WATERWELD EPOXY PUTTY STICK - 4 OZ.

WaterWeld will set and cure underwater, but it bonds best to a dry surface. Shut off the water, dry the area, sand off any gloss, and clean it before you apply. Once the putty is pressed into place it will continue curing even if it is submerged. Wait for a full cure, at least one hour and preferably overnight on plumbing, before you restore pressure.

Yes. WaterWeld is certified to NSF/ANSI/CAN 61, the standard for drinking water system components, under J-B Weld Company LLC's NSF listing. That covers potable water pipes and fittings; NSF's listing limits exposed sealant surface area to 1.3 sq cm per litre (0.2 sq in per litre), which a normal patch on a pipe is well inside. Let it cure fully before restoring flow. The certification covers drinking water safety specifically, not food contact.

J-B Weld rates WaterWeld to withstand water pressure up to 500 PSI once fully cured, roughly ten times typical household supply pressure. That rating assumes a properly prepped repair: shut the water off, dry and sand the area, clean it, and let the putty reach full cure before restoring pressure. It is still a patch, not a replacement for a damaged section of pipe. On a supply line that has failed from corrosion or age, plan on replacing the section.

J-B Weld lists fuel tanks among WaterWeld's applications, but we don't recommend it there. Fuel tank work carries real fire risk, and ethanol-blended gasoline is hard on epoxy repairs. For a steel fuel tank, TankWeld (8217) is the purpose-built product. For plastic or polyethylene tanks, J-B Weld has no repair product that bonds reliably, and replacement or professional plastic welding is the dependable fix.

Yes. Once cured, WaterWeld can be drilled, tapped, filed, sanded and painted, and it cures to an off-white color. Sanding does not affect the seal as long as you do not cut through the patch. If you plan to paint, support recommends letting the repair dry at least three days first, then wiping it clean before you prime or paint.

WaterWeld will not bond to polyethylene (HDPE or LDPE), polypropylene, or polycarbonate, and J-B Weld does not offer an epoxy that will. It does work on PVC, ABS, fiberglass, porcelain, concrete and most metals, provided you sand the gloss off and clean the surface with acetone first. If you are unsure what a plastic is, check the recycling code before you buy.

Yes. Once fully cured, WaterWeld can be painted with enamel or latex paints, so your repair can blend in with the surrounding surface.

Enamel and latex paints both work well over cured WaterWeld. Make sure the repair has reached full cure before you paint.