Cast Pewter Rocket Badge

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Introduction: Cast Pewter Rocket Badge

About: The answer is lasers, now, what was the question? If you need help, feel free to contact me. Find me on Reddit, Tumblr and Twitter as @KitemanX

I have idly thought for meany years that I ought to do some metal work.

What put me off was, to be frank, laziness. Being from a steel town, my mental image of "working with metal" involves huge furnaces, forges and really heavy tools.

Then I realised two things:

The melting point of pewter is only around 200 Celsius, and the hot-air gun I use to bend acrylic can blow waaaay hotter than that.

So, I resolved to make some pewter jewellery - specifically, a rocket.

I'm stepping outside my comfort zone here, but let's see what happens...

Please read all the way through the instructions before you start actually working - unlike most of my projects, there are points where you cannot pause to check what to do next without spoiling the end result.

UPDATE: I have published another pewter-casting project with more details.

Step 1: Materials, Tools and Brain Damage

Materials:

  • Pewter
  • 3mm MDF
  • 3mm clear acrylic
  • Butterfly badge-pin

Tools:

  • A hot air gun
  • Tongs or pliers (more than one pair)
  • Clamps
  • Something to cut MDF (I used my laser cutter, because I can, but ordinary hand tools are absolutely fine)
  • Ladle.
  • A heat-proof surface over which to work. I used an old baking tray.

If you want to make a badge like mine, I've attached a variety of versions of the file to this step.

The "ladle" needs to be steel, but beyond that there are many options - you could use an actual soup ladle, use a serving spoon or cut a clean food can into shape. I found a set of measuring spoons - the smallest turned out to be perfect for the ingot of pewter I bought, and had a flat bottom (so balancing was a lot easier). Bonus points; Kitewife gained an almost-complete set of measuring spoons.

There are lots of suppliers of pewter online, but I always recommend supporting a local physical craft store if you can.

Use lead-free pewter - the presence of lead doesn't really affect the use of the finished item if you're making a something nice to look at, but you don't really want it on your skin, and (worse) you don't want to breathe in hot lead fumes. Lead is a cumulative neurotoxin - each exposure damages your brain a little more.

If you are working indoors, please make sure that you have plenty of ventilation - open windows and doors, have fans maintaining an air-flow away from you (and especially away from any children or pregnant or nursing mothers).

Step 2: The Design.

Making a rocket badge needs three layers of MDF.

The central layer is the outline of the rocket, with a small notch at the top to let you pour in the molten pewter.

The front layer is just a rectangle of MDF.

The back layer has a circle to mark where to place the rocket's window, and a small hole cut to allow the spike of the badge-back to poke through.

The window was cut from 3mm acrylic.

Step 3: Clamp It Up!

Just what it says - get the parts lined up, and clamped as firmly as you can.

The window needs to be tacked in place to stop it slipping in the mould. All you need is a tiny dab of PVA glue. Too much glue could spoil the finish or explode in the heat of the molten metal.

I didn't push the spike of the badge-back all the way through the hole in the mould - the plan was for pewter to flow all around the pin & hold it firmly in the metal.

You want the parts clamped as firmly as possible, held vertically over a surface you don't mind spilling molten pewter over.

(I'm an old hand at this, but guess who forgot to take a photo of the clamped-up mould?)

Step 4: Melting Your Pewter

The joy of using pewter is that you do not need a furnace, just a ladle.

If you have a small metal ladle, then you're good to go. You could also use a large spoon (with a pouring lip bent into the side of the bowl), or cut down an empty can to make a ladle.

One advantage of using the measuring cup I used (or an old can) is that it has a flat-enough bottom to stand without spilling.

I put my pewter ingot in the ladle, and blasted it with the heat gun until it was melted. Standing the ladle on the part-open vice meant I could heat it from above and below.

Don't forget that metal conducts heat, and the handle will get hot - use the pliers to pick it up and pour.


Step 5: Pour

With the mould propped firmly in a vertical position, gently and carefully pour molten pewter into the funnel-shaped cut-out of the mould.

The design I was making needed only a small fraction of the pewter in the ladle - the mould filled quickly and over-flowed.

Step 6: De-mould

After the pewter has had time to solidify (officially just 2-3 minutes, but I give it five), release the clamps of the mould.

The pewter seemed to glue the layers of MDF together - I had to slip a knife blade between the layers to prise them apart.

Resist the temptation to immediately pick the badge up with your bare hands - despite being solid, it might still be hot. It will only take a couple of minutes to cool enough to handle, though.

Step 7: Trimming Sprues

Once the pendant is set, you may have excess material, known as a sprue.

These need trimmed off - a mall pair of tin-snips easily removed the bulk of the sprue, and then a pair of toenail clippers removed the rest (the clippers had already been damaged by a certain child using them to trim brake cables on his bike).

Step 8: Finishing

If your finished piece is grubby, just clean it.

Soap and water should work fine, but if you have small corners or details to work around, you may need to scrub with a toothbrush.

The finished rocket, at 4cm tall, is a bit heavy for a light shirt, but perfect for a jumper, fleece or suit lapel.

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    13 Comments

    Very Nice. Question however. I'm a high school tech teacher and I am looking for a small casting projects. This might work but...where did you get your pewter?

    2 replies

    I bought mine from (UK) Ebay, a single one-ounce ingot that is less than half-gone with the two badges I have made so far.

    I do know that a lot of UK high schools do this as a project in Resistant Materials ("shop"?) lessons - some laser the moulds, others hand-cut the MDF, depending on what skills the school wants to develop (or whether they own a laser cutter).


    (BTW, do you see at the very top of the page where it says "Teachers"? If you haven't clicked it yet, do so now.)

    I have bought from rotometals. I see they sell on Amazon now as well.

    Is the MDF mold reusable or is it one use only?

    1 reply

    With a low-detail piece like this, the MDF looks fine for another go. My other badge* was only a one-shot mould, though.

    I don't know if that's because of the greater detail, or because I heater the pewter to a higher temperature (it seemed more "watery" when I poured it).

    *https://www.instructables.com/id/Cast-Pewter-Robot-Badge/

    I've found, with insetting acrylic into a pewter mould, is to carefully chose a piece of acrylic marginally thicker than the MDF the middle layer is made from. MDF and acrylic being nominally 3mm thick, but I've seen variations from 2.7 - 3.2mm. Slightly thicker acrylic means it stays in position when clamped up and pewter won't be tempted to flow across it's face.

    2 replies

    Oh also, using a piece of 3mm polished aluminium plate as the "show side" or the mould can yield a very shiny surface on the cast that requires no finishing. The aluminium can be preheated on the mould so the pewter doesn't cool too quickly and flows into all the nooks. I really enjoyed pewter casting and this brings it all back.

    Thanks for those points - I have also heard that you can clamp the MDF really tightly to make it bow in slightly and hold in thinner acrylic.

    I've entered this in the Casting Contest - if you've enjoyed reading it, I'd appreciate a vote!

    Shades of my youth and images of Flash Gordon starring buster Crabbe. You made this look simple, something I'd even attempt -- er -- maybe. Good job.

    HIGH 10.jpg
    1 reply

    Thank you - it is a lot easier than I was expecting!

    An easy way to start casting! I'll keep this one in mind, the rocket turned out nice btw.

    1 reply