How to make a round thing without a lathe (plus model making tips)

You want to make a model of something that you've seen in a film, but it's round and has lovely compound curves and you don't have a lathe. Don't worry, this instructable will show you how you can use a simple profile and some car resin filler to get a lovely round shape with out using any machines at all.

For me I used it to make this alethiometer from the book Northern Lights (aka the Golden Compass in the US) and shortly to be released as this Christmas's big hit, the Golden Compass. Which looking at the trailers is a mixture of Riven (the game for those that know), Steam Punk and a bit of Round the World in 80 Days thrown in for good measure.

Full instructions on how to use this instructable to make a Golden Compass can be found on my website dadcando here, including free printable templates for all the graphics and an accurate profile template guide.

But then you can make loads of round things using this method... I'm sure you'll think of them. Post pictures here if you do, we'd love to see them.

Step 1 Make the basic shape

In this case I wanted a flat disc a little bit like a large ice hocky puck or in fact a pocket watch, to match the shape of the device drawn on the front of the book. I made my basic shape out of cardboard, but really you can make it out of anything.

Model Maker's TIP #1

If you model is of something that has weight, i.e. it is made out of metal, plan to fill it with some ballast. This will make the final model much more realistic and fool people into thinking that it has been made out of metal, or has more of a quality feel to it. But be careful not to stick anything over the centre hole area, you are going to need to be able to poke something through the card right there in the next step.

In this case I cut two discs and then used up right spacers to make sure they were at a constant space apart and then wrapped a piece of card round the assembly to give me the disc shape.

Comments

[throbscottle]

This rocks! I shall try the technique to make pulleys!

[verdastel]

A state of art indeed!

[underkill]

 Absolutely brilliant tutorial.

[KaptinScarlet]

thank you

[jamwaffles]

This is genius man!

[KaptinScarlet]

glad you like it... it's a time honoured technique, I'm just passing the baton on

[jamwaffles]

well its been passed on in style. Also, i'm guessing this would work using a lost-foam (instead of lost-wax) technique?

cheers

[doxsys]

A laser cutter would be the perfect tool for cutting the profile to spec, if you have access to one.

[KaptinScarlet]

great idea

[Blakeney]

You are absolutely brilliant! I've been wishing forever that I had a lathe for small jewelry projects but don't have the money to buy one or the time for the learning process right now - will have to give this a try. I remember your Harry Pottter wand tutorial on dadcando - another amazing use of humble resources!

[KaptinScarlet]

thanks that's nice

[iminthebathroom]

Awesome - This is one of those instructables you go back to a year later when the need arises.  Its like the maker version of learning how to tie a tie.  Simple, yet elegant technique that breaks down a daunting task for the first timer.  Thanks!

[KaptinScarlet]

thanks, that was the idea

[Patent Dragon]

This could be JUST the technique I need for a similar prop device I have in mind. I'm sure that, once I read through the instructions several times, AND check out all the comments, I should have all I need to know. I discovered this instructable quite by chance, and I'm so glad I did!

[KaptinScarlet]

Glad to hear it. this is an old modelmaker's technique for making complex shapes using filler and a former. This instructable uses a roiund one, but basically if you want to make complex curved surfaces then a former and repeated sanding and filling (using the former) is definitely the way to go.

Thanks for the comments.

[kaptaink_cg]

Pretty clever!

[KaptinScarlet]

thanks

[Broom]

You're brilliant, your work is beautiful. Kudos! And thanks!

[KaptinScarlet]

thank you, that is a very kind thing to say. Cheers

[mg0930mg]

I found an error in step 10, the stuff is not free....

[KaptinScarlet]

Sorry about that, now corrected. I had to start charging (only a small amount) for dadcando as it was costing me too much to offer it for free. It's only £9.95 per year or 95p per project, which is not much really. But thanks for spotting that mistake.

[mg0930mg]

Cool, any new projects coming soon. Also do you know how much that would be in american dollars.

[KaptinScarlet]

$14.17 at today's exchange rate I believe. Loads more projects coming up. Going to be working on some projects with a National Newspaper here in the UK This week I am trying to get a new paper plane done. I try to keep the new projects coming over a wide range of ideas. What's your favorite type of project??

[mg0930mg]

I may pay it if I get money soon.... sigh, although I do need to make some stuff to sell... ANYWAY, enough babbbling. My favorite projects, have to be movie props, or book props, or anything cool like that .I like a lot of your projects, almost all of them.

[cowscankill]

Haha! I found another error! Step 8, I can almost each it xD

[cowscankill]

And step 10, prpping you work piece.

[mweston]

After step 7 you could get a machine screw and nut then place the screw through the center hole and tighten it with the nut. Put the remaining screw in a drill and use it as if it were a lathe to sand down the sides and top - I did this all the time when I made circular wood... thingys Cool project otherwise, the bondo mold was pretty creative!

[AnarchistAsian]

woahhh, my sister would like this too... ^{curse you for making stuff my sister likes}

[RaisedByRobots]

I'm impressed by your ability to make such a uniformly smooth object out of this stuff. After an hour of sanding, mine went from looking like a stone birthday cake to a crude pitted wheel made by some prehistoric tribe. I guess I need Sanding 101 or Bondo 101 class. It would be interesting to see a video of how you did the bondo step. You made it look easy, but I'm finding it isn't.

[KaptinScarlet]

OK, you need to start off with coarse grit paper, and I mean coarse 40 or 60 I think. then when you use the form to sweep round you do it lots of times and sand a bit between each time. To start with the shape looks rubbish but each time you do the sweeping round with new filler, the form makes sure that all the old gaps and cracks are filled by the filler. Don't try and put too much on to start with. when a layer has set, sand off coarsely until you can easily turn the form round without it snagging. Then mix up some more stuff and smear it on again. When you are putting stuff on that is smoothly going in the scratches of the previous snadpaper it's time to switch to finer grade sandpaper. It might seem tricky, but it's just a step wise process. However, the filler is tricky to handle when it has just been mixed up and it can be to fluid and then once it starts curing it goes off very quickly (it is called snap cure), so some practice is needed. Don't get too disheartened, I had to chuck my first one away, because I used wood filler and it wasn't smooth enough, nor easy enough to sweep round. BTW, this is one of the standard ways in which model makers make flowing curves on their models. AND yes, those styrene vapours over the years have probably killed off many brain cells and totally wasted my sense of smell, but it is an odour that reminds me of all my model making, so it is a happy smell for me. Good Luck, do get back to me and tell me how it's going, and send pictures in if you have them.

[RaisedByRobots]

Here is a video of the thing in action. Like all magical devices, it is frequently reluctant to work until the energies are right. :)

[RaisedByRobots]

Well, I finally did it. I could not resist trying to make it "work" (fingers making quoting gesture). So, here it is. I had to enlarge the pattern to allow for the workings inside (composed mostly of a pc fan and a meter needle from an old analog meter). I could not achieve the beautiful perfection of your finished piece. I struggled quite a bit with that. Maybe I could come up with some sort of old beat up tarnished look for it to make the blemishes just look like wear and tear. To your instructions I would add that the detergent bottle plastic for the profile is more of a necessity than nicety. I didn't get a clean edge as you mentioned until I used that. I also used a mask while sanding the bondo, which is good because I found that my entire work room is coated with a fine particulate dust of the stuff everywhere! So, if I were to do it again, I'd try to cover everything up with some cloth or something first. When I get a little more time and motivation, I am going to redo the faceplate and figure out how to make the crown glass part come out right. I just need to purchase some ink jet transparancies I think.

[KaptinScarlet]

That's amazing. The forming thing has worked really well. I know what you mean about the plastic forme. I would be even better if you were to make a profile from a thin sheet of acrylic, but I am fixated by making things from junk... mostly. However I'll look at the instructions and modify them. I love the video and the motor inside is a real bonus and innovation and very brave. How do you power it? BTW... I am redesigning dadcando at the moment and within about a month there will be a facility to upload pictures of your projects and each week I will be giving away prizes for the best. So keep an eye on dadcando, as this project looks as if it would definitely win!

[RaisedByRobots]

Yes, making things from junk is a great idea. The thick plastic of the detergent bottle worked great and was flexible and soft. Acrylic is too hard to cut I think, for me it shatters. The computer fan inside the contraption is powered by a little 9 volt rectangular battery. Turns out I only need one moving hand for it to work "correctly", so I might revamp it to work the way it's supposed to. I was at a loss as to how to solve the problem of the opening in the back/bottom for putting the parts in and changing the batteries. So I just put a thin wooden sheet in the back that I could lift in and out, but it doesn't look so nice as yours does. Ooh a contest, love those. Thanks, I'll keep an eye out on your site.

[RaisedByRobots]

I'm trying to find the filler you mention: two part auto body repair filler (resin car bodywork filler). Does it have a brand name?

[KaptinScarlet]

There are various brands, but i bet they are differnt in the US (from the UK), but any body filler should do the trick, like this one Get an easy sand one, that will be one with more talc and less resin in the mix. A quick search on the web for body filler should find something. you want two part epoxy so that it sets really fast. Read the instruction before mixing it up. you'll only need a $10 or less can for this project, and even then you'll have loads left over for the next project!

[RaisedByRobots]

Thanks, I found some bondo auto filler two part stuff at the auto shop for $11.00. My god, how do you cope with the vapours? I wore a new two cartridge organic vapor mask and I could still smell the ghastly heady smell of the bondo through it, while working outdoors. Phew!!

[benide]

Great instructable! Thanks, I think I'll use your tips this weekend. BTW, I've found that I can get a really smooth sanding job by using a piece torn from a paper bag. It like the equivalent of P1200 -1400, and very cheap and easy to obtain.

[KaptinScarlet]

good idea about the bag, but only when you have flatted off the shape with coarser grit paper, otherwise you will be there forever!

[GorillazMiko]

I forgot, what was the program you used again to make the awesome pictures? And how do you take such great photos, they're awesome!