Casting Issues

[rodwha]

So I decided to cast a few RB's yesterday evening. I began having trouble getting my mold to heat up well enough so I did as I've often read, which is to dip the mold into the molten lead. What happened though was lead stuck to the aluminum.

And one of the chambers has some sort of dark film that imprints on the cast balls.

Eventually I noticed that the mold would no longer close tightly and left a raised ring on the balls.

I've also noticed how beaten up the top of it looks, as well as one of the holes looks like someone took a screwdriver to it or something. This is only the second time I've used.

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As you can see there is lead stuck all over it, and I'm not sure if that's lead inside the cavities or not, but why wouldn't it have melted when molten lead was poured in?

 

[Arkansas Paul]

This may be a stupid question, but how much of the mold did you dip in the molten lead? You should only dip a corner into it. If the lead was sticking to the aluminum, you didn't leave the mold in the molten lead long enough. You should leave it in long enough to come out clean.

The dark film appears to be a spray on non-stick substance like Frankford Arsenal's Drop-out or something along those lines. An old toothbrush and some hot soapy water should take care of that.

It looks like the lead on top, in the last pic is just from not letting it set up long enough.

 

[rdstrain49]

There really is no need to pre-heat aluminum molds. They heat up fast. (dipping any mold into molten lead is very dangerous, any moisture on the mold will result in a steam explosion, a very unpleasant experience) Use mold release, paraffin, silicone or the like to lube the sprue cutter. To clean your mold, you may have to heat it with a torch (careful you don't warp the mold) and wipe it clean with a cotton rag on a dowel.

 

[Pulp]

The only thing I can think of, did you coat the inside of the mold with carbon before using? I wanted to phrase that as "did you smoke the mold first?" but wasn't sure how that would be interpreted.

 

[rodwha]

I had initially dipped just a corner in the lead, but after a few tries it still wasn't filling in so I dipped maybe 1/3 of it into the lead, the base.

This lead was on the highest setting. It cast nicely last time and I had turned the heat down a bit. It was also fairly cold that day compared to mid 60's this time.

I did use a lighter on it the first time I used it. It's only needed the once correct?

So I should warm up my Gulf wax and apply it to the underside of the sprue plate?

 

[Driftwood Johnson]

Howdy

Do you have a casting thermometer? That is the only way to tell how hot your melt is. Turning dials up and down without a thermometer to tell you what you are doing is not a very reliable method. Aluminum molds heat up fast, particularly a two cavity mold. When I am casting with six cavity molds I just start pouring lead into the mold and allow it to heat up that way. The first bullets will be poorly formed, I set them aside and keep pouring until the bullets are well formed. The poorly formed ones go back into the pot. It takes a little bit of patience before the bullets start dropping well formed.

 

[Arkansas Paul]

dipping any mold into molten lead is very dangerous

That's how Lee recommends heating them up.

any moisture on the mold will result in a steam explosion, a very unpleasant experience

Hasn't happened in my time casting, which granted is only a few years. Obviously you should make sure the mold isn't wet (don't really know how it would get wet to begin with). There may be an off chance that some condensation would build up on it, but I haven't had that experience yet.

I had initially dipped just a corner in the lead, but after a few tries it still wasn't filling

Patience is a virtue my friend. If the pot is full, you can rest the mold where the end of the sprue plate holds it up and the end is dipped in the lead. Leave it for 20-30 seconds and you should be good to go.

 

[rodwha]

I do not have a casting thermometer.

Should I warm up my Gulf wax and apply it to the underside of the sprue plate?

 

[Foto Joe]

Some of Lee's instructions are spot on, others not so much, such as: Lee recommends smoking the mold or using a mold release agent prior to use. This is NOT necessary if the mold is properly cleaned by the user. Lee also recommends dipping the mold into the melt to heat it up, this actually works very well but keep in mind the mold blocks should be closed and only hold the mold in the melt until the alloy doesn't stick. You really don't need/want to put anything into the mold which will make the RB/Boolit smaller.

As far as what you've got already stuck on the mold face(s) simply heat up the mold in the above manner then take a round ball and hold it with a pair of needle nose pliers and CAREFULLY rub it against the stuck lead and it should wipe off with a few swipes.

You say that the top of the mold blocks looks pretty beat up, I disagree. I think it looks pretty good compared to some of the molds I use. Regarding lubricating the sprue plate, I've found that synthetic 2-stroke oil on the tip of a toothpick applied under the sprue plate near the pivot works well.

 

[Chawbaccer]

Remove the sprue plate and clean the burrs up on the under side, rub it a few passes over 1000grit or finer wet or dry sand paper. Make sure the edges are properly chamfered too. Do likewise on the top of the mold, clean that gulling up. Don't sand the mold to remove metal, just to clean it up, or you will have a bigger sprue. You can lead solder aluminum, so get that lead cleaned up on the inside of the mold, get it away from the dowel pins and any mating surface, try a tooth pick, just do not mar the mating surfaces or the edges of the cavitys. Lee makes a good inexpensive mold, but they do benefit from a tune up when first bought.

 

[Driftwood Johnson]

I do not have a casting thermometer.

You need one. Otherwise you are poking around in the dark trying to figure out how hot your melt is.

 

[Foto Joe]

Well said.

 

[Zeke/PA]

Aluminum molds have taken a lot of headache out of the casting procedure. First of all he molds heat up fast and stay hot.
I've never saw the need to smoke/blacken an aluminum mold and I own several both for bullets/balls and fishing lures. I use an ancient Lyman bottom pour furnace and when I think the lead is up to temperature, start casting.

 

[fdf]

rodwha,

You can cast without a thermometer, I have managed since 1974 and have done okay thus far, I am still placing at the State and National level with my home made balls..

If I remember right you live in San Antonio. Call John L. Hinnant, in San Antonio, his number is in the book. He will mentor you.

Join your local club, they will guide you, you need help as you seem to be struggling in some areas.

 

[Arkansas Paul]

You can cast without a thermometer, I have managed since 1974 and have done okay thus far

I haven't been doing it nearly that long, but I've managed just fine as well. My cast boolits are just as accurate as the ones I've bought online from various manufacturors. They're pretty and I've only had one issue with leading (not the bullet's fault. I was over crimping and sizing it down). I have no immediate plans to buy one.

 

[J-Bar]

Folks, I love, respect and admire Driftwood Johnson's encyclopedic knowledge of all things related to firearms, but I gotta disagree about the thermometer...

Can you imagine Lewis and Clark's Corps of Discovery, the soldiers in Revolutionary War and Civil War camps, and the pioneers from mountain men, trappers, and settlers saying, "Dang, I won't be able to cast any balls tonight, I've mislaid my thermometer!"

I don't use a thermometer either, I vary the pot temperature to keep the bottom spout from freezing up, and to fill out the mold without wrinkles on the balls. I use only aluminum molds from Lee and Big Lube Boolits. It is surprising how fast you can cycle these molds. I open the sprue cutter as soon as the sprue freezes with thumb pressure only. (I wear welder's gauntlets on both hands when casting) The longer you wait the harder it is to open. No need to whack it with anything. By the time the sprue freezes, the outer layer of the ball is frozen too; I have never been able to open a mold fast enough to catch a ball while it is mushy. Try casting fast, you might like it. These molds like to run hot.

 

[wgaynor]

I always clean my molds with rubbing alcohol very very thoroughly and then smoke it with matches. Using a lighter didn't deposit carbon inside the mold.

Might have to clean and smoke it more than once. Sometimes the slightest nook can cranny can be a pain to clean.

As for heating the molds, I use 2 methods. The first, just set it on a hot plate and turn it on. The second is not just dipping the corner of the mold in the lead, but letting it stay i nthere until it heats up. Might take about 30 seconds or so. If it's not hot enough bythen, it's close. Casting a few wrinkled ones quickly will bring it up to temp.

 

[PRM]

Well, fry me in butter and call me a catfish. I've been casting for years and always just put the wrinkled ones back in the pot till the mold heated up to the point it produced a good cast. Never thought about dipping the mold in the molten lead.

 

[Driftwood Johnson]

Well, I guess lots of folks like to cast without a thermometer. I like to use one. I have a Lee bottom pour pot, and it has no reference to temperature. I just plop my thermometer into the pot and keep an eye on it as I cast. When I add lead to the pot, the temperature drops. I tweak the pot a little bit to raise the temp, then I drop it back down again when the melt comes back up to temp. I like to cast hot. And I agree, the Lee six cavity molds can pour out a lot of bullets in a hurry. As soon as the sprue stops shimmying I cut the sprues and dump them out. Then pour in more lead for the next six.

 

[72coupe]

Be very careful when you lube the sprue cutter. It must not get in the cavities or be where it will be drawn in.

I have been casting off and on since 1970. When I cast I usually cast at least 35 pounds of any particular bullet. The exception being 224 diameter 55 grain bullets. My endurance runs out on those at about 15 pounds.

I wish I had a lead thermometer but I have never had one.

 

[44 Dave]

I use my plumbers pot and ladle. I can tell when the lead is right by the way it pours and looking at the cast bullets, the thing I have to watch with this set up is it getting too hot.
I have tried dipping and pouring lead over the mold, but just casting and dropping back in the pot seems to do the best for me.

 

[StrawHat]

It looks like you have lead stuck in the cavities and on the face of the blocks. A hardwood stick will help remove that. Heat the mold and use the stick to scrape the face of the block.

I cast a bit and use a hot plate to heat the molds. Also, ANY coating you place inside tha cavity will reduce the size of the castin. If the ball does not drop freely when you open the blocks, there are ways to prepare the mold so they will.

 

[earplug]

I have used a propane heat shrink torch to preheat gang molds.
You have lead stuck inside your mold keeping it from closing. If a piece of wood won't remove it, A lead pencil tip might then try a razor blade type paint remover. Be careful not to ding the mold cavities.
After removing the stuck lead hold the mold up to a bright light and check if the parts line up, no light should show between the blocks.

 

[Jaymo]

I heat my molds on an electric hot plate. I tend to cast with at least 4 molds at one time.
It's a quick, easy, and effective way to heat the molds.
I turn it on low, and set the mold blocks on it.

 

[hartcreek]

That mold is all crudded up with slag and probably antimony. You need to clean it up by heating it to get that crap out. You can also see that you have let the debris build up on top so that the sprue plate is not closing properly.

Once you get the mold cleaned internally you will have to get it flat again. I had some like that and I draw filed them and got them squared up again.

If I aam in a hurry to get casting i just heat the mold up on a stove burner. If in no hurry I just cast a dozen or so an the mould get warmed up fine.

While waiting for my pot to remelt I have a piece of lead flashing that I cover my Lee pot with and I place my mould on top of the flashing to stay warm.