{"id":1738,"date":"2019-06-06T19:07:57","date_gmt":"2019-06-06T19:07:57","guid":{"rendered":"http:\/\/ngtrains-com.stackstaging.com\/blog\/?p=1738"},"modified":"2020-10-31T12:40:57","modified_gmt":"2020-10-31T12:40:57","slug":"snatching-defeat-from-the-jaws-of-victory","status":"publish","type":"post","link":"https:\/\/ngtrains.com\/blog\/snatching-defeat-from-the-jaws-of-victory\/","title":{"rendered":"Snatching Defeat from the Jaws of Victory"},"content":{"rendered":"

\"\"<\/a>Well, yes, it would be fair to say I am pretty fed up at the moment.\u00a0 The first of the brass castings arrived and they’re rubbish. Not what I want to put in a kit I produce.<\/p>\n

I had been warned that they hadn’t come out great with the caster complaining that the waxes didn’t burn out cleanly and that the surface was very pitted. He also said he didn’t like this resin\/wax and wouldn’t do any more.<\/p>\n

I was gutted. Felt like giving up for awhile. So disappointed that I wouldn’t have any complete kits to sell this weekend at the 7mm NGA Convention.<\/p>\n

Well, after a bit of naval gazing during which even the cats stayed out of my way I got to thinking. Formlabs couldn’t make claims like…….\"\"<\/a><\/p>\n

…….If it didn’t actually work<\/p>\n

Time for a bit of digging.<\/p>\n

A chat with Formlabs online support pointed me to a spec for using this material. A chat with the caster revealed another clue and a further chat with Formlabs covered the situation in one.<\/p>\n

\"\"<\/a>The spec and chats with Formlabs brought home the fact that a wax filled photo polymer needs handling differently to ensure a clean burn out without residue.\u00a0 This is a very precise temperature and time schedule.<\/p>\n

This is shown in the graph to the left.<\/p>\n

There’s a whole load of other stuff on material handling and casting mould materials for best results and some pictures of the work fine detail the process can produce if done right.<\/p>\n

\"\"<\/a><\/p>\n

So it works then<\/p>\n

Right, so the next stage in the investigation was to have a chat with the caster which was quite revealing. Don’t get me wrong he is an excellent caster and has always done great work for me by the traditional method and I will still use him for this sort of work.<\/p>\n

\"\"<\/a>I asked about the burnout method used and did it follow the spec. of which I sent a copy. Short answer was no, didn’t read it, did it the way I’ve always done.<\/p>\n

Not changing!<\/p>\n

 <\/p>\n

Hmm, back to the drawing board then.<\/p>\n

Now one of the problems with these castings is I have designed them to take advantage of the printed wax process and they won’t reproduce in the normal silicon mould to make waxes method.\u00a0 Seems like there are two options for the way forward.<\/p>\n