How do I calculate the GSM of a wrap, and why is it useful to know?

What does GSM mean?

GSM stands for “grams per square metre”  (also written as Gr/m²) and tells you much a 1m square piece of any cloth would weigh.

GSM gives a rough scale that allows you to determine the thickness of the cloth- with 150GSM being pretty thin and 400GSM+ being a much thicker wrap. What is considered ‘medium weight’ differs from country to country and also changes over time as carrying fashions and styles alter. Firespiral’s medium weight tends to be around 245gsm.

Why is GSM useful for wrappers?

  • It gives you an idea of how thick/heavy a wrap is, regardless of its length.
  • It allows you to directly compare wraps that are different lengths/widths by using a standardised measurement
  • You can calculate the gsm using your wrap and should get (pretty much) the same answer as another person with the same wrap- even if they are both different lengths.

What are the problems with GSM?

It only gives you one part of the puzzle, and needs to be understood in context.

A good analogy is with the BMI (body mass index) scale. The BMI uses just your height and weight in its calculation to determine whether or not you are at a healthy weight. We know that the BMI is flawed in that it doesn’t take into account other factors such as muscle tissue, build, fitness etc and GSM is the same. There are other factors like weave and fibre blend which will affect how a wrap feels and behaves, so two wraps with the same GSM may not feel or wrap in the same way. GSM needs to be understood in the context of these other factors. It is unhelpful, for example, to decide that a wrap would be unsuitable for you based purely on GSM alone.

How do I calculate GSM?

Knowing your way around the metric system is a bonus for working out the gsm, as it requires you to measure in metres and grams! As a reminder, there are:

100 centimetres (cm) in a metre (m) and 1000 grams (g) in a kilogram (kg).

To give you an idea of imperial weight equivalents, one metre is just over 3 feet long and 1kilogram weighs 2.2lbs.

We’re guessing that you don’t fancy snipping a 1metre square piece of cloth out of your wrap, but fear not! Calculating the overall gsm is very simple to do, regardless of dimensions. All you need to do is divide the area of the wrap by it’s weight, but we’ll break down how to do that in practice.



weigh your wrap in grams (using whatever scales you have available)1. Weigh your wrap in grams.

Jen doesn’t have any flat scales and ends up balancing the whole thing in the kitchen scales (which is a bit of a faff but does the job)! It is important to make sure that the figure you come up with is in grams rather than kilograms- especially if you are using flat bathroom scales which are designed for heavier weights.

If your scales give their weight in KG then simply multiply that figure by 1000 to convert to g


For example 1.23kg = 1230g


2. Measure your wrap.

We advise you to measure ‘soft tape measure in hand’ (STIH) to get the most accurate measurement results, and we’ve explained why and how to do this. As with the weight, it is important to get your results in metres, so a wrap that measures 4 metres and 22 centimetres (422cm) would be 4.22m for the purpose of the calculation.
You need to get two measurements from your wrap. The first is the length along the hem, the second is the width of the wrap from one hem to the other. Measure straight up at right angles to the long hems. DON’T measure the the slopey tapered edges. You’re not measuring the perimeter of the wrap! Your wrap is a parallelogram, which is essentially a squashed rectangle, so the two pointy tapered ends balance each other out in terms of overall area.

3. Find the area of the wrap

Multiply the length measurement by the width
For example 4.22m x 0.68m = 2.87metres squared

 

4. Divide the weight by the area

Take the weight in grams and divide it by the area that you just calculated. It is likely that your answer will be somewhere between 100 and 500, so if you’ve got a result of 0.00002, then you’ve probably made a mistake and should recheck! You should get that same result even if you measure and weigh a longer (or shorter) version of the same wrap, because whilst the figures will change, the weight to area ratio won’t.

 

For example 1230g / 2.87m2= 428 gsm

Easy as that!

Measuring a Woven Wrap: Soft Tape Measure in Hand (STIH)

Woven cloth is ‘dynamic’- it can stretch and contract, grow and shrink depending on what is happening to it at the time, whether or not it has been washed or ironed recently (and even how it was washed).

Trying to measure something that can change length is pretty tricky! The babywearing community has created a general standard for measuring which is designed to create some consistency. This is important because different measuring methods can give very different length readings for the same wrap. By sticking to a single system we minimise discrepancies.


The style of measurement that we use is referred to as “soft tape measure in hand’, often abbreviated to STIH. There are two key points to this system

Soft Tape Measure
A soft tape measure (or measuring tape) is sometimes known as a tailor or dressmaker’s tape. As the name suggests, it is soft and very flexible. Many will have both metric and imperial measurements on them. Rigid measures such as metal retractable tape measures, metre rules or yardsticks as less adapted to measuring fluid surfaces. They are also harder to use accurately when holding something floppy to measure it. 


soft tape measure for measuring wrap length and width  


Soft tape measures do need treating with a little care, as they can become stretched and distorted if put under undue stress.

In Hand

It might seem more sensible to lay all the cloth out on a flat surface and measure it flat. This however,  can only give you the measurement of the cloth in its current state of contraction. If your wrap had just been washed it would be likely to measure considerably shorter than if it had been worn all day.
By measuring in hand, you are placing the cloth under a certain amount of tension- you’re stretching it out slightly to find its optimal length. By this, we don’t mean pull it as tight as you can possibly manage, just stretching it as far as it will comfortably go, to reach its naturally taut state. 

This mimics the stretching that occurs when you wrap your child, so it gives you a more accurate reading of length. 



For example, you may have two wraps that, when laid out on the floor, both measure exactly 4m with a wooden metre stick. The first wrap has just been washed, is a looser weave and has more natural stretch. When you measure it STIH, you find that it actually measures closer to 4.2m (and could stretch to 4.24cm if you pulled it ridiculously tight, but 4.2m feels like its ‘natural’ comfortable tension).
The second wrap is quite densely woven, well broken in and doesn’t have much recoil. When you measure that STIH, it still measures just over 4m, so no real difference between the contracted and taut states. You then find that the first ‘wraps’ much longer than the second, even though they measured the same laid out on the floor.


Measuring STIH gives you a ‘working’ measurement- one that tells you how much actual length you’ll have to tie round you when you are wrapping, not how much length you’ll have when the wrap is sat on the table!

The length of a wrap is measured all along one of the hems, from the tip of the taper point along to the end of that hem. Wraps are parallelograms (squashed rectangles), so although the two long ends don’t sit directly above each other, then both measure exactly the same.
On the diagram below, you would measure along one of the longer lines, from point A  to point B. 
measuring of the long hems from A to B gives the wrap length
This same technique works for measuring both the length and width of a wrap. The width often needs to be stretched a little more taut than the length in order to get an accurate reading, as making a seat for your child puts it under maximum tension.

wraps will stretch under tension

 

 

 

Calluna Moorland Birch Trees

Weft Name: Calluna 

Warp Name: Moorland

Design Name: Birch Trees

GSM: 335

Weave Structure: Alchemy

Average Width: 65cm

Blend: 50% combed cotton, 50% merino lambswool

Related Wraps: Calluna Callisto Birch Trees shares both the same weft and design. 
Greystoke Glasto Birch Trees uses the same weight/blend of weft and design, so shares wrapping properties.

Wrapping Qualities: Spongy and thick in hand, very supportive, a little bounce, mouldable, makes a large knot. A great wrap for heavier wrappees, and single layer carries.  Wraps a little short due to thickness, so size up if you usually tie near the tails. Slight initial prickle when new, but a few washes and a little wear makes this wrap very soft.

Care Requirements:

  • Use a delicate, wool specific liquid detergent. These are widely available in shops
  • Do not use fabric softener
  • Wash on a wool specific or handwash cycle at the lowest temperature, and with the lowest spin available. We recommend 600rpm or below. If you do not have a wool specific or handwash cycle on your machine please handwash your wrap.
  • Do not be tempted to add non-wool items to the drum (pillowcases, towels etc). The wool cycle isn’t designed to deal with these items.
  • Air dry only, do not hang on a radiator or other heat source or tumble dry.
  • Iron on a gentle/cool setting.

Notes:  ‘Calluna’ is the botanical name for common heather which seemed fitting for the delicately flecked colour of this wool weft, especially as it is a common sight on the moorlands that surround where we live. 

Release Date: 8th January 2018

Label Identification Code: BRP001

 

New Prices for Blends, Heavy Weight Wraps and Scarves

Our new double weave wraps (which we’ve named ‘synergy weave’) will be in the heavy weight price band. We are also increasing our prices on new releases for both the heavy weight and the blend category by £5 per wrap, and our scarves by £2 per scarf (our scarves are also now 25cm longer).
We are holding off from increasing prices on our standard weight cotton wraps for as long as possible, as we had done with this price rise. We have always tried to keep our prices as low as possible, because we want our wraps to be accessibly priced.

However, our prices also need to reflect the fact that what we make is pretty special. Even our largest releases are absolutely tiny compared with standard retail, we operate ethically and environmentally, we keep all production local and to the highest standard, we pay fair wages and ensure that our suppliers do too, and all of this makes our manufacturing cost incredibly high. There are no ‘easy profits’ in this business, and there are compromises that we just aren’t willing to make, so putting our prices up slightly is one of the only options we have.

In the past we’ve wanted to avoid the marketing hype of referring to our wraps as ‘limited edition’ because we want our wraps to be loved for what they are, rather than have perceived scarcity drive an inflated desire for them. We’re confident that this anxious and frenzied climate in the babywearing world has passed, and we can give recognition to the fact that each wrap is a fairly unique thing, deserving of both its initial cost and also the lifetime of love and memories that it will become bound up in with each family that uses it. 

As a company built on liberal socialist principles, the current political climate is frustrating and disheartening (especially today with the news of Brexit agreements) and it has had a massive impact on our business certainly in the past few months.

We’ve always managed to run Firespiral in a way that is both innovative and practical, so we are a strong little company who can weather the storm through creativity and a sense of humour. We’re grateful to all our customers for giving us the opportunity to make these wraps, and for inspiring us to continue! 

 

Calluna Callisto Birch Trees

Weft Name: Calluna
Warp Name: Callisto
Design Name: Birch Trees (winter birch design variation)
GSM: 335
Weave Structure: Alchemy weave
Average Width: 65cm
Blend: 50% combed cotton, 50% merino lambswool
Related Wraps:
Calluna Moorland Birch Trees shares both the same weft and design. 
Greystoke Glasto Birch Trees uses the same weight/blend of weft and design, so shares wrapping properties.
Wrapping Qualities: Spongy and thick in hand, very supportive, a little bounce, mouldable, makes a large knot. A great wrap for heavier wrappees, and single layer carries.  Wraps a little short due to thickness, so size up if you usually tie near the tails. Is a little prickly when new, but a few washes and a little wear makes this wrap very soft.
Care Requirements:

  • Use a delicate, wool specific liquid detergent. These are widely available in shops
  • Do not use fabric softener
  • Wash on a wool specific or handwash cycle at the lowest temperature, and with the lowest spin available. We recommend 600rpm or below. If you do not have a wool specific or handwash cycle on your machine please handwash your wrap.
  • Do not be tempted to add non-wool items to the drum (pillowcases, towels etc). The wool cycle isn’t designed to deal with these items.
  • Air dry only, do not hang on a radiator or other heat source or tumble dry.
  • Iron on a gentle/cool setting.

Notes: ‘Calluna’ is the botanical name for common heather which seemed fitting for the delicately flecked colour of this wool weft, especially as it is a common sight on the moorlands that surround where we live. 
Release Date: 8th December 2017
Label Identification Code: PUP001

 

Garnet Moorland Kaleidoscope

Weft Name: Garnet

Warp Name: Moorland

Design Name: Kaleidoscope

GSM: 270

Weave Structure: Alchemy weave

Average Width: 69cm

Blend: 72% cotton 16% hemp 12% viscose 

Related Wraps: Garnet Callisto Kaleidoscope. 

Wrapping Qualities:  Lightly and evenly textured with a good amount of grip, the viscose lends stretch and softness,  with extra body and substance given by the hemp, whose stretch is far less. Moulding and supportive.  yet tightens evenly so that you don’t get tight sections digging into shoulders; easy to wrap with and to get right.

Care Requirements: No special care requirements, can be machine washed, tumble dried and ironed. 

Notes: There are multiple coloured yarns in this wrap which lend a visual texture to go with the delicate pattern. The brighter salmon pink weft thread amongst the coppers is the ‘seashell’ combed cotton that we used with some of the earliest elements wraps. The copper hemp is the same as used in Copper Octarine Winter Hill, Copper Glasto Harvest  and Copper Glasto Tentacular Spectacular

Release Date: 8th December 2017

Label Identification Code: BRP007

Geode Nocturnal

Weft Name: Nocturnal

Warp Name: Callisto

Design Name: Geode

GSM: 315

Weave Structure: Synergy

Average Width: 65cm

Blend: 100% combed cotton

Related Wraps: Geode Diurnal

Wrapping Qualities: Cloth isn’t prone to pulling, passes glide easily over each other. Smooth texture but not silky, thicker feel in hand, dense but good stretch and recoil. Ties with a large knot, wrap softens even more with use. 

Care Requirements: No special care requirements, can be machine washed, tumble dried and ironed.

Notes: The first official release of cloth using the Synergy and also the first run of the Geode design.

Release Date: 8th December 2017

Label Identification Code: PUP004

Geode Diurnal

Weft Name: Diurnal

Warp Name: Moorland

Design Name: Geode

GSM: 315

Weave Structure: Synergy

Average Width: 65cm

Blend: 100% combed cotton

Related Wraps: Geode Nocturnal 

Wrapping Qualities: Cloth isn’t prone to pulling, passes glide easily over each other. Smooth texture but not silky, thicker feel in hand, dense but good stretch and recoil. Ties with a large knot, wrap softens even more with use. 

Care Requirements: No special care requirements, can be machine washed, tumble dried and ironed

Notes: The first official release of cloth using the Synergy weave and also the first weave of the Geode design

Release Date: 8th December 2017

Label Identification Code: BRP004

Small Business Saturday: Our ‘shop small’ Christmas gift guide!

As the concept of ‘Black Friday’ sales really takes hold in the UK, we think it is important to really champion smaller, independent businesses; those of us who don’t buy or produce in massive bulk, and who don’t build obsolescence or excess into our business model. Whilst we all love a bargain,  we know that there is a hidden cost to our high turnover, consumerist lifestyle.
  Small Business Saturday  (Saturday 25th November in the US and Saturday 2nd December for those of us in the UK) aims to champion the smaller voices in the marketplace, so here is Jen’s personal Christmas gift guide, featuring some companies that she just really likes and want to share with you!

1.Firespiral Scarves
  

 

We may as well start with ourselves eh?! Our scarves make excellent gifts, even for non-babywearers, (after all, it would be hard to go to any high street store and buy limited run, locally and ethically woven scarves- these are truly something unique)  They are versatile to wear. They also work really nicely as doll slings.

 

 

 

 

 

 

2. Oak Wren

 

Oak Wren is a sister company to the fabulous Baie slings and they make ponchos, cloaks and capes out of wrap fabric. 

They offer both in stock options and also a make-to-order service where they can transform your wrap into something that you can keep on enjoying long after your babywearing days are over. 

 

 

 

 

 

 

 

 

 

3. Ravenstonz

What better way to fasten your new cloak than with a bespoke made pennanular brooch?! Inspired by nature and ancient British adornments/ clothing fastenings, Peggy makes beautiful and unique jewellery in a range of prices for all budgets.

 

 

 

 

4. Interlude Pottery 
Beautiful mugs and delicious coffee are two of Jen’s small but perfect pleasures in life, and some of her favourite cups come from Interlude pottery, based in Penrith, Cumbria. A mug should feel good as well as look beautiful, and you can feel the love that went into making these mugs as they sit warmly in your hands. Bliss! They also make all manner of other crockery if mugs aren’t your thing!

 

 

 

5. Grumpy Mule

 

You need good coffee to grace your handmade mug, and Grumpy Mule roast beans that are not only delicious but ethically produced and fairly traded. Some of Jen’s favourites are produced by the Cafe Femenino project (a foundation supporting female coffee growers). 

 

 

 

 

 

 

 

 

6. Red Thumb Print 

Little wooden Rudolph has quickly found his place in Jen’s family Christmas traditions. The children love going out for a walk on a crisp sunny morning and searching for two suitable branches to become his antlers for the year! The larger Rudolph would make a fun and re-usable alternative to a Christmas tree. Red Thumb print is based just up the road from Firespiral HQ.

 

 

 

 

 

 

7.CocoBand
Cocobands joined us at Winter Wovenland this year and even made some Firespiral wraps scrap headbands! Jen has a lot of thick, unruly hair, and cocobands are an easy way to give the appearance of a stylishly tied headscarf without any of the effort! Business owners Sarah and Jake say that they trick to getting their headbands on just right is to ‘shimmy’ them down onto your hair, and that trick definitely works!

 

 

 

 

8. Lunar Drops

 

 

 

 

 

 

 

Lunar Drops make affordable semi-precious bead jewellery with a quality finish and beautiful attention to detail. Jen’s favourites are the aromatherapy bracelets, with a naturally porous lava stone bead to which you can add a drop of your favourite essential oil.

 

 

 

 

 

9.Of Alp and Ash

Back to coffee (naturally) and Alp and Ash make lovely drinks coasters featuring the topography of the British Isles. You can choose your favourite hillside or local area, but our favourites are the lake district coasters, as the lakes and waters are created using transparent acrylic inlays.

 

 

 

 

 

 

 

 

  10.Maisy Muffin

 

 

 

 

 

 

 

 

 

 

 

 

Jen’s eldest boy was given one of these lovely rag dolls years ago, and she has been a firm favourite since then and loved by his siblings too! The 

perfectly detailed clothes are probably what makes her so special. Whilst they aren’t suitable for the under 3s, they are incredible easy to dress and very sturdily made to cope with some rough handling! There is no diversity in the range any more however- they now only offer two dolls, ‘Maisy and Mo’, both identically white skinned with brown hair.

We’d love to hear your recommendations too!