Spray on insulation

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It's a sickness!
Apr 21, 2006
Reaction score
Central coast
I have been using my MT with a hot water heater blanket for some time now with good results, but latley I've been loosing a little more heat in an hr than I would like. I recently saw a product by 3M that was a spray on insulation and thought that it might be perfect for insulating a MT. Anyone out there tried this stuff or a comparable spray on insulator?
All of the spray-on foams I've used (urethane & latex) burn, so if you have some way of fire-proofing it.
Ahh yes, fire, I didn't think of that. I will have a direct fire MT as soon as I get my pump, so I guess that won't work. Unless I cover the outside of the MT with a fire blanket over the spray on insulation.
www.mcmaster.com has a bunch of insulating products. One that you might consider is part #9356K13, 2" thick high-temp wrap ($26.95 for a 24"x96" sheet). Wrap your mash tun in that, then wrap the water heater blanket around it, and I bet you get good results.
Hey Yuri have you used that product before? I would be interested in trying it out. I have duct insulation on my MT right now wrapped with a hot water insulation on top of that. I roughly loose 2-5 deg in an hour. Not up to my standards!
Thanks for the feedback Yuri. I'm wondering what the chances are of that spray on stuff actually catching fire. Probably not worth trying to rig something up.
One of the reasons to have a direct fire MT is so that if you lose a little heat, you can bring the temp back up. I could be wrong, but I don't think many of the DF guys on this board worry that much about insulation.
That could also be true Orfy! I wouldn't want to drop dead after mashing in. I think a little insulation would be beneficial , so one is not constantly having to keep the burner going to keep a certain temp. I found some spray on insulation today in my new Grainger master catalog. It says it is R-6 and meets fire requirements. I'll have to investigate a little more on this.
Hey: My old boiler has asbestos. I could send ya some. I need to get rid of it and you need fireproof insulation. I see a win win situation. ;) Charlie
I just insulated my tuns with Reflectix and love how thin and easy it is to wrap with. It has a .75 R-value but I wrapped three times and had less than a inch thickness when all was said and done. You can check out more of my progress if you're interested here. You could always stop just above the bottom keg skirt and coat with something fireproof and thin.

Here's a picture of my mash and liquor tuns before I coated them with duct tape for bed liner priming (which will give me even more R-value and toughen everything up).

It goes on very easily.
Bed Liner? That is awsome. Is that for chucking the keg when you F up or under shoot your OG. HA Ha! Love it! I have used that Reflectix befor, good stuff. I'm just looking for a more permanent solution.
I use Carbon-X welding blankets at work for pre-heating large castings. With 500F metal on one side of a 1/2" blanket, the other side is cool enough to touch. They are fire proof and (relatively) inexpensive when you consider the insulating qualities.

Here's a link: http://www.buyweld.com/b-cbn16-6x8.html

The carbon fiber blankets are available in various sizes and weights. You can easily google up more sources. I've been considering using this stuff for quite a while. It really does appear to be the best way to go and I need something completely heat and fire resistant for my direct fired MT. I think you could easily make a removable wrap for the MT and maybe use brass snap thingys to secure it. I wonder what the brass snap thingy's are called. You know, like you sometimes see used on jackets etc. The price is not too bad for the blankets. It's a little high, but still within reach for me anyway.

Well, they are called, of all things, "brass snaps". Who would know? http://www.diyupholsterysupply.com/K4708-11-DZ/Snap-fastener.html
i used a combination of a water heater insulation blanket and the great stuff expanging insulating foam to insulate my keg mash tun. Its also enclosed by steel on all sides. basically I built a box around it and stuffed the insulation inside the box. works great for me and it is not direct fired.
spray foam is great for many things... but not fire. You could likely get away with spray foam on the top half and something like a ceramic fiber blanket on the bottom half. I've used a simpler product and it's great stuff. With some careful designing you could likely improve the efficiency of your heating by making a small fire box with this stuff under the keg.