Metal Casting Zone

Gents,
i'm new here, and totally dummy about casting,
i'm building boat..and sailing boat need a heavy ballast to stand up ! my actual project need a 8300kg lead ballast..so ..i'm in the middle of nowhere in the philippines, no way to order this ballast in local foundry (they don't want to do anyway) i decided to go head and cast here...
the lead is lead alloy/antimonial 4% to get strenght, the ballast shoud be one piece.
I shape the model in foam and intent now to buried this foam inside greensand, in the ground, with strong renforcement around...the shape is lnog and flat, so the wieght is well concentrated on the ground, max hight is one foot. hope nothing will move wioth iquid lead in...
the furnace is a old air receiver, with two rotating pipe each side to act as "tape"
i intent to heat with wood charcoal/fan/ and two big gas torch.
i'm almost ready to do, but as novice..try to find more advise before any risk...
all comment and question welcome... some pict on my blog
best regards to all

wow this is a big project! welcome to the forums.are you pouring your lead into weights and "stacking" them in to add ballast??? or is it one big block???how much weight is in one pour??? you arent using the foam as lost foam ... more info please im sure we can figure something out as lead casting is really easy.

XL, thanks to reply so quickly !
i should be one pour... few will be to easy ! it's a big amount of heat and load...
i'm do the shape with foam to avoid to have a mold in two part and the plug to remove, and easy to shape and modifie, look on the blog www.fusionschooner.blogspot.com you can see the part ..in foam...!
cheer's

just been looking over your project. its a beauty. i havent heard of "lost foam" being used for lead. even when used with aluminium (700c) it has problems with gas ..vents and so on as it seems it doesnt "burnout" entirely. others here have more experience with lost foam and i will be very interested in what they say. my short term advise is dont do it yet!!! how about trying on a smaller scale first??? i would hate to see you waste your pattern. how do you propose to control your pour????that is lift and pour??? lead is easy to "weld" so doing it in sections and welding it together may be an option.if you go ahead it may be advisable to apply a ceramic shell over your pattern as the weight of the lead may "bleed" through the sand creating much cleanup work and lead doesnt grind well. i will follow this thread closely. member jammer may have some clues as he works in a steel mill.in the meantime i will try some small scale experiments .

XL,

i just use the foam to have a close mold, as i like to have the flat "contact" face down, and close mold to avoid to lost to much calorie and alow the lead to cold slower.. also, i want to almost remove all the foam before pouring the lead, using acetone solvent and insert a torch inside the cavity to pre-heat the mold, idealy i create a ..cavern.. i just wondering if the green sand will be hard enouth to keep the form?? i look now for som more hard bidder to keep the ..cavern in shape when no more foam inside....i just read about adding ?? sodium silicate ??
if i can reuse the sand for another will be fine , if not, i prefert secure the casting ... and add some ciment ??
all this is new for me..your experience will be a great +++ for me guys !!
thanks
bertho

XL,
also external surface aspect is not critical at all for me, the lead will be roughtly grinded, and epoxy fairing will follow.. no problem for that, the goal is to get one solid block in one shot... welding not reliable as to much inertial mass, all ballast for boat always cast in one shot.. i anticipate shrink in all dimensionss about 1% for this alloy..what make already 7 cm on the lenght...
regulation during pouring is conical tape with i can almost close from inside my..furnace.. but i will prefert fill as fast as possible the mold.. to get a hot mass as same temp.
i can do many large vent all along the mold and have 2 simultaneous pouring acces.
will be a fun day !!

best rgds
bertho
prefert to thinks 2..or 3 time before to melt and pour !! and will sleep better after !!

i would be happier if you were pouring it straight into a sand mold...this i can see working well if you dont mind the surface a little rough.

XXl..
do you agree for a quick pouring ? to avoid lead to cold before reach all part of the mold? it's only 378deg celcius fusion temp... and any advice to hardener the sand+clay? any good aditive to make it stronger? (i will feel confortable with a block of..concrete... hahaha !! rgds

"(i will feel confortable with a block of..concrete... hahaha !! rgds"

maybe you should consider concrete as investment. It seems like an awfully large pour for greensand. I have never worked near that volume so I may not be that helpful but I would be inclined to use a more sturdy investment and do the burnout in advance.

This project looks amazing.

FYI, here's a link that may have some good info as to methods and what it may take to do this. www.rutuonline.com/html/wheel_weights.html This guy did the same thing that you are proposing to do. Hope this helps and good luck!