Diy insulated mash tun

[osprey brewday]

Just after any thoughts on my idea for a mash tun before it gets set in expanding foam. I plan to add 1 or 2 2000w silicon drum heaters around the pot (600mm dia) to maintain mash temps, the whole area between the pot and the ice machine bin will be filled with 2 part foam. Still to source a false bottom looking at wedge wire screen any one around Newcastle purchased any of that?
150L total volume, planning a 100L batch (.full volume mash) I will use a hang in element to assist it to get to strike temp then the drum heater can maintain it during the mash with a digital controller. Do you think I need 1 or 2 band heaters.
Cheers Troy

 

[SBOB]

You're going to bury that drum heater in the expandable foam? That doesn't seem like a good idea to me...

 

[husky]

I would use both heaters & no insulation. I was visiting a very small micro yesterday that use these same heaters on their MT. They had 3 x band heaters on a 200L MT. Ramp times are slow but you could add an over the side to get to mash out.
Always wanted to give band heating a go myself.

 

[malt junkie]

As above, 4000w to maintain and raise mash temp, I wouldn't insulate either, I don't know how you would go about insulating something like that safely, ie without risk of fire.

 

[osprey brewday]

You're going to bury that drum heater in the expandable foam? That doesn't seem like a good idea to me...

I was planing to, I might just stuff some loose insulation in there so it can be serviceable if anything fails, the bin itself is insulated also.

 

[osprey brewday]

As above, 4000w to maintain and raise mash temp, I wouldn't insulate either, I don't know how you would go about insulating something like that safely, ie without risk of fire.

Done some investigating on this I figured it would be fairly safe limited to 80 deg c

 

[husky]

If you wanted to insulate it I would use a glasswool/rockwool as commonly used on steam line insulation. I thought poly started to melt @ 80C.

 

[wynnum1]

vermiculite or perlite

 

[osprey brewday]

vermiculite or perlite

That's the go will just funnel it in and vibrate it,can vacuum it out if I need access.

 

[wynnum1]

That's the go will just funnel it in and vibrate it,can vacuum it out if I need access.

Plus can recycle in the garden about $30 to buy 100l.

 

[Lyrebird_Cycles]

There's a fire rated version of expandable foam made by Silka (it's pink rather than yellow), it's rated to higher temperature and doesn't produce the nasties that the ordinary stuff does .

I run a composites curing oven that goes up to 120 oC, it's worked well for that.

$$$ though.

 

[MHB]

I would use Aeroflex sheet where the heat belt isn't, you can glue it on and wrap in tape to keep it water tight. You can also make cutout covers for the heat bands to maximise the heat going in rather than escaping.

Rated to about 150oC, I've used a lot of this over the years and find it very good both as insulation and value for money.
Mark

 

[Feldon]

You might also need to consider, not just the affect heat will have on the foam insulation, but the affect it will have on the drum heater components. Even silicone has a heat limit before it starts breaking down, and there mifght be other plastics etc involved in the wiring. How hot will it get inside all that insulation?