The Foundry: Part 1 – The First Casting

So we had our aim, and a basic design based off we saw in the videos we had watched. Now we needed to start the process of making it. We made a list of materials we might need, and had a basic look around on the internet, and off we went to the shops. During our travels we visited Screwfix, Wickes, B&Q, Hobbycraft and even Homebase. There were some pretty simple things we needed. Listed below:

  • Sand
  • Plaster of Paris
  • Drill (and drill bits)
  • Steel bucket
  • Safety Goggles
  • Safety Gloves
  • smaller plastic bucket
  • cheap measuring jug

Some of these items you might already own, (and we did) but it was listed as things we needed to complete this stage of the project.

Safety Notice (don’t ignore)

At this point I am going to stress a couple of those boring safety points. We have worked with some materials that could be considered quite dangerous if improperly used. So use safety gloves wherever possible (these can be as cheap as £1.50 in some stores, so there is no excuse!) and goggles and masks are a good idea, especially with dust, and when drilling. If you don’t understand why these are needed, maybe you should stop reading at this point.

Location

We would recommend thinking about where you do this project, there is the potential for spillage of plaster of paris, and that can ruin surfaces; so kitchens are probably out of the question. We recommend outside on a nice sunny day. Its always a good idea to be in a nice open area with plenty of ventilation, even when not working with toxic chemicals, it’s just good practice. We chose out outbuilding, its airy, already has paint stains, and contains all the tools we need as it doubles up as a basic workshop.

The Making

So let’s get on to the bit you care about how we made the foundry. The method starts with mixing together a mixture of 3.5 parts plaster of paris, 3.5 parts sand, and 2.5 parts water. This can be scaled up or down depending on how much you need to make to fill your bucket. We used a standard 14 litre bucket, and a standard liquid measuring jug to mix parts.

14 litre bucket
a 14 litre steel bucket found at most hardware stores
measuring jug
standard measuring jug

A few good tips to add in at this point. You should probably get some friends for this project, a few extra hands can be really useful. while we were making ours, we had one person stirring the mix, and another adding in the parts. Notice below, how many hands are in the images. The other point is to add the sand and plaster of paris before the water. As soon as the water is added, the mix will start the process of setting and you need to get that stuff mixed as fast as possible before it gets too hard. The last point is to mix this a lot, you want it to be thoroughly mixed together, else it could separate in the drying process.

Also, it would be a good idea to wear gloves at this point in the making, plaster of paris can cause burns if it gets in contact with the skin. Read the packaging first, and be careful when handling the powder and the mix.

mixing it together
Mixing it all together

While the mix is almost at its fully ready state, somebody needs to get the smaller plastic bucket, and fill it mostly with water. The amount of water used will depend on your buckets and mix. The water makes it much easier to hold the smaller bucket in place while the main mixture sets. If you get it right, it should not need much force to keep it in place until sufficiently hard.

placing the inner bucket
Placing the inner bucket

Once it is held in place for around 5 minutes it should be hard enough to let go of. if not, it may need to be held longer. You could always put heavy items on top to keep it in place. After a while it should look like the one below. Able to be left without touching, slowly drying.

still drying
Waiting for the mix to dry, but it still hold the inner bucket

Remember that at this stage, it still needs to be left for a long time before we actually take the bucket out, preferably for 24 hours, but it will depend on the mix you made, your climate, the temperature, all manner of things. We recommend leaving it overnight. When you touch the top of the mix, if it is moving then it isn’t ready yet.

The next stage is very fragile though. First empty all the water out of the inner bucket. Then we used a pair of pliers to slowly move the sides of the bucket away from the newly set mix. The bucket was slightly damaged, but with patience it is possible to remove the inner bucket to leave your new fire hole. If it doesn’t collapse in on itself it’s considered a success!

finished
The finished article, ready for fire

Thanks for reading this post, I hope to be posting some more updates about our foundry in the coming weeks, so watch this space. Also, if you have been making your own foundry, leave a comment below. We would love to hear from you.

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