Komodo
Well-Known Member
Thought I'd pass along my experience since searches pulled up some evidence and references but nothing conclusive.
I've got a 5 gallon round Rubbermaid cooler mash tun, but I imagine this would apply to most any cooler lid. The round ones specifically though. First I tried drilling several holes the size of the spray foam tube around the side of the lid. (brand new can, shaken thoroughly) When you spray the foam in it, it seems to be shooting in there fine, and you can even see the foam expanding out of the holes....but, it's a lie!!! Through some research i found that the foam needs moist air to expand and does nothing inside the lid but create a pile of wet goo. NASTY, ungodly, sticky, wet goo. So, I decided to open it up with the intent of seeing what happened and then filling it and putting it back together.
I carefully sliced the top of the lid off, just under he top rounded edge all the way around the lid with my bandsaw. I held the top against a fence and slowly rotated it. Like hot butter really, no problem. You could probably easily do it with a hand saw. Once removed, you could see the foam did NOTHING. Don't think you have partial foam areas, and it's good enough. You got nothin. First I tried wiping out the bulk of the goo with paper towels, and got 80% of it out. The rest started to turn opaque yellow and expanded slightly!? So, I waited for awhile for that to dry then sprayed foam into both halves, filling them up. Later, I'll shave them flat and somehow glue them together, and use aluminum tape around the edge/seam and that should do it. Super insulated lid and peace of mind. Maybe you don't have to totally remove the top, but if you are just spraying in holes, you are just making a mess.
I've got a 5 gallon round Rubbermaid cooler mash tun, but I imagine this would apply to most any cooler lid. The round ones specifically though. First I tried drilling several holes the size of the spray foam tube around the side of the lid. (brand new can, shaken thoroughly) When you spray the foam in it, it seems to be shooting in there fine, and you can even see the foam expanding out of the holes....but, it's a lie!!! Through some research i found that the foam needs moist air to expand and does nothing inside the lid but create a pile of wet goo. NASTY, ungodly, sticky, wet goo. So, I decided to open it up with the intent of seeing what happened and then filling it and putting it back together.
I carefully sliced the top of the lid off, just under he top rounded edge all the way around the lid with my bandsaw. I held the top against a fence and slowly rotated it. Like hot butter really, no problem. You could probably easily do it with a hand saw. Once removed, you could see the foam did NOTHING. Don't think you have partial foam areas, and it's good enough. You got nothin. First I tried wiping out the bulk of the goo with paper towels, and got 80% of it out. The rest started to turn opaque yellow and expanded slightly!? So, I waited for awhile for that to dry then sprayed foam into both halves, filling them up. Later, I'll shave them flat and somehow glue them together, and use aluminum tape around the edge/seam and that should do it. Super insulated lid and peace of mind. Maybe you don't have to totally remove the top, but if you are just spraying in holes, you are just making a mess.