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Flamemaster/Chemseal Usage

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BenJason007

I'm New Here
Hi Everyone,

Apologies for a potential dumb question but I can't find a clear answer on this question. I've read that Flamermaster/Chemseal is basically the same composition as Proseal brand but the later is favored by everyone specific to tanks. My question is for the other areas like where rib assemblies meet at the skin or on the trailing edges...Is Flamemaster/Chemseal acceptable to be used in these areas. Is there any reason why it couldn't be used on the non tank related joints that need dampening?

~Ben
 
Thousands of RV's flying with the Flamemaster sealant with no issues. Just sayin.....

Proper prep, cleaning, mixing etc. are keys to success. Proseal will also fail if one fails to properly address those concepts and procedures.

Also, I would not go adding sealant to areas not specified by the plans. No need for it. All it will do is make your airplane's useful load decrease.
 
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The Proseal failed in my tanks and I have cleaned it out and replaced it with Chemseal... the failure was caused by avgas residue.

Failure is not brand related, as far as I am aware. There is a mil spec for polysulfide sealants that they conform to per the product spec sheet.

I believe it would be quite OK for you to use Chemseal/Flamemaster as supplied by Van's or Aircraft Spruce.
 
Thanks guys. All I was looking to understand is if I could use the less expensive Chemsel for items like trailing edges & where dampening was called out in the plans. Input received & much appreciated!
 
BenJason007 said:
Thanks guys. All I was looking to understand is if I could use the less expensive Chemsel for items like trailing edges & where dampening was called out in the plans. Input received & much appreciated!
Click to expand...

It will work perfectly fine for those areas as well as for fuel tanks.
 
The shop that maintains my corporate jets uses Flamemaster to seal tanks, windshields, etc…. I used it on a tank repair with no issues. YMMV
 
Snowflake said:
I'd be interested to hear how you made this determination.
Click to expand...

Here's the logic:

I constructed the tanks and sealed them with fresh Proseal (brand) from Vans.
The tank pickups and screens were prefab by Vans, using their sealant. NB this was a different can of sealant, at a different time, by a different installer (not me).
I leak tested the tanks with low air pressure (balloon) and soapy water and they passed.
Some weeks later I put 2 litres of avgas into each tank and rotated to test for leaks and found none. I then left the tanks with the caps off and allowed the avgas to evaporate.
The tanks then went into storage for several years (never flown).
When I opened the tanks later on to complete the service bulletin for the anti-rotation fitting on the pickups I discovered that the sealant inside had reverted to goo. This included both the sealant mixed and applied by me and that by Van's. The sealant on the outside of the tanks that was not exposed to avgas was still hard.

The only variable that can account for the sealant failure was exposure to avgas that evaporated over time.

Theoretically the sealant should not have failed, but it did.
 
PaulvS said:
Here's the logic:

I constructed the tanks and sealed them with fresh Proseal (brand) from Vans.
The tank pickups and screens were prefab by Vans, using their sealant. NB this was a different can of sealant, at a different time, by a different installer (not me).
I leak tested the tanks with low air pressure (balloon) and soapy water and they passed.
Some weeks later I put 2 litres of avgas into each tank and rotated to test for leaks and found none. I then left the tanks with the caps off and allowed the avgas to evaporate.
The tanks then went into storage for several years (never flown).
When I opened the tanks later on to complete the service bulletin for the anti-rotation fitting on the pickups I discovered that the sealant inside had reverted to goo. This included both the sealant mixed and applied by me and that by Van's. The sealant on the outside of the tanks that was not exposed to avgas was still hard.

The only variable that can account for the sealant failure was exposure to avgas that evaporated over time.

Theoretically the sealant should not have failed, but it did.
Click to expand...

The theory certainly makes sense, but have to question it. A lot of us do not keep full tanks at all times. Therefore the sealant on the top of the tank spends a LOT of time with no avgas contact. The liquid would evaporate and leave just the residue you refer to. It would only be washed away during flight when the fuel is sloshing around only for the cycle to repeat when you park the plane. Maybe it turns to goo for all of us, but still seals well for many decades. Maybe it was another cause in your case, but certainly odd that two different batches had the same issue.
 
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PaulvS said:
Here's the logic:

I constructed the tanks and sealed them with fresh Proseal (brand) from Vans.
The tank pickups and screens were prefab by Vans, using their sealant. NB this was a different can of sealant, at a different time, by a different installer (not me).
I leak tested the tanks with low air pressure (balloon) and soapy water and they passed.
Some weeks later I put 2 litres of avgas into each tank and rotated to test for leaks and found none. I then left the tanks with the caps off and allowed the avgas to evaporate.
The tanks then went into storage for several years (never flown).
When I opened the tanks later on to complete the service bulletin for the anti-rotation fitting on the pickups I discovered that the sealant inside had reverted to goo. This included both the sealant mixed and applied by me and that by Van's. The sealant on the outside of the tanks that was not exposed to avgas was still hard.

The only variable that can account for the sealant failure was exposure to avgas that evaporated over time.

Theoretically the sealant should not have failed, but it did.
Click to expand...

lr172 said:
The theory certainly makes sense, but have to question it. A lot of us do not keep full tanks at all times. Therefore the sealant on the top of the tank spends a LOT of time with no avgas contact. The liquid would evaporate and leave just the residue you refer to. It would only be washed away during flight when the fuel is sloshing around only for the cycle to repeat when you park the plane. Maybe it turns to goo for all of us, but still seals well for many decades. Maybe it was another cause in your case, but certainly odd that two different batches had the same issue.
Click to expand...

There has always seemed to be a connection between sealant reversion and exposure to evaporating fuel mixed with ambient air.

This case seems to parallel with that since instead of the tank being filled entirely with either fuel and/or predominantly fuel vapor, as is the case when the tanks are in normal service, the tank included a mix of ambient air because of the open fuel cap.
This could have set up the same Situation that exists when fuel is wetting the exterior because of a leak.
 
rvbuilder2002 said:
There has always seemed to be a connection between sealant reversion and exposure to evaporating fuel mixed with ambient air.

This case seems to parallel with that since instead of the tank being filled entirely with either fuel and/or predominantly fuel vapor, as is the case when the tanks are in normal service, the tank included a mix of ambient air because of the open fuel cap. ...
Click to expand...
First time I've heard of this - good to know. Another reason to keep the tanks full and the caps closed and sealed.
 
rvbuilder2002 said:
There has always seemed to be a connection between sealant reversion and exposure to evaporating fuel mixed with ambient air.

This case seems to parallel with that since instead of the tank being filled entirely with either fuel and/or predominantly fuel vapor, as is the case when the tanks are in normal service, the tank included a mix of ambient air because of the open fuel cap.
This could have set up the same Situation that exists when fuel is wetting the exterior because of a leak.
Click to expand...

That seems more logical and accounts for the different variable here. Thanks for sharing that experience.
 
Many of us have noticed this on our traditional Van's fuel caps. Many left a fillet of sealant around the edge of the hole in the skin and the base ring. Over time this just turns to goo because it is both exposed to fuel occasionally and air.
 
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