A Uniseal is a single molded pipe-to-tank seal that passes a draw or return line through a poly tank wall with no bolts or gaskets. It seals curved walls a flat-mount bulkhead can't touch, and it removes the air-leak points that starve a suction line. Key Features One molded part: No bolts, gaskets, or o-rings to source or lose. You buy the seal and a length of pipe, nothing else. Seals curved walls: Mounts on round drums, cone-bottom tanks, and Brute cans where a flat bulkhead won't seat. Kills suction-side air leaks: Removes the threaded joints that let air into a draw line and cost you prime. Holds pressure and vacuum: Built for low-pressure tank service on draw, return, and recirculating lines, not high-pressure discharge. Fast, tool-light install: One hole saw, soap and water, and a firm push. No threading, no sealant cure time. Five sizes, priced each: 3/8" through 1-1/4", from $4. Buy the size your line needs. Specifications Construction Single injection-molded compression seal, one wide flange Material Molded elastomer Max wall thickness Up to 1/2" (13 mm) Service Low-pressure tank penetrations; holds pressure and vacuum; not for high-pressure discharge lines Sold as Single seal, by size (each) Match the seal to your pipe's nominal size and measure the pipe OD, since PVC is nominal-sized. The 1/2" and 3/4" seals use the same 1.25" hole saw, so you can bump a draw line up a size in the same hole. Size SKU Pipe accepted Pipe OD Hole saw Price 3/8" U038 3/8" Sch 40 PVC 0.675" 1.00" $4.00 1/2" U050 1/2" Sch 40 PVC 0.840" 1.25" $4.00 3/4" U075 3/4" Sch 40 PVC 1.050" 1.25" $4.00 1" U100 1" Sch 40 PVC 1.315" 1.75" $5.00 1-1/4" U150 1-1/4" Sch 40 PVC 1.660" 2.00" $6.00 What's Included One Uniseal per quantity ordered, in the size you select No pipe, hardware, or lubricant included Fits Schedule 40 and Schedule 80 PVC at the matched nominal size, plus ABS, poly, copper, and steel pipe. It's built for soft wash poly batch-mix, dilution, and storage tanks, and it works on curved or flat walls up to 1/2" thick. It's not for thin, flexible walls that flex under liquid load. Use a Poly Bulkhead Fitting there instead. How the Uniseal Installs Cut a clean, round hole with the hole saw sized for your seal (see the table above). Press the Uniseal into the hole with the wide flange facing out. Deburr and bevel the pipe end, wet it with soap and water, and push it through from the flange side. The inner wall thins and compresses around the pipe, gripping it without clamps or threads. Skip silicone and grease. A slick base can let the pipe slip under load. Soap and water is the standard field lube. In a batch-mix tank, one seal carries a draw, return, or recirculating line through the wall in place of a multi-part bulkhead. Pairs Well With Crushproof Suction Hose for the draw line that runs through the seal Stainless Steel Hose Clamps to clamp the hose to the barb on the inside run PVC Ball Valve for a shutoff on the draw or return line Soft Wash Proportioner for the batch-mix build the tank feeds Poly Bulkhead Fitting for thin or flexible walls where a Uniseal shouldn't go Frequently Asked Questions What size hole saw do I need for a Uniseal? The 3/8" seal needs a 1" hole saw, the 1/2" and 3/4" both use 1.25", the 1" uses 1.75", and the 1-1/4" uses 2". Cut a clean, round hole. An oval or rough hole is the top cause of leaks. Can you use a Uniseal with SH? Operators run them on SH draw and batch-mix lines every day, and they hold up in that service. No seal maker publishes a sodium hypochlorite rating for the material, so we don't sell it as a certified bleach-rated fitting. Run your normal mix, keep the wetted rubber rinsed, and swap the seal if you ever see swelling or splitting. What's the difference between a Uniseal and a bulkhead fitting? A bulkhead clamps two threaded halves through a flat wall with a gasket. A Uniseal is one molded part that seals on curved or flat walls and installs faster for less money. On a thin wall that flexes under load, a bulkhead is the safer pick.
