Starched Fabric Update

A quick update on how the starched fabric behaved.
Before ironing
This is the block I was most worried about — the lines are narrow so there isn’t much glue holding the fabrics together, and most of the lines are on the bias. However, I was pleased to see that there was minimal stretching — just a little bit of waviness, slightly more on the bias than on the straight.
After ironing
And, as you can see, it all disappeared after ironing, so I have a beautifully flat, non-distorted block. Success!

Starch (and another cautionary tale)

One of the projects I’m working on at the moment involves machine appliqué of fairly large shapes, which means that the background material needs to be reinforced. Products I’ve used previously include:
— spray starch (not stiff enough);
— spray stiffener (fantastic, but no longer available);
— synthetic fabric stiffener (doesn’t wash out well, especially after ironing);
— very heavy fusible interfacing (good, but has to be removed after stitching unless you want a board-like quilt);
— water-soluble backing (not stiff enough); and
— paper (also very fiddly to remove and it makes the needles blunt very quickly).

This time around I decided to use natural starch. I used a variant of Paula Storm’s recipe (which I would link to but her website has disappeared — I’ve copied it below). I made two changes. First, I increased the proportion of starch to water — the original is 1:30, while this batch is 1:15 (if I use this batch for appliqué pieces I’ll dilute it by half). The second change was that I left out the alcohol. The reason for this is that alcohol reduces the solubility of starch so it preciptates out, leaving you with a starch suspension rather than a colloid. It works if you shake the bottle before pouring, but it’s difficult to get a consistent mixture. I have to admit, though, that the alcohol has done an incredible job of preventing mould — I’m still using the batch I made back in 2017, and while it’s been in the fridge for a lot of that time, there have been months at room temperature and it’s still good.
Starch mix before heating
So, here is the liquid as it first appears: 4 tsp (20 mls) starch + 300 mls cold water. (Don’t worry about seeing a metal whisk in a non-stick pan — it’s almost 40 years old and the coating is in shreds, so it hasn’t been used for food in a good ten years. I only use it for boiled eggs and non-food projects now.)
Starch mix starting to boil
And here it is when it’s almost at the boil — you can see how much clearer it is. It doesn’t thicken like a white sauce does, but it should be a little thicker than water. Most sites say to aim for a “milky” feel; I think it’s more like a very thin gravy, but then I did double the starch.

Once the starch had boiled for five minutes I covered the pan and left it to cool on the stove. It took about an hour to cool down to the point where I was happy to pour it into a jar.
Ready to pour into the jar
Because I’m not adding alcohol I had to make sure I used a clean container. I washed an old coffee jar and its plastic lid, rinsed them both with 99% ethanol and left them to dry upside down on an oil column heater. I did consider sterilising the jar in the oven as you do for jam, but I couldn’t find a jar of the right size and shape that had a metal lid (I think I need to buy more Beerenberg jam). I’ll monitor this batch and I’ll let you know if/when it goes off.
Ready to roll onto fabric
In order to apply the starch to the background fabrics, I poured some of the mix into a shallow container and used a sponge roller to saturate the fabric. This isn’t the best container, actually, as it has a gutter around the bottom, but I managed. I think I’ll use a loaf pan or lasagne dish next time.
Starch fabric waiting to dry
The fabric was then placed flat on an old towel to dry overnight. I didn’t have any excess starch this time but if I had, it would have been discarded — never put it back into the bottle. I covered the squares with another towel after I found Vanima sitting right next to them when I returned from washing up (no photo, sorry).

The next morning I ironed the fabric. It turned out to be roughly the same stiffness as light card stock (210 gsm for metric countries, no idea how that would translate to American units). It’s not quite as stiff as I’d hoped for but much better than spray starch, and since my appliqué pieces will be backed with fusible web I think they’ll do well. If these were destined to be the appliqué pieces themselves and not background, I’d still want fusible web as I don’t think they are quite stiff enough to resist buckling under zigzag stitch.
Dry fabric showing shrinkage

One thing I was not prepared for was the amount of shrinkage on the cross-grain. The intended block size was 9″ square, so I had cut the fabric 10.0″ square, allowing 5% shrinkage, but in some cases the shrinkage was closer to 10%, with a couple of the blocks ending up at less than 9.5″ wide. It’s not a disaster by any means, though (thank goodness). The appliqué will still fit, and the design calls for vertical sashes that I haven’t cut yet, so I’ll simply cut them wider and have blocks that are 9″ x 8.5″. However, it’s definitely something to bear in mind for future projects.

Lessons Learned:
1. Doubling the amount of starch in the recipe leads to a good useable stiffness in background fabric.
2. Starch will cause shrinkage, particularly on the cross-grain (weft). Allow at least 10% when cutting blocks.

Paula Storm’s Recipe:
10 ml (2 tsp) cornflour
1 cup (250 ml) water
50 ml vodka (unflavoured)
5 drops essential oil (optional, just for scent)

Combine water and cornflour in a pan, bring to the boil and simmer for five minutes, whisking throughout. Remove from heat. When cool, add vodka and (if desired) essential oil. Mixture should be the consistency of milk — if too thick, add more water (up to 250 ml). [Note: A whisk allows you to keep the liquid moving without it creeping up the sides of the pan.]