Fuel tank sealant removal machine

[isaacpr7]

Still doing research on methods others have used for sealant removal and I found the following quote from Mooney65E to be interesting:

"Nearly 10 years ago I machined two cover plates from .250" aluminum that covered the lower access panels. I drilled and tapped one hole in each and installed a brass sprinkler fitting on the inside of the outboard panel. On the bottom of the inboard panel I installed a return line which drained stripper fluid to a metal tub where it was recirculated through a submersible pump back to the sprinker/spray head inside the wing tank. About 5-6 hours and we were completely rid of the old sealant and ready to apply the new (we also used Flamemaster)."

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[ArtVandelay]

1 hour ago, isaacpr7 said:

 

Still doing research on methods others have used for sealant removal and I found the following quote from Mooney65E to be interesting:

 

"Nearly 10 years ago I machined two cover plates from .250" aluminum that covered the lower access panels. I drilled and tapped one hole in each and installed a brass sprinkler fitting on the inside of the outboard panel. On the bottom of the inboard panel I installed a return line which drained stripper fluid to a metal tub where it was recirculated through a submersible pump back to the sprinker/spray head inside the wing tank. About 5-6 hours and we were completely rid of the old sealant and ready to apply the new (we also used Flamemaster)."

 

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That submersible pump will need to be able to withstand the chemicals, not sure how hard that will be to find but I don't think you'll find it at Home Depot.

[isaacpr7]

I bought one a Lowes made out of cast iron but thinking about trading it for one that pumps less GPH. Even if it was a plastic one, I only need to use it once so I don't mind dumping it in the trash after I'm done. A bilge pump goes for about 20 bucks at Walmart but I'm thinking about buying one from Harbor Freight that has a float in case the sump becomes empty for a short period.

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[1524J]

http://www.instructables.com/id/Inexpensive-easy-to-build-peristaltic-pump/

This would work great for your application and they work well. 

Didnt watch the video before I attached the link. You'd need to attach a motor, but a peristaltic pump would eliminate any contact of the pump with chemicals. 

 

[carusoam]

If you can build a peristaltic pump....

It is proof that you have some pretty good DIY skills!

The nice thing about the peristaltic pump is it's ability to separate the solvent from pump parts that are easily dissolved.

The challenge is flow rate is relatively small and pressure is near zero.

Ebay probably has many of this type of pump.

Solvent washing is a nice way of removing a solute.  Each time you repeat the process, it really lowers the amount of solute left behind.

From Chem lab 101...

If the first wash removes the 99% of the solute.

the second will remove 99.9

the third will remove 99.99.

There is a diminishing return on each additional wash.

 

Applied to fuel tank sealant removal...

the first wash may leave a couple % behind in small chunks in important places.

a second wash is a good way to go after those tough chunks and make them easier to see before sealing over them.

 

Best regards,

-a-

[isaacpr7]

http://www.instructables.com/id/Inexpensive-easy-to-build-peristaltic-pump/

This would work great for your application and they work well. 

Didnt watch the video before I attached the link. You'd need to attach a motor, but a peristaltic pump would eliminate any contact of the pump with chemicals. 

 

OMG! I wish I had known about these are long time ago. I can replicate a much better version of this now that I know how it works. For now I might stick with the pump I have on hand but I will definitely upgrade when I move to the east coast and share the plans with you guys. The wheels are spinning super fast in my head now. I love that idea. Thank you so much bud

I don't even need a sump to hold the solvent anymore. I'll just dump it all inside the tank and recirculate the fluid that way with that type of pump.

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[isaacpr7]

For now I found success in the second to last test of the recirculating system I have been working on. Final test will be while installed inside the tank. I installed a one way check valve in the line and a valve. The valve allows me to set desired flow to the nozzles as seen in the two pictures.

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[Yetti]

On 3/28/2016 at 6:55 AM, teejayevans said:

That submersible pump will need to be able to withstand the chemicals, not sure how hard that will be to find but I don't think you'll find it at Home Depot.

Seems like the pump on this should work... and you have a tank for the chemicals....

http://www.harborfreight.com/6-1-2-half-gallon-parts-washer-96952.html

 

[ArtVandelay]

24 minutes ago, Yetti said:

Seems like the pump on this should work... and you have a tank for the chemicals....

http://www.harborfreight.com/6-1-2-half-gallon-parts-washer-96952.html

 

I don't think so, 1st warning from the manual:

1. Use only water-based solvents. Do not use caustic, volatile, or combustible solvents, such as gasoline or toluene 

[1524J]

Just now, teejayevans said:

I don't think so, 1st warning from the manual:

1. Use only water-based solvents. Do not use caustic, volatile, or combustible solvents, such as gasoline or toluene 

Polygone is water based.

I like the pattern on the 2nd photo. Should cause agitation which will help dissolve the polysulfide.

 

 

 

[isaacpr7]

Just now, teejayevans said: I don't think so, 1st warning from the manual:

1. Use only water-based solvents. Do not use caustic, volatile, or combustible solvents, such as gasoline or toluene 

Polygone is water based.

I like the pattern on the 2nd photo. Should cause agitation which will help dissolve the polysulfide.

 

 

 

It is very easy to adjust the pressure by turning the valve to the desired position. In the second photo the valve is only open about 45 degrees from full. I just have to tweak the setting so that I don't run the sump dry while more solvent returns to the bucket/sump from the fuel tank.

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[1524J]

Isaac,  I purchased case lots of 40 ea. on the #3 & #8 3M cutters as well as the 3" radial bristle discs. If you try the cutters and like them let me know.

[isaacpr7]

Isaac,  I purchased case lots of 40 ea. on the #3 & #8 3M cutters as well as the 3" radial bristle discs. If you try the cutters and like them let me know.

I just had a chance to try it today and I felt it was to aggressive at first so I stopped using it. I later gave it another shot and noticed that as it gets used, it becomes more and more dull and I began to feel comfortable using it. Pressing the trigger about 1/4 down also helped control the drill much better. The only thing I don't like is that they do not last long and they are not cheap so I might stick to the hand scraper.

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[1524J]

On ‎3‎/‎28‎/‎2016 at 10:20 AM, carusoam said:

 

Started to reply to carusoam but can't figure out how to "undo" 

Anyhow.......3M recommends the drill be no more than 1000rpm, 800rpm preferred. Were you trying to remove sealant that had Polygone applied or did the heat from the bit cause the sealant to melt? Video I watched didn't appear to gum up that way. I paid $155 for a case of 40 of the #3. 

[carusoam]

I have a lot of polymer experience...  Cleaning them out of the processing machines is one of those experiences....

Best regards,

-a-

[Marauder]

Since you guys are talking removing stuff, will this polygone remove silicon?

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[1524J]

28 minutes ago, Marauder said:

Since you guys are talking removing stuff, will this polygone remove silicon?

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Polygone 505 specifically states it's for silicone sealant removal. We're using polygon 310-AG Gel. I've got two gallons of SR125A that someone can have. It's five years old and has been sitting in a hanger.

• All Polygone Products
• PolyGone 305
• PolyGone 305 Gel
• PolyGone 310-AG
• PolyGone 310-AG Gel
• PolyGone 505

POLYGONE 505

PolyGone™ 505 High-Performance Silicone Depolymerizer / Stripping Agent – Made In The USA

DESCRIPTION: PolyGone 505 is a high performance silicone sealant depolymerizer / emulsifier designed to remove cured silicone and other sealants from a variety of surfaces. Silicone has numerous applications including aviation, medical, potting removal, electronics, aerospace, marine, household, aquarium building & repair, dispensing equipment, telescope repair and microscope repair to name a few. Specific aviation uses include removal of silicone from turbine stators, thrust reversers and other engine components.

CHEMISTRY: PolyGone 505 is a proprietary formulation designed to penetrate, break down, and emulsify tenacious sealants. Once broken down, the sealant is suspended to prevent re-deposition and enable easy rinsing.

APPLICATION: PolyGone 505 is intended for use at room temperature (68°F-80°F). It may be continuously sprayed or used in immersion-based cleaning systems. Heat (120ºF/49ºC) and/or gentle agitation, including ultrasonic, is not necessary but significantly enhances performance. The agitation removes the digested sealant and exposes underlying layers to fresh PolyGone 505. However, do not use a sparging system, as this will quickly deactivate the emulsifier. PolyGone 505 must be used at full strength. Dilution and/or excessive heat, above 120ºF will deteriorate the emulsifier. RPM Technology recommends using PolyGone 505 in a well-ventilated area and in a covered cleaning apparatus to prevent product evaporation.

RINSE: PolyGone 505 is water-soluble. Although water may be used to rinse the product, rinsing with a mild cleaner such as eOx®, also available from RPM Technology, followed by pure water will improve removal of all residues. An emulsifier will improve rinsing via a “sheeting” effect, reduce sealant re-deposition, and reduce water usage. In cases where water is not preferred, a compatible solvent such as IPA or acetone may be used.

COMPATIBILITY: PolyGone 505 is metal-friendly. The formulation is non-ionic and non-reactive. Metals such as Cu, Fe, Al, Zn, and Ti have been tested with PolyGone 505 with no detected metal loss. However, PolyGone 505 attacks many types of polymers and plastics. Polyvinyl chloride (PVC), polyvinyl alcohol, and similar plastics should not be treated with PolyGone 505. Many elastomers are also not recommended. RPM Technology recommends the following plastics for application and storage, Polypropylene, Poly Olefin, Polyethylene (low and high density), Teflon, and Butyl Rubber. Testing is necessary to demonstrate full compatibility.

PPE: Recommend personal protective equipment (PPE) includes safety glasses/goggles and nitrile or butyl rubber gloves. Aprons may be used to protect clothing. Do not use gloves made from latex or vinyl.

TOXICITY: PolyGone 505 contains a blend of polar organics. PolyGone 505 has a low inherent toxicity and at diluted levels, is essentially non-toxic to aquatic life. The material is readily biodegradable and does not bio-accumulate.

STORAGE: PolyGone 505 must be stored in a cool and dry environment away from light and incompatible materials. The recommended storage temperature is between 50ºF-80ºF (10ºC-27ºC). Under these conditions, unopened containers of PolyGone 505 have a 1-year shelf life.

DISPOSAL: PolyGone contains no halogenated, reactive, or other EPA regulated components. Conformance with Federal, State, and Local disposal regulations is required. Diluted PolyGone can be disposed of by discharge to a sewage treatment plant with prior approval. Used PolyGone may need to be disposed of as organic solvent waste depending on the sealants and contaminates removed. PolyGone has a high BTU value and waste can be managed through a fuels-blending program.

AVAILABILITY: PolyGone 505 is available in individual poly gallons, 4×1 gallon cases, and 55-gallon steel drums.

[isaacpr7]

On ‎3‎/‎28‎/‎2016 at 10:20 AM, carusoam said:  

Started to reply to carusoam but can't figure out how to "undo" 

Anyhow.......3M recommends the drill be no more than 1000rpm, 800rpm preferred. Were you trying to remove sealant that had Polygone applied or did the heat from the bit cause the sealant to melt? Video I watched didn't appear to gum up that way. I paid $155 for a case of 40 of the #3. 

My drill is only 770rpm.

I saw the same video you watched but the sealant in my tanks mostly has a consistency of play dough clay. Other areas are like rubber. It seems like different materials have been used in past patch jobs. The video also had a thin layer of sealant. Mine seemed to have several coats layered between patch jobs as well.

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[Marauder]

28 minutes ago, Marauder said: Since you guys are talking removing stuff, will this polygone remove silicon?

Sent from my iPad using Tapatalk

Polygone 505 specifically states it's for silicone sealant removal. We're using polygon 310-AG Gel. I've got two gallons of SR125A that someone can have. It's five years old and has been sitting in a hanger.

• All Polygone Products
• PolyGone 305
• PolyGone 305 Gel
• PolyGone 310-AG
• PolyGone 310-AG Gel
• PolyGone 505

POLYGONE 505

PolyGone 505 High-Performance Silicone Depolymerizer / Stripping Agent – Made In The USA

DESCRIPTION: PolyGone 505 is a high performance silicone sealant depolymerizer / emulsifier designed to remove cured silicone and other sealants from a variety of surfaces. Silicone has numerous applications including aviation, medical, potting removal, electronics, aerospace, marine, household, aquarium building & repair, dispensing equipment, telescope repair and microscope repair to name a few. Specific aviation uses include removal of silicone from turbine stators, thrust reversers and other engine components.

CHEMISTRY: PolyGone 505 is a proprietary formulation designed to penetrate, break down, and emulsify tenacious sealants. Once broken down, the sealant is suspended to prevent re-deposition and enable easy rinsing.

APPLICATION: PolyGone 505 is intended for use at room temperature (68°F-80°F). It may be continuously sprayed or used in immersion-based cleaning systems. Heat (120ºF/49ºC) and/or gentle agitation, including ultrasonic, is not necessary but significantly enhances performance. The agitation removes the digested sealant and exposes underlying layers to fresh PolyGone 505. However, do not use a sparging system, as this will quickly deactivate the emulsifier. PolyGone 505 must be used at full strength. Dilution and/or excessive heat, above 120ºF will deteriorate the emulsifier. RPM Technology recommends using PolyGone 505 in a well-ventilated area and in a covered cleaning apparatus to prevent product evaporation.

RINSE: PolyGone 505 is water-soluble. Although water may be used to rinse the product, rinsing with a mild cleaner such as eOx, also available from RPM Technology, followed by pure water will improve removal of all residues. An emulsifier will improve rinsing via a “sheeting” effect, reduce sealant re-deposition, and reduce water usage. In cases where water is not preferred, a compatible solvent such as IPA or acetone may be used.

COMPATIBILITY: PolyGone 505 is metal-friendly. The formulation is non-ionic and non-reactive. Metals such as Cu, Fe, Al, Zn, and Ti have been tested with PolyGone 505 with no detected metal loss. However, PolyGone 505 attacks many types of polymers and plastics. Polyvinyl chloride (PVC), polyvinyl alcohol, and similar plastics should not be treated with PolyGone 505. Many elastomers are also not recommended. RPM Technology recommends the following plastics for application and storage, Polypropylene, Poly Olefin, Polyethylene (low and high density), Teflon, and Butyl Rubber. Testing is necessary to demonstrate full compatibility.

PPE: Recommend personal protective equipment (PPE) includes safety glasses/goggles and nitrile or butyl rubber gloves. Aprons may be used to protect clothing. Do not use gloves made from latex or vinyl.

TOXICITY: PolyGone 505 contains a blend of polar organics. PolyGone 505 has a low inherent toxicity and at diluted levels, is essentially non-toxic to aquatic life. The material is readily biodegradable and does not bio-accumulate.

STORAGE: PolyGone 505 must be stored in a cool and dry environment away from light and incompatible materials. The recommended storage temperature is between 50ºF-80ºF (10ºC-27ºC). Under these conditions, unopened containers of PolyGone 505 have a 1-year shelf life.

DISPOSAL: PolyGone contains no halogenated, reactive, or other EPA regulated components. Conformance with Federal, State, and Local disposal regulations is required. Diluted PolyGone can be disposed of by discharge to a sewage treatment plant with prior approval. Used PolyGone may need to be disposed of as organic solvent waste depending on the sealants and contaminates removed. PolyGone has a high BTU value and waste can be managed through a fuels-blending program.

AVAILABILITY: PolyGone 505 is available in individual poly gallons, 4×1 gallon cases, and 55-gallon steel drums.

Thanks for the details. What is SR125A?

[1524J]

SR125A is also a polysulfide/paint remover. When I stripped and resealed my right tank five years ago it's the product I used and it worked very well.....at dissolving polysulfide and stripping paint. O:   Stripping paint wasn't intentional. Now the PPG website says it not recommended for fuel tanks even though they show fuel tanks in their advertisement. Anyhow....sales rep said they had issues with people not cleaning the surface good which causes problems with sealant adhesion. I didn't/haven't had any problems but won't use it again because I know my A&P wouldn't be happy if I used a product that wasn't recommended.....and I like to keep my A&P happy!

[isaacpr7]

28 minutes ago, Marauder said: Since you guys are talking removing stuff, will this polygone remove silicon?

Sent from my iPad using Tapatalk

Polygone 505 specifically states it's for silicone sealant removal. We're using polygon 310-AG Gel. I've got two gallons of SR125A that someone can have. It's five years old and has been sitting in a hanger.

• All Polygone Products
• PolyGone 305
• PolyGone 305 Gel
• PolyGone 310-AG
• PolyGone 310-AG Gel
• PolyGone 505

POLYGONE 505

PolyGone™ 505 High-Performance Silicone Depolymerizer / Stripping Agent – Made In The USA

DESCRIPTION: PolyGone 505 is a high performance silicone sealant depolymerizer / emulsifier designed to remove cured silicone and other sealants from a variety of surfaces. Silicone has numerous applications including aviation, medical, potting removal, electronics, aerospace, marine, household, aquarium building & repair, dispensing equipment, telescope repair and microscope repair to name a few. Specific aviation uses include removal of silicone from turbine stators, thrust reversers and other engine components.

CHEMISTRY: PolyGone 505 is a proprietary formulation designed to penetrate, break down, and emulsify tenacious sealants. Once broken down, the sealant is suspended to prevent re-deposition and enable easy rinsing.

APPLICATION: PolyGone 505 is intended for use at room temperature (68°F-80°F). It may be continuously sprayed or used in immersion-based cleaning systems. Heat (120ºF/49ºC) and/or gentle agitation, including ultrasonic, is not necessary but significantly enhances performance. The agitation removes the digested sealant and exposes underlying layers to fresh PolyGone 505. However, do not use a sparging system, as this will quickly deactivate the emulsifier. PolyGone 505 must be used at full strength. Dilution and/or excessive heat, above 120ºF will deteriorate the emulsifier. RPM Technology recommends using PolyGone 505 in a well-ventilated area and in a covered cleaning apparatus to prevent product evaporation.

RINSE: PolyGone 505 is water-soluble. Although water may be used to rinse the product, rinsing with a mild cleaner such as eOx®, also available from RPM Technology, followed by pure water will improve removal of all residues. An emulsifier will improve rinsing via a “sheeting” effect, reduce sealant re-deposition, and reduce water usage. In cases where water is not preferred, a compatible solvent such as IPA or acetone may be used.

COMPATIBILITY: PolyGone 505 is metal-friendly. The formulation is non-ionic and non-reactive. Metals such as Cu, Fe, Al, Zn, and Ti have been tested with PolyGone 505 with no detected metal loss. However, PolyGone 505 attacks many types of polymers and plastics. Polyvinyl chloride (PVC), polyvinyl alcohol, and similar plastics should not be treated with PolyGone 505. Many elastomers are also not recommended. RPM Technology recommends the following plastics for application and storage, Polypropylene, Poly Olefin, Polyethylene (low and high density), Teflon, and Butyl Rubber. Testing is necessary to demonstrate full compatibility.

PPE: Recommend personal protective equipment (PPE) includes safety glasses/goggles and nitrile or butyl rubber gloves. Aprons may be used to protect clothing. Do not use gloves made from latex or vinyl.

TOXICITY: PolyGone 505 contains a blend of polar organics. PolyGone 505 has a low inherent toxicity and at diluted levels, is essentially non-toxic to aquatic life. The material is readily biodegradable and does not bio-accumulate.

STORAGE: PolyGone 505 must be stored in a cool and dry environment away from light and incompatible materials. The recommended storage temperature is between 50ºF-80ºF (10ºC-27ºC). Under these conditions, unopened containers of PolyGone 505 have a 1-year shelf life.

DISPOSAL: PolyGone contains no halogenated, reactive, or other EPA regulated components. Conformance with Federal, State, and Local disposal regulations is required. Diluted PolyGone can be disposed of by discharge to a sewage treatment plant with prior approval. Used PolyGone may need to be disposed of as organic solvent waste depending on the sealants and contaminates removed. PolyGone has a high BTU value and waste can be managed through a fuels-blending program.

AVAILABILITY: PolyGone 505 is available in individual poly gallons, 4×1 gallon cases, and 55-gallon steel drums.

If I decide to use the machine the other tank I'll take you up on the offer for the SR125A I just don't know right now if I can continue to fiddle with an experiment right before moving.

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[isaacpr7]

Took me a bit to find detailed instructions but finally found them. Details below for those interested:

Rev1 – 01/12 Page 1 of 3

Instructions for Polysulfide

Sealant Removal Using

PolyGone® 310-AG

Liquid or Gel

1) PolyGone 310-AG fully removes cured polysulfide sealant (PRC, Flamemaster, and A.C.

Tech) material from aircraft structures and components. PolyGone 310-AG is available

in both liquid and gel formulations. The liquid product is designed for parts that can be

immersed in the liquid such as, fasteners, clecos, and access panels. The gel is suited

for parts that cannot be immersed, vertical surfaces, inverted surfaces, or while inside a

fuel tank. Note: Before using PolyGone 310-AG, consult the MSDS for proper personal

protective equipment. See the Technical Data Sheet for additional information.

2) CAUTION: Avoid contact with non-stretched acrylic transparencies due to

potential crazing. This type is typically found on non-pressurized aircraft.

Acrylic windows on pressurized aircraft are will not craze with PolyGone. Also,

avoid contact with painted surfaces. PolyGone may have a negative effect on

painted surfaces depending on the age, type, and manufacturer of the paint.

We recommend testing in a small area prior to extensive exposure.

3) To clean small components i.e. fasteners and clecos, fill a suitable container with

PolyGone 310-AG and completely immerse the component(s) until the sealant is

digested. To enhance the performance of the PolyGone, RPM recommends a gentle

agitation while soaking. Once the parts are clean, they can be rinsed with eOx AC (see

Step 6) and dried. The eOx AC is a surfactanated cleaner that quickly breaks down the

PolyGone for easy rinsing. If your operation requires cleaning large amounts of small

parts, please contact RPM Technology for additional information on large-scale cleaning

operations. Note: To extend the life of the PolyGone, the vessel must remain covered

at all times.

4) To remove sealant from larger parts or to remove sealant inside

the fuel tank, apply PolyGone 310-AG Gel directly and liberally

onto the cured sealant using a stiff non-metallic brush. See photo

at right.

a) Mooney Supplement: If you are working on a Mooney, they

you must remove the buna-n lining first. This is accomplished

by scoring the surface in long “linguini” strips prior to gel

application. These cuts enable to PolyGone to wick underneath to begin

depolymerizing the polysulfide. Once this occurs, the buna-n has nothing to adhere

to and is easily removed. Then spread the gel out on the surface and continue.

5) Agitate the Gel with the non-metallic brush every 30-45 minutes until the sealant can be

wiped away. Reapply PolyGone 310-AG Gel after 4 hours of dwell time. The dwell time

for PolyGone 310-AG Gel depends on the thickness and type of polysulfide sealant.

When complete, remove all traces of PolyGone 310-AG Gel by rinsing the area with eOx

AC (see Step 6).

Properly applied gel

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[kellym]

On 3/8/2015 at 5:36 PM, isaacpr7 said:

On 3/8/2015 at 5:31 PM, mooneyflyfast said:

Have you talked to the people who sell "Polygone" they may be able to give you some good ideas.

 

Good luck with your project!

I had not thought about that to be honest. I might give them a call.

It is much easier to protect your paint and keep your project manageable if you do one bay of the tank at a time, with a combination of Polygone gel version, and manual scraping with non-metalic scrapers intended for the purpose. Even Harbor Freight sells some, as well as aircraft tool suppliers. There are also some rotary sealant removers. The Polygone gel will soften the sealant initially, and when you get most removed, it will help get the final sealant with tooth brushes to work the gel around bits of sealant remaining. I figure around 40-50 hours of labor to complete the work of removal, spread over how many days your arms need for recovery. Using the liquid has all the noted issues with damaging your paint, controlling where the liquid goes. When you get the sealant removed at the wing spar to fuselage intersection you will have a large passage direct into the cabin. Are you ready to control that and keep stripper out of your carpet and upholstery?

Most important is that you need the tanks to be perfectly clean of old sealant and other contaminants to start the reseal. You need temperature that is between 70 and 80 to use the normal A2 and B2 sealants. Otherwise your application pot life will be difficult. You want a pneumatic SEM gun to do the application...best if you can borrow. It allows precise control of the flow, where a manual caulking gun will not shut off flow when pressure is released.  Best to get some training and supervision from an A&P that has done work with ProSeal (or other brand) polysulfide sealants. In fact, such supervision is a requirement, as their signature for supervision of the work is needed to return the aircraft to service.

Just my thoughts having done my own Mooney tanks. First one done 6 years ago and still leak free.

[1524J]

1 hour ago, kellym said:

It is much easier to protect your paint and keep your project manageable if you do one bay of the tank at a time, 

There is a downside to one tank at a time.....after you've finished the first tank you'll say to yourself "man, that was a job. Think I'll wait a couple of weeks before I start the next tank." Five years later you'll still waiting to start the second tank.

Just reread....you said one bay at a time. 

Edited April 5, 2016 by 1524J

[isaacpr7]

So I have been keeping a time log every time I can manage to head down to the hangar to work on the tank with the gel option. I will do the other tank with the machine and keep a time log as well so that I can give you guys an idea of how long it may take someone who has never done this before and hopefully in their decision to take on this project.

The first time I applied the gel it took most of the sealant off but a few of the rivet strips were still caked in very thick. I applied a second round of gel and the coat barely did anything so the third time I applied a generous amount of gel in said strips and let it sit over night. This morning nearly everything came out except for small traces around the rivets. I believe it will only take me one more coat of gel to complete the stripping process. This time I will try the other method for applying gel as specified in the instructions I found on the manufacturer's website. After applying the gel I will agitate the sealant every 45 minutes and it should all come right off with a clean rag. I did notice in the previous coatings that whenever I agitated an area where I previously applied gel, the sealant would melt all the way to bare metal. Below is a pic of the progress after the third application.

I purchased a set of sanding disks from Harbor Freight as suggested earlier; however, I opted to not use them because they felt too aggressive. This may be due to the fact that they were 80 grit but it was all that was available at Harbor. I think the ones made for this type of projects should work very well. Below is a picture of what Harbor Freight had.

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