Lumpy Lead bullets

[Gazz]

A bit of a casting rookie here. I had cast some .54 Maxiballs years ago that came out fine by using a dipper and an aluminum mould. My lead pot was rather large as at the time as I had job supplying cast 20lb lead weights to a local company. Recently, I acquired a RCBS furnace with the bottom pour valve. It had some lead alloy that was quite hard in when I bought it and I wanted to cast pure lead for a muzzle loader so I used it up casting .458 slugs which came out very nice. Moulds were iron. When it was empty, I melted a bunch of lead flashing and tried to cast some .45 caliber maxiballs. I had preheated my aluminum mould by hanging it over the molten lead in the furnace by swinging the sprue cutter out to rest on the edge of the pot. Furnace temp was turned to max. My first 20 or so slugs were not quite formed and were returned to the pot and I figured that soon I would be getting good slugs but it never happened. It seems the first few drops of lead into the mould are not filling the mould out like the mould is to cold or the lead is to cold. I cast about 50 but they never got any better. So I'm wondering if I need to add some other metal to my lead to get it fill the mould better (I do want straight lead for the muzzle loader though) or should I go back to the dipper method which I think fills the mould faster thus pouring hotter lead. Also, if I operate the valve with no mould under it, the lead comes out drip drip drip and not a solid stream Is there crud in the valve? What do you folks think?

[quilbilly]

It sounds like you have a bad batch of lead. In addition to boolits, I have been commercially making fishing jigs (saltwater and freshwater) for over 40 years and have had your experience many times. If that batch has too many of the wrong impurities, I call it (sinker lead) then use it up on sinkers that don't require surface details or be bend-able. When that happens I clean down the hot sides inside the pot then get rid of the scrapings without completely emptying the pot. I also very carefully run a wire slightly up the spout from the bottom to clear the spout hopefully. Once done with that, I put a couple pounds of pure lead into the pot to melt then make a couple ingots running pour wide open to clear the spout again not completely emptying the furnace. The bad news is that there have been a couple times that this routine hasn't helped possibly due to zinc contamination so the pot had to be replaced. Hopefully you don't have that issue and you have enough pure lead on hand for the process. Good luck and happy pouring.

[littlejack]

Gazz
You might try casting a few from that same bottom pour pot, using your dipper from the top. If they come out ok, then your lead is at least up to temp. I used to cast with a bottom pour pot, and yes, they can get plugged up. When this happened, I would use a very small allen key that was sharpened on one end to clear the spout hole from the bottom. The bottom pour pots will collect heavy material at the bottom of the pot, which if big enough or a large amount will plug the spout hole. I switched back to using the ladle (which I started with in 1969) about a decade ago. Doing so, keeps a lot of the inclusions out of my boolits. Make sure that you're using good clean lead, or, if you're going to use ww's, melt and flux them a few times to get most of the dirt, crud and junk out of them before pouring your ingots. Hope this helps.
Regards

[Winger Ed.]

Clean the nozzle and/or adjust the needle to lift higher.

Lift the needle--- then poke up in the nozzle with a paper clip wire and wiggle it around to get the flow going,
then bounce the needle up & down a few times.

You should be getting a much faster flow.
In a perfect world, it'll fill a 4-500 grain mold in about a second.

[243winxb]

Maximum heat & pressure cast. Botton pour spout in contact with mold. Careful, hot lead may spray your way.

[Castaway]

Pure lead is your problem. It’s fine for round balls, but with conicals, you need to add some tin to get it to flow freely and fill out your mould. I’d start at 1:20.

[Soundguy]

Drip drip drip is the problem. Bottom pour should make a stream!!

[country gent]

If you cast the fist lead to empty you very well may have gotten dross in the spout valve. A torch tip cleaner paper clip small drill or nail will work to clean it out.Om th dpout this can be harder to remove. you may need a set of number drills and actually use them to ream it out.

I also recommend trying with a ladle as this may give an idea if the above dosnt help.

You need to fill the cavities as fast as possible so that the sprue is formed before the first starts to solidify. With big high volume bullets this is important. Long bullets also.

You control mould temp with your cadence lead temp and fill rate. The sprue should take 3-4 seconds to frost over.

By getting the lead in as fast as possible poring a big sprue the sprue can fill the bullet as it cools making for very even weights and form.

[jsizemore]

#4d finish nail fits up the spout from the bottom and will lift the metering rod. I stick the nail up in there with needle nose pliers gripping the nail close to the head. Only put clean ingots in your casting pot. You may need to clean the pot.

[Sasquatch-1]

I agree with running a paper clip or similar item up the spout. Open the flew regulator quit a bit and it would be wise to hold what ever you use with a pair of pliers.

Oh yeah, make sure you put something underneath to catch the lead. I use SS condiment cups from Sam's Club. The cups make it easy to feed the lead back in.

[243winxb]

Flux and clean the pure lead. May help keep the bottom spout cleaner?

[Soundguy]

I agree with running a paper clip or similar item up the spout. Open the flew regulator quit a bit and it would be wise to hold what ever you use with a pair of pliers.

Oh yeah, make sure you put something underneath to catch the lead. I use SS condiment cups from Sam's Club. The cups make it easy to feed the lead back in.

Ditto. I keep a lee ingot mold under my bottom pour pot. drips just make ingots eventually. ;)

[Gazz]

Thanks for all the comments and ideas! I'll let you know my progress.

[Gazz]

Cleaning the nozzle on lead furnace worked as well as adjusting the amount it opened - getting good casts now, sort of. I cast a bunch of .45 maxi balls and some 54 maxi balls as well as some .50 slugs for a 50-70. The issue that I am having now is there is sometimes a small hollow in the base of the boolits. I tried holding the mould to the valve longer which sometimes works but not always. These holes can be nearly .25" deep by .063" wide and I perplexed as to why they form. What is happening?

[Soundguy]

Are you pouring a very small sprue? if yes.. make a generous sprue.

[Gazz]

I'm using the sprue plate that came with the moulds.

[Soundguy]

I'm using the sprue plate that came with the moulds.

That's great.. but I didn't ask about the sprue plate.. I asked what size sprue you poured.

[Gazz]

Seems to me that the sprue plate forms the sprue. The countersink matches up to the taper of the bottom pour valve body and I hold the two tight together, fill the mould until lead pours out indicating a full mould. I will hold the mould in place until that leaked lead solidifies and sometimes the base of the bullet is flat where the sprue plate shears off from the base of the bullet. Other times there is the small deep hole. So when you ask about the sprue size I don't know what sprue you are referring to. The lead enters into the mould cavity directly from the bottom pour valve through the sprue plate so really there is no sprue as there would be if the part were lost wax investment cast.

[Dusty Bannister]

When you cast, you allow extra alloy to well up on the top of the sprue plate in a puddle. This is liquid for several seconds and allows the melt to be drawn into the cavity as it solidifies in the mold and your shrinkage voids may resolve. If you are holding the mold tight against the nozzle of the pot, you might be trapping air in the cavity instead of allowing it to vent out.

[Soundguy]

Ditto what Dusty said. Your method of pouring prevents you from having any excess lead at the spruce cut area..this means you can get a depression from a venting air void..and depending on the alloy..there is minor shrinkage at freeze too.

Lower that mold down.. Pour till you get a puddle.. Once it freezes.. Cut it. Bet you got flat base bullets and not hollow base.

By you preventing there being any excess.. You are actually causing the problem by starving the mold.

Google the image of the lyman cast bullet handbook 4th edition. You will see a dipper pouring a mold and a big puddle on top.. That's a hair excessive..but that's what you want..when you knock the spruce plate open..you want lead on top sheared off.

The guy pouring that mold surely doesn't have any hollow base problems!

[Petander]

Good advice all above.

I have one particular single cavity slug mold that likes me to wiggle the mold a bit while holding it to the valve during the pour. I get a proper sprue and a good fill that way only. It also likes a full (Pro Melt) pot for max pressure.

Try moving the handles up and down a bit.

[Gazz]

Thanks for that explanation. I guess I assumed since the sprue plate and the valve had similar tapers, they were designed to be used together. I did try using a dipper and that eliminated the cavity in the base but didn't pour as sharp an edge to the boolit base.

[Soundguy]

Try the pot..you get a good pressure pour from the unlimited flow..then run yourself a good dime width puddle..or heck..if a high volume mold..a nickel sized puddle. If I'm pouring 458 projectiles in the 400-500gr range and I just have a filled spur cone and no puddle..sometimes the bottom line on bullet base isn't crisp... Thus..make a puddle..besides..the spruce go right back in the pot anyway..its not like it's a waste or anything. Overfills always better than a light pour.

[Soundguy]

Look at the puddle in this add. Don't have to drench it..but a good puddle up top solves lotsa problems.

https://images.app.goo.gl/ZE15UwXjWDuV5fn79