The Waiting Game

I am conscious that after last weeks almost daily updates its all gone very quiet this week but things are happening behind the scenes – I hope.

Silence will probably be misinterpreted so here is a bit of a recap followed by an update.

When we left the story on Thursday the first brass castings had turned up and were horrible. Investigation revealed that most likely the caster didn’t follow the different burn out procedure required by these printed resins. At that point we had to concentrate on getting ready for the 7mm NGA Convention. The show was a massive success with some cracking layouts, more then usual due using the AGM room and no lull in the afternoon caused by the AGM. I can’t help but think that we should sack the AGM off to the back room of a pub somewhere and just have a cracking narrow gauge model show each year.

Anyway, on our return to York investigations started on finding a caster who would work with these resin waxes. With the help of the printers support three were identified for initial enquiries. There were two in the UK and one in Poland. The responses so far have been: –

  1. No response
  2. Grumble, Grumble, waxes, don’t burn out properly, no we don’t do the burn out differently. Net very helpful.
  3. Yes we use a Form 2 Printer. Use it all the time with great result. Best thing is you send me the STL file and I’ll show you what I can do

I let you guess which response goes with which company but I am looking forward to a parcel from Poland.

For the trial they are using their printer whereas for production I would be sending waxes I have printed but the whole process takes several days with print time, mould setting time, burnout time and so on but I am hoping for some results next week sometime.

 

Snatching Defeat from the Jaws of Victory

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

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.

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.

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…….

…….If it didn’t actually work

Time for a bit of digging.

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Not Sure I can stand the Tension

I’m not sure I can stand the tension of this run up to Saturdays release of our new model. The story so far……….

For this model we are doing brass castings by printing the waxes instead of  (1)printing a master, (2)making a silicon mould round it, (3)casting multiple waxes, (4)making a ceramic mould round the waxes, (5)burning the wax out & (6) pouring molten brass in.

By supplying the waxes were only doing 4, 5 & 6

A test with 3rd party printed waxes I had worked fine.

So with the deadline fast approaching the printer printed through the night producing gooey masters on the build platform. From here they’re popped off into a tub of Iso-propyl Alcohol to wash of any uncured resin.

Cleaned up they look like this. They then have to be trimmed off the printed supports, packed in sets and then shipped off to the caster.

The plan was get them to him on Monday, casting and shipping on Tuesday, I get them Wednesday.  We were at a show on Saturday but the waxes went with us and Annie posted them Special Delivery in Doncaster.  They arrived with the caster early Monday as planned. Now things have gone a bit crook……..

  • I missed a call on my mobile only finding the message in the evening. It went something like “that’s different wax, it doesn’t burn out so well. Ring me.

So now I am imagining all sorts of issues and seeing the project snatch defeat from the jaws of victory. The statement doesn’t ring true because the blurb for the resin says “A 20% wax-filled photopolymer for reliable casting with zero ash content and clean burnout”  Frustrated I can’t call until this morning but missed doing it first thing – something to do with being up changing the print job at 2am, so when I do call…..

  • Sorry , we can’t take your call. Please leave a message

So, currently none the wiser, fearing the worst and needing a nap. I’m hoping the unavailability is because he’s busy casting my parts!