Expanding Foam

[Rhodesy]

I have a 40L Igloo rounded cooler which I am currently using as a Mashtun. I have placed a thermometer with thermowell above the ball valve and also an additional hole 4/5 of the way up to accommodate the Blichamann Autosparge. There is space at the two fittings which I have stuffed with the insulation I pulled out when cutting the holes out with the hole saw.

I noticed on my first 2 mashes I was losing heat which could partly be down to head space but also these additions I have made. To combat the headspace I have a poly foam piece around 3cm thick which is almost the circumference of the tun wrapped in several layers of tinfoil which I place on the grain bed to limit head space. This has helped reduce the drop but I am still seeing it drop a couple of degrees on a 60 min mash.

I was wondering if I could use expanding foam firstly in by drilling holes in the hollow lid and filling that? Would it also be possible to do so in the gap behind the thermometer and also the space around the auto sparge opening? I know this may cover the fixtures but if I ever did need to remove fully I could do so with relative ease. My main concern being that with expanding foam it should not be exposed to temperatures over 50 degrees. Now I know there would be no naked flame or element exposure in the tun but is there still a danger if this is used where the surface of the plastic will be over this temp? Any advice welcome

[sbond10]

Some one recommended Lil foam beads sold in b n q garden centres as a better and easier to handle than expanding foam. Could be something else to consider

[Grumpydev]

Expanding foam isn't a very good solution to this because it needs spraying with water (or at least be exposed to moisture) to set - there's a few forum posts around where people have had it sloshing around in the lid forever more because it doesn't set properly.

I insulated the inside of the lid on mine with themawrap, and made a thermawrap insert to sit just above the mash to reduce headspace - I got zero degrees of loss over 60minutes the last time I used it.

[Rhodesy]

Thanks for the suggestions. I may look into Thermwrap then.

[Sadfield]

Some one recommended Lil foam beads sold in b n q garden centres as a better and easier to handle than expanding foam. Could be something else to consider

viewtopic.php?p=735827#p735827

[Grumpydev]

Thanks for the suggestions. I may look into Thermwrap then.

Some pics of my "mods" if it's a help:

[Rhodesy]

Thanks! Looks good and something I can look to do.