Polypropylene sheet is the standard material for pickling and plating tanks for good reasons: it shrugs off hydrochloric and sulfuric acid at workshop temperatures, welds quickly, and costs a fraction of lined steel. But “PP sheet” covers a wide quality range. Here is what tank builders should specify.
Thickness: Size the Wall, Not Just the Budget
For self-supporting tanks, a common starting point is 8–12 mm wall for baths up to about a meter deep, moving to 15–20 mm with external steel bracing for larger vessels. Drip trays and covers can drop to 3–5 mm. When the liquor runs warm, remember that PP loses stiffness with temperature — brace more, not thicker only.
Virgin Resin vs. Regrind
Sheets extruded from virgin homopolymer weld predictably and stay weld-compatible across batches. High regrind content shows up later as brittle seams and color drift. We extrude our tank-grade sheet from consistent virgin resin batches — and supply welding rod drawn from the same material, which is the single best thing you can do for seam strength.
Color Conventions
Beige and grey are the traditional colors for acid service in Asia; white dominates in cleanrooms and food-adjacent plants; green and blue often mark rinse or alkaline baths. Functionally the pigments matter less than the base resin — but a consistent color scheme helps operators tell baths apart at a glance.
Welding Tips from Our Shop
- Bevel plates ≥8 mm to a 60–70° V and root-gap them slightly; fill in two passes rather than one heavy bead.
- Hot-gas welding runs best around 300 °C air temperature for PP — too hot chars the rod, too cold leaves a cold joint that peels.
- Test critical seams with a spark tester or soap solution before the tank ever sees acid.
We stock tank-grade PP sheet in 2–30 mm with cut-to-size service, matching welding rod and molded flanges and unions — one order, one resin system. Email jinhaofeng298@163.com for a price list.