Fresh water tank fitting repair

[jjw4413]

I'm replacing two defective fresh water tank fittings on my fresh water tank and was wondering if anyone has used a water safe epoxy to install the fitting. I purchased the fitting but the spin weld tools are $250 a piece and I need two. No one in my area does this kind of work. Any help would be greatly appreciated.

 

[Domo]

Water tanks expand and contract due to temp and due to hundreds of pounds of water splashing. The longevity of epoxy, which is solid, should be suspect. Here's some comparisons of methods. (Please note the comment that "no sealer works with poly") - I'd go with the Sika 291 or 3M DP, as mentioned below.

• Mechanical Sealing: Use a threaded inlet with PTFE tape or a soft hose clamped with a jubilee clip. This is the most reliable method for inlets, as no sealer works well with polyethylene.
• Polyurethane Sealants: Sika 291 is a highly rated polyurethane sealant that bonds reliably to polyethylene if the surface is properly prepared. It is NSF-approved for potable water and FDA-approved for incidental food contact.
• Specialized Adhesives: 3M DP8005 is an acrylic adhesive optimized specifically for polyethylene bonding.
• Repair Kits: For cracks, a combination of drilling stop-holes at the crack ends and applying FlexSeal paste or a 2-part epoxy repair kit (like FerroPre) may work, though longevity is uncertain. Covering the repair with Eternabond tape can add durability.
• Plastic Welding: Hot air welding or ultrasonic welding are considered the preferred methods for permanent repairs on split tanks, as they fuse the material rather than relying on adhesion.