I am casting my own manifold this summer and I have been doing HELLA research the past 2 months. If everything goes on schedule I will have a polyester prototype by August and an experimental Aluminum setup by the end of September for my 287 PONTIAC. I have had a few people give me some advice and imput so far and I still have plans to talk with a few more here in KC. If I get it right I am going to do all one off pieces for the mill. Valve Covers, Air Filter and whatever else is in my control! I am using the 287 for practice but I want to also get some 389 and 400 PONCHO heads to cast a setup that could really kick some serious ****. I hav e done tons of research on GREEN-SAND casting and have had a bit of experience with it. The other option I have been looking into in GYPSUM plaster casting. Its used by companies that make prototype parts and small run (1 to 500 pieces) jobs. Has anyone had any experience with casting aluminum in a plaster mold? Any help would be greatly appreciated!! Cody
Does anyone try the "lost wax method"? Worked in a foundry when I was a kid. If you could make a part out of casting wax, you could cast it. Used to make simple things like knives and skulls. Just a thought?......OLDBEET
The issue with doing lost wax is that the wax pattern would have to be two peices in order to get the hollow runners. Not much of a problem really. Just more work. You could really fine tune the intake internal textures too . Biggest issue is getting the wax into the mold pattern mold. Injectors aren't cheap. But if you have a pattern a good foundry should be able to do that for you.
Well with lost wax you would make your shape in two pieces out of a latex mold surrounded by plaster. That would be the easier way to go in the garage. Then join the two halves together. Then things get triky. To keep the quality where you would want it you would need to attach a Sprue (a wax shape in the form of a funnel) the n you need to dip it in a ceramic slurry about 8 times letting it dry inbetween. From there you need to put it in an oven hot enough to melt out the wax and bake the ceramic, so you need kiln temperatures. With a manifold you just exceeded your space you might have in your backyard furnace to melt your aluminum. If the temp is controlled right this would work for smaller parts. You would want to make sure that the wax that was melted out in the furnace has drained out of your cleanout hole in the furnace so it won't interact with your metals.(I don't know if the interaction would do anything but it doesn't seem like a good idea.) After that you need to make a box(also called a flask) and place the ceramic piece in it you will need to adjetate the flask while you add the green sand so it will settle and hold the ceramic mold while the metal is heating it up again. From there you break the flask appart and extract the poured shape. The ceramic coat will still be on it so you will have to bead blast it. From there you have your contacting surfaces machined, and your bolt holes marked and drilled. With Green Sand you just skip past a few steps except you have to make cores(the pieces that will be removed) these will become your phlumes when the piece is finished. You would have to make a mold to remake the cores everytime. Anyway I was hoping plaster Gypsum would be a reusable mold where I would just have to make new cores for each manifold. With sand you make a new mold with each pour.
DAAAMMN!! If you get a custom 350/400 intake made You better post it up here. I might be into buying one of those bad boys. Especially if it looks rad.
I am shooting for a 4 - 2 barrel setup with an optional SUPER SECRET® riser that would put the carbs setting above your hood (ment for a 28 Ford hoodless project when I get the space and money)
At the foundry I worked at "PRECISION CAST PARTS" , we would make a wax part exactly like the finished part (leave a little meat to be milled later for example, carb and head surface). Add some "gates" of wax to let the air out when pouring, and a funnel to fill. Dip the part in wet ceramic then white sand a couple times. Bake the whole works.Break the tips of the "gates" to let the hot wax run out. Pour the metal, cool, tumble to break the ceramic, cut off the "gates". (Picture a part that looks somewhat like a porcipine) Mill machined surfaces, bead blast=finished part the short version. And by the way, you "LOST the WAX"........OLDBEET
OLDBEET, I might just have to rethink my strategy. Did you cast anything in size similar to a manifold? Did you stick the part in a flask after the ceramic and sand? Would I need to for a part the size of a manifold? If I tried this method, what should I make the phlumes out of so they can be removed? Thanks for your help by the way!!
I did 20mm cannons, Transmission cases for Boeing, hip joints and sockets for surgery, all of stainless steel, impelers and anything else that couldn't be sand cast. Its been over 40 years ago, but I think the method is about the same. You can do cute little skulls with the ones they sell at holloween (the wax ones with juice in them)with a little fix-all and silver solder, and the wifes oven. I'm sure there is a site that goes into detail, or someone here does it..........OLDBEET
Maybe Dennis from O'Brien Truckers can comment, but I always thought that aluminum shrunk a bit after the casting was poured and it cooled, and you had to factor that into the form/mold, especially for casting precision close tolerance parts like intake manifolds.
A lot of engine blocks and other parts are being done with a "lost Styrofoam" process. similar to lost wax but the foam stays in till you drop the molten meal on it and then it just vaporizes letting the metal into the void as it does.
KCsleds, I am a member of this group: http://groups.yahoo.com/group/hobbicast/ on yahoo. These guys can help. A few of them are working on manifold projects (straight 8). The time honored method for intake manifolds is working with matchplates and a core (the main pattern is split and each section glued to a board for ramming - then a core is inserted for the pour). For cores, I use Sodium Silicate (or liquid gl***), in a core box and solidified with CO2, works great! PLEASE keep us posted on your progress!!! whizzerick - Foundry Fanatic. P,S: Remember to take into account that AL will retract 5/32 a linear foot when cooling. That's a LOT . Hence the matchplates should be overbuilt.
DrJ, lost foam works GREAT! I've done a few pieces using 1 inch 'blue' foam in green sand. You can build with a hot glue gun or sculpt into the foam. Most engine blocks now start off as foam engines (foam is injected in a die) and are sandcast under pressure in huge pressurized tanks. Neat'o! WZrick
[ QUOTE ] especially for casting precision close tolerance parts like intake manifolds. [/ QUOTE ] Anything important gets machined after the casting has cooled.
Anything important gets machined after the casting has cooled. I know that, but I had a friend who worked in a local foundry that would do "one off" pieces for local inventors, and a few of those customers did not take into account the shrinkage and were all kinds of pissed off after they got their part that AFTER the machining was not going to fit their application. They "thought" they had left enough "extra meat" on the form that the machining would get it "spot on", not taking into account the aluminum casting reducing in size as it cooled.
I have had an interest in the lost wax technique for casting and have bought a few books on the subject but have yet to try it. There is a show on the Travel Channel with Norm from "Cheers" called "Made in the USA"...one episode that I happened to see was filmed at the Ruger Firearms factory. They molded pistols from wax and then dipped them in ceramic slurry, just like Beet described. They put these slurry-dipped pieces into the oven where the wax melted out and the ceramic baked to a hard mold. While the ceramic was still glowing hot they poured the molten metal into the ceramic molds. I thought that it was rather ingenious how this was doen, especially pouring the molten metal into the red hot molds which ensured that the metal didn't set before all the cavities in the mold were filled. The ceramic was then broken off the cast pistol bodies leaving an amazingly smooth surface on the parts...very little machining was necessary before these parts were ***embled.
if you use hard and brittle casting wax and keep it cool, it'd hold up. the issue with wax is often that if it isn't the above-mentioned, it'll sag if left in warm temps. we do sculpture, so we often use red (softer wax) because it is easier to work with and doesn't crack as easily. if you use ceramic, burn at 1500 degrees for an hour to melt the wax out, and burn for another hour to vaporize any other **** in the mold. makes em CLEAN. we alway reheat the molds as we generally take a whole day to burn out and the next to pour. to prevent cracks in the ceramic from wax expansion during burnout, we drill 1/4 inch holes in the ceramic around the sprues (no more than two per, usually just one) and occasionaly one or two on the piece. we do life sized and above statues mostly, so a drill mark here or there is easily covered up, especially if it is on a seam where two pieces will be welded together, like a thigh to a knee, etc. there is a product that looks like thick oatmeal that we use to plug these holes, as well as refractory cement. the oatmeal stuff should be heated with a torch to set it, though the reheating would likely take care of it. bronze can shrink, usually have the most problems with it on thick m***ive areas where it can pull away from the form of the mold as it cools. i did a small aluminum casting, didn't notice much shrinkage but i'm sure it did some. after you pour, i'd suggest letting the pieces cool overnight in the mold, as the ceramic often cracks off on its own very cleanly if you have a smooth piece. good luck! oh, and i think that made in america show came to my dad's business partner's gallery. heard about it, never saw it so i don't think they've released it yet.
The project is in super slow motion right now. But is still progressing. This is where I am currently at with the design mostly on paper right now. Although I did get this rendering done. You will have to pardon my spelling. I could not for the life of me remeber the word plenum. It came out as pflume (like a log ride at Disneyland). Anyway lots of more research on my part needs to be put into the runner tapers and everything else. But the link below is where the concept is at. http://www.jalopyjournal.com/forum/showthread.php?p=515619#post515619 I have decided on a large tilting furnace plan made with a 55 gallon drum. It should hold enough Al to pour a manifold with some to spare, I hope. As far as the casting method I am still undecided. The mill it was origonally for has p***ed hands as well but I still plan on working a design for a 389 poncho. Maybe a 401 nailhead too. I just think that there would be less machineing on a manifold that isn't also the valley pan. Cody
Also I have come to the conclusion that the more I research the more indepth the undertaking really is and the less I really know. That is the reason why I am undecided on the casting method. Lost wax, greensand, gypsum molds. They all seem to have their own intricacies in their processes. It will probably come down to a just do it kind of at***ude, and keeping a book with detailed notes on my setup, successes and failures.
Ya that is one of the things that I have thought about alot. There are aspects that I just don't know where to turn for information. I got a couple of good engineer links but for the most part what they talk about is way too advances for this style project. Well, maybe just way too different than how my mind processes information. I think that I need information like this http://auto.howstuffworks.com/question517.htm so I can visualize the content. The engineers couldn't put the information in a less technical jargon. I hope that I can figure out the logistics myself but I might end up outsourcing that part of the project if I can't figure it out.
Too many "Engineers" just talk a good story to confuse people, and then just fake it. Or get the guy on the shop floor to figure it out for them, and then p*** it off as their idea. ----------------- Sounds like you have 2 basic problems, each of which has it's own sub-problems. #1 How to make the part ? - making patterns,gates,vents,etc. - casting - machining #2 How well will it run ? - idle quality -throttle response - drivability - Horse power #1 is probably more difficult than it sounds. #2 you will probably just have to try it,and see what happens. It's hard to tell exactly what you've got planned,but I would want the floor of the runners sloping towards the head,and try to make the turn as gradual as possible.Such a tight turn is going to hurt flow,and create problems with wet flow.
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