Ya http://****************.com/smile/emthup.gif Good point, Im gonna drill mine, or maybe just fit the core box on it/them the other way clamping them together. Its not too bad given you can see both ends, but on a big mould, with only the fill open then the caps are an ace idea http://****************.com/smile/emthup.gif
Ive used threaded rod too in the past on a different setup, with drinking straws pushed over the section in the upper mould.
Whatevers handy really
Nice screen name by the way http://****************.com/smile/emthup.gif
On the sand, Ive a whole pipe of cool stuff on route, you cant get damn all in Ireland, has to be shipped in
I know you've seen my core making video, in that, I didn't have any such thing for registering the two halves but, because I could also see both ends, just like you can, it really wasn't much of an issue, I just lined the two halves up visually and clamped them together. Pins or bottle caps or whatever would have made it absolutely foolproof and I think maybe I'll add that feature on my next core box.
Ya sure did, and a damn good video it is http://****************.com/smile/emthup.gif I think Ill add them too on the intake plenum core just to be sure, ill have more room too for them. Your so lucky too, to have all these chemicals to had/not too far away
I had to travel about 60 km (one way) to get my silicate, with that supplier, I was restricted to one type of silicate and not the most ideal one for this application, the manufacturer of the stuff has a location another 25 km further down the road with a much broader selection of products, I'll probably go there when I need a refill.
BTW, any estimate on how much sand you'll need to mold the cylinder head, my manifold project required about 60 kg of green sand and the core was 1.4 kg.
Definitely an outstanding thread. There was a pretty good episode on "How it's made" (iirc) where they showed the whole process of casting engine blocks start to finish.
All very cool stuff http://****************.com/smile/emthup.gif to you for this thread.
Back to the core box again for a minute, the plaster is now dry enough to remove casing so Im going to whip it off to allow it to dry further.
Top casing removed, it came off real easy due to the short pins, and probably due to using plenty of release agent.
With the bottom casing removed the two halves split very easy, I removed pattern from also.
When this are dry fully I'm going to clean off release agent and coat the mould area with lacquer to make removing the sand core easier.
You can now see the core former together, it'll will soon be ready to make some sand cores.
Ill be doing a mould mock up in a while on a random shape to check everything in the line of what the sand is like to work, the tools, and just to get a general feel for it regards cutting the gate and creating the fill sprue shape etc.
I wont be pouring this mould, its only a test run.
Then after that I'll be moving onto the flange, mounting the patterns to plate, making the sand moulds, core, and pouring. http://****************.com/smile/emthup.gif
I don't think you'll need the lacquer, I didn't coat my plaster core box with anything at all, I just very throughly cleaned off the release agent from molding process and I found that the core sand with the silicate binder pulled away from the plaster without any trouble at all.
Really? Im not going to use Co2 cure in this, just normal green sand with a chaplet pin down the centre, I may need all the release powers I can get, It should be ok though, its pretty small...
If not, ill wait for my proper sands to arrive, but I dont see why green sand shouldn't be able to pull it off on this core
For a relative small simple core like this, I think normal green sand should work okay, dust the core box with a little talc or other suitable parting compound and I think you'll get a good release
For the more complex and delicate cores you'd need for a cylinder head, I'm quite sure green sand will not be adequate. What type of core binding agents do you plan to use for those?
Oil bond along with co2 cure sand. I have to do a lot of testing yet but co2 will be my main choice. I have some talc here ill try that first, ive read though that it has to be water proof dust, like parting dust, I really dont know till I try stuff http://****************.com/smile/emthup.gif
This bit is just a fast ''get to know the procedure'' rundown for me, Im waiting for the core mould to dry out fully so I may as well. I want to see how the sand holds it shape and if I need to add more bentonite. I also want to get familiar with the tools, ramming the mould, and how easy the sand is to work when cutting the gate, removing sprue former, etc...
Its also a test as to how the sand comes up on camera and if the various shapes can be seen in it.
Everything is laid out on a clean board.
The cope and drag, the plate and the various tools. Even after studying casting for ages I still sometimes forget as to which is which with reference to the cope and drag, I remember them this way, drag starts with a ''D'' ''Down'' starts with a ''D'' also so I think of the drag as ''down'' or bottom so that kinda makes sense for me!! Im still going to call them the top and bottom flask for a while so no need to worry yet, actually, I may just write it on them so the camera picks it up to avoid confusion.
The tools used, I have seen these called different names so Im going to use the ones I know, from left to right:
The moulding trowel, The sprue former, The pattern screw(used to remove half a pattern from the sand), The mini heart trowel, The Gate trowel, and The vent wire.
The bottom flask(drag) is placed on a clean board and the moulding sand container behind it(which should be kept closed to prevent it drying out)
Its filled up a bit, paying attention to filling around the sides first.
The sand is rammed with a stick, but not too hard or this could effect the sands permeability, if its too tight the gas/steam may have trouble passing through it and the mould could rupture before the metal hardens.
More sand is added and packed.
Any excess sand is drawn off with a stick pulled along the top edges of the flask.
The parting plate is then fitted.
Of course in this mock up, I wont really be using the lower flask as I wont be pouring any metal, but its no harm to fill it to practice..
The upper flask is fitted(cope).
I placed in a random part with a bit of detail, the part has a good draft angle on the sides so it will release from mould no bother, its actually a seat winder from a Mk2.
Sand is sprinkled on first then the flask is filled around sides filling in to centre around the part.
At this point the sprue or ''fill'' former is also placed, its just a bit of tapered timber.
The sand is rammed and more is added.
Rammed again and the finishing top layer is added and packed.
Once flat or pretty flat a scoop or funnel shape is dug around riser with the trowel, this helps with the pouring and guides metal in.
Its actually hard to see it here which means Ill have to take the flange moulding pics a bit different or at a different angle to fully show things off fully, but thats what this test is for.
Once thats done the top flask(drag) is lifted off, you can now see the underside of the pattern, and the tip of the sprue former. The flask is on its edge here so you can now see how much of a hold the sand has inside it.
One thing I noticed is, some sand came out between the flask and parting plate as I rammed it, you can see it all around the edge, Im going to have to clamp the flasks together on the proper run.
Once the pattern is removed, You can see the sand detail, the shape got a bit lost when photographed so again Ill have to change the angles I take them at in the real run, but you get the idea. The detail was held very crisply so Im pretty happy with the sand.
The sprue former is now removed in a twisting action from the top, it comes out pretty easy. I cut a rough gate from the sprue to the part just to see how easy the sand is to work, it cuts real good and sand Is harder than you think!
Thats the test done, Im happy with the sand, it seems to be ok, Ill have to try photographing it a bit different for the flange run but I think I should be able to capture it a bit better. Its pretty hard see the detail in them photos.
Up next, Fixing the flange patterns to the parting plate. http://****************.com/smile/emthup.gif
So the cope's the top one, right?
So maybe... "Cope" and "Cap," the cope's the cap flask?
Correct. Cope (or a variation of it) is the word for head in several European languages, German, Dutch etc. I thinks that's probably where the word comes from. Your head's on top of your body, the cope's on top of the mold.
Here's a picture of one of my molds with a few of the parts and features labeled.
The box the mold is made is is referred to as the flask, they're usually in two pieces, top and bottom, cope and drag respectively, some more complex mold require a flask with more than two piece, the additional pieces are called cheeks.
The sprue is a hole that runs all the way through the cope, you pour the metal into the sprue, from the sprue, the molten metal goes through the runner and fills the mold and the riser.
The riser is a reservoir of metal which, if you've designed it properly is the last thing to solidify, metal shrinks quite a lot when it solidifies, the riser helps control/eliminate shrinkage defects.
The core fills selected sections of the mold cavity thus allowing hollow castings to be made.
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