Problem: Broken arm – GHD straighteners
Cause: Messy bedroom walking about without due care and attention. I would guess late and probably rushing about getting ready to go out. It’s text book stuff.
As you can see a less than clean break, not sure what the material is that’s used to make these. More importantly they look like that can be salvaged. Price for a new pair. Between £80 to £100
Now I could glue them at the point of the break. An epoxy glue like Gorilla Epoxy would probably do the trick.
Looking at the straighteners the break is right at the location that the owner would be holding them. Also, there is a big spring that is used to force the straighteners to open each time they are used. I’m thinking that gluing them would work, but perhaps a strengthening part made specifically and glued in place over the crack might help to ensure continued use.
Okay, first things first let’s get these stripped out so we can see what is going on. GHD actually do a good job of putting these together. The wires are not soldered to the terminals, but rather fixed on with small screws. So small in fact that I lost one on the floor which took an age to find.
Once I had taken everything apart I had a better idea of the damage. As I said, you could epoxy glue it, but that may not give it the strength it needs. My initial idea is to create a small “fillet” of plastic that sits over the break. I will glue the break back together, then glue the fillet over the break itself. Well that’s the plan.
Notice that the break runs up close to the part that’s used as a pivot, and where the owner of the straighteners would exert the most pressure. I am going to need to cover this part with the plastic insert to give that area some extra strength. But this can’t be too thick otherwise the spring will be compressed to tightly when used and adding to the pressure at that location.
First thing I did was to glue the arm back together. I needed it to be fixed together so I could figure out the shape of the fillet I was going to have to make.
You can see here, that the break was not straight, rather it was in a V shape. Good for our straighteners because it means more of a face to initially glue together. Bad if you have an OCD about tidiness. Although I bet the person who these belong to has no OCD about tidiness. Actually lets give the owner a name. Lets call her Curly!
Now it’s time to take some measurements of the internals of the straighteners. We can then take these into Tinkercad and make the support piece.
This is a small part, and we won’t want to make it very thick. Just enough to get it to give some support to the actual area of the break.
This won’t require hours of design and hundreds of iterations, because we are working with an internal part. We can always take a sharp knife to the part and trim it down. It won’t be seen, it only serves a purpose to strengthen around the area of the break.
Now we know what we want to create and have some measurements it’s time to head over to Tinkercad.
This is a simple 3D design package, but it does the job. It’s just the thing for creating little objects and comes in very handy for jobs like this.
So, the general shape of what we want in Tinkercad terms is called a “Round Roof” we need to flip this over, so it looks like the idea we need to work with. Save some brain power by using parts that closely mimic the part you want to create. That way, you are constantly focused.
I have resized the shape to be more in line with the measurements I took earlier from the straighteners.
When you are designing a part know in your head what shape you are looking to model. Don’t be afraid to play with the tools and shapes available. If you make a mistake that’s a good thing because you are learning what does and doesn’t work. Looking at the straighteners I can see that there is a small step where the hinge meats the rest of the arm.
I need to add this step into the shape. If you see the shape that we have on the screen has a shadow line that tells you where that edge is on the grid. This makes it easy to measure from an edge that isn’t directly laying on the workplane.
I need to create a box to fit in where the step in the straighteners will be. I need to make it just big enough to allow this step to be modelled. I can use what Tinkercad calls a “hole” If it’s not a sold shape, it’s a hole. A hole cuts away material. You can create either a solid or a hole and interchange between both as you design your object.
You can find the hole selection icon near the top right-hand side of the Tinkercad window.
I have positioned the hole shape where I think it needs to be. Move these around until you are happy that what you are making looks reasonably like the finished product.
Don’t be scared to try out different things. You might think it looks stupid at the time, but if it works its not stupid.
When I had the first side right, I hit Ctrl and D and this duplicates the part that’s highlighted. This saves you having to do it all over again for the other side. All you have to do, is move the part to the other side put in its place and hey presto that side is done too. When you duplicate a shape in Tinkercad it puts the duplicate on top of the one you originally had. You might think that it hasn’t duplicated it, but grab that part and drag it away with the left mouse button pressed down then you will see the other one there. If it didn’t work hit the “undo” button once and try again.
I will group these parts now, so I can see what it looks like. If it looks correct I can more to the next part. To the right at the top of the screen there is the group button.
Hold the mouse down and draw a square over all of the shapes. Alternatively, hold shift while you left click the parts you want to include. This highlights your design then select the group icon this will make the hole shapes part of the main shape cutting away that area.
We need to hollow out the rest of the object and cut away some of the excess shape from the outside first though. Try to think where this part will go. In this illustration I want this to be glued inside something else. So, I am more interested in the outside of the part, the outer walls of this object. Which in this case will be glued against the inside walls of the straighteners.
Now it’s time to hollow out the centre piece. Here we will create a shape something like the first, but small enough to fit inside the first part. I will then make this new shape a hole, thus scooping out the inside parts that we don’t want.
I will have to make two parts. Notice that in this one shape, there are two widths. A narrow part then a wider part. I will create an object that hollows out the narrow bit at the back, then another part that is slightly bigger to hollow out where the part widens.
So I can see what I am doing I have changed the original part into a hole (transparent). The new object I made is 1mm smaller so that it can fit inside the original leaving a 1mm border. I also lifted the new object up a little so that it leaves about 1mm thickness at the bottom. There is a black up arrow on top of the object that I can use to move things up and down as required. When you place the mouse pointer over the arrow it turns red to let you know you have it selected.
As you can see it’s important that you leave space at the bottom as well as the sides.
I used the align tool to align both these up before fitting them together. Using the align tool helps when doing the heavy lifting. You need to make sure that everything is aligned to the exact centre, the align tool helps you accomplish this. So, all you have to do is move the new part inside the original object. Making sure all other dimensions have been aligned makes your job a lot easier. Below, is the icon for doing alignments.
Now we need to align the two before we move them into place and join them as one part.
I need to align the two parts so that when I move the solid part to when it’s meant to be. I will know that its in the place without having to worry about the left to right dimension or the height.
First off I will use the align tool selection point at the front of the part. This will make sure its spot on in relation to the centre of the larger part. Then when that is done I can align by the second point (highlighted in the picture to the left) which will move the smaller part to a better position. Then I can use the direction buttons to move it the rest of the way.
NOTE: when using the arrow keys you need to be looking at the part in the direction you want it to move. Say for instance you want to move a part using the Left and Right arrow keys. You need to have the part turned and looking at it correctly, so that any object travels left and right. as seen below.
subsequently, your workplane for Up and Down movement should be turned in the direction of the arrow keys you want to use. This time the illustration is turned for the Up and Down arrow keys, as seen below.
Back to the story then.
When I have it as far as I can get it I can move it the rest of the way using the arrow keys.
I need the back of the solid object to be moved up to the very back edge of the narrowest part of the object. This will scoop out the middle of that area just to the point where it meets the wider area of the object. I can do this with two shapes fitted inside the original then change them to a transparent (hole) which will do the scooping out. Now a second object needs to be made and positioned. I will butt this up against the smaller one, then group the parts to make them one.
I know it sounds frantic, I’ll show you what I mean…
So, I made another object in the shape of what I want to scoop out. I made it higher and longer as it won’t matter when I turn it transparent. Plus it allows me to see it better as I move it into place.
Make sure the new part has been lifted to create a bottom, the same thickness as the first part.
Now it’s the right height and positioned dead centre in the right and left direction. By using the align tool I can make sure its positioned right then slide it into place. In the next picture you can see that the first part is just poking out into where the bigger block is going, this is fine because in actual fact it’s going to be transparent. So, it doesn’t really exist. This is called magic!
Keep moving it back till it is level and leaves a thin border all around like in the picture below.
Highlight the large object block that you just moved and click on the “Hole” icon on the right-hand side (below).
It should look something like the following when the inside objects are made transparent.
Now select all the objects, the original and the transparent ones by either clicking on them in turn by holding down the Shift key. Alternatively, draw a square around them all by holding down the left mouse button. This will highlight them all. Then select the Group icon, below. And “Volia” you have your strengthening shim
The only thing I have to do now is to tidy up the face of the outside. I want to shave a little off this area so it isn’t too thick and will sit better in the straighteners concave handle. I did this by adding some transparent triangles to the outside edge to remove the thickness from the back outside shoulder. Till it looked like this (below), then added two more to take a little more off what I had already done.
You can shave off bits of an object then group them to see if you need to remove more. If you do just add more transparent objects to get the shape you desire. Think of it like you sculpting something by moving blocks to hide certain areas.
I got it to look like this in the end, which I thought what okay for the job I had in mind.
Right nearly done. All I need to do now is to add a small cut out that allows the top cover to screw in to the locating hole once I had put it back together. I made up a small transparent block to take away some of the plastic so it fits together, but still retains the strength of the original part.
Made the block and got it close then used the Align tool to get it dead centre, like so.
Made it slightly wider, then little bit shorter and Bobs your Uncle! Doesn’t look bad at all. OK, it doesn’t look great but it’s going to do its job just as well.
Group that lot..
That looks good enough to print. So, I did. I used some Silver PLA – only took 10 minutes to print. Now, it’s time to put it all together. Lets make sure that it actually fits inside the handle. Nice one Cyril.
I know what you’re thinking it looks gash right? Yeah but Einstein, listen up because it’s going to be hidden from view. Aesthetically it’s appalling, but it’s only mending a break also we are looking for strength not beauty.
Now we need a tonne of epoxy resin glue. Epoxy is stronger than most glues. No good using Super glue here because after a little time it will weaken and just break. I mixed up some glue and got out my trusty “part sticker in place helper”.
No, not my finger the living room table. The finger was just to position it while it went off a little bit. When I was sure it wasn’t going to move too much, I transferred it to the finishing department.
Left it like that for a couple of hours to make sure it went off properly then put it back together and tested it by turning it on and left it like that till it turned itself off due to not being used. I just wanted to make sure I hadn’t messed anything up and it all worked as normal after putting it back together.
Tinkercad might not be the greatest application for doing intricate work but it’s simple interface and ease of use make it an easy to handle application for most jobs. If you spend the time you can make anything within reason.
The straighteners were reunited with their untidy, rightful owner and the last I heard they were happy being late and messing up the bedroom once again. Although little Butter Fingers did manage to knock them off a table and they might be coming back for a second fix any time soon.
So, was it worth doing? Yes, I think so
- Money saved about = £90 (new pair)
- Repair cost = 10p in filament
- How long to fix = 4 hours
- Pride knowing I’d fixed it = 100%
So, we take the cost of new item, divide it by 10 then times that by 4 add 67 units then minus the rest and you are left with a total score off 88 out of 100. Not a total waste of plastic!!
If you got this far, I thank you ;O)