Insulating Material

edited June 2016 in General

I've got a 26 gallon water/oil jacket boiler with heating elements in the jacket.

I'm interested on what y'all would recommend for insulating the outside of the unit as I would like to reduce the transmission of heat outwards. Right now I care about how it works and not as much about looks, though if I have a choice less-kludgy-the-better.

My temps will be able to get hotter than the boiler by a significant amount as I don't want a super long heat-up time, so non-melting insulation is required.


  • Are you actually controlling the temp of the jacket or or just turning it down when it starts to smoke?
    Google boiler insulation and you'll get plenty of hits.
    Rock wool and cladding sounds like what you need but there are whole industry's devoted to It that can give you a better answer.

  • was planning initially to use the auberins controller and just turn it down once to temp.

    I did google boiler insulation and the results were what I thought. Used plenty of rockwool and fibrous blankets in the past on other projects and didn't particularly want to deal with fibers everywhere. It is a good product, but was hoping for something had experience more like armacell, etc that would be a cleaner installation and perhaps easier to take off for maintenance.

    I googled heat transfer coefficients and I guess unless I pressurize the jacket the maximum temp of the jacket will be around 100C.

    I'm guessing that an agitator would help heat up times. Does anyone have any experience/pointers/direction with smaller sized agitators or pump overs in this scenario? The kettle size is only 26 gallons and will not have any grains.

    I know I've been asking a bunch recently and will be happy to become a contributing member of the community once I hit the ground running and offer some pics of setup, experience, and drinks once I have something worth sampling 8-}

  • Armacell works well. You could also use closed cell foam (wet suit material), upholsterers do custom work for boat motors etc and could sew one up for your boiler easy enough.

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  • edited June 2016

    Why not thin rockwool, like 1" and then use that super thin decorative aluminum sheeting to clad it.

    The only real challenge is getting a clean top lip. The bottom would be open to let out condensation, spills.

    If you took some time, you could probably just notch an inch in with tin snips, and fold them all over neatly.

    I used sheet like this to clad something for another project, a slightly different pattern (it was just slighly engine turned) and it was very easy to work with. Once you get your cylinder, just use pop rivets to join it on the back side (where you don't see the seam).

    You can cut the top lip out of a single piece, but joining it is a problem unless you can weld - that and you waste a ton of the sheet.

    If you don't have any side protrusions, you can probably fit the whole thing over the top, run it straight down to the floor, like a kind of pretty floor length still dress...


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  • edited June 2016

    I also did a steam injected boiler once using closed cell foam and rubber matting. It works really well, the boiler is still in use as my BK although i stripped the insulation off the bottom third as it now runs on gas.




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  • I used Superlon fire rated sheeting to do mine. Then I covered the lot in aluminium tape.
    It's fine if you only going up to 100C. It's a bit like a tight fittings tea cozy.

  • edited June 2016

    I have used expanded foam covered with a fibreglass skin on bath temperatures up to 130 deg C. Worked ok. Its only a small boiler made with a big aluminium pot, but the principle is the same.

    Make a card cylinder to surround the boiler, fill the gap with foam, trim it and lay on a fibreglass coat over the outside.



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  • I go a little more ghetto; An old comforter wrapped around the boiler. Also used around fermenters during the winter

  • I direct-fire my boiler with propane, so I use dragon scales to insulate my boiler. I followed @smaug around the ADI conference for five days picking up the scales he shed. A few more conferences and my boiler will have full coverage! :))

    I'm more like I am now than I was before.

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