by Tony Martin
Permaculture Association member
So how can such a material be considered acceptable to permaculturists? The answer is of course in the “perma” part of permaculture. Stainless steel is a lot like Captain Scarlet, nearly indestructible (unless you are using particularly strong chemicals or high temperatures)
There are a number of different grades of stainless which are made from iron with varying amounts of other metals, including chromium, nickel, manganese and molybdenum.
Type 316 which is more expensive but has good resistance to corrosion and heat and is often used in making insulated twin wall flues for wood burners. Cheaper grades such as type 304 (AKA type 18-8) are used for items like sinks where heat and corrosion resistance is not so important.
So when might stainless be of use to a permaculturist?
By chance I acquired some 0.5mm thick pieces of varying widths and lengths (Around 10 cm x 2 m) which I use to lay between rows on veg beds and for other gardening duties:
- Mulching: Even knotweed cannot penetrate stainless steel!, (but it can grow around the sides).
- Extra light is reflected onto your plants which is especially helpful at the beginning and the end of the year when light levels are lower.
- Being shiny it can be laid around fruit bushes or other places as a deterrent to birds. However remember to remove it at the appropriate time if you are employing birds to do pest control for you.
- Can be placed in the ground to form impenetrable edging.
- If you have a large enough piece it can be wobbled in a humorous fashion whilst singing about restraining a kangaroo.
Quality stainless steel buckets can be purchased for about £10-15 each and will last almost indefinitely and can be used in many ways that the cheap plastic buckets cannot.
- When not in use elsewhere they can be left covering small tree stumps or tough weeds to prevent or reduce new shoots appearing
- To boil water in, or even to cook meals over an open fire or stove.
- With a lid they can be used to store seeds, produce etc to prevent small creatures from ram raiding your stores (rats can chew through low density breeze blocks and chicken wire but not stainless).
- Can be left outdoors in the sun and elements without being degraded by anything short of a meteor strike, which suggests yet another use.
So a very useful material, but how about the environmental damage and energy costs?
|Stainless Steel Bucket||Plastic Buckets (HDPE)(note 1)|
|Initial cost||High (£15)||Low (£1)|
|Durability||Very high, immune to weather||Low, weak and photodegradable|
|Energy required to make one bucket||17.6kWh (Note 2)||7.1 kWh (note 3)|
|Recyclable||100% indefinitely||Partially and will degrade|
|Durability||Hundreds of years?||Perhaps a few years|
|Lifetime energy and materials||Low||High|
|Flexibility of use||High||Low|
So, as one stainless bucket that is 100% recyclable or maybe 50+ plastic buckets that may be (but often aren't) recycled, I know what makes sense to me.
Where to source this wonder material?
My favourite source is a local non-ferrous scrap yard where they let me wander around digging through piles of that. I pay around £1 a kilo but this goes up and down depending on the market and how much I buy. I have also had some good deals on Ebay, local ads, car boot sales and freecycle. Remember, scrap yards can be dangerous places, get some strong builders rubber or kevlar gloves to rummage with as stainless steel is the material of choice for razor blades amongst other things. Most importantly of all, don't kick the bucket, especially the stainless one, pick it up instead.
Tony Martin has around 42% Womble genes and will be assisting on a full PDC being held at his 5.5 acre site in South Wales with Aranya (Lead teacher) from the 5th-19th of July 2014. You should easily recognise Tony, just look for someone covered in mud, holding something shiny with a big grin on his face.
Please see here for further details of the course or contact Tony on 01639 845 144 or via email.
I have not tried to quantify any other energy costs other than the raw materials due to lack of data. I am assuming however, that over it's lifetime the energy costs of manufacturing and transportation of a single stainless bucket will be less than that of the large number of replacement plastic buckets you would have to make, transport and dispose of.
Article and photos produced using free software including PCLinuxOS, GIMP photo editor and Libreoffice office suite.