Direct Fire MLT Insulation Project

[jaginger]

That does look pretty slick. Would be interested to hear how it improves heat retention.

 

[Bobby_M]

I'm sure it will be at least as good as reflectix and I won't have to take it off to light the burner. Actually, I just checked Mcmaster. Both reflectix and mineral wool is an R4.3 at one inch thick and I only had 5/8" of reflectix prior to this.

 

[conpewter]

Looks great! Might have to copy that What do you plan to do around the top to keep any liquid from spilling on the wool?

 

[brewmonk]

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

nice job, looks warm ... "...bug in a rug..." comes to mind.

as far as the carcinogens go, can/did you cover the insides of the handles with foil tape (or something else)?

 

[ThePig]

Great job - looks real nice. I like the releasable wrap idea. Throw a skirt on the top of that bad boy to keep the sticky stuff off the wool and keep you from snorting a noseload of wool when moving around up there during cleaning, maintenance, etc...

 

[AnOldUR]

Wow! Nice job. That looks great and puts my aluminum tape version to shame.

Damn, now I'll have to rework mine. How thick is that aluminum sheet?

 

[Bobby_M]

Wow! Nice job. That looks great and puts my aluminum tape version to shame.

Damn, now I'll have to rework mine. How thick is that aluminum sheet?

Too thick. I haven't put my calipers on it but if I had to guess, it's 16 gauge. The tightest diameter I could muscle by hand was like 24". It was only after using the ratchet straps that the ends met.

If I hadn't gotten that aluminum for free, I would have never paid for it. It's so expensive that you'd be better off with stainless sheet at half the thickness.

A compromise solution is to pick up some aluminum roof flashing on a roll. It's really thin stuff but you could always double up the thickness for more rigidity. I'd also fold the ends over where you want to attach any hardware and maybe even roll a small piece of flatbar in on the ends to take screws.

One of my ideas for the "endgrain" protection on the top was to cut 100 slits, 1" deep and then fold all the tabs over. That might work on thinner material.

My next idea was to spread some RTV silicone on top of the wool with a little olive oil on the keg as a release agent. I figured a couple very light coats would keep it from getting wet. If I can find some cheap 1" square neoprene rubber or other closed cell foam, it would be so much easier to jam down into the gap. Mcmaster to rescue I guess.

I do plan to seal the keg handle holes with something, but more importantly the drain holes. I think a little silicone or JB weld in there would work. I don't want every little dribble to run into the wool.

 

[Dog House Brew]

And you said you had no metal working skills........I think it looks great and I think it will work better for sure. Look forward to hearing how much better it is. Looks great!

 

[Bobby_M]

I think I'll run a beer tools pro vessel calibration on it some night this week.

 

[ThePig]

You could cut the sidewall down below the handles and find a piece of 10ga big enough to cut a keg sized donut and set horizontally on the top of the sidewall of your 16ga. The ID should be the keg diameter and the OD would be the keg + the wool + the 16ga. You don't need to fasten it with anything. The ring itself will hold in place perfectly if you cut it tight and use a very light bead of silicone on the gap. A rotozip is the perfect tool for this.

Damn, if you were out here in Seattle, I'd cut you a section of diamond plate and bling you out ;>0

I'll send you a 19-20" piece of 10ga aluminum sheet if you pay the shipping and do your fab work. If this works well, I'll build one for myself.

 

[Birdgunner]

You could cut the sidewall down below the handles and find a piece of 10ga big enough to cut a keg sized donut and set horizontally on the top of the sidewall of your 16ga. The ID should be the keg diameter and the OD would be the keg + the wool + the 16ga. You don't need to fasten it with anything. The ring itself will hold in place perfectly if you cut it tight and use a very light bead of silicone on the gap. A rotozip is the perfect tool for this.

Damn, if you were out here in Seattle, I'd cut you a section of diamond plate and bling you out ;>0

I'll send you a 19-20" piece of 10ga aluminum sheet if you pay the shipping and do your fab work. If this works well, I'll build one for myself.

Good idea but would you slice your torso off if you brushed up against it? haha
What about using some AL tape and just tape over over the gap? May need to overlap two pieces to get it go from keg to the jacket but it should work... won't be pretty like the above suggestion but will be cheap and easy.

 

[Bobby_M]

Actually, what I'm leaning towards is shoving a bicycle inner tube in the gap and lightly inflating it. I don't want to over think it.

 

[AnOldUR]

Actually, what I'm leaning towards is shoving a bicycle inner tube in the gap and lightly inflating it. I don't want to over think it.

How about taking the bike inner tube and slitting the side wall all the way around? You could than slid it over the end of the insulation and sanwhich it between the aluminum and the keg so that only the rubber showed on top.

Kind of like this stuff:

 

[Bobby_M]

Hmm, wheels are turning. How about taking a 16" bike TIRE... and removing most of the sidewall on one side. Looking top down, it would be an intact sidewall with the bead tight against the keg, then the tread curved over the edge of the jacket. Any spill would just roll off and I think tire tread would look kinda cool. Maybe.

 

[Willie3]

I like what you suggested Bobby. Maybe you could take a bit of black rubber stripping and glue it to the insulation prior to gluing the insulation to the sheet. You could do this to the intake and outtake ports as well surrounding the openings with rubber, then adhere the sheet to the insulation. I mocked up a drawing of what I mean but cannot seem to paste it. Either way you go, looks good.

WW

 

[klyph]

Great idea.

But, if you're going with a RIMS, isn't this just an energy efficiency upgrade?

 

[Bobby_M]

Well, I'm technically a direct fire RIMS right now but yeah, when I finally get to building an element tube, it will be less important but still beneficial. I'm just happy to be able to direct fire without removing insulation first.

 

[AnOldUR]

Well, I'm technically a direct fire RIMS right now but yeah, when I finally get to building an element tube, it will be less important but still beneficial. I'm just happy to be able to direct fire without removing insulation first.

Plan on doing anything to automate stirring during your direct fire mashing?

 

[chrisknight]

We have mineral wool at work. The cable guys use it to stuff EMT sleeves for cable going into server rooms.

Why didn't I think of that?

Nice job!

 

[Bobby_M]

Plan on doing anything to automate stirring during your direct fire mashing?

No sir, just recirculation for heat distribution. I try to throttle the flame as low as I can and run the pump at a rate so that the temp coming back on top of the grain is under 170F. Since I started milling a little more coarsely, I can run the flow a little faster than before without compacting the bed.

 

[AnOldUR]

No sir, just recirculation for heat distribution.

Reading here I find that recirculating is the accepted way of doing this, but I just can’t get my head around the idea. The enzymes are in the thin wort, so I keep thinking that the temperature swing would mess with their function. Too many people do it for there to be a problem, but it just seems wrong.

 

[Bobby_M]

Agreed with the confusion here. The fact is, I only apply heat when necessary. With the new insulation, I'm figuring one short heat cycle at the 30 minute mark. The enzymes have to be exposed to denaturing temps for a good 10-15 minutes before it starts mattering. I heat for 3 minutes max and the time the wort is at say 165F is limited to 5 second bursts before it hits the colder mash again. Even with that rationalization, I can't presume to know my mash temps are rock solid at XX degrees for 60 minutes but the beer is decent.

 

[humann_brewing]

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.

Great job on this Bobby, have you had a chance to test it's insulating ability? Also, where did you get those latches? I am putting a order in at McMasters so if you have a part number that would be great.

This will also be my excuse to get a rivet tool

 

[Bobby_M]

The latches are 1794A43
Internal Compression Spring Draw Latch Bright 303SS, Nonlocking, 1-13/32" Latch Distance
In stock at $7.38 Each

Although I had them laying around from another project.

Another promising one: 1889A37
Draw Latch 304SS, Nonlocking, 1-3/8" Latch Distance
In stock at $5.06 Each

You could also secure with some 6/32 screws and nuts if you don't want to buy rivets.

The insulation definitely works. In my BTP calibration, the bare kettle lost 17 degrees in an hour while the insulated tun lost 7. The ambient temps were 42F. This was only tested with 8 gallons of water. Mash would lose a lot less, but I don't have that data yet.

 

[humann_brewing]

The latches are 1794A43
Internal Compression Spring Draw Latch Bright 303SS, Nonlocking, 1-13/32" Latch Distance
In stock at $7.38 Each

Although I had them laying around from another project.

Another promising one: 1889A37
Draw Latch 304SS, Nonlocking, 1-3/8" Latch Distance
In stock at $5.06 Each

You could also secure with some 6/32 screws and nuts if you don't want to buy rivets.

The insulation definitely works. In my BTP calibration, the bare kettle lost 17 degrees in an hour while the insulated tun lost 7. The ambient temps were 42F. This was only tested with 8 gallons of water. Mash would lose a lot less, but I don't have that data yet.

Thanks, do you think it is worth it to double up the Mineral Wool Insulation?

Also what about cutting out a circle for the top of the keg or is the stuff too brittle and would need a custom lid to go with it?

 

[Bobby_M]

I wouldn't double up on the wool because most of the heatloss you're left with is through the bottom of the keg. They do have it in 1.5 and 2" thickness, but that's getting a little ridiculous. I still have a little circle of reflectix I've been using for the top, but I'm probably going to make one with 3-4 layers. The mineral wool would fall apart swiftly.

 

[humann_brewing]

I wouldn't double up on the wool because most of the heatloss you're left with is through the bottom of the keg. They do have it in 1.5 and 2" thickness, but that's getting a little ridiculous. I still have a little circle of reflectix I've been using for the top, but I'm probably going to make one with 3-4 layers. The mineral wool would fall apart swiftly.

Alright cool, that is what I was thinking too, plenty far enough away from the heat and don't have to work about pieces flaking off into your mash

 

[humann_brewing]

I keep forgeting to measure the keg at home but I am guessing that 48" will go around correct? Just want to make sure and get my order in today.

 

[brewmonk]

2*R (pi) =circumference

3.147x 16.25 = 51.13

 

[Bobby_M]

You'll be cutting like a 4" strip off the long end so a small piece of that will make up for the missing piece around the circumference.