Tank Test?

So I'm in the middle of building my tanks and now I'm to the part where you close it up for good and so I was wondering if there is something that I can do or need to do to test for leaks before closing it up?

cwharris said:

So I'm in the middle of building my tanks and now I'm to the part where you close it up for good and so I was wondering if there is something that I can do or need to do to test for leaks before closing it up?

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If by "closing it up" you mean attaching the baffle I can tell you I took the advice from others here and put them in the cradle and filled them with water and let them sit for a day.

I am very glad I did because I made a couple of rookie mistakes that would have required cutting access holes later. As it is I am just about to pressure test them and may have to cut holes anyways, but my leaks were on the end ribs at the leading edge where I thought I had put enough sealant but clearly did not. I also had a minor leak on the bottom of the j-channel where access is difficult. Make sure you fill them enough to submerge the bottom of the j-channel.

A thourough visual inspection for voids in the fillet seals adjacent to the end ribs and fuel fittings is about the only useful "check" you can do. Filling the tank with water to leak check it at this point would only identify leaks that would be easily seen by performing a visual inspection, and is therefore a waste of time and effort.

Mike H said:

A thourough visual inspection for voids in the fillet seals adjacent to the end ribs and fuel fittings is about the only useful "check" you can do. Filling the tank with water to leak check it at this point would only identify leaks that would be easily seen by performing a visual inspection, and is therefore a waste of time and effort.

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Mike I am sure you are correct, however as a first timer it looked sealed to me but a slow leak was there and required additional sealant. So if you are going to visually inspect look VERY closely.

My advice, if you inspect the interior prior to final assembly of the rear baffle and think you have enough sealant in place, go mix up a new batch of sealant and apply more sealant on all the seams. Forget about the notion of saving weight when sealing the tank. If saving weight is important to you, find savings elsewhere. You can never have too much sealant in the seams of these tanks. While it is still accessible is the only time you can do this. This wisdom is coming to you from hard lessons learned from past experiences of my own failings in not doing this very thing when building my tanks.

Will New Sealant stick to sealant that has hardened? Do I need to do anything to the hardened sealant before applying New sealant on top of it?

cwharris said:

Will New Sealant stick to sealant that has hardened? Do I need to do anything to the hardened sealant before applying New sealant on top of it?

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You will want to thoroughly clean and prep the area as usual. You may want to remove any extra cured sealant from the seam prior to applying new sealant and then make sure the new sealant adheres to the aluminum skin on either side of the seam. I am assuming you will be applying new sealant to a seam. I would make attempts to insure that the new sealant is making a solid contact with the aluminum and not just to any cured sealant.