How can I remove the curl of the filament?
The single strand fiber optic filaments that we carry are not straight, but rather have a curl associated with them. The degree of the curl varies on the diameter of the filament. The curl is in large part due to the manufacturing and shipping process. For the technical applications that utilize fiber optics, the curl is actually factored in to the attenuation equation. However, given that our quest aligns more with the aesthetic applications and the filaments ability to transmit visible light, every so often I will have a customer ask how they can eliminate or remove the coil, as their fiber optic project requires a straightened fiber optic.
To be clear, depending on the diameter and length of fiber optic filament, it is possible to reduce some, but not all, of the curl. Also, the thicker filaments (1.50 mm – 3.00 mm) are a bit more challenging as the curl is more firmly set in the filament due to it’s thickness.
That said, here’s a technique that we’ve utilized with some success on filaments with lengths to approximately 6 feet.
- First, cut the fiber into sections slightly longer than you’ll need. We add an additional 6 inches.
- Next, suspend the individual filaments. We hang them in a door frame using the blue painters tape holding the top. Sometimes, we will roll the end of the strand of filament around a dowel, then secure it with the blue painters tape. The few inches of filament that is rolled onto the dowel will be discarded after you’re done with this process.
- Then, on the bottom end of each strand, you attach a weight. Not too heavy where it will pull the filaments out of the top assembly. For the thinner filaments (0.25 mm – 1.00 mm) we’ve used everything from several large metal washers per strand to the larger fishing weights. We found that fishing weights work great on these diameters as they clamp right onto the filament. Note: clamping or attaching a weight to the filament will usually damage the fiber at the location area of attachment, that’s why we cut them longer than we ultimately need.
- Once the fibers are hung, we then encourage the filaments to relax by using a heat gun or blow dryer. We’ve used both, and prefer the heat gun. You’ll want to start with it on a low setting. The heat gun we use has a digital display, so we’re able to see the specific temperature level — we use it in the 200-300 degree range. Slowly blow or guide the heat over the filaments, without pausing too long in one area. Depending on the thickness of the filament, the length and the strength of the heat gun, you may want to gently hold the filament with your other hand to help prevent them from tangling into each other. What’s interesting is that you can actually see the filaments relax as you slowly apply the heat. Again, don’t pause too long in one area.
- If possible, we let the filaments hang in this configuration overnight, and apply another healthy dose of heat the next day before we take them down.