Adjuster Nut

[dallen]

Thanks John, it did have a slight shrinkage thats hard to see because of it being pretty even across the top of the casting.

Graham, your right that big blob (I don't use a shape I just dig a cavity between the Sprue Well and the mold to act as a riser to feed the casting as it cools, only problem this time was like most of the time I didn't cut the gate big enough to feed as it should of, actually two gates would of worked better.

Goaly, the way I do my casting is from what I learned from some books I bought and posting on the forums that I belong to, a lot of people use the 1 1/4 drain tubes cause there thin and cheap. I assume that you do your gating the way you were taught which is what I would do if someone had of showed me, now I know for a fact that the way I do it isn't right cause I have one hell of a high reject rate.

With thin casting in aluminum if your having problems with them filling you probably need to use multiple gate with some vents on the far side so the metal can push the air out. I helped a guy in Tulsa pour some propeller blades that to fill the mold and all the gating it took 71 pounds of NiBrAl, it took less then 30 seconds to put that 71 pounds of metal and most of the blade was less then 3/8". How hot are you getting your metal when you pour and how big are the parts, do you have a picture.

I poured these and to get good castings I had to heat the melt to around 1350 1400 degrees

I ran the gate in at both ends and put two vents on the far side and at times I still had parts that wouldn't be full, most of the part is only a quarter inch thick.

if your pouring with a big sprue most aluminum castings can be done without a riser on a lot of casting.

real life made for purchase sprue cutters come in different sizes, the size of the sprue is one way of controlling the fill rate of the mold.

A log book either in a handwritten binder, better is on the computer with photos to show not just the good but the ugly also will help with you thin parts problem, as you said the other day with aluminum just the humidity in the air can affect how things go.

Hope I was able to help. Almost forgot the sand that I use is homemade oilbonded sand, greensand is sorta hard to use when it dries out faster then you can add water to it.