Monday, 18 June 2012

Going Mouldy

So how did my first go at resin casting turn out? Read on, all will be revealed.

The first task was to glue the master face up in a homemade moulding box, which is nothing more fancy than four bits of styrene glued onto a thick base.

(I don't have photographs of this bit - sorry - Mrs Bron Hebog had taken the camera to work with her.)

Then it was time to mix the rubber moulding compound. It's probably the trickiest bit because the recipe calls for you to add 5% of the catalyst - by weight - to the rubber goo.

With such a relatively small part to cover with rubber this meant I needed just 1g of the catalyst, which necessitated the purchase of the most economical set of electronic scales I could find in the Argos catalogue.

Well, they did the job. I'm proud to be a cheapskate!

What followed was a bit of mixing and pouring - that's really not very technical, honest - and you have something very boring like this which you leave for 24 hours to cure.

Being the first time I've ever done this I have to confess I couldn't resist the urge to give it the tiniest wee prod every couple of hours to see how it was setting, but finally 24hrs were up and it was time for the big reveal...

To my untrained eye the negative image in the mould looked a little rough around the edges, and a little messy, to be frank, but the acid test - or perhaps I should say the epoxy test - would be to fill it with resin and see what happened.

The resin is a little easier to make up - the instructions say an approximate 50/50 mix will do - but the flip side is it sets really fast.

You're given 30 seconds to introduce the two liquids and blend them, and then just another 90 to pour it carefully into the mould, which when you've done it looks like this..

This is a lot easier if you're an impatient type of person, because just 20 minutes or so later the resin has set hard and you can release it from the mould, which peels away easily as soon as you flex it.

And here we have my first cast DZ wagon panel.

I don't think that's bad at all, for a first effort, you know. Not bad at all.

1 comment:

  1. The 5% mix doesn't need to be precise, I just slosh it in by eye. When the mould appears to have set, I remove the side walls first to check all is OK before taking out the rest.

    The finished moulds often look a little ragged around the edge but some nail scissors are very handy to tidy up. Mind you, it doesn' really matter much as you've discovered.