incomplete pour problem

I've tried twice to pour the base to the Gingery lathe and both times
the aluminum has solidified about 8 inches from the sprue. This last
time I had mad absolutely certain that the vent holes were plentiful
and open. I was wondering if it's possibly the temperature is too
cold even though it is liquid. Also, if I put two more sprues, one on
each end, and pour there after the middle pour would that make such an
incontinuity that it would ruin the base.
Maybe I need to increase the airflow to the foundry to make it hotter.
Is there a pyrometer that I can get to check the temperature?
thanks,
Robert
If time is the 4th dimension, then money is the 5th dimension.
We are always concerned about dollars per hour for the space we occupy.

- Rod White
Reply to
Dies Deambulo
Loading thread data ...
Just keep it on the fire longer. It simply needs to be hotter. Much hotter than "just molten". If you do this at night, the metal should be glowing a reasonable amount (red; orange is way too hot).
Pouring simultaneously from two or more sprues is possible but ONLY if it is simultaneous. Aluminum will never weld to itself as you are trying. However, if both pours are still liquid when they meet, it will weld properly.
I've made worse castings than this so I know it's possible. Have fun!
Tim
-- "I have misplaced my pants." - Homer Simpson | Electronics, - - - - - - - - - - - - - - - - - - - - - - --+ Metalcasting and Games:
formatting link

- Rod White
Reply to
Tim Williams
Thanks! I'll let it simmer a bit. And weather permitting I'll try tomorrow night.
Robert If time is the 4th dimension, then money is the 5th dimension. We are always concerned about dollars per hour for the space we occupy. - Rod White
Reply to
Dies Deambulo
Yes, a pyrometer either of a thermocoup0le and meter or a regualr pryrometer thats used in fundry work is just abaout essential to make sure your metal is of the correct termp, but you can go by the seat of the pants and get a feel for it but it may mead to a few failures. As Tim pointed out its easier to see the color ar night.
When you do pour keep the fill sprue choked full until it refuses to accept any more material. Just a slight hessitation can cause a freeze, especailly if your not using a means of checking the temp and your metal may be on the cooler side, but still fluid. Fast and hard is the general rule when pouring a mold.
Visit my website:
formatting link
expressed are those of my wifes, I had no input whatsoever. Remove "nospam" from email addy.
Reply to
Roy
Dies, Consider warming the mold. The hotter it is, the less heat will be wicked out of the molten pour. Steve
- Rod White
Reply to
Steve Lusardi
great idea. Things should work a lot better here in Texas in August!
Robert
If time is the 4th dimension, then money is the 5th dimension. We are always concerned about dollars per hour for the space we occupy. - Rod White
Reply to
Dies Deambulo
What part of Texas are you in? Gary Brady Austin, TX
Reply to
Gary Brady
This Old House showed a doorknob replicator where the molds were removed from an oven just prior to the pour. Not sure how well this would work with Gingery's wooden molds though :o
Joel. phx
Reply to
Joel Corwith
Its not too good of an idea if your using water bonded greennsand either as it makes the molds dry out and get crumbly. It may work if yo use petro bond (oil bonded sands) but it really shold not matter how hot or cold it is outside if a mold is properly gated and vented, and the greensand or oil bonded sand is mixed right, and the molten metal temperature is know, which is the big thing, you can heat a bit more or heat a bit less and then pour. heating a mold is not the way to go, even if Steve or Bob says it is on this old house! It may be ok if your using an investment type mold but this fellow is probably using oil or water bonded greensand to cast a Gingery item...........
Visit my website:
formatting link
expressed are those of my wifes, I had no input whatsoever. Remove "nospam" from email addy.
Reply to
Roy
IIRC, the "This old house" show was investment casting where the mold is ceramic. Usually around 1/8" thick. The ceramic is fired at something like 2000 degrees, comes out of the oven, and is the pour is done within seconds. I've seen stainless steel done this way, mold is glowing bright orange, pour in the steel and it instantly goes incandescent.
Joel Corwith wrote:
Reply to
Roy J
Yeah, that occurred to me after the previous comment. They also had to melt the wax out and lose it {lost wax technique}.
Joel. phx
Reply to
Joel Corwith
Plano. just north of Dallas.
If time is the 4th dimension, then money is the 5th dimension. We are always concerned about dollars per hour for the space we occupy. - Rod White
Reply to
Dies Deambulo
I am using petro bond. Got it from BCS.
If time is the 4th dimension, then money is the 5th dimension. We are always concerned about dollars per hour for the space we occupy. - Rod White
Reply to
Dies Deambulo
I got a personal guided tour of a high volume investment casting house. Brass, aluminum, stainless, you name it. Pretty nifty process.
I also found the prices qouted on the TOH segment to be pretty outlandish. The shop I toured would do them for about 20% of the price quoted on TOH This would be in quantities of 20 to 50 or so.
Joel Corwith wrote:
Reply to
Roy J
- Rod White There are several member of our casting group in your area. I think it would be possible for you to see them at work and pick their brains. Our group is:
formatting link

Ron Thompson Was On the Beautiful Mississippi Gulf Coast, Now On the Beautiful Florida Space Coast, right beside the Kennedy Space Center, USA
formatting link

The ultimate result of shielding men from the effects of folly is to fill the world with fools. --Herbert Spencer, English Philosopher (1820-1903)
Reply to
Ron Thompson
Why not mix a little paste or flour with the greensand?
Reply to
Offbreed
After a short while, it will turn into a stinking moldy mess.
If the pour is freezing in the runners, it's not hot enough.
Do you have a pyrometer? I got multimeter with a type K thermocouple from my local purveyor of quality imported tools for the princely sum of $12. Pretty basic job to place the thermocouple into a bit of steel tubing to use to get actual temperatures of the metal. Or you can just continue to experiment and adjust your work to the results you get.
Too cold, it'll freeze up in the mold, too hot and you get exessive shrinkage and porosity in your castings. Thin sections require a hotter pour than thick ones.
Cheers Trevor Jones
Reply to
Trevor Jones
And what purpose do you think that would serve? Organics like flour cornstarch etc needs to be kept out of water or oil bonded greensands as in no time they get moldy and rancid. Stick with a good known proven components or way of doing things and then you do not compound things when problems creep up. Visit my website:
formatting link
expressed are those of my wifes, I had no input whatsoever. Remove "nospam" from email addy.
Reply to
Roy
Ah, the sand gets reused, then.
Reply to
Offbreed
yes, Greensand weather its water or opiol bonded is reuseable many many times..........probably never wear it out in a home shop environment. When it gets weak in strength, you add more binder and add oil or water and remull it and use it again.
So its important to not put anything that may screw up your sand in the mix. Visit my website:
formatting link
expressed are those of my wifes, I had no input whatsoever. Remove "nospam" from email addy.
Reply to
Roy

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.