min. This forces the still-semi liquid sealant into the same cracks that fuel would be trying to seep into. We don't leave the pressure on too long so not to force it completely through any possible seep ports. 

I have yet to figure out how much of each type of sealant to get though for a tank. I'm only going to do the left tank completely as the right one only has one small seep showing. After filling it completely and letting it set for two weeks, the left tank has dropped 4-5 gallons. Hard to believe really.

 

   That would probably work on a patch job. Not sure it would work on a complete strip and reseal.That's essentially what Don Maxwell does to find leaks (except he uses soap and a vacuum) but then they patch with sealant. You've got to be very careful with your Mooney fuel tanks that you don't seal or cover the holes that allow the fuel to flow between the bay's. Also take extra care to seal the screen on your pickup tube before you start. Be meticulous in your inspection before sealing up your access panels. I've got a good relationship with my A&P/IA and only tackle jobs that I'm very comfortable completing. Mostly the labor intensive ones that don't require a great deal of experience in knowing what your looking for. He still makes me show him the service manual and explain what I'm going to do to make sure I "get it." An example......I was in the shop a couple of days ago and Pete hands me a crankshaft and said "can you believe the wear on this after 15 minutes of running?" Not knowing what wear on a crankshaft is supposed to look like I told him "wow, that really looks bad!" Then fessed up and told him I didn't have a clue what "wear" he was talking about. Being the kind A&P he proceeded to explain, but you get my point. I'm sure with your military background (Thanks for your service!) you have a great deal more experience than I do but I always follow Clint's council......:)

 

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actually you'd be better going the other way- I've heard that the better way is to fab up some plexi "windows" for the tank access - apply soapy water to the seams and pull a slight vacuum  to find the leak point - in our tanks the leak will travel and not necessarily indicate the actual spot with pressure.

[TargetDriver]

Ah yep, true. That's sounds right.

[Guest]

  On 3/15/2016 at 4:24 AM, TargetDriver said:

24J,  After studying the resealing procedures I think I'm going to use a technique we use in the field on military target fuel tanks (Composite) if there's a leak. .. I know I have to be very careful to prevent any over-pressure due to the structure but we would slosh or paste a tank (that had seams) and then apply no more than 3-5 psi for about 20 min. This forces the still-semi liquid sealant into the same cracks that fuel would be trying to seep into. We don't leave the pressure on too long so not to force it completely through any possible seep ports. 

I have yet to figure out how much of each type of sealant to get though for a tank. I'm only going to do the left tank completely as the right one only has one small seep showing. After filling it completely and letting it set for two weeks, the left tank has dropped 4-5 gallons. Hard to believe really.

 

 

 

 

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I'd be very cautious applying that much pressure to your wing tank.  With a piece of hose hooked to the vent fitting and only mouth pressure you can see the skins flex, too much pressure and you could end up with a Cessna air foil.

Clarence

[philipneeper]

I actually just did my tanks.... i used polygone and it didn't drip all over the bottom at all... and its water soluble so i used a hose to get it out, and then a heat gun on low to evap all moisture that i couldn't get out with a paper towel..... with that contraption listed above, it will not hurt the tanks what so ever. 

 

[philipneeper]

  On 3/14/2016 at 11:36 PM, TargetDriver said:

Anyone still following this chain?  Sure would like to see those pictures.

I'm building a flush system now for the K model I just bought. Left tank is the worst, right tank has one small weep.  It doesn't look like anyone on MS has mentioned resealing or doing their tanks in some time.  I've found the sealant but haven't figured out how much to buy (per tank). I'm going with 3 gal of PolyGone for the stripper. I opted for rotary nozzles for my system with more flow than pressure to keep atomization down and wet-flow up. 

The intent is to make it somewhat smaller and crate the system and for it to be shippable...just in case someone else wants to use it.

Expand  

I used the poly gone gel..... didn't see good results til the bottom of the bucket. I did my right tank yesterday, applied polygone at about 10 pm.... woke up, went to breakfast and about 10-11am reached in and it came out easy peasy. 

[TargetDriver]

Phil,  Wow, that's good to know.  From what I can see in my tanks, there isn't much beyond factory or minimal sealant...not like someone sloshed the tank or similar. Maybe the gel is the way to go. Did it stick to the upper joints/walls alright?  Perhaps I don't even need a spray system.

How much should I buy for one tank, considering it's a complete strip and reseal?