I would like to get some real data on the strength of aluminium foil. This could be done by measurement of tear strength directly or by thickness which I think would be a very good correlate. Almost every make says it is ‘extra strong’, ‘restaurant strength’ etc but they all seem rather flimsy to me and I have trouble telling the cheapest from the more expensive by touch or in use. Perhaps I would rate some as weak and others as very weak.
Builders and fabricators are not apparently expected to be swayed by unsubstantiated claims - why should cooks? If one buys metal sheet, shim or flashing the thickness is always specified so that you know what you are actually getting and how it will perform on the job.
Shouldn’t kitchen foil be the same? I would like Choice to report on foil strength or thickness so that we know what we are getting and whether paying more makes any difference.
I agree - if I can’t flash the eaves of the house with ally foil, it doesn’t cut it.
But seriously - it is so variable and there seems to be no standard, just the marketing blah blah about it’s quality - and I’m sure we’ve all done battle with foil and ended up rolling it into a ball for the cat to play with and starting again.
Sounds like a fun and useful test for someone at Choice to run. Might I suggest the ‘wrap someones office in foil’ test as part of the scoring regimen? OK probably not, but the various strength tests, ease of dispensing, cost, etc. Arguably it could be paired with a film-wrap test - that’s usually the next thing used to seal the leftovers?
The number of times I have had the foil pierced by the piece of bone peeking (and I do mean just peeking) out of the roast joint is getting to the innumerable. As all above have said or intimated, is that the brands label their foil as strong, tough, and other catchy words but the results are very very often flimsy, weak, and other such less catchy words. I remember the distinct differences between brands many years ago with some being quite thicker and much more resilient than others (and thus the preferred brands when buying foil). You only bought the less strong brands when no other was available or the need was just to please the children with their tin foil hats (or similar less robust needs).
Standard household foil is typically 0.016 mm thick, and heavy duty household foil is typically 0.024 mm.
The patterns on the aluminium foil can affect the way it moves and folds, but is unlikely to affect its strength (unless the pattern perforates the foil during manufacture).
If you are interested to see how aluminium foil is made, there is a Youtube video showing its manufacture. Unlike many other manufactured products which are extruded, aluminium foil is pressed and rolled. An interesting process.
Also, many local councils allow used aluminium foil in the recycling bin, provided it is of reasonable size (when loosely crushed about the size of ones fist. For Brisbane City, information on materials that can be included in the yellow top recycling bin can be found in this document by BCC - note, this link is to a word document which should download automatically…
Very few shoppers can be seen with calculators in super markets. Even fewer have precision micrometers in their pockets, and even fewer groceries would be happy with them opening boxes to check.
This is compounded by thickness not always being a proxy for strength since density (and other characteristics) is important. Compare the foil sold for lab work, insulation, and catering (eg covering hot foods) as examples.
Is puncture strength the same importance as rigidity and folding and tear strength characteristics? Will they be the same or have any consistent relationship?
So many questions and generalisations and so few answers.
“Very few shoppers can be seen with calculators in super markets. Even fewer have precision micrometers in their pockets, and even fewer groceries would be happy with them opening boxes to check.”
Nobody suggested any such thing. I asked for a test of products so that we can then tell from the brand which is better.
"This is compounded by thickness not always being a proxy for strength since density (and other characteristics) is important. "
We are talking about a product (kitchen foil) made of aluminium that is alloyed/tempered to make it suitable for rolling into thin sheets. I really doubt are going to find much different in metallic composition. In any case let us see from some testing.
“Compare the foil sold for lab work, insulation, and catering (eg covering hot foods) as examples.”
I am talking about kitchen foil - not all the possible uses of foil or all the ways it might be made into a composite with other materials.
“Is puncture strength the same importance as rigidity and folding and tear strength characteristics? Will they be the same or have any consistent relationship?”
I wasn’t attempting to design the test criteria on the fly. I just want to know which foil will work better in the kitchen, I leave it to the testers to determine how to measure it.
The general complaint is that foil is too flimsy, in normal use it tears and it punctures and you cannot easily tell by observation whether paying more provides a better product. I don’t care to know exactly how or why the weak ones fail, just a list that says these products are the strongest for the money.
Edit: No offence intended. The comment on the micrometer was intended as humour re the claims of heavy duty, et al vis comments on thickness. The references to other than kitchen foil were meant to reinforce how many variables there are to assessing foil beyond just thickness.
Most foil is either labelled heavy duty or super strength or not. I suspect the ones which have no special strength labeling are the 0.016mm varieties. The ones that are labelled heavy duty or super strength are likely to the the thicker ones (0.024mm).
There are also some called ‘stronger’ than ordinary foil. It could be expected that this foil is thicker than typical foil but who really knows if it is heavy duty or just somewhere in between 0.016 and 0.024mm.
What would be interesting to know if the ones labelled as higher strength, are in fact higher strength and thicker…or is it just marketing spin. This would be something for Choice to test.
The other test would be to see if different typical/standard foils have the same strength. Difference in strength could suggest perforations, damage during manufacture or varying thickness.
For metals such as aluminium foil, which is metal aluminium, the density of the material tested under the same temperature and air pressue would have the same density irrespective of the thickness.
Factors which could affect strength would imperfections in the rolled foil such as uneven thicknesses (thinner areas including as fines scratches would be more likely to break/tear) or perforations caused by the roller, rolling surface or adding patterns. In thinner foils, these perforation would most likely result in holes or scratches.
What is of interest, if one uses alfoil to provide shielding from mind reading/controlling satellites, it would be recommended to use heavy duty types as they are less likely to have perforations/holes which allow signals to penetrate into the skull.
I took your post as being in support and offering some useful observations/questions - and I say that as one who owns a selection of micrometers and verniers but who did not take offence at you making fun of me measuring my foil in aisle 12 …
Thanks for that @phb. I have a collection of kitchen foils with various labels, one being called ‘heavy duty catering foil’ that has a feel that seems for want of a better description, aerated, eg less dense than the others. All the other foils regardless of how labelled have a different feel regardless of whether they seem stronger or thicker, or not. I always assumed the catering roll underwent a special process to expand the metal to make a cheap product for the food industry, but the word ‘assumed’ often bites, and bite it has.
The exchanges in this thread have educated me that the differences among all the different foils I have are indeed thickness coupled with the quality of the fabrication plant, and apparently small differences in thickness make big differences in product. A question though, is all aluminium the same? (Using steel with the various alloys or iron (cast forged, etc) as a basis for the question.)
If it is aluminium, it will be the same. It is a bit like other pure metal forms. With aluminium, like other metals, there is a chance for some minor impurities to occur as a result of the refining processes, but these are unlikely to be consequential.
There are aluminium alloys which are a different beast. These have different properties and are a mix of other metals.