Opening the tank access hole

[mototopo]

Today was time to test my right tank for leaks.

The bad new is that there is a small leak in the inboard lower corner (in the joint between the most inboard rib, the skin and the tank brace),... the good one is that I can reach it "easily" through the access hole...

I sealed the cover without the cork gasket using just proseal, but it's cured so well I'm unable to remove it!!
How may I remove the cover without damaging it or the rib???

Thanks...

P.S. I hate tanks!!!!!

[vlittle]

As I recall, when Vans had the fuel pickup service bulletin, one of the recommended techniques was to use a serrated plastic knife to saw away at the proseal, followed by a putty knife to pry the cover off.

I'm just in the process of leak testing my HRII tanks, but this is being done without prosealing the access plate or fuel pickup. Once leak free, I will then proseal them on.

One thing I'm going to do is embed a loop of dental floss in the Proseal. The idea is that it will be used as a ripcord should the cover have to be removed later on. We'll see.

Vern

[danielhv]

putty knife... may even try using a hair dryer to warm it up a little... i assume you have not put fuel in it yet. Proseal is no joke once cured! good luck!

[mototopo]

Ok.. thank you guys... putty knife is the way to go. I'll try also to warm it up a little.

One more information: my leftover proseal expires this month. May I still use it to re-close the tank or have I to buy more? (I just need maybe 20 grams...)

[Mel]

Pro-seal has a pretty good guard-band on time expiration. I have successfully used pro-seal that was several years old when stored in the refrigerator.

[Chino Tom]

Warming the pro-seal with a heat gun makes the job very easy. No fuel in the tank for sure!

[mototopo]

oh no.. still no fuel in the tanks

thank you very much for your help... tonight back at work

[chaskuss]

Claudio,
Use either a plastic putty knife or fabricate a wooden putty knife out of either a Popcicle stick or a medical tongue depressor. Simply sharpen one end using your belt sander. Wood or plastic will not damage the aluminum rib/access cover. A wooden stick can be re-sharpened many times, as needed.
This is how professional A&Ps do this job. Remember that all the fuselage skins on pressurized aircraft are sealed with ProSeal.
Charlie Kuss

[apkp777]

http://www.yardstore.com/browse.cfm/4,4609.html

The scraper above is an awesome tool. That's what we used at UAL to remove sealant. However, we had .040-.050 skin thicknesses. You have thin skin, so take care.

[Rick6a]

Originally Posted by chaskuss

Claudio,
Use either a plastic putty knife or fabricate a wooden putty knife out of either a Popcicle stick or a medical tongue depressor. Simply sharpen one end using your belt sander. Wood or plastic will not damage the aluminum rib/access cover. A wooden stick can be re-sharpened many times, as needed.
This is how professional A&Ps do this job. Remember that all the fuselage skins on pressurized aircraft are sealed with ProSeal.
Charlie Kuss

I can endorse Charlie's comments from my own McDonnell-Douglas production shop experience. For one reason or another, I sometimes removed components attached with cured proseal. It can be a pain, nevertheless, the use of any metal tool such as a putty knife was strictly verboten. This was because it is virtually impossible to use a metal tool without scratching or possibly gouging the underlying aluminum surface. The use of heat to help soften the cured proseal was acceptable and we commonly used a plastic scraper such as the officially sanctioned one shown below. Its ends could be quickly and easily resharpened to any angle desired on a bench sander. Some guys preferred sharpened wood tongue depressors, others even used modified windshield ice scrapers they retrieved from their car out in the factory parking lot.....anything but metal.