Burn testing and fabric identification

I've been meaning to do some burn tests for a while now. I tend to buy my fabric as remnants from the discount fabric stores so the fiber content labeling is hit-and-miss to say the absolute least.

While I'm generally pretty decent at identifying fabric content by feel these days, it's always good to confirm via another method. I know a lot of people out there on the Internet have their own guides to fabric-fondling, but here's mine, before we get down to setting things aflame.

• Cotton feels 'warm' but not hot. It can feel quite smooth (Liberty Tana lawn is a very good example of deliciously smooth cotton) or quite rustic, but rustic cotton will look very different to rustic linen. Cotton comes in many forms, from thick drills and canvas to light voiles and fuzzy velveteens. A cotton velveteen will have that same warmth as a plain-weave cotton.
• Linen feels 'cool' to my skin. On the bolt it can be quite smooth and shiny, probably from how it's processed, even if the fabric itself is quite rustic and rough. Where things get hairy between cotton and linens is a finely and evenly spun evenweave linen against a thicker cotton. Linen will also be priced higher than cotton. It's possible to find linen twills and brocades but most frequently it is plain-woven.
• Silk is another cool fiber, one which feels very different in different forms. Satins in particular are almost liquid-like in the hand. It doesn't want to stay where you put it. Most silk fabrics feel very fine and smooth even when they're crepe weaves. I find taffeta and dupion both hold their shape quite well so the primary 'tell' of those is the cool smooth hand. You cannot find 100% silk velvet -- anything claiming to be silk velvet has a reconstituted cellulose fiber on a silk ground.
• Reconstituted cellulose fibers (rayon, tencel, lyocell, modal, cupro, etc) can feel very similar to silk, but their price is generally quite a bit lower.
• Polyester is sticky, plastic-feeling, and I find it can be quite rough even in a smooth weave like satin. Poly satins specifically tend to be much stiffer than their silk counterparts. Most brocades are polyester these days, unfortunately. 

Anyways. I had about ten or twelve fabrics I wanted to test the content of. So I grabbed snippets of them, a lighter, and snippets of a few fabrics that I was relatively certain of their content.

First up: suspected cotton and cotton blends.

• I found a gorgeous grey cotton (4m) and a beautiful purple (3m? I think) a while ago, both of which are fairly sturdy tabby-woven fabrics (with proper selvedges, not the shot-fluffy-bullshit that's so common on the really cheap stuff. You know what I'm talking about.), neither of which were actually remnants. I think I got them for $6/m. Decently cheap, in any case.
• a yellow poly/cotton (at $6 for 3m+ there was no way it was pure cotton) 
• a green suspected poly/cotton ($12 for 2.4m)
• a white suspected poly/cotton ($7.5 for 1.5m), which I'm currently making a chemise from.

Next: suspected wool and wool blends.

• I have a sideless surcote made in a lovely boiled wool boucle knit, which isn't period in the slightest but is still quite lovely and will meet the 10-foot rule once it's got a bit of trimming. This was a remnant which dictated its end product.
• I also got a bunch of mill ends from Creswick's outlet in the Queen Vic market before they closed of a beautiful fawn wool coating. This one I'm fairly certain is 100% wool -- Creswick doesn't seem the type to skimp on quality by cutting their wool with synthetics.
• I've been working on a surcote in what I really should never have thought was pure wool given its price. It's striped, which is a ding already (thankfully stripes don't really take on the slutty meaning 'til the 13th century or so) and this morning I made the mistake of doing this burn test indoors. Holy shit did it smell horrible! My room has been airing out for the last six hours because of it.

The final category: known fiber content.

• I took a snippet of a gorgeous blue silk dupion I purchased in two parts (mentioned here), mostly because I saw someone mention they'd purchased silk that actually turned out to be a polyester "silk" and I desperately did not want that.
• Had to bring along a bit of linen as a control, too.
• Oh, and some of that polyester batting Mom sent as packing material in the last box.
• And finally, a snippet of a grey heathered wool/poly twill in case I needed a reminder of how a wool/poly behaves. This one I think is more wool than poly, as it does indeed self-extinguish.

So, how and why should you burn test?

I think I covered the why pretty well above--you want to know how your clothing will react should it come near a flame. Wool is great if you're working anywhere you might catch on fire, mostly for its self-extinguishing properties. Polyester will melt and stick to your skin and give you third degree burns and possibly even kill you. (Not an exaggeration!)

Here's how I did my tests today:

• I used a safety stick lighter (as I really didn't feel like getting soot and ash on my tweezers).
• For a flameproof surface, I found a bit of slate alongside the house, which I figured nobody would really miss if it got covered in melted plastic or anything. This also prevented scorch marks on the driveway. 
• I filled up an old bottle of water (which has since been emptied and recycled, as it should have been weeks ago) and left the cap off just in case any of the tests got out of hand. 
• I took snippets of each of the fabrics mentioned above. Some of the snippets were from my scraps bin if they were of garments already made, others were corners of the yardage. 

The results:

• The grey and purple are definitely 100% cotton. The purple disappeared, and the grey left behind a curly bit of ash that was still in the weave pattern. You can see that to the right.
• The yellow is almost pure polyester, if I had to guess. It shriveled up, had a flame high enough to make me nervous (so I doused it in water!), and the edges went black and melty. No ash. Can be seen above on top of the poly batting.
• The green is probably mostly cotton with a bit of polyester in it, but not much. No photos of this one, as the remaining scrap wasn't big enough to pick off the slate tile.
• The white is actually almost certainly 100% cotton, to my utter delight. No shriveled up melted edges! You can see that to the upper right.
• The boiled wool boucle knit is probably 100% wool. Shocking, honestly, but awesome as it means I don't have to be careful around a bonfire when wearing that surcote.
• The Creswick fabric is also 100% wool. No surprises there. 
• As mentioned above, the striped "wool" is actually polyester with barely any wool content, if any. It melted, smelled horrible, and I'm mad that I'm nearly done with the garment I'm making from it--all it needs is the hem and it's done. I'd suspected it was polyester when I was pinning the hem last night and I am honestly devastated to be right.
• And finally, the silk is indeed, 100% silk. I had to look up the results of silk burn tests to be sure, though. I've put it in at a larger size below so you can see it (it's sitting atop the linen scrap) and how it reacted to the flame. I was initially suspect of its content when it started bubbling when I put the lighter to it. I must admit, I freaked out a bit. 
  
  

But, interestingly enough, silk burn tests that I found online show exactly the same thing happening--or at least, the same results. I didn't see any videos of silk fabric being burn-tested, only silk yarn. The image I found (below) has the same bubbling and crumbling that my fabric (above) does. 

This picture is from lilysilk.com's blog, and I've linked to an entire post about determining whether or not your silk is Actually Silk or not.

Burn testing is something I really ought to do every time I come back from a fabric shop with goodies, but doing them all in one go does give a good comparison. I hope this post has been useful for you!