ID this insulation

[Sparrowhawk]

I can't justify paying the silly money for one of these composters, but I'd like to work out which insulation material they're using and how much insulation it's providing. I don't think it's PIR or EPS. Thes are the best photos I found online:

 

From a close-up it looks layered, like packing material. Maybe polyethylene insulation?

[Iceverge]

 

It's polyethylene foam I think alright. 

 

https://www.macropackaging.co.uk/product/closed-cell-polyethylene-foam-polylam-plank-sheets-1200mm-x-2000mm-x-50mm/

 

 

 

 

 

 

 

 

 

 

Edited April 20 by Iceverge

[SteamyTea]

Looks a bit like EPS.

EPS has a k-value to 0.036.

 

PIA-brochure-Fundamentals-Symbols-and-Terminology-of-EPS-Thermal-Insulation.pdf

[JohnMo]

8 minutes ago, SteamyTea said:

Looks a bit like EPS

Would doubt it's EPS, been working with it for a few weeks, and it would soon fall apart in a a rotating composter.

 

Looks more like @Iceverge says.

 

[Sparrowhawk]

17 minutes ago, Iceverge said:

 

It's polyethylene foam I think alright. 

 

https://www.macropackaging.co.uk/product/closed-cell-polyethylene-foam-polylam-plank-sheets-1200mm-x-2000mm-x-50mm/

 

Bloody hell that's more expensive than PIR!

[JohnMo]

Just now, Sparrowhawk said:

 

Bloody hell that's more expensive than PIR!

You could used XPS - Extruded polystyrene. It's pretty tough.

 

But why do you need insulation? If you do make it inside out, hard stuff inside, EPS outside.

[SteamyTea]

8 minutes ago, JohnMo said:

Would doubt it's EPS

Think you are right, I zoomed in a bit more on the phone screen. It seems to have that waxy sheen to it.

 

k-value of 0.032 then.

[saveasteading]

It has to be polyurethane foam, and closed cell. What claims do they make?

 

If you have plenty of garden space then you don't need this.

I have a couple of the tardis ones. they take all year to fill, as the bottom rots down. then I empty them and put any unfinished composting back in the again.

They take all the kitchen veg and soft garden cuttings and weeds etc..

Sticky stuff goes in a bigger bin and I shovel the good stuff out of the bottom and let the rest settle.

 

I got about 8 barrows of amazing compost this year. It has only saved me £100 of commercial stuff but very satisfying / sustainable, and I think it is better.

 

[JohnMo]

I think the insulation material is this

 

https://www.thepackagingdepot.co.uk/s-1241/1200mm-x-2000mm-x-25mm-white-foam-sheets/?srsltid=AfmBOormE9cYSfOuxypkmQFxMf25Te6Zgn3pYwoIJnoQGgXQ6KlRuT00z-g

[Sparrowhawk]

14 hours ago, JohnMo said:

But why do you need insulation?

 

Insulation allows hot composting, which makes compost in 90 days or so. A mow of our lawn mixed with brown stuff fills half a dalek, and I only have space for 1, so it was very handy when I had it working.

 

 

3 years ago I wrapped a Dalek composter in 50mm glass wool inside thick polythene sheet, and it worked brilliantly for the first year, keeping the contents at 45C+ for 2 weeks after every new addition. That winter the rats moved in and tunnelled within the glass fibre and made nests (should've wrapped it in chicken wire), the insulation slumped and got wet, and it stopped keeping things warm. Now in 2025 the bin is still slowly decomposing last year's clippings.

 

14 hours ago, JohnMo said:

If you do make it inside out, hard stuff inside, EPS outside.

 

Yes this would seem the sensible way, I assume they chose insulation on the inside to keep their product looking smart.

 

 

[Sparrowhawk]

8 hours ago, saveasteading said:

It has to be polyurethane foam, and closed cell. What claims do they make?

 

They make no claims beyond it's robust and allows for hot composting.

 

8 hours ago, saveasteading said:

Sticky stuff goes in a bigger bin and I shovel the good stuff out of the bottom and let the rest settle.

 

What does sticky stuff mean here? Stuff in the compost bin that's gone into anerobic decomposition?

 

8 hours ago, saveasteading said:

I got about 8 barrows of amazing compost this year. It has only saved me £100 of commercial stuff but very satisfying / sustainable, and I think it is better.

 

Assuming that home compost is similar to the council-sold "soil improvers" made from green bin composting, which is £125 per cubic metre delivered (and I see plenty to say that it isn't - but those people also want you to buy their "bio" compost at £35 for 15 litres), the economics aren't there but as you say it is very satisfying to make.

 

I find the height and shape of the dalek composers makes it hard to turn their contents every couple of weeks so I've got the idea of replacing them with an insulated cube, ideally held off the ground on blocks to make it harder for rats to attack (OSB or paving slab base?)

  

 

Unless I can get offcuts of insulation to use it won't be cheap compared to my £25 insulation of the dalek, as this needs £75 of EPS, and that's before making a hard inner lining out of something, probably timber at the same cost again. Which is half-way to the cost of a ready-made hot composting bin.

 

Wrapping a hard shell in insulation would be easier and potentially cheaper, but I haven't found many cube shaped plastic containers, and plastic barrels need flexible insulation like this polyethylene stuff plus I'm back to a shape that's poor for turning the contents to re-aereate it.

[JohnMo]

14 minutes ago, Sparrowhawk said:

this needs £75 of EPS

The stuff I linked to wouldn't need the liner and is £25 a sheet.

 

 

 

[Iceverge]

 

Could something be made from  insulated metal cladding? 

 

I've seen examples of composters as elevated drums on an axle so they can be rotated frequently for agitation. 

 

 

[saveasteading]

1 hour ago, Sparrowhawk said:

What does sticky stuff mean

I meant woody prunings that are going to break down but slowly. That's why they sometimes go through twice.

I make no attempt to turn the contents.

 

In the perfect world I would have 2 timber bins with removable fronts in 2 parts, so the stuff can be turned.  One can be emptied for use while the other continues in use. If these are substantial  (1m3?) they won't need insulation.

 

These could be beautifully made, or 5 pallets.

[saveasteading]

When brown bins were introduced the promise was of we subscribers being able to get the composted product very cheap.

This never happened as I assume businesses found they could give it a name and sell it at £5/ bag.

 

But we have together stopped the use of peat and saved the peat bogs. Well done us.

 

Anybody tried sheep wool compost? Expensive, but looks and feels like quality.

[Onoff]

I reckon get two blue MDPE barrels with lids, one smaller than the other. Lay a slab of PIR in the bottom. Place the smaller blue barrel in the bigger one with decent gap around the edges - ideally the gap the same as the insulation slab at the bottom. Fill the small barrel with water. Drill some holes in the outer barrel and fill the gap with expanding foam. 

 

 

Then an axle...a support frame...a hinged hatch...

 

Or something like that.

 

 

 

 

[SteamyTea]

3 hours ago, Onoff said:

and fill the gap with expanding foam. 

https://www.cfsnet.co.uk/s-n2pstk-002/2-part-polyurethane-foam-part-a-part-b-2kg-kit/

 

3 hours ago, Onoff said:

Then an axle...a support frame...a hinged hatch...

Why not just roll it around the garden.

[saveasteading]

9 minutes ago, SteamyTea said:

roll it around the garden.

\\im going to try this. The blue bin filled from kitchen and gardening, then transferred to the dalek after initial fermentation.

Now looking on Marketplace for a £5 blue bin.

[Marvin]

Interesting.

 

There are several searchable technical trials on compost used to produce energy (mainly heat) from a small scale to an industrial scale. Reading the results and conclusions give a good general understanding of how to get the best for my garden.

 

Made quite a lot of compost and tried several versions over the years. From what I understand, basically the rotating bins help air flow and uniform decomposition.  If you start with understanding that in order for the breakdown of the vegetation you need the right temperature, humidity, aeration and fresh waste at start, all the rest is easy.

 

The main difference with the rotating ones, with or without insulation, seems to me to be to effect speedy and uniform results. What system/apparatus would be best for you would depend entirely on the supply you have, what outcome you want and when you want it (slow or fast breakdown).

 

After many trials I use a jumbo bag method. (All food waste goes in the worm bin). I shred all my garden waste (and some of the neighbours) that's woody and mix the various types either together or in thin layers in the bag. (no evergreen). Because it's so big it holds the temperature in the middle so no particular need for insulation. When it comes time to take it out I grade the result: good stuff one side, un-rotted back in a different jumbo bag to sit for a year because once the bacteria is dead (too cold/hot/dry/wet/no oxygen) you're back to rotting it the slow way. 

 

To check the temperature I use one of these: 

cooking well even after a cool night...

 

In this bag I put a layer of 2 inch old wood chippings in the bottom to help with drainage. Filled 6 of these last year: all gone on the garden.

 

You should never need to dispose of any garden waste apart from thick wood!

 

 

 

 

[Bancroft]

We bought a trendy tumbler composter many years ago (not this model) - complete waste of time and money.

 

The benefit of having an open to the ground Dalek-type composter is it allows worms and bugs to naturally get into the composter and do their stuff.  A tumbling type with no connection to the ground does not.  So, either you manually introduce worms/bugs or add in some special fluid from the manufacturer (for a small £££ of course...).

 

Just get a Dalek from B&Q and, if you feel it necessary, add some foam around it to help heat it up.

 

Our Dalek has been fed with all our household waste and some of the garden trimmings for nearly 2 years now and has never needed emptying (laziness has stopped me removing the mature stuff to use as compost - if I need that I'll go to the stables next door).

[saveasteading]

The only problem with the dalek is that I have layers. 6" of grass cutting which becomes a part composted mass, 8" of weeds which disappear beautifully,  then weeks of household veg waste ...which attracts rats.

 

Mixing would help a lot.

 

Lots of worms in and under. Slow worms inside last year.

Rats (small, country ones) this winter...but can't really complain.

[Onoff]

Got adders in my compost pile. 

[SteamyTea]

6 hours ago, Onoff said:

Got adders in my compost pile. 

[saveasteading]

Composting information on Gardeners' World tonight, BBC2 . Really interesting. About 15 minutes in.

[SteamyTea]

7 hours ago, saveasteading said:

Composting information on Gardeners' World tonight, BBC2

Would that be Bob Flowerdew, he never gets though a GQT without weeing on compost.

 

 

Edited 11 hours ago by SteamyTea