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TB20 fuel tank inspection cover sealant

Is there someone who knows which sealant for TB 20 tanks inspection covers are usable?
Thomas

Berlin, Germany

I don’t have a maintenance manual for TB 20, but as a general rule, tanks are sealed with a two-component polysulfide sealant. The choice is fairly wide, and when choosing the right one, pay attention to three parameters:
- Viscosity: liquid for application with a brush (called class A), a non-flowing thick paste for application with an extrusion gun, spatula or gloved hand (class B), or a somewhat thinner flowing paste (class C). For the inspection covers, any of these would do, so it’s a matter of personal preference.
- Curing speed: the number after the letter A/B/C denotes the application time in hours after mixing, usually between 1/4 and 4 hours. Full curing takes 15-20 times longer. Note that these times are listed for the normal ambient temperature. It can harden much faster when it’s hot and much slower when it’s cold.
- Adhesion: high or low. If the inspection cover is to be periodically removed, a low-adhesion sealant can save you some trouble removing it, though it isn’t really critical.

The one I see used most often is B2 high adhesion, which works in the vast majority of cases.

Last Edited by Ultranomad at 16 Aug 20:45
LKBU (near Prague), Czech Republic

This stuff, informally known as “PRC” and previously known as PR1422 or PR1440.

Administrator
Shoreham EGKA, United Kingdom

Thanks for the information Peter and Ultranomad, very helpful. I have found PR 1770 class B ( two part kit),
but it is expensive. Is there anything else on the market only for the inspection covers?
Thomas

Berlin, Germany

Now I found aircraft spruce USA 11,90 USD and aircraft spruce eu 16,85 €
Aerolife Polyprotech Fuel Tank Sealant – Single Component
Thomas

Berlin, Germany

Thomas wrote:

but it is expensive. Is there anything else on the market only for the inspection covers?

Is this an integral tank where the glue is eventually submerged in fuel? If yes I would not take chances. Fuel leaks are a major pain and in my experience two component products are simply stonger than one component products

A source in Germany:
https://www.globalaviation24.com/Lubricant-Chemical/Adhesive-Sealant/PPG-Sealant-AMS-S-8802-Semkit-150ml.html

If ordering from abroad pay attention to the shipping. It could be dangerous goods making international shipping very expensive.

Last Edited by Sebastian_G at 17 Aug 09:25
www.ing-golze.de
EDAZ

One-pack anything is rarely any good. Sealant or paint…

Administrator
Shoreham EGKA, United Kingdom
. . . it ain´t necessarily so . . . For sealing aggressive auto fuel tanks I use one pack polyurethane paint since 40 years – no problems then and today. But this is like clear paint and great for sealing smaller leaks, for more solid coats you´d do several applications with a few hours in between for curing by air humidity. So it depends what sort of seal you want. Avgas is a lot less critical to rubber hoses and paints so no worries about traditional glues or seals as it contains no nasties like acetone, butane, toluol and the like. POR 15 looks a lot like the Vosschemie G 4 that I use . Many traditional two pack tank seals surrendered with modern unleaded auto fuel so a big mess then how to get that crap out. Vic
vic
EDME

I’ve always used PR1428B2 on different aircraft with excellent results and reasonable ease of removal

Last Edited by Antonio at 19 Aug 20:57
Antonio
LESB, Spain
9 Posts
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