insulating a kitchen sink

[Tonyz]

have a kitchen sink that looses heat quickly, the water when first in is VERY hot, so would making a box around the sink (inside the cupboard and using either spray foam or insulation batts help or do I need to was quicker

[q9]

Automotive tar sheet sound insulation? Apply with heat gun.

[rwbuild]

Box and foam if you must, bats will do absolutely nothing short of compressing them and filling the whole cupboard. Just remember to allow for the high expansion, don't fill the whole void in one go, a small hole the OD of the nozzle on the 3 sides and bottom. start with a small amount in bottom hole first and as soon as you see it coming out of the other 3 holes, stop. 25mm cover will do the trick.

[Chief Tiff]

How about polyurethane glue over the metal surfaces? Out of the bottle it has the consistency of honey so you apply thin coats and brush over any drips or runs; pretty soon it foams up and sets pretty hard in under an hour. You can keep adding more layers as required and it’s much cheaper than builders foam. Gladwrap around the drain and water lines so you don’t end up with them permanently attached!

[BobL]

Ours just has a ~5 mm thick layer of (looks like wetsuit fabric) foam glued onto the bottom and it seems to retain its heat pretty well.

Maybe ask around for an old wetsuit?