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Kona Tetra Half Frame Bag 3.5oz Dyneema

Back in April a friend asked to make him a half frame bag. I had been waiting for an excuse to make one so I got started with one for my bike as a practice run.   I started with the same techniques I learned while working at an automotive restoration shop that focused on British sports cars.  I cut out a cardboard template to match the shape needed to fit in the frame of my Kona Red Zone which has a uniquely shaped top tube so I added some extra width to accommodate the shape and keep the maximum width without being too wide that my knees would rub while pedaling.

Once I had the cardboard template and mounting placements with correct angles for the shape of the frame tubes I transferred the shape to a paper pattern, then made the proper adjustments to accommodate a zipper on each side.  The right side zipper is the main compartment and the left zipper has a divider so it’s perfect for a phone, wallet or anything else that’s pretty slim.

I wanted to try heat seal tape on the zipper seam so after doing a few tests to make sure I wasn’t going to melt the panels I started to lay down the tape.  This heat seal tape bonded great to the Dyneema but really struggled to bond to the zipper tape.  After using it for a few months the the tape has started peeling off the zipper tape but is still strongly affixed to the Dyneema.  It would be amazing to have the roller application machine for this to have full control over time, pressure and temperature as I’m just guessing with an eight count and as much pressure as I can add.

Once I got the tape applied I basted on the left pocket interior divider then laid out the webbing placements. Attaching the first side to the center gusset which was pretty easy but getting around the tight curves while attaching the right side proved much more difficult.  In this process my little Bernina home sewing machine really struggled to sew the heavy 3.5oz Dyneema fabric. It had a lot of trouble keeping the feeding consistent because the fabric is so slippery.  The end result was sadly a little twisted and I wasn’t happy with it or confident I could make one with my sewing machine that would be 100% reliable and water proof as I required it to be.   It’s good I did too, after using it and thoroughly enjoying having a frame bag on a daily basis I’ve had both of the 1/2″ poly pro webbing straps pull out.  I was able to re-insert and sew them back in after doubling the ends and securing with a bar-tack.  The webbing pulled out because it is a very loose weave poly pro webbing.  Next time I will use a much tighter weave webbing and also double and bar-tack the ends.

 

Before adding the seam tape to the finished seams I test fit the bag and realized I had too many webbing attachment straps.  I had planned to have straps at each end of the zippers to make sure they could be operated with one hand but with the gripper velcro backing didn’t need the extra straps so I removed them to save weight, prevent unnecessary abrasions on the frame and to make it look cleaner.

 

The successes are; the velcro straps with a poly-urethane fabric backer has not left a mark on the frame over the last four months, the 1″ single sided adhesive Dyneema seam seal tape has worked amazingly well and not de-laminated at all, the fabric being very light and durable is wonderful, the white color let’s in lot’s of light to see the content of the bag very easily.

The white color does catch and absorb dirt and grease but I would like to create a design to apply to the white fabric to hide the obvious effects of use and abuse.

 

3.5 oz Dyneema® Composite Fabric Hybrid CT9HK.18/wov.32c is a 2-layer laminate material using a 50D polyester plain-weave face fabric like the 2.92 oz hybrid, but with a 2.15 DCF layer on the back
Content 20% Dyneema fiber / ~50% Polyester / ~30%Other Polymer Film
Weight 3.5 oz/sg yd
Tear Strength warp 43 lb / weft 43 lb
Made in the USA