Sponge bars on my mind lately, and I thought a little information about them might be useful to others.
So, why are sponge bars on my mind lately? I have pulled two different knitting machines out that I hadn't used in a year or two, and they both needed sponge bars. I can push on a needle tip anywhere and it pops up about 1/8". I know better than to try to knit with the machine like this! This can result in jams, bent needles, and terrible aggravation.
First of all, just about every flatbed machine has either a sponge bar, a felt bar, or a spring to hold the needles down against the bed. If the sponge bar is worn out, the machine will absolutely not knit properly. It will be absolutely miserable to use, and plenty of people have given up on machine knitting when all they needed was a decent sponge bar.
Sponge bars wear out. I've had knitting machines where I never had to replace a single part except the sponge bar! These have foam rubber, and it deteriorates over time. Also, the foam is squashed all the time, which of course flattens it. I understand you can prolong the life of a sponge bar by removing it from the machine whenever you are not knitting, but I simply cannot make myself do this. They're not all that quick to get in and out, and I like to go to my machine and just start knitting. (But hey, I might as well mention that I've always been the sort who slips off shoes without unbuckling the little straps or loosening the laces, if I could get away with it. And nothing terrible has happened to me from that particular bad habit.)
The sponge bar is a long metal stick (the length of the main bed) with foam rubber on one side. It slides in to a slot at the end of the knitting machine near the front of the bed. There is very seldom any information at all about it in your machine's manual - I guess the manufacturers all assumed we had a local dealer to help us with this. The sponge bar is installed with the foam rubber side pushing down on the needles. You need a new sponge bar if your machine's needles are not pressed firmly downward against the machine's number strip.
You can get your sponge bar out with a wooden chop stick. Push on its end until it sticks out enough at the other end to grab it, then pull it out. When you install a sponge bar, make sure you push the needles downward with the flat side of a needle pusher as you slide in the bar, because it has to be ABOVE the needles, FOAM DOWN.
Yes, you can refurbish your sponge bar. There are good directions here. I admit, I prefer weather stripping to the foam rubber in her directions, but it does take some hunting to find just the right size of weather stripping.
However, I don't refurbish sponge bar anymore unless I can't get the proper sponge bar for that model. I prefer to buy from a dealer. Rehabbing a sponge bar takes time, effort, and materials, and my rehabbed sponge bars never last quite as long as the ones I can get from dealers. If you have a dealer near you, buy the sponge bar from the dealer. First of all, it supports your dealer (you are so lucky to have one!), and secondly, she can show you how to put it in, and third, shipping these long, skinny things is expensive, so you will probably save both money and time that way.
I don't have a dealer. Lately, I've been buying them from The Knitting Closet, here. When I buy them, I try to buy several at once, to save on shipping. Sometimes, you can find a friend who needs some, too, and order together to save on shipping.