Author Topic: Made without castings ???  (Read 17192 times)

Offline ScroungerLee

  • Full Member
  • ****
  • Posts: 299
  • Southwest Connecticut, US, North America, Earth
Re: Made without castings ???
« Reply #15 on: October 27, 2012, 02:32:32 PM »
Here is my take on it.

I have made a simple coal fired foundry that readily melts aluminum.  I used it twice to melt down scraps an just made ingots from them.  I was just curious to see if i could get scraps melted, they werent even clean.

The result was so porous that when I made the body for a Kerzel hit'N'miss out of one of the ingots water seeped through it.  I was greatly amused, a little JB Weld fixed the problem, but I realized how far off I am from casting a good part.  I just need to find the time to work on those skills and meanwhile using bar stock gets me easier results.

On the other side I think casting a part is cool just so I get the "look what I can do!" feeling.  Also I am a cheapskate, and for some shapes more of piece of bar stock ends up as swarf than ends up as the resulting part.  That bugs me.

So, conflicting views on my end.  Overall I want to get to be able to cast parts just for the satisfaction.


Lee

Mmmmm.... Shiny!

Offline Bezalel

  • Full Member
  • ****
  • Posts: 376
  • - Skype:Bezalel2000
Re: Made without castings ???
« Reply #16 on: October 27, 2012, 02:34:36 PM »
Hi David
 
I share your passion for liquid metal and pattern making.
I acquired the skills well before getting into making little engines in fact.
 
Most of my furnaces have been built from old 20 litre paint drums and a few bits from the local garden supply centre.
 
I have a range of different burners that I venture would challenge Dek's paradigm on fuel cost.
 
Another factor here in the UK, would be the cost of fuel. Many old folk here cannot afford to heat there homes in winter, let alone afford fuel to melt metal. :(

Cheers Dek. :old:

My preferred burner is a simple LPG burner that uses about the same amount of gas to melt 5 kg of Ali, as the BBQ does for a family get together.
 


My next preferred burner costs almost nothing for the fuel but requires a constant supply of 10 PSI of compressed air.
It is a Babbington burner, made out of a 2kg coffee can and a brass door knobb, capable of burning used engine oil straight from the sump. It does take a bit of messing around to get a smokeless flame with straight sump oil so I mix in a bit of diesel to make the oil flow better and get a smokeless  burn from start-up to shut down. But at the end of the day, I'm happy to pay for a little LPG 'coz it is a lot cleaner.
 

 

sorry can't seem to find the photos of it puming heat, these are from the construction log.

Any one who has not been bitten by the liquid metal bug is probably not likely persist with the necessary effort required for building foundry on a limited budget.
 
There is a bit of a steep learning curve but I reckon its worth it.
 
 
Queensland - wet one day, humid the next

Offline Dan Rowe

  • Full Member
  • ****
  • Posts: 752
  • Dripping Springs TX USA
Re: Made without castings ???
« Reply #17 on: October 27, 2012, 02:49:21 PM »
I do a bit of lost wax casting mostly silicon bronze. It is useful for small parts I need a bunch of.

My first casting was a simple one. I needed a 5/8" bronze bushing and I only had 1/2" stock. I had a gallon metal can with casting sand so I pushed a 3/4" rod in the sand. I used the big tip on the torch and used a hand held crucible, I poured the metal into the hole. The casting made a sound 5/8" bar.

Dan
ShaylocoDan

Offline ScroungerLee

  • Full Member
  • ****
  • Posts: 299
  • Southwest Connecticut, US, North America, Earth
Re: Made without castings ???
« Reply #18 on: October 27, 2012, 07:26:02 PM »
I need to read up on lost wax casting, somehow it seems easier to me, not sure if that is true.  Can it be used for aluminum?

Lee
Mmmmm.... Shiny!

Offline Dan Rowe

  • Full Member
  • ****
  • Posts: 752
  • Dripping Springs TX USA
Re: Made without castings ???
« Reply #19 on: October 27, 2012, 07:57:43 PM »
Lee,
The book I learned from is "Centrifugal or Lost Wax Jewelry Casting" by Murray Bovin.

I use a vacuum pump so it is really a simple form of pressure casting with the atmosphere supplying the pressure.

Aluminium should work fine but I have only cast copper alloys.

Dan
ShaylocoDan

Offline DavidF

  • Full Member
  • ****
  • Posts: 136
Re: Made without castings ???
« Reply #20 on: October 28, 2012, 12:30:18 AM »
I need to read up on lost wax casting, somehow it seems easier to me, not sure if that is true.  Can it be used for aluminum?

Lee
  I have done some lost wax aluminum castings and it does work, but I feel that heavier alloys work out better.  As far as easier then sand casting,  well lets just say small parts lost wax and large parts sand casting.  Its one of those detail and expense things although you can do large part in wax also.

Offline ScroungerLee

  • Full Member
  • ****
  • Posts: 299
  • Southwest Connecticut, US, North America, Earth
Re: Made without castings ???
« Reply #21 on: October 28, 2012, 12:43:00 AM »
Thanks for the answers.  It seems like a commitment to try sand casting, or maybe I just get overwhelmed seeing what others do.  The right sand, copes, whatever else, just to see if I can make a part I want.

Gotta start out simple somehow.  Maybe pour hot metal into Kitties litter box and see I'd I end up with metal poop shapes  :ROFL:

Lee
Mmmmm.... Shiny!

Offline DavidF

  • Full Member
  • ****
  • Posts: 136
Re: Made without castings ???
« Reply #22 on: October 28, 2012, 01:21:05 AM »
Thanks for the answers.  It seems like a commitment to try sand casting, or maybe I just get overwhelmed seeing what others do.  The right sand, copes, whatever else, just to see if I can make a part I want.

Gotta start out simple somehow.  Maybe pour hot metal into Kitties litter box and see I'd I end up with metal poop shapes  :ROFL:

Lee
Petrobond makes it easy. Just do it and try not to think too much about the materials. After all, your just making a sand castle in reverse. Start simple and the rest will just come naturally...

Bogstandard

  • Guest
Re: Made without castings ???
« Reply #23 on: October 28, 2012, 06:26:20 AM »
David,

Getting back to your opening post.

I would just love to be able to do my own casting, but limited space has always held me back. If I had the room to do it, I would be a very willing apprentice, but sadly, never to be.

But I would like to raise one point about casting and the beginner to machining.

Many beginners think that buying castings is an easy way to start into model engine making. Maybe if it is a very basic engine and all the machining instructions come with it, then you stand a chance of getting a runner.

But when you come to the more complicated castings, it can be a lot easier to fabricate the part rather than trying to machine a casting.
Once you get more into making and machining castings, then it becomes a completely new art to be mastered.

Don't get me wrong, I buy casting sets like they are going out of fashion, and this is not boasting on my part, I know how to hold and machine them to get the required result, but the average new starter can usually end up throwing a very expensive casting set under the bench because it has turned out a lot more difficult than expected.

To my way of thinking then, if you have the room, time and expected experience to machine the results, then yes, go for the making your own cast parts, but if you are new to this game, get a little experience first about how to fabricate your own bits. Just so that you don't fall flat on your face at the first hurdle, and maybe then losing interest in the whole art form that we have going here.

John

Offline black85vette

  • Full Member
  • ****
  • Posts: 348
  • Rick in Yukon, OK
Re: Made without castings ???
« Reply #24 on: October 28, 2012, 12:48:22 PM »

To my way of thinking then, if you have the room, time and expected experience to machine the results, then yes, go for the making your own cast parts, but if you are new to this game, get a little experience first about how to fabricate your own bits. Just so that you don't fall flat on your face at the first hurdle, and maybe then losing interest in the whole art form that we have going here.

John

Agree with you John.  I am just starting my first casting set having made a few engines and gained some experience.  I am finding I am needing additional information on how to do some procedures.   Having the basic skills has helped a lot but there is still quite a bit I don't know.   The biggest issue I think is starting with a piece that has no flat or parallel surfaces.   I am going slow because unlike working in bar stock, if I screw up I can't just start that part again.

To the OP;  much like others my limiting factor is space.   My "shop" in one corner of my garage and I have just enough room to turn around and work around my lathe and mill.   No room for casting.   :(

Offline DavidF

  • Full Member
  • ****
  • Posts: 136
Re: Made without castings ???
« Reply #25 on: October 28, 2012, 12:52:03 PM »
Boggs, you make a very good point about the castings being more difficult to hold on to and machine. I found my first couple of casting sets a real learning experence on how not to do things.  But one of the great things about having a home foundry is if you do screw up on machining a casting, you can just melt it back down and re cast it.

Offline metalmad

  • Full Member
  • ****
  • Posts: 687
  • Australia Skype - metalmad11
Re: Made without castings ???
« Reply #26 on: October 30, 2012, 10:05:56 PM »
Hi Dave
Learning experence is right, yesterday I made my first attempt at casting up an engine block and had a few issues.
The sand was a little too dry, I put the fill hole too close to the flask and despite the old bench vise I sat on top, the flasks seperated a little with the resault I ran out of metal and the block is half an inch too short at the sump end.
I am going to make some minor adjustments to my patterns and repour with the bulk of the mold in the lower flask this time and a lot more weight on top.
It was great fun, very exciting to do and for a first attempt not too bad, I feel I can get it much better next time.

A little bit every day, sometimes the same little bit

Bogstandard

  • Guest
Re: Made without castings ???
« Reply #27 on: October 30, 2012, 11:03:36 PM »
Pete,

Good first attempt, so you managed to get your sand sorted then?

Rick,

I am half way through a post about my machining of castings.
Everyone has their own way of doing things, this is my way.

http://www.modelenginemaker.com/index.php/topic,158.0.html

John

Offline metalmad

  • Full Member
  • ****
  • Posts: 687
  • Australia Skype - metalmad11
Re: Made without castings ???
« Reply #28 on: October 31, 2012, 03:57:37 AM »
Hi John
The sand is bit of a work in progress as I feel my way into new territory, I did another pour today with much wetter sand and although I see some shrinkage in the center, I think it is a usable block.
I'm not sure if the shrinkage is due to the wetter sand, pouring from the top or even the smaller spew, but as long as there is enough metal there for the Cam and lifters it should not worry anything.
Pete
A little bit every day, sometimes the same little bit

Offline DavidF

  • Full Member
  • ****
  • Posts: 136
Re: Made without castings ???
« Reply #29 on: October 31, 2012, 04:28:58 AM »
Thats looking good.  Wetter?  I assume your using greensand?? for shrinkage controll try using some large feeder blocks that sit up higher than the casting to supply aluminum to the block as it cools. You can also increase the hight of the sprue and riser to give more head pressure to help out with shrinkage. one last note using a known alloy like 356 gives better results than scraps. Yea I know im throwing alot out there with not alot to go on, but youll figure it out  :slap: