Direct Fire MLT Insulation Project

[Bobby_M]

My ultimate goal is to go all electric including a RIMS tube for mash temp maintenance but there's a long list of things I need to do including a 200a service upgrade so I thought I'd try something else temporarily.

AnoldUR and I (and a few others) threw around ideas for an insulation material that could withstand direct heat. I know some folks put reflectix on their metal tuns and light the fire, but mine starts melting in 3 minutes flat, usually after I forget to remove it during heating. Anyway, AnoldUR had pulled the trigger on some mineral wool semi-rigid insulation and it was so cheap that he bought two (and kindly donated one of them to me).

Mcmaster.com 9328K41
Mineral Wool Insulation Plain Faced, 1" Thick, 24" X 48" Sheet
In stock at $6.19 Each

The first observation is that the stuff is very delicate. It can't really be handled and for sure, you couldn't just wrap it around your MLT and hold it on with bungie cords. It would fall apart. I was going to wrap it with some really thin aluminum flashing but my dad bestowed some nice 16gauge aluminum sheet. I cleaned it up with some gator grit fine pads on my grinder and put some decorative hash marks on it to hide current and future scratches.

After I form this around something like a corny keg, I'm going to hold it all together with some spring latches. More to come.


Since there are a lot of posts before I actually made progress, here's a link to the post that gets to business.... https://www.homebrewtalk.com/f51/direct-fire-mlt-insulation-project-154652/#post1819825

 

[Sawdustguy]

My ultimate goal is to go all electric including a RIMS tube for mash temp maintenance

Bobby, I remember reading a couple of threads where you criticized those of us who use some automation. Did you have a change of heart?

 

[Bobby_M]

I criticized automation? I think I might have commented about taking some of the fun out of brewing with a high level of automation like the systems proposed to automatically control fluid movement at certain times. I'm all for automatic temp maintenance.

 

[Birdgunner]

Cool idea. Are you going to use adhesive and glue one side to the AL jacket or is it not that delicate of stuff that this wouldn't be required?
You will definitely have to let us know how it works out!

 

[AnOldUR]

How'd I miss this?

Nice idea with the aluminum sheet. I intend to re-wrap mine, but wasn't sure of what to use. Look forward to following your progress.

 

[ScubaSteve]

This is cool....I imagine you could still use this when you go all electric! It might also hide your connections to the element, further insulating them from water, fingers, etc.

 

[AnOldUR]

After I form this around something like a corny keg, I'm going to hold it all together with some spring latches. More to come.

Are you planning to bond the insulation to the aluminum before bending it? If so, what's a good heat resistant adhesive (something that won't stink when it gets hot)?

 

[jtrainer]

I've been using ducting insulation (insulation that slips over the a/c ducting).

I was thinking of using Reflectix above the skirt of the keg. By feeling the heat and taking some measurements I found my setup didn't get hot enough where the reflectix would be.

How far down did you have the reflectix on the keg during direct fire?

 

[Sawdustguy]

Even though I am not direct firing my RIMS, I am watching for ideas on insulating my RIMS controlled MLT.

 

[kaiser423]

I am in to see how this goes, just for fun.....

I had never thought of using what is essentially ceiling tiles to insulate something from fire, but it's a darn good idea...

 

[Bobby_M]

Hmm, not as much progress as I would have hoped. I actually piggy backed a brew day on top of my daughter's birthday party so I was helping set that up for a day or two. I had to rely on the old trusty reflectix. It ended up losing 3.5F over 60 minutes which isn't bad for a 45F ambient garage.

Progress so far is notching the sheet for the bulkhead and thermo and bending into the tightest circle I could muscle. This stuff is a bit too thick to bend by hand but I'll make it happen somehow. I have some 3M Super 88 spray adhesive to sort of attach the wool to the shell, we'll see how that goes.

 

[AnOldUR]

I have some 3M Super 88 spray adhesive to sort of attach the wool to the shell, we'll see how that goes.

Looking forward to hearing how this works.

 

[Birdgunner]

Looking forward to hearing how this works.

+2
Hope it works out, great potential.

 

[Bobby_M]

Ugh, I guess I should get my lazy ass off HBT for an hour today and get some work done on it. It's actually a little warmer today so I have no excuse.

 

[brewmonk]

if it as fragile as described, you may want to try shaping it around the carboy first, and glue the aluminum to it while on the 'form', or do you think it will survive the compression from flat to cylindrical?

 

[AnOldUR]

Don't know if you go to this project yesterday. When I was using the aluminum with adhesive backing, it wouldn't stick to the insulation. The adhesive would just pick up a thin layer of fuzzy insulation like one of those rollers you use to remove lint from your cloths. I'm curious if a liquid adhesive would penetrate better?

 

[Bobby_M]

That's a good point, and no I didn't get to it. I got reassigned to christmas light removal duty. Of course saying that I have nothing else to do is an immediate jinx.

I'm thinking about applying a light coat of the spray adhesive ahead of time to try to bind a full layer of fibers and letting it dry. To be honest, I may be procrastinating because this is a one shot deal. Once that thing falls apart, it's toast. Then again, it's a $6 item and at least I could say I tried. If this fails, I might have to pony up for the ceramic fiber blanket.

 

[beerthirty]

You could use some of that SS lock wire you have to hold it initially to the kettle at about three positions. Then use the aluminum tape to wrap it with. Start with the tape 1/2 on the kettle and insulation and continually wrap all the way down. The tape sticks very well to itself and to the kettle. I secured my insulation this way, it has withstood the heat of all three kettles and traveling at 60 MPH down the freeway without being ripped apart.

 

[Birdgunner]

Then use the aluminum tape to wrap it with. Start with the tape 1/2 on the kettle and insulation and continually wrap all the way down. The tape sticks very well to itself and to the kettle.

How does the HVAC/Al tape hold up to the occasional flame that may go up the side of a kettle?

I was thinking of using Isofrax but wanted a good way to make sure that the fibers were contained and I didn't have some potential carcinogen's floating around (yes I know Isofrax has no hazard classes currently associated with it, hence why it is my first choice but I bet in a couple years it will be reclassified as a type 2b like all the other ceramic insulations), this could be the ticket. Sounds like a good idea if it can handle a lil flame!

 

[brewmonk]

why not sandwich it?

 

[Birdgunner]

why not sandwich it?

Between metal or the tape? Or did you have something else in mind? An AL tape insulated blanket... I like it!:rockin:

 

[beerthirty]

How does the HVAC/Al tape hold up to the occasional flame that may go up the side of a kettle?

I was thinking of using Isofrax but wanted a good way to make sure that the fibers were contained and I didn't have some potential carcinogen's floating around (yes I know Isofrax has no hazard classes currently associated with it, hence why it is my first choice but I bet in a couple years it will be reclassified as a type 2b like all the other ceramic insulations), this could be the ticket. Sounds like a good idea if it can handle a lil flame!

I dont have any flames that go up the side of my kettle. Yesterday during a wet run kladue was here with a k thermocouple and the reading at the out side of the skirt was over 500*. It has worked better than I thought it would though I have only done 2 wet runs and 5 brews since insulating.

 

[jaginger]

It triples the cost, but you can buy that insulation reinforced with wire mesh. Any idea what the R-value for a 1" thick sheet is?

 

[Birdgunner]

It triples the cost, but you can buy that insulation reinforced with wire mesh. Any idea what the R-value for a 1" thick sheet is?

For the Isofrax they cite that for the 1" thick and 8pcf dense material the Hot face at 1202F, the cold face will be 343F, 2" will get you to 248F.

 

[brewmonk]

Quote:
Originally Posted by brewmonk
why not sandwich it?

Between metal or the tape? Or did you have something else in mind? An AL tape insulated blanket... I like it!:rockin:

Well, I'm a woodworker, I have no idea what isofrax is, so I was thinking 2 sheets of aluminum- inner and outer- to surround the mineral wool-lookin stuff.

The 'outer' sheets ends would have to be "Z" crimped and (for example) popriveted to the flat sheet underneath, and allow for overlaps, and a clamping system.

When unclamped, the diameter would increase enough to allow it to be slid upwards and over the top, keeping the cylindrical shape, and not over-flexing the core.

 

[Birdgunner]

[/QUOTE]Well, I'm a woodworker, I have no idea what isofrax is, so I was thinking 2 sheets of aluminum- inner and outer- to surround the mineral wool-lookin stuff.

The 'outer' sheets ends would have to be "Z" crimped and (for example) popriveted to the flat sheet underneath, and allow for overlaps, and a clamping system.

When unclamped, the diameter would increase enough to allow it to be slid upwards and over the top, keeping the cylindrical shape, and not over-flexing the core.[/QUOTE]

Now that would be fancy. I propose Bobby_M or someone much more capable than I try this first and report to the rest of us
It would contain the fibers and handle heat extremely well. I wonder how much something like that would cost? I know the "non ceramic", ceramic type insulation would run between $40-$55 to cover a standard keggle, not sure about the AL

 

[Bobby_M]

I've been to all those wonderful places in my mind but when you get in the garage with the stuff, it's like F-it, wrap this around that and secure it with that. OK, maybe not that simple but I lack any sort of metal working skill and tools. I'm gonna have some decent pictures to share in about an hour.

 

[Bobby_M]

I made some progress.
Trimmed panel:

You can see it doesn't like to bend..

Some ratchet straps get things moving.

Spring latches attached with rivets.

 

[Bobby_M]

It turned out that the mineral wool will stick to the aluminum pretty well with both surfaces coated with 3M Super 88. I don't plan to remove this thing more than once or twice a year and only for serious MLT cleaning.

 

[Birdgunner]

Very Nice! Best part is, no carcinogens floating around! haha
Can't wait to hear how it holds heat for you.
I like it, great job...think I may be forced to copy you