Pro seal

[Dennis Harm]

Hi everyone,my left fuel tank has a slight weep, leak at the inboard nose rib. Have the tank off and wondering can I put pro seal over the old or does the old pro seal need to be removed?Thanks

 

[Kyle Boatright]

Proseal sticks to proseal, so if the underlying proseal hasn't degraded, I'd apply a new layer over the old. If your existiing proseal has turned to goo, all bets are off. If that's the case, I'd try to clean up/remove the old stuff as best as possible, then apply a new layer.

 

[Dennis Harm]

Thanks for the response Kyle,the old pro seal seems to be in good shape,firm but pliable.

 

[PaulvS]

If the leak is just a pin hole and the old Proseal is sound as you say then you may be best off using the brush on (type A) Proseal rather than the thicker type B that spreads on with a spatula. I'd also make sure the old Proseal is thoroughly clean and dry.

 

[lr172]

Hi everyone,my left fuel tank has a slight weep, leak at the inboard nose rib. Have the tank off and wondering can I put pro seal over the old or does the old pro seal need to be removed?Thanks

while proseal sticks to cured proseal, it does not stick well to dirt, oil or contaminants. I recommend extensive cleaning and even some abrasion if going over external proseal. It is unlikely that the proseal itself is leaking. Far more likely that bond between the proseal and the Al structure is the source (poor cleaning and prep can result in leakage at the bond area down the road). In that case, with limited space, removing the proseal then throughly cleaning and scuffing the Al structure and re-applying is the better approach.

Leaks are often due to bonding related to prep and therefore the safest path will alway be to remove old sealant, followed by proper prep and application. Sometimes though it is the sealant itself; shelf life expired or improperly mixed. I recently resealed a tank and removed ALL traces of sealant as I had to guarantee the job and had no desire to repeat the effort. It was a light grey (a sign that too little activator was used) and very soft (it easily came off with my fingernail); It had never fully cured. If the sealant is not firm and stable, don't even consider going over it.

 

[RVbySDI]

Laying pro seal over an exterior leak is not a good idea. Successful repairs will require sealing from the inside of the tank. You state the leak is at the inboard nose rib. If so, this should be easily accessible with the tank off and the inboard access plate removed. I agree that you should remove old pro seal before applying new material. Clean thoroughly.