Author Topic: Pattern making  (Read 7676 times)

Offline Jasonb

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Re: Pattern making
« Reply #15 on: September 17, 2015, 01:19:23 PM »
Ray you need to give them two things

1. your moddified pattern, this will have the hole filled in solid and the core print sticking out of each half. When they mould the sand around this the filled in bit obviously forms a void and the print leaves a place to locate the core.

2. You also need to supply a core box this usually a split box into which they will place sand to form the core, needs to be split so they can get the core out. The sand in the core is different and has additives which allow it to be bonded into one hard piece.

Process is they make the core in the corebox and then remove it. Next they ram up one side of your pattern, turn the box over and place the second half of the pattern ontop and ram sand around that. They will then take the two halves apart, remove your pattern halves then place the sand core into place and put the two boxs back together ready to poor. The sand core is held by the print (a sort of spigot) which keeps it away from the edges of the sand so iron can flow down the gap and form the sides of the part

Offline RayW

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Re: Pattern making
« Reply #16 on: September 17, 2015, 02:57:09 PM »
Thanks Jason. Things are getting much clearer now. In the YouTube video that you gave me a link to, I see that the core print (spigot) is just on one half of the pattern. I presume that I can do the same, or do I need the print split along the centre line so that there is half in each half of the pattern?

Whereabouts in Surrey are you? I am near Maidstone in Kent. If you were willing, it might be really helpful if we could meet up some time so that you could talk me through the process.
Ray

Offline Alyn Foundry

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Re: Pattern making
« Reply #17 on: September 17, 2015, 04:10:46 PM »
Dear Ray.

I have just posted a video here. I hope it explains better than words ?


Kind regards, Graham.

Offline RayW

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Re: Pattern making
« Reply #18 on: September 17, 2015, 06:01:11 PM »
Graham, what can I say! I have never had a YouTube video made especially for me or been mentioned in one!!
That has been really helpful. I am off on holiday on Saturday for a couple of weeks, so will have a go at it when I get back. When I fill the top cavity in each half of the pattern, does that need to be glued in, or can it be a loose piece?

Many thanks once again for your patience.
Ray

Offline Jasonb

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Re: Pattern making
« Reply #19 on: September 17, 2015, 06:51:44 PM »
Probably best glued or screwed in place, you could help the foundary man by painting the print part black which is the usual way things are done, rest can stay in your red.

Offline RayW

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Re: Pattern making
« Reply #20 on: September 17, 2015, 07:55:25 PM »
Thanks Jason.  I will use the two pieces to make the corebox before glueing them into the two halves of the pattern.

I just hope after all this effort that the cost of casting will not be prohibitively expensive!

Thanks again for all your help and guidance.
Ray