Author Topic: Hi from Anglesey North Wales  (Read 2666 times)

Offline llionellis

  • Full Member
  • ****
  • Posts: 12
Hi from Anglesey North Wales
« on: April 17, 2018, 12:27:02 PM »
I should have introduced myself earlier, apologies for barging in on you all.
I am a retired maintenance supervisor having worked mostly in power stations. My apprenticeship was with English Electric where fortunately all aspects of mechanical engineering were taught. From basic machining and hand fitting to heavy machine installation and commissioning. (mostly gas turbines and nuclear reactor stuff in my case)
I have a small engineering workshop in my garage where I can indulge myself in model making and toolmaking. My latest project involves attempting to produce aluminium sand castings. Little success to date but I keep trying.
The machines that I have are:- Boxford lathe, BCA mill/jig borer. high speed sensitive pillar drill, large pillar drill, mig welder, MMA welder, horizontal and vertical bandsaws and boxes full of hand tools.

Offline Alyn Foundry

  • Full Member
  • ****
  • Posts: 1653
  • North Wales, Great Britain.
Re: Hi from Anglesey North Wales
« Reply #1 on: April 17, 2018, 12:52:33 PM »
Hello there.

A fellow Welshman welcomes you to MEM. Sadly " dim siarad y cymreag "

I'm pleased to read you're into casting, feel free to ask for any advice.

Cheers Graham.

Offline llionellis

  • Full Member
  • ****
  • Posts: 12
Re: Hi from Anglesey North Wales
« Reply #2 on: April 17, 2018, 12:57:12 PM »
Hello there.

A fellow Welshman welcomes you to MEM. Sadly " dim siarad y cymreag "

I'm pleased to read you're into casting, feel free to ask for any advice.

Cheers Graham.
Thank you fellow Welshman. You might regret the invitation for advice re casting!

Sent from my Lenovo TB3-850F using Tapatalk


Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 15294
  • Hampshire, england.
Re: Hi from Anglesey North Wales
« Reply #3 on: April 17, 2018, 01:06:27 PM »
 :hi:

So what type of model engine are you trying to produce castings for  :naughty:

Jo
Enjoyment is more important than achievement.

Offline llionellis

  • Full Member
  • ****
  • Posts: 12
Re: Hi from Anglesey North Wales
« Reply #4 on: April 17, 2018, 01:23:56 PM »
At the moment I am trying to produce a base for an open crank single cylinder 4 stroke I.C. engine. I have produced some drawings and a pattern. I am not happy with the mould yet, my problem seems to be with the green sand. I will continue to refine it and if I am successful I will post something on here. It's not always the end product that is important to me, it's the route taken to get there. The route is seldom straight, the deviations can be interesting even if the destination is never reached.

Offline b.lindsey

  • Global Moderator
  • Full Member
  • *****
  • Posts: 13860
  • Dallas, NC, USA
    • Workbench-Miniatures
Re: Hi from Anglesey North Wales
« Reply #5 on: April 17, 2018, 01:29:43 PM »
Hi and welcome to the forum. I hope your continuing adventures with casting will ultimately prove successful.

Bilk

Offline Alyn Foundry

  • Full Member
  • ****
  • Posts: 1653
  • North Wales, Great Britain.
Re: Hi from Anglesey North Wales
« Reply #6 on: April 17, 2018, 01:53:41 PM »
Hello again.

The term " greensand " is sand tempered with water to help bind the grains to form around the pattern. Obviously the amount of water is critical, too little and poor binding too much and the mould can literally explode from the steam that's generated.

I'm using " Mansfield Red " with some Bentonite milled in. This sand is now well over 30 years old and still gives perfect results.

The " squeeze " test is a method of judging the temper, take a small handful of sand and tightly squeeze it. Relax and if little to no grains have stuck to your palm then the sand is wet enough to bond but dry enough to use safely.

Pleased to read you're into IC engines, been my interest for many years.

Cheers Graham.

Offline llionellis

  • Full Member
  • ****
  • Posts: 12
Re: Hi from Anglesey North Wales
« Reply #7 on: April 17, 2018, 03:30:22 PM »
Hello again.

The term " greensand " is sand tempered with water to help bind the grains to form around the pattern. Obviously the amount of water is critical, too little and poor binding too much and the mould can literally explode from the steam that's generated.

I'm using " Mansfield Red " with some Bentonite milled in. This sand is now well over 30 years old and still gives perfect results.

The " squeeze " test is a method of judging the temper, take a small handful of sand and tightly squeeze it. Relax and if little to no grains have stuck to your palm then the sand is wet enough to bond but dry enough to use safely.

Pleased to read you're into IC engines, been my interest for many years.

Cheers Graham.
Hi.
My green sand is kiln dried play sand with powdered cat litter (bentonite) mixed in and watered. Not sure about the squeeze test. I thought it was ok but now not too sure, may be a little too dry. When I part the boxes and remove the pattern inevitably some of the sand breaks away somthat the edges are not crisp. I have increased the radii etc on the pattern. Better but not worth trying to cast as yet. With experimentation I will get there eventually. Any suggestions welcomed.

Sent from my Lenovo TB3-850F using Tapatalk


Offline Jasonb

  • Full Member
  • *****
  • Posts: 9466
  • Surrey, UK
Re: Hi from Anglesey North Wales
« Reply #8 on: April 17, 2018, 03:44:40 PM »
How smooth a finish do you have on the patterns and what are they finished with. Also are you dusting the patterns to stop the sand sticking?

J

Offline llionellis

  • Full Member
  • ****
  • Posts: 12
Re: Hi from Anglesey North Wales
« Reply #9 on: April 17, 2018, 03:48:29 PM »
How smooth a finish do you have on the patterns and what are they finished with. Also are you dusting the patterns to stop the sand sticking?

J
The finish on the pattern is quite good, painted with an oil based paint and waxed then dusted with talcum powder.

Sent from my Lenovo TB3-850F using Tapatalk


Offline Alyn Foundry

  • Full Member
  • ****
  • Posts: 1653
  • North Wales, Great Britain.
Re: Hi from Anglesey North Wales
« Reply #10 on: April 17, 2018, 04:25:29 PM »
Hello.

We're a friendly bunch here, I'd really like to address you personally.

Regarding the use of Talcum powder it does have a tendency to grab at the water and go sticky, I'm pretty sure there are some suppliers still out there selling small quantities of " parting powder " ?

Foundry sand is different to " other " sand insofar as the grain structure is very irregular, it kind of locks to itself the Bentonite adding to this.

You can also make DIY Gas bonded sand using Sodium Silicate ( egg preserver ) .... Mix dry sand and SS together to a texture not unlike your present mix, mould the sand around your pattern then using some Carbon Dioxide gas inoculate the sand. This is a similar process that's used on a much larger scale in modern foundries. Gas bonded moulds rarely have breakage along parting lines and, sand grain size dependent, can produce really fine definition.

Cheers Graham.

Offline Jasonb

  • Full Member
  • *****
  • Posts: 9466
  • Surrey, UK
Re: Hi from Anglesey North Wales
« Reply #11 on: April 17, 2018, 04:41:52 PM »
Some oil based paint can take a long time to go hard even though it feels dry so this may not help, a modern waterbased quick drying one is probably better.

You could also try an oilbound sand which won't need anything mixing in or water added, these people do a lot of small amounts so not too pricy to try things out. The small amount of casting I did in the past was with petrobond.

https://www.artisanfoundry.co.uk/?cPath=29&sort=2a&page=1

Offline llionellis

  • Full Member
  • ****
  • Posts: 12
Re: Hi from Anglesey North Wales
« Reply #12 on: April 17, 2018, 04:49:28 PM »
Hello.

We're a friendly bunch here, I'd really like to address you personally.

Regarding the use of Talcum powder it does have a tendency to grab at the water and go sticky, I'm pretty sure there are some suppliers still out there selling small quantities of " parting powder " ?

Foundry sand is different to " other " sand insofar as the grain structure is very irregular, it kind of locks to itself the Bentonite adding to this.

You can also make DIY Gas bonded sand using Sodium Silicate ( egg preserver ) .... Mix dry sand and SS together to a texture not unlike your present mix, mould the sand around your pattern then using some Carbon Dioxide gas inoculate the sand. This is a similar process that's used on a much larger scale in modern foundries. Gas bonded moulds rarely have breakage along parting lines and, sand grain size dependent, can produce really fine definition.

Cheers Graham.
Thanks for the info Graham. I did some casting in tech during the dark ages. I was wondering if the talc could be absorbing some of the water. My pattern is very basic, but the crank bearing area is maybe a bit too long and thin. The Co2 technique is interesting and if my pattern was more complicated then I would give it a go. I'll have a look for some parting sand first.

Sent from my Lenovo TB3-850F using Tapatalk


Offline llionellis

  • Full Member
  • ****
  • Posts: 12
Re: Hi from Anglesey North Wales
« Reply #13 on: April 17, 2018, 04:52:33 PM »
Some oil based paint can take a long time to go hard even though it feels dry so this may not help, a modern waterbased quick drying one is probably better.

You could also try an oilbound sand which won't need anything mixing in or water added, these people do a lot of small amounts so not too pricy to try things out. The small amount of casting I did in the past was with petrobond.

https://www.artisanfoundry.co.uk/?cPath=29&sort=2a&page=1
Thank you for that, I will look into it tomorrow. Just had a minor opportunity on my tongue a few hours ago. Kind of suffering at the moment

Sent from my Lenovo TB3-850F using Tapatalk


Online Kim

  • Global Moderator
  • Full Member
  • *****
  • Posts: 7860
  • Portland, Oregon, USA
Re: Hi from Anglesey North Wales
« Reply #14 on: April 18, 2018, 05:51:18 AM »
Hi Ilionellis,

I know nothing about foundry work, but do want to say, Welcome to the forum!

Kim

 

SimplePortal 2.3.5 © 2008-2012, SimplePortal