collection of my projects

dallen
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Re: collection of my projects

Post by dallen »

yea that is a problem, but you will also notice that there are no alignment pins either, when they are added i will probably add in some thing to help hold the sand in with, say a strip of 1 X 1/4 aluminum flat bar on two sides should do it.

I really wasn't thinking when I made the pattern, it was more of a lets see if I can do this, the pattern is still too hard to pull from the sand what I need to do it pitch it, and start over and build the thing on a board that way I could have ribs on the backside to help hold the sand. If I had a router table I would just run these plates across it and cut a couple of grooves in them.

I guess what could be done is that once the part is molded is to just take and cut a couple grooves in the sand on what will be the inside, as long as the other side is flat it won't hurt the clean up in the mill to cut all the draft off of them specially on that one end that makes a right angle.
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Harry
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Re: collection of my projects

Post by Harry »

If you plan on casting many more of them I would make the matchplate... I even mount flat backed patterns on mtachplates because it makes molding go so much easier and quicker for me but for patterns that end up in both the cope and drag it is really a huge benefit.
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Nudge
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Re: collection of my projects

Post by Nudge »

Harry, when you use a matchplate what is the best way to lift the cope... do you rap the side of the matchplate before lifting, I having a hard time with one of my wheel patterns "letting go" the sand :evil: the pattern has a 3deg draw in it but has a lot of area to grab the sand. Any ideas
I like to build "Stuff" using Stuff that costs Stuff All!
dallen
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Re: collection of my projects

Post by dallen »

Harry wrote:If you plan on casting many more of them I would make the matchplate... I even mount flat backed patterns on mtachplates because it makes molding go so much easier and quicker for me but for patterns that end up in both the cope and drag it is really a huge benefit.

Harry Yes I was thinking the same thing with it on a match plate I can put some ribs on the inside of the part or the backside of the plate so that the sand will have some support and they will help vent the mold when its poured.
Nudge wrote:Harry, when you use a matchplate what is the best way to lift the cope... do you rap the side of the matchplate before lifting, I having a hard time with one of my wheel patterns "letting go" the sand :evil: the pattern has a 3deg draw in it but has a lot of area to grab the sand. Any ideas
Nudge vibrate the plate, you need something to hold up against the edge of the plate that will vibrate it. A small air powered vibrator would work good.
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Harry
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Re: collection of my projects

Post by Harry »

Hi Nudge, the most I ever do for pulling the cope is rattle the whole flask a little on the bench dogs. One thing I do if I have any troubles with a pattern is brush on graphite getting a good coat on the edges, sprinkling parting dust over a pattern doesnt do much for steep sides. You can also brush on whatever parting compound you use if you dont have plumbago and it will help.

Davids suggestion sounds like it would work great. Also have you tried ramming it harder or lighter? Sometimes varying this has helped me with a troublesome pattern. Last thing is super smooth on the pattern, good sand that picks up detail well will lock into the smallest deviations on the pattern.

My jolt squeeze is supposed to have jolt and vibrate but the jolts has never worked and the vibrate is rather weak. Some day I will tear all of that down and see if I can figure out what is wrong with it.

The other thing is that even with 3* that 3" is a long pull, long pins on the flask would help in pulling that.

David, the ribs would probably be a good idea. That size the sand may well hold in for you but I can tell from experience it is very frustrating when you spend 15 minutes making up a 15" flask and it falls out when you are closing it. This has happened far too many time to me, not from losing grip on the outside though but from using the backing blocks in my molds. I am ending up with about 2 to 2 1/2" of sand in the flask and the 15" spread takes its toll if I take too long closing especially if it was not rammed just right or if I take a little too long lining up the pins.
I'd rather laugh with the sinners than cry with the saints the sinners are much more fun...
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dallen
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Re: collection of my projects

Post by dallen »

yea its always someting, like this flask if I cast something on the inside surface it could end up in the way of machining the things or like drilling them so I can use the same part but in a smaller configuration.

Steve Chastian has in one of his books a vibrator that he made and hooked up to his molding table or something I can find the book and see about scaning the revelant pages, if Nudge wants a look. Air vibrators are pretty simple you have a steel ball running around in side a part like a donut, the air comes in one side thru an orfice and out the other side and the steel ball say 3/4" gets spun around and around the more air the more it vibrates.

I have a solution figured out for this flask I am going to just get some expanded metal and pop rivet it in to the plates so that the sand will have a grip, or just bolt in a short piece of say 1/2" angle. I just have to get the material to do it with.

still waiting on the damn bearings that I ordered up for the wheel they haven't arrived yet and I lost the outfit website when My desk top crashed.



David
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Nudge
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Re: collection of my projects

Post by Nudge »

Steve Chastian has in one of his books a vibrator that he made and hooked up to his molding table or something I can find the book and see about scaning the revelant pages, if Nudge wants a look. Air vibrators are pretty simple you have a steel ball running around in side a part like a donut, the air comes in one side thru an orfice and out the other side and the steel ball say 3/4" gets spun around and around the more air the more it vibrates.
Sounds good to me :) I thind I know how it is done.. but it would be good if you could post a pic thanks (maby in a different thread) thanks
still waiting on the damn bearings that I ordered up for the wheel they haven't arrived yet and I lost the outfit website when My desk top crashed.
That is a real bummer... I bet you have already payed for them too :evil:
I like to build "Stuff" using Stuff that costs Stuff All!
dallen
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Re: collection of my projects

Post by dallen »

the vibrator is pretty simple, its based on a 5/8 steel ball running around inside a piece of two inch pipe thats been casted into an aluminum housing, so the ball doesn't run on aluminum. the air comes in one side thru like a 1/8 inch orfice and out the other side, the loop thats made inside looks like a loop on a roller coaster. its only a couple pages I'll scan em or scratch someing out on paper to give you and idea and send it to you.
I don't get it to you by tonight give me a little reminder tap on the brain pan.
still waiting on the bearings I don't get them by tomorrow I'm going ot the bearing house and get something and make it work, I gotta get this thing working, I have to much time and money in it to let it sit and not get some sand or something out of it.

David
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If life seems normal your not going fast enough" Mario Andrette
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Harry
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Re: collection of my projects

Post by Harry »

Here is a PDF that shows a commercial design. Looks quite simple, I dont know if the steel raceway would be needed or not... I mean how much wear is really going to happen in this thing?

I do agree though that this is going to make for a nice project in its own thread. This will be a very nice foundry tool to have on the molding bench.
I'd rather laugh with the sinners than cry with the saints the sinners are much more fun...
Muller
dallen
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Re: collection of my projects

Post by dallen »

I guess this is where I should put these pictures as I was going to put em in the my molding bench but I lost all that I had typed so heres the pictures of the fan blade that I casted today same blade as before just a better casting, not perfect just better.


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Two things I know one the back side wasn't rammed up like it should of been, two the melt was on the cold side, or I was using too thick of a flask, I need to cut me off a could pieces of that 8 inch pipe and square it up in on the lathe and weld on some handles and pins for something like this insead of using one thats four inches deep, thats a lot of sand to ram up, and I don't have an air compressor big enough too use a air hammer with a large tamper foot.
David and Charlie aka the shop monster

If life seems normal your not going fast enough" Mario Andrette
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