Welding Capri Sun Pouches





Introduction: Welding Capri Sun Pouches

About: Just your typical Evil Mad Scientist, constantly thinking of new inventions to subjugate the world with! I'm big on hydroponics, electronics, and small portable nuclear fusion power plants. I just go crazy...

I'm a little miffed at Kraft for heavily marketing these things because they aren't recyclable.  So instead of doing something about it, they engaged in a distraction campaign with their Terracycle program.  But at least you can earn money for your kids school which is cool.

Unfortunately I can't get completely miffed about it because I love a couple of flavors of capri sun.  Plus it's handy as heck to pop them in the freezer then pop them in my lunch box cooler.  They serve a dual purpose here.  They keep things cool in the lunchbox cooler, and by the time lunch is around they have thawed out.

The other thing I love about these things is all the cool things I've seen people make with them.  Wallets, purses, bags, you name it.  Just do a google search for "capri sun projects" or "DIY capri sun".  You'll see what I mean

I have a bit higher aspirations than that.  I want to try making an umbrella or a tent out of them.  But the tent might be a bit ambitious.  Most people sew them together with thread, fishing line, or upholstery thread.   Or they will tape them together with Duct Tape or Gorilla Tape.  I wanted to weld them together.

At first I looked into how they do it industrially.  Apparently they either use microwaves or ultrasonic welding.  Do-able, but not for everyone.  Certainly not with parts I had laying around the house, and certainly not cheap.

In the end I found a soldering iron or wood burner works like a charm.

Step 1: The Science...

So a little google-ing and I found what they are made out of...

What is CAPRI SUN packaging made from? Is it recyclable?
CAPRI SUN pouches are polyester-reverse side printed to aluminum then laminated to polyethylene (a plastic polymer). Unfortunately, this packaging is not recyclable.

So it looks like a laminate of aluminum foil and polyethylene.  Ok fine.  What is the melting temperature of polyethylene?   A quick trip over to Wikipedia and I had my answer.  I love Wikipedia, best invention ever.  The nobel prize should go to the guys that invented it.  They are certainly more deserving than a couple of the past winners.

From Wikipedia:

For common commercial grades of medium- and high-density polyethylene the melting point is typically in the range 120 to 130 °C (250 to 265 °F). The melting point for average, commercial, low-density polyethylene is typically 105 to 115 °C (220 to 240 °F).

Ok so the melting point is somwhere between 220°F (115°C) and 265°F (130°C).  Ok, that shouldn't be a big problem.  I think clothes irons only get up to about 200°F so I'm thinking an Iron wouldn't work.

Step 2: Trying to Use the EuroSealer to Weld Capri Sun Pouches Together

My first thought was to use a EuroSealer.  It's that gadget that was shown on infomercials a while back.  It reseals potato chip bags, and it really works too.   It's on the left in the picture below.

You can pick them up for cheap on eBay.  I did.  It, unfortunately, doesn't have the heat needed to weld Capri Sun pouches.  So I thought I could open it up and remove the resistor in it (if there is one) or put more voltage through it by rigging a larger battery source.  It uses two AA batteries so it has 3volts.  I thought of hooking it up to 4.5 volts and 6volts to see if I can get more heat out of it.

I still think this is worth trying I just haven't gotten around to doing it yet.  But I'll update this Instructable when I do.

Step 3: Building a Capri Sun Pouch Welder.

My next thought was to take some nichrome wire out of an old space heater, toaster, or hair dryer.  Wrap the nichrome around a metal rod, then put that inside a metal tube wrap fiberglass cloth around the tube, to prevent sticking.  Then use that to clamp down on a couple bags to weld them together.  I haven't gotten too far with that project yet.

Ok so I tried taking a stainless steel bar, heated it up on the electric stove burner (on high) then I tried to clamp it down over 2 overlapped Capri Sun pouches on a wooden cutting board.  It was a surprising failure.  I could hear the remaining liquid in the pouches searing, I could see the plastic pouch melting.  But no matter how hard I pressed I couldn't get the two pouches to weld together.

Stay tuned for my next attempt along this line.  I'm going to take a copper pipe to try to weld pouches together.  What I learned from this last attempt is that I think I need something flexible underneath the pouches along the seam to help compress and set the weld.

One commenter on this project gave me a good idea.  Perhaps using some material between the bags to act like solder flux would aid the welding process.  The trouble is, what that material might be.  I'm thinking of a lower temperature melting point plastic. 

Step 4: Using a Soldering Iron or Woodburner to Weld Capri Sun Pouches

Then I stumbled across an instructable here that used a soldering iron to weld plastic bags together.  Brilliant!  I thought.  I've got a combination soldering iron/woodburner for Christmas a while back.  It actually frustrates me to use it as a soldering iron because it doesn't really get hot enough to melt some forms of solder.  So I'm thinking it's a touch on the cool side of a soldering iron.

Another quick trip over to Wikipedia and I had the information about how hot a soldering iron gets:

Lead-based solder uses 250 °C to 280 °C or 300 °C while lead-free soldering needs a higher temperature, about 350 °C to 400 °C.

So a soldering iron gets plenty hot for welding Capri Sun Pouches.  I just have to be somewhat quick and not leave it in the same place very long.  Now my Soldering Iron/Woodburner comes with a bunch of different tips, so I selected one that was flat.  This tip actually broke when I was using it, but they are cheap to get replacements (or so I hope).  But it still had a flat side on it and it continued to work for my purpose.

Now it takes a bit of practice to get this technique down.  You have to figure out the right speed with which to drag across your seem without making a hole, but still keep it in place long enough to melt the Polyethylene.  The pictures below are actually my second attempt so it's easy to pick up the technique.  The secret is lots of steady pressure, and it works best if you weld both sides.  But when I was done I had two Capri Sun pouches welded together.  The seam was water tight and wouldn't pull apart.  Brilliant!

So commence the making of things with Capri Sun Pouches!

Step 5: Using a Clothing Iron to Weld? Not So Much.

Ok I know I did some research on this before, but I almost never believe anything I read.  Plus I had some spare time to try it out.  I tried using a regular clothing iron to weld CapriSun Pouches together and it was a bust.  I cranked the thing all the way up to it's hottest and no matter how I tried I could not get it to weld the pouches.  I tried using the side of the iron and pressed down very hard first.  That didn't work.  Then I tried taking a clothing hanger and cut pouch sized strips off of it put it on the pouches then applied heat and pressure to it with the iron and it was a whopping bust.

Conclusion: A standard clothing iron just doesn't have the heat needed to weld CapriSun pouches together.

Step 6: FoodSaver Seal-a-meal on Capri Sun Pouches

It just occurred to me to try my Food Saver Seal-a-meal vacuum packager (model VAC 1075) to weld Capri Sun pouches.  I mean it seals heavy plastic bags, why not Capri Sun pouches?  Well the experiment was unsuccessful.  I tried it on two pouches and pressed down hard and put them through 3 sealing cycles, and they barely even got warm.  Darn I was really hoping that one would work.



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    28 Discussions

    Hmm I wonder what a laminator would do? They are right at the temperature range you said was needed.

    1 reply

    Now that's darn interesting! Thank you for the idea. Could you possibly clarify, what kind of laminator you have in mind?

    Have you tried preheating the bags prior to welding say 180 degrees. The aluminum is acting as a heat sink ( like soldering) and sucking away the heat needed to melt and bond the plastics.

    1 reply

    Hmmm, no I hadn't thought of that. It's an interesting idea, I'll definitely keep that in mind. Right now I'm more leaning toward the use of a small strip of plastic with a lower melting temperature to act as "flux", similar to soldering electronics.

    thanks awesome ible im going to try to make a back pack as soon as i get enough pouches :)

    5 replies

    Thank you! I can NOT wait to see a backpack made from CapriSun pouches! How cool would that be???!

    Hi I work for a well known drinks co. In the uk and I have a lot of brand new unfilled and unsealed Capri sun pouches I had the idea of filling them with alcohol like vodka "" to make those expensive nights out a bit cheaper" lol I see ur quite interested in these pouches if u like I can send u a bunch through the post let mr know .. Ps not sure if ur aware but the unsealed packs have a strip of heat activated adhesive built-in at the top..

    I'd love to put your pouches to use - we are trying to collect them for our Girl Scout Troop to use for a charity project. If you are still interested in passing them on, please let me know! Thanks.

    Well THANK YOU very much for the offer, but the wife is already mad at me for keeping the 20 or so I have for testing and experimentation. Once I get the bag welding down, then I'll need more bags to make things from them.

    However you did give me a good idea. Perhaps putting some material that would act like solder flux between the bags before welding them would aid in the weld.

    hi~! this was pretty cool! just wanted to comment: i've seen tutorials for making DIY material out of plastic grocery bags by "welding" them together. the person would flatten out the bags on the fold/seam lines. take a ruler and draw a line straight across the top right where the handles attach and straight across the bottom almost right on the edge. then cut up one of the side seam/edges. now you'll have a flat long piece. do the same to about however many layers you want; the more the stronger. then the person setup their ironing board, wax paper, lined up the layers of prepped grocery bags, another layer of wax paper and ironed away. tada! and if there's a cool logo from a bag, cut it out and put it where you want it, once again sandwich with wax paper, iron, tada! :D - very sewable material in the end too. once made a messenger bag!~ :O :D

    1 reply

    Yes, I have seen the projects of welding plastic together from sheets of plastic grocery bags. I've even tried it myself and was less than impressed with the end product. I found you need even heat and pressure in order to end up with a good end product and I was unable to achieve that with an iron. My end result had plenty of air bubbles in it that I felt detracted from the usability of the plastic.

    I checked out this instructable, very cool. Girlfriend wanted to go to the beauty supply store yesterday, wandered in after her, on the way out I noticed a pile of flat irons, the type folks use to straighten their hair with. The cost was way too much for me to consider experimenting with, $50 to $100, but some of them have variable temperature controls, from 200 to 400 degrees. Seems to me it'd be well suited for what y'all are trying to do. If I should stumble upon one in a thrift shop, I'll go mug a kid for their drinks and try it out.


    1 reply

    Oh you know I hadn't thought of those. I just happened to be in Goodwill yesterday but didn't see any with variable temperature controls. I suppose I could hook it up to a potentiometer and manually measure the heat. But I'd rather find one with the heat controls built in. I'll keep my eyes open for one from now on. Thanks!

    I have a Mini Iron made by Clover Needlecraft, Inc. Its ironing surface measures 1" x 1 3/8" . It is used for quilting and appliqueing. It has a 9" handle. I am going to test it on some Capri Sun and other foil lined packaging.

    I've seen a miniature iron used in quilting and craft work at JoAnn's that might work. It looks reminiscent of a soldering iron, but has various tips at least 2 of which might work. You can find it listed as "Clover® Mini Iron II & Assortment Tips". They sell for about $60, but JoAnn's offers coupons each week, or if luck is with you, perhaps find one at a yard sale. Nice job on the instructable. I'm going to try it.

    1 reply

    Now that mini iron thing is an interesting little thing. I'm looking into it because it might be useful for other projects as well. I've found it's a combination of pressure and heat. So I'm thinking that I need something that gets hot, is rigid enough to clamp two pouches together, and can cool down. So my latest thought is to use a piece of copper pipe to clamp the two pouches together tightly. Then use something like an clothes iron to heat the pipe up. Thank you for the info and comment!

     I too was inspired by that ible where he used a soldering iron to make pouches out of freezer bag. I didn't have much success with the soldering iron, so I tried using my Seal a Meal heat sealer(Yardsale find) it was a little too hot for the ziploc bags, but I had success when I plugged it into a heat controller for a soldering iron. the heat controllers are sold for use with leaded glass work, and I found mine where else but a yard sale. 

    1 reply

    I remember seeing heat controllers for soldering irons. Haven't seen one in years but that is an interesting idea to use it with the seal-a-meal. If I can pick one up cheap somewhere I want to try your idea. Thanks for the info!

    I've used an iron before.

    Of course, I've been resealing MRE pouches, potato chip bags, and the like for forever. It's great to seal up stuff like cigarette lighters so they stay waterproof while hiking

    I remember having to adjust the heat down slightly from the top of the range. I also put some newspaper down so I don't accidental seal it to the ironing board.

    try google/youtube with seal mylar iron