Playing with Sand

So we were too busy playing with sand yesterday to write a blog post.  Which is kind of ironic when you think about it, seeing as the blog post was meant to be all about what we were doing...!

So what are we talking about?

How about this:

3 tonnes of sand (yes that photo only shows a small amount...!).  We are talking about sand, and using it in a product which we small batch manufacture.

And we are also talking about sealing up the sand so it ends up looking like this....

And we are also talking about finishing the product so it looks like this.

Kind of cute and simple isn't it?

NO!  Not really!

Its definitely not cute if you are the one using it.  Why?  Because they are sandbags for the fitness industry.  Specifically for Bootcamps Australia.  Each are 8kg of pain.  Lots and lots of pain.  Trust me.  You will be using these bags in ways you didn't think was possible; raising them above your head, jogging with them, lifting multiple bags, passing them... so on and so forth.

As for simple?  Not if you are the one manufacturing it...!  Why?  Because it has sand in it!  Sand, the thing that gives it the 8kg weight, is also the thing that leaks out over time, or even while manufacturing.  Sand and machine oil do not mix well, and instead creates a grind paste which can quickly destroy our expensive machines.  So what do we do?

Firstly we have two problems.  Priority #1 is leaking of sand both during and after manufacture; while #2 is having to physically bring sand into the studio and on to our machines.

Fitness orientated sandbags have mostly been a DIY product, and as such the intertubes are ripe with "How To's" regarding making a sandbag.
One suggestion is to put the sand directly into a duffel bag, and not bother about it leaking.  However, this is not a good idea as sand leaks through the zip and pours all over your sweaty body.  Exfoliation anyone?
A second idea revolves around double bagging the sand in plastic bags before taping them up.  From a small batch manufacturing perspective, this is ultra time consuming.  And as time is money, the end result is an exorbitantly costly product.  Besides, plastic bags don't stretch, so if you accidentally drop the sandbag (and it will accidentally happen when you are exhausted!) the plastic will tear, resulting in a leaky sandbag.

Next thing we discovered was this ultra advanced product called a flood sandbag, used to protect properties from flood damage.  Ultrahigh tech.... not really... All this is, is a simple "pillowcase" style bag constructed from a geotextile. This geotextile is kind of like felt (for the fabric-tech-nerds, it is a 2mm needle punched polypropylene manufactured in Australia).  Not only does it allow water to flow through (this is important as Bootcamps Australia use this product rain, hail, or shine!) but more importantly is impermeable to sand.

After grabbing our hands on these, we quickly knew the solution.  Inner bag the sand in the geotextile and then stitch it into the outer bag for added protection.  Problem now being how do you seal the sand in the inner bag?  We simply did not want to get sand in our studio and all over our machines!

First we tried partially plastic bagging it, but this didn't work.  Next step was to try sewing it on the cylinder arm machine (this has the feed bed on a cylinder above the normal horizontal/flat sewing surface.)  The idea behind this was the sandbag would be held at roughly a 45 degree angle, thus reducing the likelihood of sand spillage.  Again this did not work.  There was simply too much sand all over the machines.

So we had to seal the sandbags outside.  There simply was no other option.  How about staples?  Nope, they had difficulty penetrating the geotextile.  What about sticky tape?  Nope, sticky tape doesn't adhere well to polypropylene (and it splits when dropped rather like the double plastic bagging technique).  Then finally we found our solution.  How about we sew the sandbags outside??!  After all, sewing is our specialty!  This has been done for years with animal feed, namely through an aptly called "bag closing machine".

Enter stage left, our new toy...

A bag closing machine!  What sets this machine apart from all the others are three things:
  1. It is portable.  You can take it anywhere.  Sewing outside is now possible
  2. It is a chain stitch.  Not an important feature, but it does mean we don't have to worry about bobbins/base threads.
  3. It sews on a vertical surface.  This means we can sew the sandbags while they sit there.  No need to tip the bags onto their sides!
Close up of the vertical sewing surface.

Bingo.  Problem solved!  Fill the bags outside using the geotextile pillowcase.  Sew the sandy bags outside using a bag closing machine.  Place the inner bags into the outer bag while still outside... and only now do we bring the bag into the studio for final stitch and closure.  Yes, we still bring sand into the studio, but this time it is fully sealed and double bagged!

So both our problems are solved.  The bags will not leak and there is no damaging sand destroying our machines!!  Win!

So as you can see this particular small batch manufacture job helped us expand our skill set, kept us on our toes, allowed us (made us!) purchase a new machine, and encouraged us to try new materials.  Small batch manufacture for us is keeping us pumping!!

Oh, and for the fabric tech nerds, here are the specs on this bag:
2mm Geotextile inner (manufactured in Australia!)
J-folded and chain stitched to limit leaking
1000D Airtextured Nylon outer (highly abrasion resistant)
25mm tubular webbing (2.5 tonne breaking strain!) bar tacked into a loop
Box-X tacks at handles (reduces likelihood of tubular webbing tearing away from the bag outer)
Coats Dabond M40 Thread (very strong bonded nylon thread)
25mm polyester binding tape.

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