Over here in the UK POR-15 is a bit pricy, and I have read here that once opened it doesn't stay usable for too long. I found another brand a bit cheaper and as I have a backlog of leaky hurrican lanterns as well as a Bialaddn 310 with a pinhole but nice paintwork I thought I might treat myself. FTS3000 is the product and it comes in small 250ml bottles at £21. Has anyone tried this one ?
I haven't tried that brand but I was told a trick with sealers like Por15. Don't open the tin, punch a nail hole in the tin and use a syringe to suck out the required amount. Then plug the hole until next time. My tin has been used 1/2 dozen times over 5 years.