How To Make A Knitting Machine Needle Retainer Sponge Bar Part 2: Cut and Glue Foam
Now that your old retainer bar is squeaky clean, let’s replace the foam.
Some knitters like to use weatherstripping to refurbish their sponge bars. You can find directions on page 10 of this pdf from the Carolina Machine Knitters Guild and a video at Podcasting For Machine Knitters.
For a variety of reasons, this method didn’t work for me. Either the weatherstripping wasn’t available, gluing the woven ribbon made my bar too stiff and inflexible, or the materials were more expensive, averaging $2 per bar versus about 25 cents for my approach.
What To Buy
You are going to need water-based glue, sheet foam, ruler, razor blade or rotary cutter, cutting mat, and straight edge.
The glue is a no-brainer. Any cheap, water-based glue will work. I bought a 99 cent bottle of Aleene’s Tacky Glue. You want water-based so the next time you replace the foam, you won’t have to use Goof Off to dissolve industrial strength adhesives. Elmer’s school glue should also work.
The foam typically comes in two types and two thicknesses: high density-green or low density-beige, 1/2″ or 1/4″ (1.3 or .6cm). The latter is too thin so use the 1/2″ (1.3 cm). If in your area 3/8″ (1 cm) sheet foam is available, I would definitely try it as well. It wasn’t available where I live. Regardless of thickness, when you buy your foam, buy a length that will accommodate your longest sponge bar. For me that was my Brother Bulky machines. Four feet (122 cm) is plenty long enough with a bit extra to allow for mistakes.
Work Great In Many Different Machines
I tried my new bars in a variety of machines including Brother 840, 910, 950i, 965, 260, 270 as well as a Studio 150 and 155. The 1/2″ (1.3 cm) foam worked great in all my bulky machines and older punch card standard gauge.
The 950i worked well too, but it seemed like it took a bit more umph to move the carriage across the needle bed. Now granted, the sponge bar that came out of this machine was beyond dead and the carriage zipped across from lack of friction on the needles.
The difference was subtle. Without a new sponge bar to compare, I don’t know if the greater resistance was due to the machine wanting 3/8″ (1 cm) foam – which wasn’t available to buy – rather than 1/2″ (1.3 cm) or some other factor. My 965 was fine with the 1/2″ (1.3 cm) high density. If available, use the low density foam for Brother Electronic machines since it squishes easier. I’ll be checking back as the foam naturally squishes up inside to see if the 950 gets zippier.
Where To Buy Materials
In my neck of the woods, high density foam was easier to find. JoAnn’s, a nation-wide craft store, always had it in stock. Using one of its weekly 40% off coupons, 4 feet cost less than $6. At 2 feet wide (60 cm), even with many initial mistakes, I can get over 50 usable 3/8″ (1 cm) strips from the sheet.
Low density foam is cheaper and works a bit better due to it higher squishiness. However it was harder to find. I had to travel to an upholstery shop in another town to get it. It cost about $1 a foot for an 18″ (45 cm) wide sheet.
How To Make
Lay the foam out and measure off a 3/8″ (1 cm) strip. You may need to even off the side first. The foam can sometimes be a bit wavy on the edge from the manufacturer.
Place as many tick marks as needed for you to cut a straight line.
On my first few sponge bars, I used a razor blade and straight edge to cut the foam. It worked, but I found it was easy for the blade to waver back and forth.
My cuts weren’t very smooth. The foam still worked fine. I just knew it was a bit wonky hiding inside the machine.
Here is one view of my less than square, trapezoid cuts.
An Olfa rotary cutter works much better.
It decreased my frustration and improved my cuts immensely.
For those who have never used an Olfa before, be careful. This cutter is extremely sharp.
After the strip is cut, you can do a dry fit test run. If necessary, gently squeeze the sides…
… and set in the metal tray.
Don’t stress if your cut isn’t perfectly straight.
It won’t be and it doesn’t matter. Close is more than good enough.
Set the foam aside and get out the glue. Swirl an even amount down the center of the tray.
Again, don’t stress about perfection. If you come up short, add more. If you bloop, wipe some out.
Being careful of sharp edges, smooth the swirl out with your finger. The bottom of the tray should be evenly coated with a film of glue.
You don’t have to get glue up the sides or into every corner. A finger’s width down the center works great.
For those of us who like things just so, take a look at your cut foam. One side will have ink on it, the other side will be clean.
To have the nicest looking sponge bar, place the inked side down into the glue. If you leave it up, it will bleed through the fusible interfacing when we attach it the next post.
Don’t be concerned that the foam is now off-white rather than green. The rest of the pictures are merely showing the low density foam rather than the high density. I made several bars at the same time and took a ton of pictures. I’ve picked the best to highlight each point.
With the glue evenly spread, start at one end and lay the foam into the tray. Use one hand to hold the foam in place, will the other hand gently guides the foam into place.
You want the foam relaxed. Think Goldilocks and the Three Bears – not too squished and not too stretched.
Here is an exaggerated view of foam being pulled as it is set in place.
DO NOT DO THIS!
Only when you reach the end, snip off the excess.
If you cut to fit before gluing, you will either come up too short, meaning you compressed the foam together too much, or too long, meaning you stretched it out.
Always cut after gluing.
With the foam glued down, gently push to make sure everything is set in place.
Don’t compress the foam to the bottom of the metal tray. It may cause glue to be pushed up into the foam’s air pockets.
Also, check each side to make sure nothing has popped out of the tray. If a bit of foam has gone wayward, tuck it back into place.
You are done with Part 2. Set the bar aside and let it dry for a few hours. Next, we will cut and attach the fusible interfacing, tape down the ends of the bar, and reinstall into the knitting machine.
- How To Make A Knitting Machine Needle Retainer Sponge Bar Part 1: Remove The Old And Clean For New
- What Is A Knitting Machine Sponge Bar And Where Is It Located?
- How To Make A Knitting Machine Needle Retainer Sponge Bar Part 3: Fuse Interfacing, Tape Ends, And Reinstall
- How To Take Apart A Brother Punch Card Knitting Machine
- How To Set Up A Knitting Machine – Brother, Studio, Singer, Silver Reed
July 22, 2008