[=MEASURE TWICE]
Some tank liners says to be functional, but some differences has happend the last years.... after (& moore) etanol was blended into the petrol, a lot of brands have trouble to keep up. The higher prosentage of etanol is ruining the stuff, it get easier than before dissolving it, at shorter time.
But though do they use a method of lapping weld with extra thickness at edges.
Joining metods in welding shown on the pic under. FigA show show egde to egde, and figB , overlapping type.
Welding are ways of melting, and adding metall. To make a joint holding up, it need to be hot enough to lay extra metal/melt trough, trough the joint. (figA+B,the red color) Trouble with it is to not get to much heat, then the metal could easy be distorted, and to little just laying on the outer side (not meltet trough). Metal does expand in heat, and only where heat is pointed it does, the rest is not heated (at least not similar degrees) and stay colder with not any expanding, therefore making distorting when to big differences.
The experienced welder know this and can regulate it so this dont happend, but also got melting trough, to get a good joint. The hobbyists with not so much experience would easy not get it done like this, a little to hot weld,distortion, to cold,and just "chicken****" (as called by experienced welders) on outside.
By distortion & , if any had happend under welding, when grinding afterwords to get nice & smooth shapes, gets quite easy holes grinded, or weakening the welds to much,because of the uneven shape, and you got leaks.
What i ment by the trouble with start/stopping welding who makes easy leaks, was start/stop welding does the handling with the heat easier aka; distortion. But a weld is normally harder (f.ex. by MIG welding)than the steel, and when starting again, the weld are not heated similar as it would be further down the welding, and quick pollution in the air, could create changes who gives a leak. When not grinding before starting again, you got thicker metal at the welding stop, and thicker metaljoining needs poweradjusting on the weldingmachine, thinner metal another adjustment...and this is not easy to do right under working...
If the edges of all pieces to be joined are slightly thicker than the middle I’m thinking?
To do this I would take and weld ahead of assembling by welding the edges thicker with strips of metal.
Just thinking maybe a way?
Trouble is welding strips on, just give to welds (both sides of the strips) does double the chances of distortion & leaks.. You could double it by flip edges, but then its trouble with melting trough, to hot on the outer to melt trough both......
On flat pieces where you reach the backside, then its quite easy to straighten if distorted, but its a reason to make leakproof tanks, arn´t cheap & easy to do, as you cant do this in a closed cell....! ( f.ex in S.steel and wanted it to be undistorted ,and not use filler/bondo )
Great to hear you uses a breather on the welding, then you got a better chance to breath later in life too!!
