Wednesday, June 15, 2016

Sewing with Magnets: Matching Game Experiment

Back at Easter one of my new-mother cousins asked me if I could make a soft toy rattle. She showed me one somebody gave her. It's the Leka Rattle from IKEA and you get 2 for $2.99. I really can't compete with that in a handmade item. It's a little cat with a face embroidered on both sides. The simple cat shape is sewn with right sides together. Then it is turned and stuffed with polyester filling and a rattle insert. It gave me the idea to buy fabric printed with animals that I could sew back-to-back in a similar way.

This turns out to be harder than it sounds. I showed some of my early prototypes to my aunt who is a retired kindergarten teacher. She suggested I use the big piece of printed fabric and the individual toys together as a learning tool. Make a mat with velcro dots to stick the matching animals in place. Interesting. I kept thinking about that while I waited for rattle inserts and a new sewing machine foot pedal to come in the mail.

Finding 1: A rare earth magnet will hold up a toy by the steel balls in a high quality rattle insert.

I ordered 10 rattle inserts from CRS Crafts to play with them. (They are very good. Much louder than the tiny rattles I got in a pack of 50 for $6 from Amazon. They aren't even worth a link.) When they got here I noticed how heavy they were from the steel balls inside. I tested what happened if I put them next to a magnet. It had incredible holding power. The magnet would stick through several layers of fabric. This made me go looking through my magnet stash. I had a package of 12 small rare earth magnets with a hole in them. Perfect for sewing. It could eliminate the velcro that would ruin the look of the face of the thing.

This is not working
Finally I felt like trying the whole idea. I put it off for a long time because I knew it was going to be hard to precisely cut out and sew those complex shapes when the fabric is printed with the animals practically overlapping. It doesn't give enough extra fabric to work with.

Finally I realized I can just make a rectangle and have parts of animals at the edges. I think I have a mental disability where I am bothered by representational art that is partially obscured in presentation. Apparently normal people don't care even a little bit!

Still thinking of the original rattle idea I carefully cut out, matched, and sewed some lizards face to face, turned them and stuffed them with little rattles. I just don't like the imprecise nature of this process. There's no quality control. I'm not interested in manufacturing this. I don't know how IKEA does that Leka rattle, but I'd be interested to find out. I think if you were decorating with a fabric like this and had some left over you should definitely use any extra fabric for this kind of thing in a one-off project. I'm giving this idea away for free! But be sure the finished item isn't a choking hazard. If it will fit in a toilet paper roll don't give it to an infant. My lizard experiment fails this test.

These are just OK.
But I still wanted to try my idea of putting magnets in a sewn fabric configuration to match the picture. I hit on the idea of ironing the lizards onto freezer paper to just cut them out and leave them unfinished. This turns out to work really well. Far, FAR easier than sewing them and turning them to eliminate the raw edge. I could proceed with the project.
Prepare the quilt sandwich

I cut out a long rectangle of the lizard fabric and sewed the ends together to make a tube. I rolled it around until I found a group of lizards I liked for the front. This made my seam on one side in the back. Then I got a piece of quilt batting and cut it to fit inside the tube so the top and bottom could be sewn in. The sides are just loose inside the tube. I sewed the top together on the sewing machine and turned it right side out.

Finding 2: You can sew a rare earth ring magnet with a nickel and steel needle.

I was originally worried that it would be frustrating to sew a rare earth magnet with a nickel and steel needle. The needle did pop over to the magnet but it was no problem to push it along through the fabric. This is good data.

I sewed the magnets to the BACK of the batting. The batting and fabric between the magnet and the matching lizard reduces the pull force enough to not be frightening or dangerous. Also my idea was that this whole thing could stick to a steel thing like a file cabinet or refrigerator and stay put even while somebody was messing around with the removable parts.

My method was to hold the fabric sandwich flat and lined up first. Then I stuck a needle through the place on the lizard I wanted a magnet and through the batting. Then I pulled the thread all the way through the fabric and moved it out of the way and sewed the magnet only to the batting. I tied the tail of the thread to the working thread on the inside.
Magnet sewn to the BACK of the batting, the side against the seam.
After I got all the magnets sewn on I put two more in the top corners so it would look nice stuck on the refrigerator.

(Note on the magnets I used: I got these from Harbor Freight over a year ago. They're only about 1/4" diameter. They don't have the ones with holes on the website currently. Home Depot has some 3/8" ones that are slightly bigger than this that would work. It might be good to have the extra holding power if you add layers by laminating the cards. But I expect the bigger the magnet the more difficult they will be to sew.)

After all the magnets were sewn inside I turned the raw edges along the bottom into the sandwich and sewed the bottom closed.

Next I prepared all the lizards for matching. I found two sheets of freezer paper ironed on made them nice and stiff. I cut them out after the paper was on. Then I held them over the correct lizard on the finished mat with a zinc coated washer between a third piece of freezer paper and the lizard to line it up right. Then I ironed it together.

This is probably not really durable but it worked for the experiment. I tried packing tape first but ironing freezer paper was easier. This is just a proof of concept, for a real working version safe for children the small lizard cards would need to be laminated. The minimum safe size for coins for infants is 1 3/4" diameter. So don't do this if you have a baby that can get hold of any of these parts.
Freezer paper ironed onto fabric helps raw edges not fray
I could have stopped there but I was unsure if the magnets would stay lined up under the right lizard. I decided to sew around all the lizards that had magnets sewn behind them. This is the first time I've ever done machine quilting. I used a long stitch length and pulled the thread to the back and knotted it wherever I started and stopped. 

Finding 3: You can machine sew a fabric sandwich with magnets inside on an enameled steel sewing machine.

I was curious if the magnets would make it stick to the sewing machine so hard it would be impossible to guide the project. It took a little extra tugging to get it to feed properly. But with my new electronic foot pedal with an actual slow speed it was a lot easier than I thought it would be. Also the little outline around the lizards that are part of the game is a helpful clue that there are a few whole lizards out of bounds. (I didn't have enough magnets to do all the repeats.)
Here it is on my storage cabinet (neƩ refrigerator) in my lab
Match the lizards!
I've only had one chance to user test this invention. My mother stopped by. I pulled off all the lizards and asked her to put them back. After she left I found she'd put two in the wrong place. I'm not sure if this means it is an actual challenge or if it is just not that interesting. More user testing is required.

My questions about sewing with magnets have been answered though. I'm going back to knitting. Perhaps my experience will serve as a starting point for somebody to make something better. For a decoration for grown-up geeks with the right fabric this could be a good little project. For something for kids it needs a lot of changes. I like the matte fabric finish of it the way it is now.

Friday, June 10, 2016

Repurposing: Knitting Needle Holder from a Mac Mini

My media computer broke last Friday. It was a 2007 era Mac Mini core2 duo with 4 GB of memory. It worked great to play video on my TV. Then in the middle of playing Stargate SG1 from an external hard drive it just went off. No power. Rats. A while ago my brother asked me what he should do with the old Mac Mini his kids used when they were little. I said to give it to me next time he came to visit. I emailed him to see if he still had it. He did. He said he'd mail it to me. It arrived yesterday. I tested my mini with his power supply, just in case. No luck. Apparently not the power supply. I took both computers apart and cleaned out a disturbing amount of dust. I reseated the connector of the wireless card that came loose in shipping and tested it on my TV again. I'm all set to knit in bed while I watch movies and TV shows from my hard drive. I tried everything I could think of to fix the broken one. I ended up taking it completely apart, setting aside the hard drive and bagging up the electronics.
I can't fix you
Now what to do with the good looking case? It would be a cute purse, but it's a little heavy. I decided to make a knitting needle holder. Would also work for kitchen utensils. Here's how I did it:

First disassemble the bottom plate of the computer all the way down to plastic. To get the connectors off the back panel pry the shielding back and pull on it really hard until the plastic dots fly off. Wear glasses.

Next get out a Dremel tool and a cutting wheel. I do this stuff outside because I don't like the mess and burned plastic smell in my lab.

Bare bottom/back panel. Power switch can stay on
This is the part to cut off
I clamped mine in a bench vise in a gap in
the latching ears
Here's the rough cut
There are little metal tabs backing up the plastic between the connectors. I just cut the plastic and left the tabs. Then in the cleaning-up step I cut off all the small ones. I left the big piece of metal surround from the video connector so they can be part of the dividers I'm going to add. Clean up the cut with the flat side of the Dremel cut off wheel. Be sure to wear safety glasses. My whole bit flew out of the chuck and bounced off my hat. It didn't break the wheel though, so I picked it up off the ground, tightened it back in the chuck, and finished the job.

Then I brought it inside and washed off all the plastic dust. I finished smoothing all the edges with a foam nail file.

Foam nail file is good for plastic
I have some closed cell foam scraps left over from redoing the roof vents in my lab so I used that to trim out the inside of the enclosure. One of those gardening knee pads might be a good source for foam if you don't have a stash.

Cut dividers long enough to stick out the top
I cut some dividers 1 7/8" wide (by trial and error. Too small doesn't work.) They are long enough to stick out the opening. I cut more rectangles to go between the bottom end of the divider to hold them in the right spacing and to give the needle tips some nice foam to rest on. Then I pushed the bottom onto the top. Line up the metal tabs left behind with the foam so they push into it.

Cut excess off with scissors
I cut the extra off with scissors. Then I poked the edges down into the enclosure.
It works with my 8 1/2" straight needles. 6" DPNs are a little too short for it.
Ended up using it for loose needles
I decided I liked the Mini for my loose needles. I got those long aluminum needles for doing tubular cast ons. I don't use them that much. They are so long they tended to tip over the lucite cup I was keeping them in. This is better.

Tuesday, June 7, 2016

Picot Edge Hat Brim Hack

I have a blue openwork cotton summer bucket hat that I made last year that I don't wear because it's too floppy. I recently made a summer scarf in the same yarn so I really want to wear this hat now. I got my hands on some nylon monofilament weedeater line in a complementary color and I think I can finally fix this hat. (I also have red but it didn't work with a blue and lavender hat.)
Slip the end of the monofilament under the purl loop in the gaps
Run the end through the picot edge joins
Repeat all the way around for a quick and tidy reinforcement
Once the monofilament line is in the edge you can play with the shape. If you push the ends together to really stretch the fabric you can get an interesting look with the sides flipped up. I wanted a more bucket shape so I let it relax a bit and cut the ends to length there. 
Push cable with a lot of tension to get sides to flip up like a Panama hat
Relax tension for plain bucket hat shape
I borrowed a heat gun so I could try joining hat brim wire with heat shrink tubing instead of using tape. I'm going to give it 3 out of 5 stars as a technique. I would like to try again with a stiff reinforcement inside the heat shrink, like a cocktail straw. I will get one next time I go to town. What coffee shop has plastic stirrers instead of wooden sticks?
Heat gun greatness
It's ok, but it flexes too much at the join. 
Color matched heat shrink would be even better. I'm on a mission to find clear nylon monofilament. I don't know why weedeater users need all these colors that aren't white.  Meanwhile, Parts Express has a lot of heat shrink assortments in multicolors. I should order some. When I ordered this package I didn't know I needed colors. I got it for an LED project. The 1/8" size works for the monofilament I have. Oh look, Parts Express has a 4' piece of clear 1/8" heat shrink for under $2. That's going in my shopping cart.

You can also get heat shrink with an adhesive in it. But it only comes in black. If the hat itself is stopping the cord from pulling apart I think it should be ok without the adhesive inside. I remember having a sample of heat shrink connector jackets with adhesive back in the day when I was an electronics engineer. It's kind of like the soft plastic is lined with a film of low temp hot glue. I wonder if you put a drop of hot glue on the ends of the monofilament before you slid the heat shrink in place if it would work as an adhesive? I don't think it would reflow with the low shrink temperature of the tubing. The clear tubing shrinks at 100°C or 212°F. That's boiling. So you could theoretically dip this in a pot of boiling water to shrink it. Good to know. I may have to try that.

Low temp hot glue melts at 120°C (248°F). The clear heat shrink is rated to 300°C (572°F) for short periods of time even though it will already be as small as it's going to get. So if you had enough hands you could keep heating the join and push the ends together to reflow hot glue between the the ends of the monofilament.

You could even try hot glue and a cocktail straw if you didn't have any heat shrink tubing. You would have to be really fast though. It would be best if you had a helper to hold the glue gun while you pushed it all together.