I'm sure you know this but I will say it anyway. Make sure you check it for leaks with low pressure air and some soap suds. It is very easy for an aluminum weld to be porous. Especially if it is not extremely clean. I would check it with only a couple pounds of air pressure or you will buckle the sides.
Many years ago I had a guy that wanted an alum. fuel tank for a plane modified. It was old and had sat open for several years. There was no flammable gases in it so I modified it for him. I did it as a favor to a mutual friend of ours. since I did it for free I did not go to any lengths to check it for leaks but I told him how to check it and insisted he be sure to check it before installing it. About 2 month later I get a call from my friend saying the guy installed it in the wing and skinned the wing, painted the plane and was reedy to test the pane. When he put fuel in the tank it leaked. He then wanted me to test it and reweld it. I refused to do anything more with it for 2 reasons. First was that the guy was told what to do but did not do it. 2nd he had put fuel in it and it was going to take time to get it ready to reweld. I was not willing to do all this for free to a guy that was too lazy to do what he was told needed to be done. I will never do anything again that I do not check myself weather I am being paid or not. The moral to this story is, never do any project for free . The mutual friend was an air frame mechanic and I suspect he had many larger problems with this guys plane since he was not doing the work but just inspecting it for this guy as a favor . I was glad I was not him.
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