Shawrco
04-13-2008, 11:03 PM
Have two Hoch nose pour moulds, one new 40 cal bpcr fm Midway that casts 375 gr and one used 45 cal that cast 420 gr. First casting session produced abysmal results. Before starting scrubbed both moulds with Bon-Ami/toothbrush, sprayed with brake cleaner and coated with Midway mould release. Got both up to temp and then tried to cast in tandem but gave that up. 40 cal did the best but bases were out of round. The 45 cal acted like it had oil still on it or something, alloy ran off sprue cutter and cavity wouldn't fill up. I was using Rowell ladle, but switched to Lyman ladle with spout that fit into sprue hole. Never got any decent boolits.
So, took everything back apart, cleaned again, made sure vent lines were clear, smoked the cavities and used sprue plate lube only. This time got the 45 going first, liked to be run hot (frosty bullets ~ 675-700 deg, 20:1 alloy). I didn't try the Rowell ladle this time - stayed with the Lyman since it had given best results in prior attempt. Bases STILL not rounding out. Ran the 40 cal at same temp, but boolits weren't frosty. Continued using Lyman ladle that fit the sprue hole, but found that I had to hold the ladle firmly up against the hole for a few extra seconds, then release pressure a little so that alloy flowed off the sprue plate. Same problem as 45 mould, bases not filling out completely.
This is noticeable on one side or the other - have good fill out on one half and the other has is a noticeable out of round spot.
Not sure what's causing this as this is my first experience w/nose pour moulds. I don't know if it helped any, but since I was having trouble with getting the alloy to go in the hole and fill the cavity, I broke the top edges of both moulds under the top sprue plate to help venting. Do I need to do the same thing on the bottom edges? Or, is the alloy not getting in fast enough? Or what?
The weight variance on the 45 was quite large, about a 4 grain spread, but the 40 cal did very well, +/- .75 grain or so. Temp stayed pretty constant between 675-700 deg. I use a big cast iron dutch oven on a propane "camp" stove arrangement and one of Bill Ferguson's thermometers.
Thanks in advance.
So, took everything back apart, cleaned again, made sure vent lines were clear, smoked the cavities and used sprue plate lube only. This time got the 45 going first, liked to be run hot (frosty bullets ~ 675-700 deg, 20:1 alloy). I didn't try the Rowell ladle this time - stayed with the Lyman since it had given best results in prior attempt. Bases STILL not rounding out. Ran the 40 cal at same temp, but boolits weren't frosty. Continued using Lyman ladle that fit the sprue hole, but found that I had to hold the ladle firmly up against the hole for a few extra seconds, then release pressure a little so that alloy flowed off the sprue plate. Same problem as 45 mould, bases not filling out completely.
This is noticeable on one side or the other - have good fill out on one half and the other has is a noticeable out of round spot.
Not sure what's causing this as this is my first experience w/nose pour moulds. I don't know if it helped any, but since I was having trouble with getting the alloy to go in the hole and fill the cavity, I broke the top edges of both moulds under the top sprue plate to help venting. Do I need to do the same thing on the bottom edges? Or, is the alloy not getting in fast enough? Or what?
The weight variance on the 45 was quite large, about a 4 grain spread, but the 40 cal did very well, +/- .75 grain or so. Temp stayed pretty constant between 675-700 deg. I use a big cast iron dutch oven on a propane "camp" stove arrangement and one of Bill Ferguson's thermometers.
Thanks in advance.