Direct Fire MLT Insulation Project

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ThePig said:
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.
Click to expand...

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 said:
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.
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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:

 
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.
 
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
 
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.
 
Bobby_M said:
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.
Click to expand...
Plan on doing anything to automate stirring during your direct fire mashing?
 
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!
 
AnOldUR said:
Plan on doing anything to automate stirring during your direct fire mashing?
Click to expand...

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.
 
Bobby_M said:
No sir, just recirculation for heat distribution.
Click to expand...
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.
 
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.
 
Bobby_M said:
mltinsulation8.jpg



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.
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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 :)
 
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.
 
Bobby_M said:
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.
Click to expand...

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?
 
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.
 
Bobby_M said:
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.
Click to expand...

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
 
Well I guess it is harder than I thought to find the Aluminum I need to wrap around the keg. the big box stores only have up to 48" wide and that won't cut it ;) Headed down to a aluminum shop in the ghetto to see if I can find what I need.

Hoping to do your build justice, wish me luck :)
 
How about some aluminum roof flashing? I know it's really thin but if you do two layers and use some backing washers on the rivets, it should be fine. You could also fold that edge over so that you're going through more than one layer.
 
Bobby_M said:
How about some aluminum roof flashing? I know it's really thin but if you do two layers and use some backing washers on the rivets, it should be fine. You could also fold that edge over so that you're going through more than one layer.
Click to expand...

Yeah, I may have to look at other options. I took the 45 minute drive to the metal foundary just to find out their power went out earlier that day and the office was closed. There were still workers there and said I could check out any scraps they had but they had just got rid of a big stack recently and really didn't have anything around that wasn't stainless and impossible to bend.

So it's either try to go back there or go to lowes down the street again. If I recall, the did have flashing that was wide enough for the height of the keg right?
 
Lowes:
Amerimax 20" x 10' Roll Aluminum Flashing
Item #: 12540 | Model #: 66320
$8.37

If you put your zip code in to the website, they'll tell you if they carry it at your store.
That should be enough for a double up. Even with the doubling, I'd probably put a 2" fold on the end where the latches attach.
 
Bobby_M said:
Lowes:
Amerimax 20" x 10' Roll Aluminum Flashing
Item #: 12540 | Model #: 66320
$8.37

If you put your zip code in to the website, they'll tell you if they carry it at your store.
That should be enough for a double up. Even with the doubling, I'd probably put a 2" fold on the end where the latches attach.
Click to expand...

Thanks, they didn't have it locally but didn't charge anything to ship it to me so it is on its way :rockin:

Also, I went with the small bold and nut instead of the rivets so I will use some washers on the back side.
 
To cap this one off, I wanted to show you what the end result was.

I went low tech on sealing the top of the insulation off. I picked up a tube of light grey 100% silicone caulk. There's about a 1/8" deep trough where the skin stuck up past the insulation. I applied some masking tape on the keg at the same height as the aluminum wrap and then filled that gully in with silicon. I used a squeegee to make a nice finish by riding the aluminum edge all the way around. While it was still wet, I removed the masking tape.

mltwrap1.jpg


A closer look at the finish. Not perfect by any means but good enough.
mltwrap2.jpg


I used a small piece of aluminum roof flashing between the insulation and keg to cover the handle. A bead of silicone seals it from the inside.
mltwrap3.jpg


I also put a bead of caulk down in the crevice between the keg and top skirt because grain bits always get lodged in there. It also sealed the drains. When cleaning, I found that a paper towel or sponge was needed to get water out of this place.
mltwrap4.jpg


I also have some practical data since I brewed on this thing recently. I mashed at 155F and I noted a drop to 153 at 30 minutes, then down to 150 at 60 minutes. A 5F drop in 45F ambient with only 7 gallons of mash is a success as far as I'm concerned.
 
the seam on my bk always has small leaves and crap in it. it's a PITA to clean out and I end up getting soaked by the water spray I use to try to clear it.
Bobby your MLT insulation rig looks very clean. Nice work!!
 
Bobby_M said:
To cap this one off, I wanted to show you what the end result was.

I went low tech on sealing the top of the insulation off. I picked up a tube of light grey 100% silicone caulk. There's about a 1/8" deep trough where the skin stuck up past the insulation. I applied some masking tape on the keg at the same height as the aluminum wrap and then filled that gully in with silicon. I used a squeegee to make a nice finish by riding the aluminum edge all the way around. While it was still wet, I removed the masking tape.

mltwrap1.jpg
Click to expand...

how much silicone did it take to fill up that gap? Isn't it about 1 inch wide around the whole keg?
 
It took less than one full tube for all of it. I know it looks like a lot on the outside edge but it's only 1/8" deep. Basically I made the outside wrap stick up a bit proud of the insulation. Then I put a huge bead down and used a squeegee to flatten it by riding it along the wrap.
 
Bobby_M said:
It took less than one full tube for all of it. I know it looks like a lot on the outside edge but it's only 1/8" deep. Basically I made the outside wrap stick up a bit proud of the insulation. Then I put a huge bead down and used a squeegee to flatten it by riding it along the wrap.
Click to expand...

Thanks, I put it together last night, had to work with it a bit to get the fittings to stop leaking with the extra space but now to seal it.
 
anybody else do this to their kegs? those insulation numbers were pretty impressive.
 
i am going to give this a whirl in the very near future, maybe even ordering everything i need tomorrow. currently, my mlt is naked and I have always relied on recirculation with a "strong pilot" going throughout the mash. sometimes i fire up the burner for a minute or two in addition, but with a 5 degree drop over 60 minutes, I wouldn't even be concerned.

Initial plan is to go with 2 layers of aluminum roofers flashing, and use screws and nuts over rivets. I do have 3 questions though.

Did you cover both sides of the insulation with aluminum sheeting, or just the outer side, letting the inner side of the insulation butt up against the keg?

What type of adhesive works best? Would you recommend the same adhesive you used or something else. I don't plan on having to take it off anymore than you, if at all.

thanks
 

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