Foundry recommendation

[Andrew EntwistleParticipant @andrewentwistle]

I have been asked to help in replacing four church railing support columns. Does anyone have a recommendation of a foundry who could cast in cast iron or possibly aluminium from a 3D printed pattern (with suitable draft angles and shrinkage allowance)? Overall length including mounting spike is around 500mm. I am in Manchester, but could easily post the pattern(s).

Andrew.

[mgnbukParticipant @mgnbuk]

You could try H Downs in Huddersfield

I had one-off iron castings done there for work (including the patterns) some years ago. Contact at the time was Nigel Downs.

Some years ago there was a TV program about the first cast iron bridge at Ironbridge which included making a scale replica (half size IIRC) cast in the manner of the time & erected as it would have been done at the time. H Downs supplied the castings.

Nigel B.

[Andrew EntwistleParticipant @andrewentwistle]

Thank you Nigel, I’ve dropped H Downs an email.

Andrew.

[John HaineParticipant @johnhaine32865]

Home

 

[Bo’sunParticipant @bosun58570]

Good afternoon Andrew,

Have you tried the foundry at “Blists Hill” Victorian Town, Ironbridge?

[JasonBModerator @jasonb]

The patterns I have been making and doing the CAD for over the last couple of years are being cast by these two both iron and aluminium

Graydon or Purbrite.

re the 3D patterns you will need to print them with a good wall thickness and at least 50% fill if they are to survive being used for more than one casting, failure to do so can result in this when the pattern is pulled from airset sand which is what most use these days.

[duncan webster 1Participant @duncanwebster1]

I’ve used http://www.jte-castings.co.uk/

In Wigan, very helpful. There is also a foundry in Altrincham, Whiteheads I think, but never dealt with them.

[Andrew EntwistleParticipant @andrewentwistle]

Thank you all for the suggested foundries and to Jason for the heads up on required print strength. Three options are within 40 minutes drive so I will start there.

Andrew.

[noel shelleyParticipant @noelshelley55608]

In view of the application DO NOT even consider aluminium ! A wooden pattern will last and be far better, and kept safe can be used 100s of times if need be. Noel.

[vintagengineerParticipant @vintagengineer]

Hoyles in London might have the patterns in stock.  https://www.jameshoyleandson.co.uk/

[Andrew EntwistleParticipant @andrewentwistle]

Finally picked up the cast iron railing supports from S Whitehead foundry in Altrincham. Perfect job and the 3D printed pattern and core box look like they would survive many more operations. The sand was sodium silicate for both the core and the main casting.

[Bill PhinnParticipant @billphinn90025]

Looks like a good result, Andrew. The Whitehead foundry is very close to me.

I’m surprised to see churches still have the money to spend on railings, particularly in this neck of the woods.

[Bo’sunParticipant @bosun58570]

Thanks for the follow-up Andrew.

[Andrew EntwistleParticipant @andrewentwistle]

Hi Bill, I was also surprised that the Church could and had chosen to put resources to a cosmetic issue rather than say to a food bank, but it turns out the railings belong to a War Memorial, which may affect funding source. Anyway the cost for casting the the three 7 kg 400 mm high pillars was only £120 including VAT.

Andrew.

[noel shelleyParticipant @noelshelley55608]

Good to know you got the job done,thanks for letting us know. Noel.

[hurnbyParticipant @hurnby]

It’s great that the result was so successful

[noel shelley]

On noel shelley Said:

… A wooden pattern will last and be far better, and kept safe can be used 100s of times if need be. Noel.

True, but wooden patterns are a lot more trouble to make in the first place and wasteful unless used repeatedly.   They have to be kept safe and used 100s of times!  3D printed plastic will have a shorter life, but replacements can be reprinted at any time.   And because the design is electronic, there’s no need to store physical patterns at all.   This is a major advantage when a business pays for storage.

There must be a cross-over point at which a 3D printed pattern becomes more expensive than wood, but not clear where it is without doing the maths.   Broadly, plastic favours low-volume production runs whilst wood favours high-volume.   Judging by Andrew’s photos, his casting requirement was well met by plastic.

There’s another interesting cost cross-over between casting and 3D-printing in metal.    3D-metal printing removes the need for moulds entirely and can produce objects that are impossible to cast.   But 3D metal printing is slow and expensive, most useful for prototyping, high-tech, and short production runs.   Casting is much faster and cheaper for simple shapes and high-volume production.

Change is in the air.   At the moment,  kits and one-offs still make use of castings machined to size by the Model Engineer.  A classic technique that once dominated Victorian engineering, but mostly superseded during the 20th Century by alternative methods.   Since then the cost of 3D metal printing has dropped during this century, and 3D-metal printing as a service may be becoming hobby affordable.  Rather than using 3D-CAD to define a mould and then machining a casting made from it, the hobby might switch to having near finished parts printed in metal, ready to fit.

I’m fascinated by Model Engineering because it covers traditional and modern technology.   We can enjoy workshop methods dating from the 18th and 19th centuries, whilst also using CAD and a 3D printer to make projects stuffed with electronics!

Dave

[JasonBModerator @jasonb]

Not sure I would agree with all that Dave

Printing can be a lot more trouble than traditional methods if you are not able to produce a CAD model of the part and this is the first and major sticking point for many. I’ve had a few nice little earners where people have had access to 3D printers but not been able to model the part they wanted and it was not a toy boat.

On the other hand I have also remade patterns where the original wooden ones had not fared well after being stored in a damp workshop for 20years  or ones that had moved due to being made from wood that was not correctly seasoned.

I would say wood and printed both favour one off to short runs, once you want to start doing more it is better to make the wood or plastic pattern oversize and cast a metal or PU resin pattern from that for further use.

3D metal printing in some cases need not cost any more than a comprable size casting. Run a few .stp files trrough an online service and compare their prices with what an ME supplier might charge. Examples can be seen on forums where more people make things of 3D metal printed parts being used

I’ll not say much more you can read the rest in a forthcoming MEW.

 

Castings turned out well BTW

[Andrew TinsleyParticipant @andrewtinsley63637]

I always use wooden patterns. Great uncles worked in the Ford casting factory in Detroit. That would be the very early 1900s. I was taught how to make patterns by one of them. So I keep the old traditions alive. I suspect it takes a fair bit of time to produce a printed pattern. Must be a steep learning curve. I must admit I prefer the smell of wood to plastic.

Andrew.

[Andrew EntwistleParticipant @andrewentwistle]

Hi Andrew, It does take a long time to produce printed patterns, but that is mostly printing time rather than my time. I am sure wood is more appropriate for larger and more durable patterns, but in this case the form of the railing is almost symmetrical in x and y so I just imported a photo into Fusion360 CAD and traced one edge of the railing support. The traced line was dragged to fit the measured dimensions. mirrored and extruded in two planes (the extrusion in one plane was defined with a taper to produce the draft angle). The model had to be separated into two parts with a dowelled fit because of the 300mm max height of my 3D printer, but little more than pressing go to print and coming back 10 or so hours later to collect each print. There is virtually no smell from PLA plastic printing but even if using slightly smelly ABS plastic, the printer is in a well ventilated cellar and I was elsewhere. Some overhanging regions which had support towers beneath them were less than a perfect finish, so needed a bit of sanding and filling.

Andrew.

[Andrew Entwistle]

On Andrew Entwistle Said:

Anyway the cost for casting the the three 7 kg 400 mm high pillars was only £120 including VAT.

I would say that’s an absolute bargain. They look great, a credit to everyone involved

[Author]

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