Introduction: How to Make a Solder Buddy (from Sheet Plastic)

Picture of How to Make a Solder Buddy (from Sheet Plastic)

[UPDATE - Thank you to everyone who voted in the UP! 3D Printer Contest - I was lucky to win an UP! Plus, so now I can proceed with Solder Buddy Mark III (Mark II is improving Mark I with you suggestions below) and then release the CAD files*.
*I am also looking for CAD software to do this in [sponsorship welcome if you know anyone who works for a CAD company!] - as Sketch-Up is going to take forever!

The full videos are up in a playlist, here.   Everything is free on Design Modelling, so thanks for your support!

Hello, I'm Jude - and I'm a Design Engineer. I've been making models of all sort of things since I was a kid... however, I've been doing it professionally for it for about 4 years now and I'm still enjoying it immensely!

I created a website called Design Modelling  and I’ve been running workshops showing people how to use simple materials to explore their ideas, be it for professional work or personal creative projects... as some point it really helps to get ideas out of your head and into your (or someone elses) hands!

Solder Buddy was a quick project that I did one evening to show the possibilities for what could be made with ABS plastic sheet. I’ve had a few requests on how I did this so I have uploaded an Instructable. However, if you are new to working with plastic or would like to know a few ‘pro’ tips I’ve picked up along the way, check out the techniques first.

This instructable should be a good example to show the possibilities of working in plastic, but if you are really serious about learning, I have a full video going into more detail of how I made this and explaining some of the design thinking behind it, here. The combination of the techniques covered and the application will be valuable to anyone trying to create robust models for the design industry.

Please let me know how you get on (Design Modelling on Facebook) - and have fun!

Step 1: What You Need

Picture of What You Need

I have included a layout of the ABS Plastic Sheet parts, as well as a [poorly drawn] exploded diagram. Try to have a go yourself, to plan things out - as obviously you will have different equipment and parts to what I had available. The trick is to ensure you have enough space for things to fit, so be generous on your first attempt.

(If you have never set out a plan for something like this before, you might like to work in cardboard first, as it is cheaper - I did a previous project which might be useful too).


- Brake Cable.
- Servo Motor (from an old RC car, but you may modify a new one too).
- Sugru (making handles, grippy feet on box, etc).
- Bearing or small rotating wheel on a mount.
- Rubber bands / inner tube from bike.
- ABS Plastic (about 2mm thick).
- ABS/Styrene rods/tubes/etc. (assorted sizes from hobby shops).
- Solder on a reel.
- Enough batteries to power servo.
- ‘push-on’ switches.
- Heat-shrink (covers solder joints).
- Extra wire.
- Brass Inserts - with bolts to fit.
- 2 small springs.

- Pliers.
- Soldering iron.
- Dremel / Proxxon (latter is better, imho).
- Scalpel + blades.
- Metal ruler (NOT plastic).
- Calipers.
- Marker.
- Insulation tape.
- Zona/Razor/Hack saw.
- Screwdriver.

Step 2: Techniques - for Working in Plastic

Picture of Techniques - for Working in Plastic
You might be familiar with working in Sheet Plastic, in which case, skip this step, if not - please take a look at this playlist:

The key with this whole Instructable is to develop the techniques to your style of working.

Step 3: Plan the Layout of Your Solder Buddy

Picture of Plan the Layout of Your Solder Buddy

To begin, take a piece of paper and position the components you will use to make your solder buddy. As you can see from the diagram - you will need to fit the batteries and other electronic components inside. The servo and solder reel on top - along with space for the brake cable to be securely fastened.

You might find it helpful to try out a few different designs.

Step 4: Box Assembly

Picture of Box Assembly
Here the parts of the [larger] top box and [smaller] bottom box are laid out.

The nest step is to glue these together with super glue (please wear goggles).

Tip: Insulation Tape will not stick to superglue (easily) and hence, can be used to hold things in place - both before glueing and also while drying (and avoids you getting stuck to the model!)

Check out the video if you need a demo.

Step 5: Sanding Down

Picture of Sanding Down

Sticking a sheet of sandpaper to a block of wood helps keep edges flat, stops the paper slipping around and gives a level finish.

Pictured, is black 'wet and dry' [sand] paper. It is available in many different grades, so you could either go for a fine polish (1200grit) or have your box with a 'matt finish' (around 600 grit).

As you can see, I have also made improvised sanding tools, which is a good thing to be aware of to work in difficult areas and to stop your fingers aching as much! More tips, here.

Make sure the open sides of the box are both flat - by sanding in circular motions.

Step 6: Servo Modification

Picture of Servo Modification
Originally when I made the Solder Buddy, I took a nondescript 'servo' from a RC Car (shown left)... so I have shown how you can buy a proper servo motor and take it appear to make it spin 360 degrees (shown right).

You will need to Google this info if you have a different one (than my HS311) - but it's quite simple to do.

I made a quick video of the image below, for more details, here.


Step 7: Roller System

Picture of Roller System

Creating the solder-wire rolling mechanism is probably one of the trickiest parts of the project.

I have also made a video, here, but these are the steps involved:

- Cut the rubber into a strip. Wrap it around the bearing. Measure where it goes all the way round. Cut this measurement 1 or 2 mm shorter - to give a tight fit. Glue the ends of the rubber (use a cocktail stick to apply super glue). Join together carefully. Allow to dry. Snap around the bearing. Use a scalpel blade to apply glue in between the rubber and the bearing.
- Repeat for the wheel of the servo.
- Using an off-cut of ABS plastic - make a 'cross' for the bearing to fix onto. Glue it lightly in place, so that you can work out the position - before gluing permanently.
- The bearing and wheel should be fixed so that they are close enough to provide grip (without stalling) and not too far apart (so slippage occurs). Use a bit of plastic tube to feed the wire in between the wheel/bearing - while running - to check performance.
- Glue in place thoroughly, when happy with it.
- Make supports for the feeding tubes - on either side of the wheel/bearing. Glue in place.

Step 8: Check Roller Operation

Picture of Check Roller Operation

Show on the right - you will need to make a spindle for the solder-wire reel. This can be simply done using the score and snap technique (shown earlier).

After this, you can put the servo/Roller Mechanism beside it and power it up to see if it all works.

Step 9: Brake Cable

Picture of Brake Cable

The brake cable has three 'layers' to it. Care need to be given not to cut through them, as you do not want the solder touching the metal winding of the brake cable.

See the diagram of how to create this assembly.

Step 10: Stand for Brake Cable / Spring on Roller / Connectivity Check

Picture of Stand for Brake Cable / Spring on Roller / Connectivity Check

Next you can see that the brake cable needs to be mounted to the top case of the solder buddy. One can make a ‘A-frame’ from the plastic to secure it into place. The Brake Cable should be at the same height as the wire exiting the Roller system. This will be tricky. Take you time - you you want a smooth transition.

Secondly you will need to add a spring onto the end of the ‘in’ side of the roller mechanism tube. Then attach a wire to this, so that a connection can be made between the solder and the rest of the wiring. (see diagram again if unsure).

Finally, I have used a Multimeter (on ‘beep’ mode) to check the connections along the bike cable and the solder winder.

Step 11: Cut Button-hole / Solder the Circuit / Heat-shrink

Picture of Cut Button-hole / Solder the Circuit / Heat-shrink

Using a dremel/proxxon drill out the hole for the 'feed' button. Tidy up with a scapel - take care not to cut towards yourself and only trim a little at at a time!

Step 12: Brass Inserts (a Professional-style Fixing for the Base)

Picture of Brass Inserts (a Professional-style Fixing for the Base)
This is really an example of how to have a go at a professional design technique - using Brass Inserts.

These are used when you need to repeatedly take apart and reassemble an 'enclosure' / box, as if you used conventional screws (self-tappers) in a boss, these would eventually wear out.

*Given that you've 'made it' this far, I guess you must be pretty serious about learning something, so in this case, I'd say this is a great section and has the potential to really raise your test-rig-building game, as it were. It's pretty lengthy stuff, so I included another video again.

Brass inserts can be used in a variety of ways, but this is one of them that is common.

Step 13: Sugru Time

Picture of Sugru Time

If you are not familiar with Sugru, check this out!

I have used it here, to do a few things:

- create a handle for comfort.
- secure the workings of the button on the brake cable.
- give durability to the end of the feeder.
- insulate the wires from shorting out.
- stopping the case from sliding around.
- add some funky colours.

The clever bit, on this project, for me, was taking covering base in Sugru - and then working it flat, but putting it on a flat surface and adding a little water - then buffing it flat.

I also needed to cut-out the excess Sugru that got in the holes for the screws, but it was very easily removed.

Step 14: Final Assembly & Thanks!

Picture of Final Assembly & Thanks!
So, after 24hours, your Sugru should be dry and you have a working Solder Buddy!

Thanks for watching and please do visit Design Modelling website or Facebook - I'd love to see/hear how you got in.... and most of all what you did differently. After all, these tutorials are about enabling you to define your own design direction.

Have fun!


Step 15: Appendix - Feedback

Picture of Appendix - Feedback

Here are some more photos of the mechanism, as requested by people, here on Instructables.

Please let me know if you have any other questions!

Best wishes,

PS - In case you are wondering why it looks different - I built it 'on the fly' first of all and then remade it again for this tutorial.


Hey Jude (author)2013-04-09

Wooo! Made the finals. At last - my own Instructables T-Shirt. Will be worn with pride =)

Thanks for everyone who voted - and especially to those of you who posted your awesome creations of your own Solder Buddy. I've learned some great tips from you guys!

I look forward to working on the CAD for the Mark II soon. Stay tuned.

macobt (author)2013-03-17

Very good tool and good instructable how to make it.
Here is my version:

Hey Jude (author)macobt2013-03-17

This is OUTSTANDING. Love it!
Really excited to see it working so well. Will you put up a few details...
...I have actually made a alternate speed controller using the potentiometer out of the Servo (HS 311) which will change the speed. I will show it on the Mark II, I think, as it's a nice way to 'recycle' the guts of the servo.

However, it looks like your electronics skills are far more advanced than mine! - as it looks like you used a 555Timer Chip and some other stuff to control the speed, right? Would you kindly upload your circuit diagram for everyone to see.

Really excited to see this, thanks so much - and hope you enjoy using it! Please let me know of any 'bugs' with the design I should consider for Mk II.

demond101 (author)2013-03-08

well hello i have now made my own solder dispenser pen /solder buddy it works great and has a reverse off and on switch i used recycled parts from my parts bins and around the area im am going to add a power in put connector so i can run it off my pc bench top psu and save on batterers thank you for making such a great instructable here's a photo of it

Hey Jude (author)demond1012013-03-08

This has truly made my day. Thanks =)

If you fancy taking a few more pics from different angles/close-ups, this would also be great on the Design Modelling Facebook, if you'd like to add them there as well as here?

bricabracwizard (author)2013-03-06

This is so well documented and the solder buddy looks a joy to use. Now I'll have to have one! I'll try to make a spring loaded wheel so that I can use different thicknesses of solder.

Hey Jude (author)bricabracwizard2013-03-06

Awesome - I look forward to seeing what you come up with. I think I confess in the video that I had considered it, but was not sure how to do it just yet. Certainly one for the Mark II version!

Hey Jude (author)2013-03-05

OK - so I have uploaded some new images - See Step 15 - Appendix. Kinda enjoy this angle, I have to say.

projectsugru (author)2013-03-04

WOW, incredible project, I laughed with joy watching the solder move forward in your video, this is awesome :)

MoTinkerGNome (author)2015-01-29

This is a bloody Brilliant project mate. I am gonig to have to make one as I reinvented the wheel with a Mechanical pencil solder feeder and was sketching up a way to electrically feed.. Old servos I have solder I have old brake cable etc. YOU ARE THE MAN! Thanks for making.

Hey Jude (author)MoTinkerGNome2015-09-13



PeterT29 (author)2015-09-12

can i buy the solder buddy

Hey Jude (author)PeterT292015-09-13

I'd say this Solder Buddy is not for sale (sentimental reasons!!), but I hope to make a V2 in future, which 3D printable parts of it will be - watch this space :o)

Biscuitus (author)2015-01-15

I'm sorry I didn't find this when voting was enabled but congratulations and thank you very much for this. I've used MIG welders before and quite honestly I don't know how I didn't think of this so cheers to you mate! I'm going to make one for myself, the only addition will be some free spinning small bearings to ensure the solder is straight. I know I don't have to worry about it, but sometimes OCD can be a mother.

Hey Jude (author)Biscuitus2015-01-17

Sounds cool - would love to see how you get on. I've been wondering about how best to 'tension'/'spring-load' the roller system so that it can accommodate solder ranging from 0.3-0.7mm dia. to avoid slippage.(I think most people on this site are a bit compelled to obsess; so join the club!)

Biscuitus (author)Hey Jude2015-01-17

I was thinking of applying a small coat of RTV (silicone gasket sealer) as that would allow for most common sizes to pass through as the RTV would deform or I could slot the holder of the middle roller use socket head cap screws to adjust the tension as needed. I'll need to sketch it out first as you bring up a good point.

Hey Jude (author)Biscuitus2015-01-18

Good suggestion. I'll certainly keep it in mind. I've used RTV a lot at my last job and it has a good 'tacky' feel when dry - good for friction and compliance to the wire.

From electronics guys I've spoken to - most have a 'favourite' gauge of Solder, and most use the 'thinner' stuff, so I'll probably optimise it for this and see how it copes with thicker solder.

flokeiner (author)2015-01-16

Wazzup with Mk2 or Mk3?

Hey Jude (author)flokeiner2015-01-17

Funny you should ask - it's been a busy 'interval' between this an now. I've got sponsorship from SolidWorks to release the CAD for 3D Printing, and I've been learning Arduino coding to try to make a 'click=forward / doubleclick=backward' command with the Solder Feed. I've also found a better alternative to a brake cable. Needing some time to put it all together, but I'll be sure to keep Instructables posted :o)

flokeiner (author)Hey Jude2015-01-17

Very nice :D just asked because there wasn´t an update for a long time. I thought about building one and didn´t know if i should wait or just build the mk1

Hey Jude (author)flokeiner2015-01-18

Yeah - long time indeed. I felt that I wanted to explore different user experiences with this, so hence the Arduino (and learning it).

As you can probably gather - I'm a bit of a perfectionist, so I'll do the MkII when I'm pleased with it. Sorry to keep you waiting ;o)

Lucif3r945 (author)2014-04-21


Best. Dispenser. Ever. I am so going to build one of these, although I know it wont be nearly as good looking as yours (mainly because I dont have the patience :/). I think Im going to add a motor/servo to the solderholderpin-thingy as well so it can also be reversed without tangling itself up :)

Also great 'ible, and awesome vids.

Hey Jude (author)Lucif3r9452014-04-27

That's a really cool idea - the reverse thing. In many ways, I recon the 'reverse' has become an issue as I have to re-wind the [un-used] solder from demo-ing it to people...but when I use it as intended it is not really needed. That said, I've got a cool trick I'm working on with an electronics-boffin, which should be cool when we show it! Do post some pictures or email me if you have any questions - always cool to see how you ideas take shape! Good Luck!

ohararp (author)2013-08-30

Dude, you totally need to crowd fund this. I'd totally buy if price was under $50.

Hey Jude (author)ohararp2013-08-30


Thanks for the suggestion.... For now, I'm working on a Mark III version that will be in CAD - so it will hopefully be available for 3D Printing. Finger's crossed!

You might also like the Ergo Mouse I just did:

But also if you are in the UK - I'm also doing a workshop in Brighton 8 Sept and you can see all these things and more on the day.

Hope you have a go at making one, or check out @Jude_Pullen for updates on the MkIII. =)

tjesse1 (author)2013-07-19

What kind of soldering gun is that?

Hey Jude (author)tjesse12013-07-21

It's a 'VersaTip' - gas powered iron. I did a review of it here:

Not as accurate as a pro-soldering iron, but very handy for quick tasks.

DemolisionWolf (author)2013-06-29


sofiadragon1979 (author)2013-05-31

This is a fantastic item, it's like having a mini MIG welder.

Hey Jude (author)sofiadragon19792013-06-01

Thanks very much. I'll be doing a new version shortly - so let me know if you have any suggestions for Mark II.

(I have not MIG welded, but I did realise I may have been inspired by this or perhaps 3D Printer nozzles...makes you wonder what else you can feed - strawberry lace?)

sofiadragon1979 (author)Hey Jude2013-06-01

3D printed strawberry lace yum yum lol. What I was thinking of doing when I make it is making the whole shell w/a 3D printer & also adding a bar roller guide @ the spot before the solder meets the rollers kind of like a guide on a threading machine. I am still working things out since I saw the way that you have this set up. A MIG welder basically feeds out welding wire & pumps out an inert gas to contain the reaction of the welding & keep the weld from oxidizing, it's funny how close the machine looks to this if you think about it lol.

Hey Jude (author)sofiadragon19792013-06-01

That's really cool - Thanks for the info! Please take any pic for me and other to see, if you have the MIG.

My plan is to make a Mark II version in plastic to resolve things like:
- Variable wire diameter
- Working with a Solder Reel
- Variable Feed Speed
- Reverse
- Improve aesthetics / functionality in general.

Following people's reaction to Mark II, I will then freeze the design and make a Mark III in CAD. I will make it so it works with the UP printer I won for this Instructable.

Looking forward to your ideas!

sofiadragon1979 (author)Hey Jude2013-06-01

For the variable wire diameter I'd use an auto adjusting tension wheel, to make the solder spool move easier you could make the mount that it sits on rate w/ a bearing as well. For the variable speed there are two ways around that one that I can think of 1: using a potentiometer only & 2: using a micro controller & a flexforce pressure sensor, that will basically adjust the flow speed dependent on how hard you press it. The reverse is going to need a micro controller from what I am thinking.

Hey Jude (author)sofiadragon19792013-06-02

This sounds really interesting - but if you felt like uploading a sketch for the tensioning mechanism, that would be cool. (I was thinking of something with a spung bearing mount).

As for the speed control - you are right with the POT. In fact you'll see that when you take appart a Servo you will have this as 'waste' - so I intend to re-use it. It needs some modification which a friend helped me with. Alternatively, I will also try out macobt's 555 timer verion of speed control as this will work nicely, but is more complet for people. That said a good soldering lesson, perhaps.

The full videos are up here:

sofiadragon1979 (author)Hey Jude2013-06-02

I've got a few projects that I'm designing on my own @ the moment so I'll drop you a pic when I get a chance.

I've signed up for your YouTube page, it is really nice how well your videos are done, they are very clear & very informative.

mrmerino (author)2013-03-06

Oh, it that what... Oh wow, that's brilliant. I'll take six.

Hey Jude (author)mrmerino2013-03-10

Out of interest - how much would you think pay for:
a. kit you RP (I would upload CAD to thingyverse, etc).and assemble yourself?
b. kit supplied with injection moulded parts and all included?
c. off the shelf / online hobby shop?
thanks. just curious to know what people think =) I might do one or more of the above in time.

Spokehedz (author)Hey Jude2013-04-26

Printing the plastic bits myself, but you sending all the non-printable parts: $10.
Injection Molded Plastic kit with all parts: $15.
Hobby store: Naaaaah. Online is where it is at.

Shipping would be the biggest killer I think that is why I would just like the CAD model to print out myself, and i'll suss out the details with other bits and bobs I got laying around.

Hey Jude (author)Spokehedz2013-04-27

OK cool - good to know.

To be honest I'm sure that would be cost price at $15, given a servo on ebay is about $7 at least, possibly more.... so you see my point for making this an Instructable and not a Kickstarter! You are right - postage is killer. Tricky, the will is there, but not the money to even break even at $10 I'm afraid.

However, may main motivation for doing this was to get people hands-on with different materials. I'm happy to release the CAD when I finish it and will document how and why I made certain feature on the model. I would have found this more exciting than modelling a Mouse at Uni in CAD to be honest, so hope it might get used as a simple teaching aid, or whatever?

Going back to sales - perhaps I guess I could put a fill kit on Tindie?(
for anyone who really wanted to just make it that way - or more likely buy it for a gift.

Let me know if you (or anyone reading this) have any other good ideas.

Thanks for your thoughts. Much appreciated. Jude

mrmerino (author)Hey Jude2013-03-10

Well I don't know what RP is, but I would probably pay fifteen-twenty for a kit and maybe thirty for a fully assembled unit.

Hey Jude (author)mrmerino2013-03-11

Sorry, should stop doing that!
RP = Rapid Prototype - as in 3D Print or something similar....
Thanks for the comment. Interesting to know.

technovative (author)2013-04-24

Congratulations on your UP win! Enjoy your 3D printer mate!

Hey Jude (author)technovative2013-04-24

Hey - thanks a lot. Am actually working a new one right now. It's tricky (for me - hopefully not for others!).

I did a 'simple' one to relax:

Got any new stuff cooking yourself?

technovative (author)Hey Jude2013-04-26

I saw your boot carrier, that's clever.

I will have a new Ible up soon. I recently got my first RasPi and I have an idea for a li-ion battery/power supply/charger circuit for it that I will be sharing.

Hey Jude (author)technovative2013-04-27

Thanks - glad you thought it was clever and not blindingly obvious =)

I guess it's nice to mix up the super-complex with the supe-simple.

Really looking forward to seeing the charge circuit - I don't know much electronics, but am learning - so would love to see this. email me when you post it!


Jayefuu (author)2013-04-26

Hey Jude!
Excellent instructable, I'm definitely going to make one of these. I like your ABS guide, can you recommend somewhere in the UK I can get some A4 sheets of the plastic you used?

Also, you might like to check out Randofo's handy guide to making a servo continuous.

Hey Jude (author)Jayefuu2013-04-27

Hey Jayefuu,
Thanks for the support and enthusiasm - would love to see a result!
I put a Materials page on my website for such an occasion:

Though if you want larger quantities and have a business account, RS Components a better value in bulk.

Thanks for the servo guide, I followed a similar process myself. Thought I worked with a friend on a way to use the Potentiometer (that you removed) as a speed controller for the Solder Buddy....

...Stay tuned for Marke II.

Nicapizza (author)2013-04-20

Ok thanks. I made this for invention convention, and it took about 5 months, and I don't ant someone to steel my hard work.

It is encased in a glasses case and has a heating element from an old soldering iron and I guide tube coming out. When a small rubber wheel turns, it uses the same principle of yours to push the solder onto the heated tip. It opens and you can see the innards. The drive mech is a heavily modified servo with some rubber lego wheels for the pushing mechanism. It was designed so I could solder with one hand. It uses 2 AA batteries. Any questions, please ask. I'll post an 'ible soon.

Hey Jude (author)Nicapizza2013-04-20

Hi Nick,

As for your great work - it seems many of us have had similar frustrations. Following my Solder Buddy post a while ago, I had a nice comment from tgferreira184 - who it turns out has also made a great version of solder feeder (it's manual, not automated). But also uses a brake cable - but not in the same way to create an electrical circuit as I have. Check it out:

Your version actually seems to be a combination of mine / Macobt's work and tgferreira184. Though I would still we might both benefit from Macobt's electronics, as they are clever and I will try them myself.

I had wondered about how to create a solder gun (like a glue-gun) myself, but had trouble in managing the flow of solder. This would be the 'challenge' for me - perhaps you can have a go as well and we'll see which works best?

I think it's exciting to explore this global community of development of ideas. Thanks for sharing.


PS - Not sure if you intended to direct message me these pictures or post them for everyone to see. Just thought I'd say. Otherwise - thanks for sharing with the Instructables community - Looks cool!

Nicapizza (author)Hey Jude2013-04-20

I haven't tested this yet, but I think it will work. I'll share my findings!
Before I posted the pics, my mother started freaking out that someone would see them and try to make their own. I replied "Yes mom, it's called open source!" I meant to share them to all and I hope others try to replicate/improve my design.

Also, what specifically dos your l

About This Instructable




Bio: I'm a Product Design Engineer, currently living in the UK. I have been fortunate to have lived, studied and worked in Hong Kong, Norway ... More »
More by Hey Jude:Hands-Free Shooting With DSLR Foot PedalsZocus - Wireless Zoom & Focus for Your DSLR CameraCustom-Made Wax Candles (Cast using Sugru Moulds)
Add instructable to: