Instructables
Picture of How to Make a Heat Sealer
Well, finally, as promised, here's my how-to.

Q. What's a heat sealer?

A. Also known as an impulse sealer, a heat sealer uses a resistive heating element to seal and/or cut thin plastic bags or sheets. Rather than using continous heat, which would turn the bag into a gooey-edged mess, it uses a timed impulse of heat - hence "impulse" sealer.

This instructable reveals to you many secrets that certain people do not want you to know! I have already received several death threats from one of the major recloseable bag companies. Please enjoy this instructable, which might be my last....
 
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Step 1: Why would I want a HEAT SEALER, anyway?

HeatSealer 007.jpg
HeatSealer 005.jpg
Using a proper heat sealer, you can do a much more than making toothpaste packets!

Click on the pics below to find your reason. If you do not see it, then perhaps playing with Dremel tools and electricity is reason enough.

And dare I say, you can even store your beads with it?!
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You can find nichrome wire in toasters and electric fires or can be salvaged from electric blankets. Take the wire out from the wife's side of the blanket and keep stum :)

Frankcw3 months ago

I realize this has been up a while but I've wanted to make one of these. I have finally found a schematic for the part of the circuit that would replace the custon PIC With a 555 chip and potentiometer. It took lots of searching, reading and learning.

It is step 3 in this instructible:

http://www.instructables.com/id/555-Timer/step3/55...

In the last paragraph he tells how to make it into a variable timer. I needed a variable timer because I plan on using various thickness plastics. He gives an excellent explanation of how the circuit works as well. When I build mine I will do an instructable including the final circuit diagram.

Frank

kemperburt5 months ago

I would like to know if you are still making these. My electrical expertise needs much improvement to say the least. can you direct me to the forum link you describe above thanks. Or your forum name so that I can find you.

Thanks

denewf1 year ago
I've read all the posts and comments on this instructable hoping to find if it could be made substantially wider. I have a requirement for a 4' (yep, 4 foot) sealer and not a clue as to how to go about it. A kit of some kind would be a blessing. If you are still responding to this instructable after 3 years any suggestions and/or sourcing info would be most appreciated. Thank you.
boing101 denewf8 months ago

It occurred to me your problem is not a problem, but a case for lateral
thinking!

Have a look-see at my solution for a multi-length sealer.

http://plusoneproducts.co.uk/imagesof/circuit_for_multi_length_heat_sealer.pdf

I was faced with a problem of requiring different lengths and not wanting
to buy a long 16 inch sealer to be sealing 2 inches most of the time.

The setup might seem labour intensive, but how hard is it to twist a knob
and press the same button four times.

This setup uses one length of wire, each section will burn for the same
amount of time using the same amount of power, rather than the obvious route of
four wires of different gauges with four different timer settings etc.

The two indicator LEDs are for ‘Element On’ and ‘Cooling’. Not shown is an
electromagnet circuit. The lock-down is released when the cooling period is
finished.

I could have used a PIC that had some more I/O pins, an AD pin for a
potentiometer, memory for modes, and a transistor and relay for each of the
sections, thereby getting rid of the need for a double-pole rotary switch and
adding in a bit of flexibility to suit the particular plastic thickness and
type, next time!

klee27x (author)  denewf11 months ago

I'm sorry, I am not much help, here. Sourcing the heating element is the hard part. Try googling "nichrome wire" or "resistance wire." Any steel wire actually has resistance, so you might find something around the house that might work. AT 4' you probably want to use mains current and an SCR. Please be careful when working with mains.

bgroicahn4 years ago
 An incandescent light dimmer though a GFI breaker would be just a useable and a lot easier to make.
klee27x (author)  bgroicahn4 years ago
That would miss the point. This isn't a foam cutter. The PIC doesn't do PWM power control. It is just a fancy way to provide a user-adjustable full-power timed pulse with a single button. (Actually 2 timers... there's an adjustable delay BEFORE the pulse starts, too, in case you want it. For instance, you might want a half second or so to readjust your hands after pushing the button, if you're sealing a bag in a way that you can't use one hand.)

You have to melt the plastic. The idea is to get the wire up to temp AS FAST AS POSSIBLE, then immediately cut power. So you could use an on/off switch, if you have good timing. But a light dimmer would do nothing to help for a heat sealer. Sure, you could set the power to the point where it would only just be able to reach the melting temp of the bag, but then it'd just take LONGER to actually reach that temp, and you'd still have to turn it off and wait for it to cool down before opening the heat sealer.
Dear klee27x,
please let me know if the current to be passed through is AC or DC.

I have tried for both AC and DC in one of my designs where i have a grid system to pass the current through. Please answer my few quries :

10 Ni wires in series total resistance 25 Ohms with : (each piece : width 1mm, 18inch long, 2.5 Ohms )
1. Do we have information regarding plastic bag thickness and temperature needed to seal it and corresponding current required?

2. I am able to seal it with naked wire but when put behind a teflon tape(standard one used in impulse sealers), then it does not seal at all. to solve this problem, should I pass more current or should I heat it for longer duration.

I have a very simple circuit designed for the pulse.
I am not using any transformer as AC supply is 240 V, current being passed is around 10 Amp for this 25 Ohm series strip. if any one is interested.. i will post the full design details.
Hi bhushan1572, I´m interested in see the details of you circuit for the pulse, seem quite more simple. I´ll would be very grateful. I´m making an automatic bag sealer and once if finish it i will post my instructable. My e-mail is francisco.g.h@live.com.mx
Hello, thanks for your interest. I have actually completed and successfully implemented the circuit.
As mentioned earlier, I took 10 Ni wires of 2.5ohms/18inch in a grid based structure. We have 230 V AC supply at home. I prepared a timer - RC circuit through a relay where in i used a switch.
Once the switch is turned ON, the capacitor starts charging, within 3 seconds the capacitor is charged and the relay is cut-off (reverse action through a NOT gate to a transistor).
So actually I am passing around 9.2 A AC current through the NI grid for 3 secs. This heats up suffieciently to seal up the bags.
The said design as attached is used for packaging 25 bags in 6 seconds.
This is faster than an automated machine.
Please find attached images for the actual design
current delivery circuit.JPGNi Grid.JPG
klee27x (author)  bhushan157211 months ago

That's awesome. But I wouldn't call that my circuit at all. This looks to be 100% bhushan! I'm glad you found my instructable helpful.

hi bhushan,
I came across this instructable when trying to concept some thing you seem to have done. I'm actually trying to build a batch packing machine. I think ill use your plans. Just a couple of things though. How have you been using this and any problems yet?
klee27x (author)  satwikUnderhill11 months ago

I'm still using it. I had to rebuild it after a couple years, though. The wire had melted into the plastic enough to cause trouble. When I refurbished it, I put teflon tape UNDER where the wire sits. (On commercial sealers, the tape goes over the wire; mine is not powerful enough for that). My GF and her roommate also have been using a copy of the improved version for almost 3 years, now.

Note, my plans include a schematic using a PIC microcontroller. Without the firmware, it will not actually do anything. You might prefer to use a "monostable 555" circuit. Try google.

The hardest part is finding the exact right wire to work for your power supply and length of sealer.

I believe most commercial sealers use an SSR to trip mains current. So they can use thicker heating elements for a stronger seal. If you are need something robust, you might consider going that route. It's not much different, except you should be more careful if you are unfamiliar with working with mains AC.

klee27x (author)  bhushan15723 years ago
1. No.
2. Dunno what your timing circuit is, but it shouldn't be too hard to increase the pulse to see what happens? Or just trip it twice, quickly?

Be careful!
klee27x (author)  klee27x4 years ago
Well, to be fair, a light dimmer would be useful if you were running a very low resistance filament from AC power, and you had to reduce the current draw (to prevent overloading your outlet and/or circuit breaker). But timing the pulse would still need to be done with a separate method.
Larzag2 years ago
how deep is the grove for the wire?
thks,
lz
klee27x (author)  Larzag11 months ago

There is no groove for the wire. The groove is only to hide the power wires. The heating element is stretched over flat plexi (with Teflon tape underneath to prevent it from melting).

mzminty1 year ago
hi any ideas on making a continous heat sealer to seal drinking straws in bulk.like a machine type which does not really involve manual labour
c-face2 years ago
Sweet! I was thinking about making one of these. I was wondering have you thought about using an industrial timer for this?
JanxAngel6 years ago
I've seen ribbon versions of the nichrome wire, which is better? I have yet to see 27ga but I have seen close to that, how hard is it for the electronic assembly n00b to substitute?
klee27x (author)  JanxAngel6 years ago
The ribbon is usually better for heavy duty sealing. The ribbon is typically laid out so it presses flat against the bag, producing a very wide seal. But you probably need a high amperage power power supply for that. It all depends on how much the resistance of the wire is, and also how much heat it would take to raise the temperature (thicker wire means more time or energy to heat up). So in other words, if you go just a little bit thicker, and you end up needing A LOT more power.
Nice work, really looks like a pro one...
Just a thing, wire is usually used to cut the plastic bag meanwhile the ribbon is used to seal, the power needed depends of the ribbon width up to 9mm, the same with the wire gauge. Ribbon and wire are not used with the same kind of machine, your looks likes more at a thermo forming sealer means you make a bag around the product and you schrink your polietilenol with a hot air pistol to let him stick on your product, working with a wire( because of the low level between the work base and the sealer), meanwhile a sealing bag machine is higher, bags are generally full of product...)
If I can make a suggestion, if one day you look inside a professionnal sealer you will see very few components: a 110/24V transfo( for a 8'' sealer normally 200W), a 555 based monostable with a relay, a end of course switch (who is triggering the 555) and that's it. the simpliest the best. one thing more the pro model always got the hot stuff on the lowest jaws, helps you to have a better continuity on your sealing especially when you have more than 18'' to sew
Got some timer plan if interested, can send you a PDF
once again really a good job, sorry for the english but it's not my native language
Laurent
I am wondering if I can heat seal an irregular line with something that will NOT gunk up the plastic mess. (Not a straight line).

I am enjoying your humor on this instructable ...
klee27x (author)  urbanwoodswalker2 years ago
Hmm. Not sure how you'd do that with a nichrome wire. They expand when heated. That would be tricky, for sure. You might need a thicker, formed piece of stainless steel for a heating element. But then you'd need a lot more power and it wouldn't cool off as fast. Yes, that would be tricky.
celiagp2 years ago
Wow I definitely have to try this. Do you think I'll be able to use it to seal polyethylene tubes like the ones used for lotions and such?
Thank you for sharing.
Francisco.G2 years ago
Hi, this intructable is awesome. I´m doing an automatic bag sealer as a project to collage, I have all the automatic mechanics done but I really having trouble with the actually sealer part. I already have all the components to make this instructable but I wanted to know what PIC and program environment do you use and if there is a chance you share you program?? My e-mail is francisco.g.h@live.com.mx I´m new at instructables and I´m enthusiastic about share my first instructable that will be this automatic bag sealer. Thanks a lot.
VadimS2 years ago
I'm thinking of building this, but using 12v and thin copper wire. I'll probably use a relay instead of a mosfet, they can handle much higher peek currents.

You can get 6 mil Polyethylene rolls for use in construction (vapor barrier). 16"X375' for about $32. Enough for a lifetime supply of bags :P
It's really good quality (I use larger rolls when insulating), should be perfect
Peraloca3 years ago
The Photobucket pictures are in a private album and can't be seen. Also, the link to the video, is missing. Can you help with that please? Thank you.
Ok, I will answer my own request. I already found your comment about this in another section of this page. Thank you anyway.
useful14 years ago
I made a 555 astable circuit using stainless steel wire as the wire sealer, with the claim on this instructable, saying you can make a heat sealer using a 555.

It's currently connected to a 12V power source. It doesn't work. The wire doesnt get hot enough to melt plastic. I believe that 200mA, which is the amperage, of a 555, does not make the stainless steel wire to get hot enough.

Perhaps, it is the wire im using. But as far as making a 555 heat sealer, I believe that myth is busted. Unless someone points to me a webpage which tells me how to make one correctly.

using the 555 as a straightforward output source probably won't be enough power, what would be more effective, would be to route the output pin of the 555 to a transistor or mosfet. In this instance the 555 would only function as an adjustable signal generator (think pulse frequency modulator using a potentiometer) that triggers the mosfet which would be able to draw more power to your heating element/wire. you could either use separate power sources, or the same power source/battery, as long as the 555 signal generator part of the circuit was protected with a voltage limiter. the advantage of this over simply making an oscillator or astable multivibrator with only two transistors, is that you can control the frequency of the pulses easily and accurately with the 555.
hope that helps.
msw100 useful14 years ago
I think the author said nichrome wire was used not stainless steel,nichrome wire can be found in electric fire heating elements
klee27x (author)  msw1003 years ago
"Nichrome" is a trademark, I believe. But it's a commonly used term, sorta like calling any tissue a Kleenex. The wire I'm using isn't actually nichrome, FTR.

Stainless steel wire is generally pretty good for this kind of thing.
msw100 klee27x3 years ago
its resistance is different from stainless steel,whats so hard to ubderstand about that?
klee27x (author)  useful14 years ago
Hi. The 555 IC is suitable only to make the control circuit. To deliver the power, you just use the 555 output to control a power device such as a power relay or a power transistor.

Also, you must carefully choose the wire gauge, length, resistance, and power supply to work together. Using 12V, you would probably need at least 6+ amps and a suitable matched wire to make a decent sealer impulse. This is much more than 200mA!
ykikeg4 years ago
Hello
Is it possible to use an ac transformer 110 to 19v ac, or i can only use dc?
Like David said, technically you could rectify the ac first using a full wave (or even if desperate half wave) rectifier (diode bridge basically ,easy to find on google) and could then change the desired frequency of the DC by using a pulsed capacitor system on your output. You may ask, "frequency of DC??? but pulsed dc is fairly common depending on your rectification method. Anyway once you rectify the dc, you can control the power and speed of your pulses by using capacitors of varying sizes to determine charge/ discharge times. Variable capacitors are also an option. Additionally you would not necessarily need a separate DC source, as a voltage limiter such as LM78M05 could be used on the input of an IC to prevent any damage. However ykikeg's question i believe is if you can step AC voltage up and down, to which the answer is yes.
Step up and step down transformers do this all the time. using thicker/thinner wire, and varying combinations of turns on your primary and secondary windings of your transformer, you could change 110 vac to 19vac. hope that helps all.
You could just use a bridge-rectifier to convert it into DC. You would need to use a smoothing capacitor on the output of the bridge rectifier and then probably also regulate it using a simple voltage regulator IC.
klee27x (author)  ykikeg4 years ago
Well, if you want to control AC current, you can't use simple transistors. You would need to use TRIACS, relays, or SCRs. Also, you'd still need a separate source of DC to supply the uController or timer IC. Or you'd need to be much smarter than I am with electronics and design a timing circuit to run off AC.
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