When fabricating a tank liner the more accurate dimensions we are given the better the fit of the liner. What we require are the exact inside dimensions of the tank. From that we will undersize or oversize the liner accordingly to make for a great fitting liner.
On thinner gauge liners – 60 mil or thinner – we don’t make any sizing adjustments. We fabricate those liners to our tolerance of plus or minus a ¼ inch. With heavier gauge liners there is a need to undersize all dimensions by ¼ inch to ½ inch. This is because of the small radius formed in fabricating the corners. Without this under-sizing the liner would not fit properly.
On liners that are 20 ft. in length or longer we don’t undersize the length and may even oversize the length by ¼ inch to ½ inch. There is some natural undulation in the material and at these lengths it can affect the fitting of the liner. There is also a marginal amount of shrinking in such large liners and by over-sizing the liner we can maintain the great fit that Witt liners are known for.
We ask that you leave it to our experienced fabricators to make these adjustments. Provide us with the exact interior dimensions of the tank and we will make you a liner that fits!