mmmm why - Printable Version +- MetalworkingFun Forum (http://www.metalworkingfun.com) +-- Forum: Machining (http://www.metalworkingfun.com/forum-5.html) +--- Forum: Welding & Casting (http://www.metalworkingfun.com/forum-9.html) +--- Thread: mmmm why (/thread-3373.html)

mmmm why - oldskoolron - 11-05-2016 ok so im like pete o first time casting .no problem with my furnace melts ally brass easy as but done a pour and ended up with a heap of micro holes made a couple small cylinder type moulds in my flasks done everything ive watched been told ect an they came out good not great but thatl come with practice I spose . ok so had alloy in my 1kilo gas bottle made crucible and was melting great added some Epsom salts wrapped in ally foil also added some washing soda wrapped in ally foil then once all were melted I scrapped dross of the top and poured .betwwen having the last bit of ally melt and turning off the gas was about maybe 7 to 12 mins maybe a flyshit more .so poured the ally and went in great let cool for 30 mins then broke open .geez the moisture in my greensand really drys up .put the rough bits in lathe and took a few skims off after first cut I noticed some holes so went deeper but they are all through the ally what do you ppl think I done wrong would like to sort it as I have some pattens I made of twincam rocker boxes to fit evo cheers in advance for the help/advice below the bits n holes RE: mmmm why - oldskoolron - 11-05-2016 RE: mmmm why - awemawson - 11-05-2016 Hydrogen absorption. Dry everything by heating to hot before melting, this includes tools, crucibles, ingots - everything. Pour just as soon as the melting and degassing is finished, not 7-12 mins later. Consider using a cover flux while melting. I used to degas by bubbling dry argon through the melt using a bit of 15 mm stainless steel pipe with the end sealed by flattening and a few 1 mm holes drilled in the sides. Hydrogen from water in any form of moisture is highly soluble in molten aluminium. A humid day can give you issues. RE: mmmm why - dallen - 11-05-2016 whats the Epsom salts for?? most people use sodium chloride and potassium chloride mixed 50/50 then melted, cooled and crushed for homemade aluminum flux. RE: mmmm why - oldskoolron - 11-05-2016 its easier for me to use the salts as where im at in the bush most ppl have never heard of the stuff you blokes use /recommend I watched it on a youtube vid where doubleboost/john uses it an washing soda to make a lathe wheel