Lost wax casting advice needed

[Neil WyattModerator @neilwyatt]

Each, I assume? Useful to know, thanks Brian.

You could sell them and make back your investment.

Edited By Neil Wyatt on 01/03/2017 22:07:22

[BrianParticipant @brian]

How much shrinkage did you get, outside diameter and height?

[not done it yetParticipant @notdoneityet]

How much shrinkage did you get, outside diameter and height?

About 3% for brass, I think. Easily calculated. Take dimensions at close to melting point and apply the coefficient of expansion, for the metal, between ambient and the solidified hot-melt. If really picky you could take into account the expansion of your particular mould material between ambient and casting temperature, but that will be negligible in the whole scheme of things.

[JasonBModerator @jasonb]

Posted by Neil Wyatt on 01/03/2017 22:06:38:

Each, I assume? Useful to know, thanks Brian.

You could sell them and make back your investment.

But there are not many other traction engine builders named Abbott who have sons

Brian, I think if you were to make a tight fitting plug and press or stick them onto that you could then spin them up and use some abrasive on a stick to remove the printed texture and polish them up. For the face it would be best to put some wet & dry on a flat surface and give them a gentle rub.

Edited By JasonB on 02/03/2017 07:31:41

[Chris Evans 6Participant @chrisevans6]

A bit late for my input now I know but I would have turned from solid and had them engraved by a firm I used when working in the mould and die tool making trade. I use an engraving company in Walsall West Midlands who are cost effective. You did get a good price though, I have some aluminium and also some cast iron castings done a few times a year at two different foundries and they charge a similar amount. You pay for the time setting the pattern in the sand box rather than the material used. Nice end result though, if you do any more patterns six thou to the inch is a good rule of thumb for shrinkage.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Neil Wyatt on 01/03/2017 22:06:38:

… make back your investment.

.

… a 'Lost Wax Casting" pun !!

MichaelG.

[Brian AbbottParticipant @brianabbott67793]

Yep, £12.50 each

The outside dimension of the pattern is Ø34.1 and the height is 8.45 ( this allowed for some very slight machining )

The finished casting came out at Ø33.25 x 7.95.

The text on the pattern measured 2.3 tall by 0.5mm high, i think this is possibly the limit, any smaller and i think the process would struggle.

If i was to do these again, i would leave the text as is, but raise the outer and inner ring slightly so i could run this on a pierce of wet & dry but not touch the lettering.

but for now, as Jason suggests I think i will just give them a nib over as i quite like the cast look,

PS..

If anyone does know a chap called Abbott who has a son, and who is building a 1" minnie then pass them onto me, could do them some cheap(ish) hubs..

[richardandtracyParticipant @richardandtracy]

The 3D printing company 'Shapeways' will do 3D printing in wax, which is intended to go directly for lost wax casting. I think the minimum feature size is 0.1mm. Take a look here: **LINK**

Shapeways' wax production is primarily intended for jewellery stuff, so is limited in size. However their equipment is a fair bit better than most home outfits can afford at the moment. They have a branch in Belgium, and I know a few pen makers who have used them for creating models for silver pen clips etc as well as complete pens from plastics, and been very happy with the service. The surface finish of the direct metal printing isn't very good yet. May come later.

Regards,

Richard.

 

Edited By richardandtracy on 02/03/2017 10:31:50

[JasonBModerator @jasonb]

You also need to allow for any losses when the mould is taken, when the wax is cast and also the usual shrinkage of the metal when that is cast. That is presuming the printed pattern is spot on, a machine that is not callibrated may be 1 or 2% undersize.

[Brian AbbottParticipant @brianabbott67793]

The printed pattern is slightly bigger than the cad model,

The cad model outside diameter measured 33.85 whilst the pattern measured 34.1.

[Brian AbbottParticipant @brianabbott67793]

One down one to go. i think it turned out ok.

[JasonBModerator @jasonb]

They look the part.

J

[Ian PParticipant @ianp]

Having followed this topic and now seen the last picture, I dont think you could have got such a good result by any other method. It really does look the part, I'm really impressed.

I was surprised the cost was as low as you said and I will certainly consider using that company if/when I have a suitable requirement. Out of interest what did you finally use for the pattern? (I know there were several ideas mentioned in the thread, but I'm not clear)

Ian P

[Neil WyattModerator @neilwyatt]

Passable

Lovely finishing touch.

Neil

[Senior YatesParticipant @senioryates]

Nice work Brian, they have cleaned up well. I can see a show winner on it's way.

[Brian AbbottParticipant @brianabbott67793]

Nice comments, thank you.

Just find the whole casting process really interesting.

Ian. the pattern was printed in liquid polymer then a mould made from this for the wax pattern.

I think the wax printing would be good, but my thoughts were if i have a mould made its there for any future parts ( If i scrap one )

Thanks all.

[Richard S2Participant @richards2]

Glad to see the finished article(s) fitted Brian . A very smart enhancement.

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