THis will get some discussion. I can hear it now, I don't want to put black stuff on my nice new, shiny custom aluminum mould. I want it to look purty.
Was much the same way myselt until I was taught different by an "in the know " old timer. Felix Robbins to be exact.
I'm basically an iron mould man. I've owned NEI aluminum moulds, some Lee aluminum moulds, a few brass moulds and even a couple of old bronze Yankee moulds. I'd rather pay extra for a meehanite mould over aluminum and have put my money where my mouth is.
Back to coatings. There are many out there. I have used two different ones. Graphite based and spray moly. Both work equally well but moly tends to outlast graphite based by far. Both will discolor a nice, shiny aluminum mould. I would much rather have a discolored mould than one that don't cast well.
I'll talk basically moly here. Procedures apply between the two.
Why do we coat moulds? To make 'em cast better obviously.
I was once skeptical about coating unti Felix took me under his wing and educated me. Had a shooting partner named Petey that was a custom jeweller. We got into this together on the coating. Both of us had the desire and he had tools to enhance our studies namely high magnification viewing devices.
Mould blocks when cut are full of very minute flaws. Cutting is not the smooth process that we envision when looking at it with the naked eye. It's cutting, tearing and gouging and to be truthfull, leaves holes, gaps and cavities in the cavity of your mould. Aluminum is especially bad. When you cast, these places fill with lead and aggravate the process of the cast bullet releasing from the cavity.
If you doubt me, take a 10X or more powerful magnifier under a good light and look.
The only solution is to fill these holes, gaps and crevices. Mould lube is the solution; black stains or not.
Moly is easy to work with as is graphite. Both messy.
Heat the mould to casting temperature. Let cool until you can spay and it dries instantly. Do cavities about three times with a few minutes dry time between. Do top of mould about three times and underside of sprue plate about 3 times. This will eliminate smearing if you open sprue plate too soon. Set mould aside and let dry for several hours.
The holes are now filled. Take an exacto knife and some soft pine splinters and a good light. First take the exacto knife and clean out mould vent lines or you will have venting problems. Expect as cast diameter to be a bit bigger after this procedure. Won't hurt to get spray on mould faces. Next sharpen pine splinters and carfully burnish the inside of the cavities until all excess moly has been removed. Cavities will be burnished black and shiny. Repeat this operation later paying careful attention to the bands and corners.
Fire up the pot and give it a try. If you've done the procedure right, the mould will drop bullets like shelling peas.
Notice I said do all surfaces of the mould. This is on iron moulds. Only cavities and sprue plates on aluminum moulds.
On iron moulds, this prevents surface rust on outside of moulds and I normally give a couple of squirts outside after I shut down pot while mould is hot.
This is the procedure that Felix recommended step by step on balky moulds and it works from my experiences. If you don't mind a few black stains it will make your casting chores considerably easier./beagle
Was much the same way myselt until I was taught different by an "in the know " old timer. Felix Robbins to be exact.
I'm basically an iron mould man. I've owned NEI aluminum moulds, some Lee aluminum moulds, a few brass moulds and even a couple of old bronze Yankee moulds. I'd rather pay extra for a meehanite mould over aluminum and have put my money where my mouth is.
Back to coatings. There are many out there. I have used two different ones. Graphite based and spray moly. Both work equally well but moly tends to outlast graphite based by far. Both will discolor a nice, shiny aluminum mould. I would much rather have a discolored mould than one that don't cast well.
I'll talk basically moly here. Procedures apply between the two.
Why do we coat moulds? To make 'em cast better obviously.
I was once skeptical about coating unti Felix took me under his wing and educated me. Had a shooting partner named Petey that was a custom jeweller. We got into this together on the coating. Both of us had the desire and he had tools to enhance our studies namely high magnification viewing devices.
Mould blocks when cut are full of very minute flaws. Cutting is not the smooth process that we envision when looking at it with the naked eye. It's cutting, tearing and gouging and to be truthfull, leaves holes, gaps and cavities in the cavity of your mould. Aluminum is especially bad. When you cast, these places fill with lead and aggravate the process of the cast bullet releasing from the cavity.
If you doubt me, take a 10X or more powerful magnifier under a good light and look.
The only solution is to fill these holes, gaps and crevices. Mould lube is the solution; black stains or not.
Moly is easy to work with as is graphite. Both messy.
Heat the mould to casting temperature. Let cool until you can spay and it dries instantly. Do cavities about three times with a few minutes dry time between. Do top of mould about three times and underside of sprue plate about 3 times. This will eliminate smearing if you open sprue plate too soon. Set mould aside and let dry for several hours.
The holes are now filled. Take an exacto knife and some soft pine splinters and a good light. First take the exacto knife and clean out mould vent lines or you will have venting problems. Expect as cast diameter to be a bit bigger after this procedure. Won't hurt to get spray on mould faces. Next sharpen pine splinters and carfully burnish the inside of the cavities until all excess moly has been removed. Cavities will be burnished black and shiny. Repeat this operation later paying careful attention to the bands and corners.
Fire up the pot and give it a try. If you've done the procedure right, the mould will drop bullets like shelling peas.
Notice I said do all surfaces of the mould. This is on iron moulds. Only cavities and sprue plates on aluminum moulds.
On iron moulds, this prevents surface rust on outside of moulds and I normally give a couple of squirts outside after I shut down pot while mould is hot.
This is the procedure that Felix recommended step by step on balky moulds and it works from my experiences. If you don't mind a few black stains it will make your casting chores considerably easier./beagle
