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Pro-Seal?

T

tom_AZ

Well Known Member
K&N air filters that I've purchased recently have tended to run 1-2mm "short" (62-63mm v the 64mm spec), which potentially comprises the seal between the top of the air filter and the plate on the bottom of the throttle body (IO-540). My plan is to fabricate and install an aluminum plate on the bottom of the FAB; it will have a hole in it to allow any leak-down fuel to escape via the existing FAB vent line. This seems to be a relatively common fix for FAB abrasion, and should also solve my issue by raising the filter by a couple of millimeters. Pro-Seal seems to be the adhesive/sealant that I see others have used.

Questions:

1) Is pro-seal indeed the best adhesive to use for securing the plate to the bottom of the FAB? Given that no one seems to enjoy working with Pro-Seal, is there another reasonable alternative? This is about simply securing a piece of aluminum with an adhesive that will stand up to fuel--not something as critical as sealing fuel tanks.

2) Surfaces obviously need to be clean. Thoughts on acceptable solvents to clean/de-grease the fiberglass portion of the FAB?

3) A friend passed some pro-seal to me should no alternatives emerge from Q1 above. I've been keeping it in the hangar fridge. The other day, I noticed that a couple of soft drink cans were empty. Others were OK, but presumably the fridge temp dipped below freezing at some point. Does that render the Pro-Seal unusable? If yes, I have all the more reason to consider an alternative.

Thanks in advance.
 
I used pro-seal (FlameMaster) and rivets to secure the bottom aluminum plate on my FAB. The sealant was several years old at the time and set up just fine. I store it in the hanger fridge/freezer. I like lacquer thinner to clean fiberglass up from oil/grease. Just used that old pro-seal again today on my canopy. Last of the can. The mix cup is saved to test for proper curing after a couple days. It will probably cure quickly in the closed hanger which is like an oven lately.
 
9GT said:
I used pro-seal (FlameMaster) and rivets to secure the bottom aluminum plate on my FAB. The sealant was several years old at the time and set up just fine. I store it in the hanger fridge/freezer. I like lacquer thinner to clean fiberglass up from oil/grease. Just used that old pro-seal again today on my canopy. Last of the can. The mix cup is saved to test for proper curing after a couple days. It will probably cure quickly in the closed hanger which is like an oven lately.
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Thanks.
 
airguy said:
Interestingly, I noticed last night that Vans now sells "expired" proseal that has been on their shelf past the expiration date, for only $10.
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That is interesting. I can't imaging how $10 would be worth the potential grief of someone crying foul when their Proseal install fails. I'd just throw it out.
 
bkervaski said:
That is interesting. I can't imaging how $10 would be worth the potential grief of someone crying foul when their Proseal install fails. I'd just throw it out.
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They do specify that it's NOT good for fuel tank use anymore, but should be good for anything else, like bonding trailing edges etc. It also appears the price has been adjusted since I saw it last night - it now shows $15 instead of the $10 that I know I saw.

https://store.vansaircraft.com/mc-240-b1-2-esl.html
 
airguy said:
They do specify that it's NOT good for fuel tank use anymore, but should be good for anything else, like bonding trailing edges etc. It also appears the price has been adjusted since I saw it last night - it now shows $15 instead of the $10 that I know I saw.

https://store.vansaircraft.com/mc-240-b1-2-esl.html
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Expired = Expired

... I would avoid the meager savings here and go for the good stuff ... $150K+ airplane and all that ...
 
bkervaski said:
Expired = Expired

... I would avoid the meager savings here and go for the good stuff ... $150K+ airplane and all that ...
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True enough - but there are countless tales here on VAF of builders who store their Proseal in a freezer until using it, and have no issues with it setting up properly and lasting a long time - I'm one of them. Personally I think most of the woe and angst associated with bad Proseal can be traced back to bad habits when measuring and mixing the batch.

Remember too that you can buy a bottle of water with an expiration date - and water has been on the earth since the beginning.
 
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airguy said:
True enough - but there are countless tales here on VAF of builders who store their Proseal in a freezer until using it, and have no issues with it setting up properly and lasting a long time - I'm one of them. Personally I think most of the woe and angst associated with bad Proseal can be traced back to bad habits when measuring and mixing the batch.
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Same, I keep it in the freezer. Is Vans doing that with their Proseal?

I guess I don't know why anyone would want to save a few dollars doing things like this [buying expired adhesive] ...

For $15 there's no math that works out on Van's selling expired products. If they need the $15 they can turn the lights off when they leave for the day.
 
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Walt said:
Except for the fact that they likely have to pay a Hazmat disposal fee, can't just toss it in the trash.
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I think paying a hazmat disposal fee would be better than risking negative PR later ... or just stack it in the corner ... just don't thin Van's should sell it, in light of the recent issues.

Best case they make a few hundred bucks, worst case: "NTSB found that <whatever> departed the airplane and <whatever> due to a failed adhesive".

At which point the only thing that will matter is that Vans sold expired adhesive, not where the buyer, hopefully still alive, used it.

I just think it's not worth selling expired products, just one more thing to not have to worry about.
 
I'm not here for a war, but 45 years of working with Proseal and the derivatives, including maintaing KC10 refuling tankers, I have never seen any , no matter the date, that didn't cure unless it was unmixable. I don't advocate using out of date sealant for internal tank work, but we are all pretty smart folks..I use it for way more than fuel tanks and probably have 50 tubes of "expired" in my shop. I do keep it stored in a climate controlled room. Just my 2 cents on expensive stuff. And yes, the hazmat disposal is way more expensive than Fixnflyguy's shop...I'll keep all I can get.
 
Aircraft Spruce sells expired Proseal as well. And nobody says you have to buy it to use it on an airplane. I've used some in the past to repair a leaky watering can.
 
I think $10 is a good deal. Nobody should use it on their tanks, but there are countless other things it can be used for. I have a can that’s been in my freezer for two years and it’s been used for numerous things around my house and in my shop. After my airline job I flew corporate for 10 years and our maintenance dept kept pro seal tubes in the break room frig. When they expired, guess who got to take them home…….
 
bkervaski said:
ThenThat is interesting. I can't imaging how $10 would be worth the potential grief of someone crying foul when their Proseal install fails. I'd just throw it out.
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I have collected and saved expired aircraft sealant for years and never had a problem. One guy at work used a entire box to seal the bottom of a boat. As one of the previous posters said: save a sample for evaluation after it cures.

If it is stored cold it’ll be good for years.
 
I used West Systems G/Flex epoxy to bond my aluminum plate under the K&N filter to the fiberglass airbox. Great stuff. I also used it under the hinge sections on the cowling.
 
rockyfatcat said:
I have collected and saved expired aircraft sealant for years and never had a problem. One guy at work used a entire box to seal the bottom of a boat. As one of the previous posters said: save a sample for evaluation after it cures.

If it is stored cold it’ll be good for years.
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My comment wasn't that you shouldn't use expired products (I won't, but to each their own). It was that Vans shouldn't SELL expired product. If something happens all that's going to be in the headlines is that they sold expired adhesive that led to something terrible happening, regardless of what the installer chose to do with it.

I'm saying for $15, in the light of recent events, why would Vans even take that risk?
 
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