Ideal Pre-heat Temperature for Moulds

[dmftoy1]

So I finally picked up a hotplate to pre-heat my moulds and while waiting for the lead to come up to temp I started playing with the infra-red thermometer, hotplate and moulds. It looks like 350-400 degree's is dead simple to get . . . what would an "ideal" temp be for a "pre-heated" mould? Would Aluminum "pre-heat" be different than Iron?

Just trying to steal from your experience! :)

Have a good one,
Dave

[Lonestar22]

Dave,
I set my hot plate at 600*F-650*F for steel and aluminum molds. The temperature range is based on how cold the garage is when I start casting. Hope this helps.
Tim

[44man]

With my little mold furnace that heats the whole mold, I use 500*.

[dmftoy1]

Thanks guys! I guess I was running it too low yesterday. (I was running it at around 380) Prior to this with the "small" molds I was preheating by dipping a corner in the melt, but with the big six banger group buy molds I had to just cast until they heated up, and that's just wasted effort.

[leftiye]

I have gotten good results with various molds at around 327 degrees - measuring the MOLD temp with an IR thermometer. I continue to control mold temp while casting with a mold heater is probly why this low of a temp will work. I would call this the lower end ballpark for having a mold warm enough. Note: You can cast with alloy as cool as just hotter than what freezes in the spout of a bottom pour furnace by this method. About 600 degrees.

[NVcurmudgeon]

Weuns who are ladle casters jest lay the mould close to the fahr.

[13Echo]

I folded a little shelf out of sheet metal to hold to blocks off of direct contact with the hot plate coils and made a small box to help hold the heat in so the blocks tend to heat soak more evenly. I have a thermometer that fits through a hole in the box to monitor the temperature. I have very good results at 450 deg F with the first or second bullet being a keeper. The hot box is also a very good place to keep the mould when doing things like fluxing. I do not like putting the mould in direct contact with red hot coils. It just seems like a good way to warp the mould and the base is going to be much hotter than the top.

Jerry Liles

[leftiye]

13 echo - That's a mold heater. Works even better if the hotplate can be thermostatically controlled too. Coils don't need to be red hot probly.