The type of Foam is very important when it comes to knitting machine sponge bars. The reason why so many DIY sponge bars fail is because the kind of foam needed to make a resilient sponge bar strip is generally not available outside of industrial resources. There are two main factors when it comes to foam – the density and the structure of the cells of the foam. Let’s start with Foam Cell Structu
re. The reason DIY Weather Stripping / Weatherseal foam fails is because it is made from closed cell foam most of the time – especially in the USA. It may work for the first couple of weeks, but eventually the sponge is not able to regain its original shape and quickly gets flattened and therefore useless. Unless you like replacing your Sponge every month – this is not a good option. The Ultra Sponge Bar is made with Open Cell Foam – a cell structure that provides maximum resiliency. Think of it kind of like a new kitchen sponge – you can squeeze it, but it quickly bounces back to its original shape.
2. Okay, now onto Foam Density. Generally, foam comes in three classes: High Density, Medium Density, and Low Density. Density is exactly what it sounds like – the higher the Density the heavier the sponge will be. While a heavier sponge is great for certain hardware applications, it is not great for a knitting machine because the needles literally end up getting squashed against the machine. They have no room to move up and down and can get stuck because of this. Low Density may be good for certain home insulation purposes – but again, not good for the knitting machine. You may have heard you can use Craft Foam from your local fabric store to make your own sponge. While, yes, this is true – your sponge will not last very long. Here’s why: Low Density foam is very cheap and weak. It deteriorates quickly and because of how light (or ‘soft’) it is – it will stop working in your machine within a year, maybe even a few months. All foam degrades with time, but low density foam degrades the fastest by far. The Ultra Sponge Bar is made with Medium Density Foam – allowing the perfect combination of strength, resiliency, and endurance.
3. And then there’s the Fabric which sandwiches the Ultra Sponge Bar. The reason there are two types of fabric is simple: The Black Mesh Fabric of the Ultra Sponge Bar has tiny holes and texture – allowing better adhesion to either a metal retainer bar or plastic sponge bar channel. The White Tightly Knit Fabric top layer of the Ultra Sponge Bar Strip creates a smooth surface for the knitting machine needles to rest on and bounce off of.
4. To stick or not to stick? We are the only Sponge Bar Strip Retailer who gives you the option to add a sticker back to your sponge bar – so you can decide whether you’d like to glue it in or stick it. Keep in mind that most plastic machines do not need this (such as the Singer LK150 and LK100). Take Care of Your Ultra Sponge – Basic Tips to Ensure Your Ultra Sponge Lasts A Long Time:
Do not get water on the Ultra Sponge – this will significantly reduce its lifespan. You can gently steam the sponge if you really need to, but we do not recommend it. All moisture is bad for this foam, so if you live in a very humid area keep your unused Ultra Sponges in a ziplock plastic bag to prevent moisture damage. If you need to cut down your sponge bar, use scissors. Because of the two layers of fabric, this foam is a bit harder to cut than other simpler sponges. For this reason, please be safe and avoid using razors as it can slip and we want you to be safe!
