Any chemical engineers out there? Proseal

[bobmarkert]

So I mixed up a large batch of pro-seal (Flamemaster) to close the back of my fuel tank. The resulting product looked darker (black) than usual, but I thought it might be my imagination. I use a very accurate scale but I was very tired after a loooong session building the tank. Twenty four hours later it seems that the proseal is setting up a lot faster than normal. What are the ramifications if I inadvertently added too much hardener (sic)? Will the end product seal as well?
Thank You
Bob
RV8 Sloooo Build

[Walt]

Not a CE but mixing the stuff "hot" is pretty standard procedure in the field, no worries, it'll be fine.

[bobmarkert]

Thanks Walt..... on to the next tank
Bob

[GusBiz]

Chem Engineers push chemicals around they are chemical plumbers, Chemists (the industrial kind) makes it all happen, they are chemical chefs ;-) I used to be the later.

So what has occurred is exactly as walt alluded to.

Its most likely reacted a little quicker. A couple things will do this and they are all based on the energy of activation. So heat will make it go quicker because there is more energy to overcome the energy of activation and the catalyst lowers the energy of activation.

Either way it is just doing what it normally does at a higher rate.

The repercussions of this are that it will stay plastic for less time. As you know when you tick the two surfaces together there is a time when proseal is still a completely plastic (moveable) fluid. Then it begins to cure (cross-link). When reacting faster you have less plastic time and so if you?re going to move it in position you need to be accurate with your actions.

Issues with this? Once it has begun to cure, if you move it, you don't have as much "give" in it. ie it will tear or break. Before curing there is nothing to tear, it?s not cross-linked, so it just flows.

However like Walt said, if you made it up, put it on, then stuck your surfaces together, and leave it then it?s no different to normal.

[airguy]

Originally Posted by GusBiz

Chem Engineers push chemicals around they are chemical plumbers, Chemists (the industrial kind) makes it all happen, they are chemical chefs ;-) I used to be the later.

If you didn't notice anything wrong besides the color and the fact that it started to set up a little faster (24 hours later!!) then you are good to go.

The diploma on my wall says I'm a chemist, by the way. Build on.

[bobmarkert]

Thanks guys. I'm already working on the second tank, but now I don't have the nagging thought of cutting multiple access holes in the back of my tank to fix massiver leaks...... that may still happen but not because of the mixture!
Bob

[Tweetr]

So do you chemists and chemical engineers have an explanation as to why avgas softens the sealant when leaking outside the tank, but leaves the sealant firmly cured inside the tank? Shouldn't FUEL tank sealant be impervious to, you know, FUEL under all conditions? Frustrated RV mechanics who would rather be out flying than chasing fuel leaks in the hangar want to know!

My experience with softened ProSeal is detailed here: http://www.vansairforce.com/communit...ad.php?t=86434