More casting questions

[Bob58]

Thanks to all who have responded to my initial post on bullet casting.

I have a couple more questions to ask, along with a few observations.

1. Is it OK to leave the Lee Pro 4-20 pot filled with metal at the end of a casting session? I have been "draining" it down to about 1/2" depth, but this seems like wasted effort. Won't the metal heat up faster for the next casting session if it's in to pot as a solid block, rather than in the form of rejects and sprue cutoffs from the last casting session?

2. How often should I be fluxing the metal? All I have used for fluxing so far is some fine cedar mulch (purchased originally for pet bedding), and that seems to work well. After fluxing, the metal looks clean and bright on top. What I have been doing is waiting until the cedar all appears charred, then mixing the pot well (using either the RCBS thermometer that I use to measure the metal's temperature) or a length of hardwood dowel rod. After mixing, I have been removing the charred cedar, and replacing it with fresh cedar mulch.

3. What is a reasonable range of casting temperatures to try? My Lee pot doesn't want to pour unless the temp is at least 650 degrees. I have been trying to stay close to 700 degrees, but have tried casting as high as 800 degrees, for better fillout (didn't work.)

4. At one casting session, I did get a few of the very narrow driving bands to fill out on the 255 grain Lyman GC .45 caliber bullets. I saved these bullets, and found that the weight from each of the two individual cavities on this mold were very consistent (less than about 0.3 grains for each cavity.) The problem is that the two cavities are casting bullets with slightly over 1 grain difference in weight. Is this likely to create accuracy problems, if I load with bullets from both cavities?

5. One of the two cavities had quite a burr at the top of the cavity, which I didn't realize until I was looking at the "good" bullets with a 7X magnifying lens. I have since removed that burr with very careful stoning, but I wondered if, since these are GC bullets, would the slight heel imperfection result in accuracy problems (the defect is entirely hidden by the gas check.)

6. I just finished my fourth casting session, and had the poorest bullets from any of the sessions. The front driving band, on many of the bullets, doesn't appear as anything other than a slight rounding on the surface of the bullet. I suspect that I didn't get the mold sufficiently degreased (I had sprayed it with Rust Prevent after the previous casting session.) Thanks for all the comments on mold storage - I will see about getting an airtight container for the mold, and storing it in this container with desiccant when the mold is not in use.

7. I tried Midway's spray Mold Release during one casting session, but didn't think that worked as well as smoking the cavities with a match. (Match smoked cavities produced the few only completely filled out bullets I have seen so far.) I plan to buy a butane lighter for future mold smoking purposes, unless someone has a better suggestion. How close should the flame be to the mold surface when smoking the cavity? How long should it be held there, so that a sufficient "smoke barrier" (?) will form on the cavity surface?

[MT Gianni]

Hi Bob, as to answers:
1] that's how I do it but i don't refill it to remelt it. In other words i leave the lead level how it is when I finish casting, though I may add sprues and spills to the top of cold melt for the next melt.
2] I generally flux liberaally when smelting ww or blending alloys and once when casting with clean metal.
3] i cast hot around 750 though each mold has a temp that it likes best. Take notes when you find it.
4] I don't think the difference will be noticible though if you are shooting competition you may want to make a slight mark in one of the cavitys and only shoot either cavity during a competion.
5] no eye deer, but probably not.
6] I think you are on te right track
7] smoke til it looks right, if that sounds too basic it involves the temp of the cold surface as well as the hot. The carbon comes from incomplete combustion of the flame so the most carbon [blacking] comes by putting the mold into the top 1/3-1/4 of the flame come and disrupting the flame process.
Godd luck with it, Gianni.

[bruce drake]

:drinks: I'll try to answer you with a few of my findings/opinions.

1. Leaving the extra lead in the pot is fine and it does speed up the remelt later.

2. I usually flux when I refill my pot with fresh lead. If I am just setting the cutoff sprues back into the pot, I don't flux as they are already clean.

3. I find that the Lead in my Lee pot likes the halfway point between 7 and 8 for good mold fillout. This of course is predicated off the alloy that you melt. I use Wheelweights with a bit of 60/40 solder added for the tin. Experiment with what works on your alloy.

4. A grain difference between two 255gr bullets is less than 1% variance. At this stage in your casting, shoot them and focus on other things.

5. How big was the burr? If this is the 1 grain difference you are talking about, than I wouldn''t be concerned unless you are looking for perfect concentricity.

6. You pegged one potential reason. You had oil from your spray still in the mold. Wash it out with a good degreaser and reseason. Another would be that the lead or the mold was too cold. Either add some heat to the pot or ensure you can preheat the mold through either dipping the mold in the melted alloy for a short while or sitting it on the edge of the pot while you are melting the lead in the pot.

7. Butane lighters don't soot as well as a wooden match. Continue to use your matches. You''ll prefer the fillout on your bullets.

You are entering into the advanced levels of reloading. Congratulations for making the first step. We are always ready to help out with questions.:castmine:

Bruce

[Leftoverdj]

No need to drain the pot if your normal alloy is in it. I do drain mine if I've been casting with straight lead, but that's just to keep track of what's in the pot.

Far and away the most common cause of poor fillout is mould contamination. Once I have them clean, they stay clean. It's harder to get the mould clean than most people will credit. Storage in a gasketed ammo can will prevent rusting. Add VPI paper for long term storage.

The spray mould releases reduce the size bullets drop. If you smoke with a propane lighter, you want the mould well down into where the flame should be. This produces more carbon by causing incomplete combustion.

The small variation in weight you describe should cause no problems. One of the benefits of GCs is that they cover up slight imperfections in the bases. Next time, deburr with an eraser. It'll take off a burr, but you'd really have to work at it to remove enough metal to be seen on the bullets.

Lastly, relax. This ain't rocket science and perfection ain't required, or most of us could not do this. Cast 'em and shoot them. You'll get better at it over time, and no point in fretting when they are not absolutely perfect.

[Leftoverdj]

I gotta differ on wooden matches. I had a couple of cases of poor fillout I am pretty sure came from resin in pine matches. This may not be common, but I don't wanna have it happen again.

[454PB]

I have some different ideas than the majority. I empty my pots when done casting. I use many different alloy mixes, and it's easier to empty the pot and mark the recipe on the ingots that result than to have to remelt and empty if I want a different alloy. If you only use one alloy, leaving the pot partially full sure doesn't hurt anything.

I flux just before I start casting, then leave the dross in place until either I'm done casting, or refill it with alloy. The dross acts as an oxygen barrier in a bottom draw pot. I use Marvelux for casting, since I cast in a non-ventilated room. I use anything carbon based when I have the luxury of ventilation or when smelting, usually parafin or boolit lube.

I've owned Lee moulds since they were introduced. I smoked them as recommended when I first began using them, but have learned that it is not necessary if the mould is thoroughly cleaned before the first use. Proper venting and degreasing are the key to mould fillout. I also quit lubing the Lee moulds, all it does is produce caked on carbonized crud that slowly plugs the venting. In the 30+ years I've owned Lee moulds, I've never ruined or damaged one by lack of lubrication (or for any other reason).

In my opinion, weighing boolits is a waste of time. Yes, I've done lots of weighing and segregating, but found that a good visual inspection produces just as good a result. I allow absolutely no defects in the base.