What's the best way to remove the fuel inspection panels on top of the wing

[nels]

The inspection panels on my wings have never been removed. I pulled the screws from the inboard panel and the adhesive is reluctant to let the panel lose. I bought a pry tool that was suggested in an earlier thread and I'm sure it will work well but I need a little clearance to get that tool started. Thought about a narrow razor blade but figured I'd ask here first as there may be a standard method that I'm unaware of.

Also, I would think there would be a different sealant to use on the panels other that the patching sealant? Something that would make removal easier in the future?

[RobertGary1]

I wonder if someone used the wrong sealant. The top access panels are supposed to be sealed with access panel sealant. It does not get hard like the B2 does. You should be able to push down on the panel and there be enough give that you can get a plastic putty knife or similar in there.

If someone used regular sealant on your top panels life will just be tough

 

-Robert

[RobertGary1]

BTW: There are a couple p.n's in your manual. Here is what I use...

 

 Flamemaster CS-3204 B-2 Gray AMS-S-8802C Type 2 Spec Integral Fuel Tank Sealant - Pint (12 fl oz) Can Kit CS3204B2PT

 

Flamemaster CS-3330 B-2 Red AMS-3284B Type 1 Spec Access Door Sealant - Pint (12 fl oz) Can Kit  CS3330B2PT

 

-Robert

[carusoam]

Generally, when it comes to removing sealants, we have three tools...

1) heat, softens and melts and improves dissolution....

2) chemical solvents, dissolves the sealants...

3) mechanical scrapers, thin enough to get under the edge...

 

Important to know... 

4) damage to the paint is a strong possibility.

5) damage to the inspection panel is possible.

6) collateral damage to sealants inside the tank is possible.

 

Just some thoughts while putting your plan together...

My top inspection panels all got resealed along the way, before my ownership period started...

PP thoughts only, not a mechanic...

 

Best regards,

-a-

 

 

 

[N201MKTurbo]

I've never seen a panel you could just push down. Put aluminum tape along the edge of the panel to protect the paint. Grab the pry bar firmly with both hands and push it firmly down in the gap and work it between the panel and the wing skin. Do this between the screw holes. When you get the tool in about an inch work it out and move on to the space between the next two screws. After you do this about four times you cas start to gently pry the panels apart working around the panel. After you get about half way around the panel will start to bend down and you can peel it off.

I assume you are using an ATS skin wedge. It is the best tool it has no sharp edges and is strong enough and thin enough to do the job.

It will be easier to start the process if you clean the sealant out of the 1/16 inch gap before you start. Use a small screwdriver or pick to get the sealant out of the gap.

Edited August 11, 2017 by N201MKTurbo

[Yetti]

A kitchen boning knife.   There should be some sealant in the seam.  Work through that.  Then on the round ends keep working the blade in various spots till it goes all in.   The good handle of the knife gives you control.   Work in various spots.  Once you get a good gap, the rest is easy.  My Grandfather would be horrified at the improper use of the knife.

[N201MKTurbo]

So, why are you doing this? Do you have a leak to fix? If you just want to inspect the inside of the tanks, you have already committed yourself to the bulk of the work involved in a tank repair by taking the panels off.

[N201MKTurbo]

2 minutes ago, Yetti said:

A kitchen boning knife.   There should be some sealant in the seam.  Work through that.  Then on the round ends keep working the blade in various spots till it goes all in.   The good handle of the knife gives you control.   Work in various spots.  Once you get a good gap, the rest is easy.  My Grandfather would be horrified at the improper use of the knife.

While the boning knife is a good choice the skin wedge is much better and it is only $8

[nels]

The skin wedge is what I bought and the boning knife may be a good starting point. The sealant appears to be a red color. Also, I just got off the phone with Aircraft Spruce and they don't know anything about a special sealant for the access doors. I had purchased a Proseal ac236 sealant for the tank seal.

Yes, there are some leaks that I would like to address which is the reason for the inspection cover removal. I figure the annual is a good time to attack the leak.

[RobertGary1]

Just now, nels said:

The skin wedge is what I bought and the boning knife may be a good starting point. The sealant appears to be a red color. Also, I just got off the phone with Aircraft Spruce and they don't know anything about a special sealant for the access doors. I had purchased a Proseal ac236 sealant for the tank seal.

Yes, there are some leaks that I would like to address which is the reason for the inspection cover removal. I figure the annual is a good time to attack the leak.

Do not reseal the access panels with that! It will be a nightmare to remove. 

See the links above for th access panel sealant Mooney calls for.  Also 

http://www.donmaxwell.com/publications/MAPA_TEXT/_overlay/Fuel Tank Repair_How We Fix Them 2-05.htm

[carusoam]

+1 for RG's input on the two different flame master products. One seals forever, the other one is intended for removal at some point...

Bets regards,

-a-

[Guest]

Normally the tank access panels are sealed with a lower strength sealant, other than the panels in the wing walk area which requires higher strength sealant.

Clarence

[pinerunner]

When I did it I left the screws in place sticking out a quarter of an inch. Then I put a flat board and heavy weight on top and left it over night. The next morning one of the access was down and the other I put more weight (220 lbs) on it and it partially  broke free. That one I had to work a thin putty knife around to get it off. I also took a file and rounded off the edges of the putty knife. If they haven't been touched for decades they can come off hard. 

I was concerned about bending and/or denting the aluminum. It worked out fine. I managed not to mess up the paint either.

Edited August 11, 2017 by pinerunner

[nels]

4 hours ago, pinerunner said:

When I did it I left the screws in place sticking out a quarter of an inch. Then I put a flat board and heavy weight on top and left it over night. The next morning one of the access was down and the other I put more weight (220 lbs) on it and it partially  broke free. That one I had to work a thin putty knife around to get it off. I also took a file and rounded off the edges of the putty knife. If they haven't been touched for decades they can come off hard. 

I was concerned about bending and/or denting the aluminum. It worked out fine. I managed not to mess up the paint either.

That sounds like a good approach. I got one out this afternoon but two more to go. I may try your board trick tomorrow. I'm not sure where to get 220#'s though. I guess I could stand on the board but not all day and I'm a little short of the 220 #'s. I bus's a towel between the board and the wing would be a good idea.

The one I did get lose I started with a razor blade then gently pried just a little with a small flat blade screw driver while inserting the end of a cheap steak knife. I worked it back and forth enough to get the blade through the sealant then gently pried with the screw driver again to get the skin wedge between the skin. After this was accomplished the job went quickly prying up with the skin wedge and cutting the sealant with the steak knife. Didn't damage the paint at all.

[nels]

One other note worth mentioning. I last flew on the tank I wanted to repair but still had about 10 or 15 gallons of fuel left in it. I needed to get the fuel out of that tank and into the other. I saw that Harbor Freight had manual fuel transfer pumps for sale for $6.99 which included four or five feet of hose for the intake and also for exhaust side. The reviews were good so I bought one. It worked great. About 25 pumps on the cylinder per gallon. Before I used it I bought a fuel filter from the local auto parts store so I could filter the fuel coming out of the wing into the can then again filter it from the can to the other wing tank. 

[BDPetersen]

I found a heat gun, carefully used, made screw removal and panel release go fairly well. No paint damage. Just warm it up a bit.

[carusoam]

Now that you mentioned it...

Fire extinguishers on hand, prepare for the worst....

Good ventilation.   Fuel vapors can be tricky...

Best regards,

-a-

[nels]

21 minutes ago, BDPetersen said:

I found a heat gun, carefully used, made screw removal and panel release go fairly well. No paint damage. Just warm it up a bit.

I was thinking about a heat gun but I am concerned about potential sparks around the vapors. Probably ok but still would worry me. However, as an alternative I thought about pushing it out of the hangar tomorrow, it's supposed to be sunny, and put a small section of black roofing rubber over the two panels and see if I can't get Mother Nature's sun to heat up the area and soften the sealant.

[nels]

25 minutes ago, carusoam said:

Now that you mentioned it...

Fire extinguishers on hand, prepare for the worst....

Good ventilation.   Fuel vapors can be tricky...

Best regards,

-a-

I know an empty gas tank is way more dangerous than a full one.

[carusoam]

Depends...

are you more afraid of the explosion, or the ensuing fire...?

Neither would be very good...

The thought of using a heat gun brought this up.

My local airport had a mechanic accidently open a panel on the bottom of a Mooney wing with a powered driver.  

Simple mistake.  Flaming disaster...

It would be best to have all the fuel drained out the bottom.  The fuel sampler valve being removed doesn't leave much in there...

If the tank has no fuel in it....  much less vapors this way... i'm not sure how to get the vapors out afterwards, but good ventilation would be helpful...

 

Good to think this stuff through...

 

PP thoughts only, not a mechanic...

Best regards,

-a-

[Sean S]

To get vapors out of an empty tank, a pneumatically operated vacuum should be used to purge the fumes. You do not want any spark generating equipment any where near those fumes. The venting equipment and aircraft should be bonded, and the aircraft grounded.

 

http://www.rhineair.com/compressed-air-driven/

[nels]

OK, I got all three top panels off. I'm glad I asked the question on this forum as I came up with the right suggestions. I didn't try the solar heat on the panel but started with Pinerunners suggestion to leave the screws in and put a board across the screws with weight. What I did was to leave the end three screws on the radius ends out further than the others. I then put a short 2x4 across with a towel underneath each end.I then stood on the 2x4 shifting my weight from right to left. This loosened the joint enough to get the steak knife in between the panels then I was able to get the skin wedge in and the rest was history.

Now that the panels were off I finished draining the gas, washed the tanks with Dawn and water, applied vacuum and started looking for leaks in the outside tank chamber. I found a few small leaks as the bubbles appeared but nothing too gross so far. So tonight I cleaned the soap residue out of the outside chamber, scuffed it with a scotch brite pad and thought I'd wipe it down with enamel reducer. This is what now has me confused! The inside of these tanks appear to be pretty much factory virgin. The seams all have an amber shellac coating on them. When I wiped them down with enamel thinner this shellac coating began to soften and peal so I stopped. What is under the amber sealant is a bubble gum colored chalky substance. When I pushed my screw driver into it it was similar to scraping dried plaster. I was fully expecting something more on the line of silicone sealer. Can anybody straighten me out here? This was on the floor of the outboard tank next to the lower access panel.

 

 

 

[N201MKTurbo]

Any bubbles are bad. Just make sure you are seeing real bubbles. Real ones will grow. The shellac stuff is liquid butyl rubber. It is ok to clean it off with solvent because you should replace it when you are done with your repairs. The sealant shouldn't be chalky, it should be rubbery. If it is all chalky it may be time for a complete reseal.

[N201MKTurbo]

BTW, when it comes to cleaning up the last dregs of sealant or softening the sealant, MEK is the best, but denatured alcohol works almost as well and isn't quite as nasty.

[nels]

Is it absolutely necessary to remove the top layer of butyl rubber? It all looks good except where I used the enamel thinner. Also, is the 3M  AC-236 A-2 base ok to use for the patch. Should it be followed up with a top sealant of some sort. I realize I need to get the proper  sealant for the access panels.

Maybe just a coat of butyl instead of the patch would be a better avenue?

Edited August 13, 2017 by nels