Fun With a Cranky Mold

[us920669]

I needed an oddball bullet recently so I called a high-end maker - $100 price tag.  I expected aluminum in 6 to 8 weeks, got cast iron (Meehanite?) in under a week, so it was obviously one he had lying around, and I could see it wasn't new.  I decided to keep it and it is a joy to use - big beefy sprue plate, bullets drop right out.  What bugged me was a faint  (sometimes not so faint) shadowy swirl of roughness, usually on the nose but sometimes down into the bands.  There is no real pattern to it.  I think it's just a cosmetic defect - if I rub the bullet with a patch a lot of it goes away, but I still don't like it.  Under some light the very top of the cavities look like grey steel, but the rest of them have a dirty yellow look, so I decided they were contaminated.  I tried alcohol and some really rugged stuff called MEK - no help.  Some old timers at the show told me to use a low-speed drill with a brass brush - I did a little but I didn't like the idea and it didn't seem to be helping.  I have read about brake parts cleaner so I sprang for a can, hosed the mold down, no good.  A weird angle - when I got the mold I was surprised how quickly it heated up, maybe 4 or 6 cold wrinkles, but after the brake parts cleaner, I must be tossing over a dozen back in for that.  The stuff really chilled mold - no, I didn't use it on a hot mold and months later the situation is unchanged.  For the life of me it seems like that one quick chill has changed the characteristics of the mold for good.  Anyway, I wondered if the way the lead was flowing had anything to do with it so I tried hand-pouring with a ladle.  Bingo, problem solved.  The column from the ladle is much thicker than with the bottom pour furnace so I guess that was it.  Only thing, I like the bottom pour idea.  The ladle sometimes picks up crud and it's much more fatiguing.  I also get a lot of bad bases, since I don't think I turn it up to 12:00 every time.  I have probably made thousands of bullets over 50 years but I still don't know much about it.  What do y'all think? 

[luckydawg13]

can you open the sprue hole on the mold ? so it can fill quicker do you preheat your mold
just putting it out there good luck

[Land_Owner]

Not saying these suggestions will work 100%, I am a Noob at this myself, but start by adding heat. 

1.)  Put the leading edge of the mould in the melt for 15-20 seconds and bottom pour a couple.
2.)  Repeat 1.) above if they are still wrinkled, but chill down if they get frosted by slightly cooling the mould on a wet dishrag for 5 seconds.  If this by itself doesn't work then...
3.)  Turn up the heat in the pot by another 10-20 degrees and combined with 2.) above, pour a couple.

There should be a sweet spot.  Find that and write those setting down for future reference.  Also, I believe this question has been discussed a time or two on http://www.castboolits.gunloads.com/index.php  You might discover other alternatives there as well.

[Lloyd Smale]

I clean new molds with a toothbrush and brake cleaner then sit them slightly submerged in the pot for about 5 minutes to get then good and hot. then let them cool a bit and start casting. It usually takes care of any contamination. If that doesnt cure your problem try casting a bit faster or bumping your temp up a bit.

[Swampman]

I recently sold my Lee .459-405HB mold because it gave so much trouble.  A huge pain in the butt.

[us920669]

I probably put too much info in the original post.  The cold problem doesn't really bother me that much.  I just thought it was fascinating that it got much worse after the sudden chill-down from aerosol brake cleaner.  It sounds impossible, but that one event does seem to have changed the mold forever.  I was mostly worried about the frosty roughness, which is not from heat.  I have tried all sorts of variables, and it is definitely the punky stream from the Lee 4-20.  I have wondered if there is dirt in the nozzle.  The top screw pulled out long ago so I drilled another hole just beside it, so the plug shaft is at a slightly different angle.  I have never had trouble with it before.  If I adjust it higher the usual drip becomes much worse.  I usually don't like to pre-heat - I keep my molds inside so they are already room temp, and I might hold it over the pot for a few minutes.  My holes are about 13/64, which is a lot larger than other molds.
I wasn't going to say it, but it is a NEI 424 x 350, and it was cut very nicely, no doubt an excellent mold. The metallurgy may be a little flaky.  The sweet spot - or window - is pretty narrow.  I think I've seen a faint cold wrinkle and heat frost on the same bullet, like there is a hot spot running around inside the blocks.  I have to park it for a few minutes pretty often, and I think the best looking bullets come way into the pour, after the mold has cooled down a few times.  I take all opinions very seriously, keep em coming.   

[Graybeard]

Some folks talk about a process called "lee-menting" or some such. You should be able to find it via a search engine. While I've not read the specifics I gather it is basically lapping the mould to remove imperfections of the cheap Lee moulds.

Looking at the photo of your mould I think it might benefit from a lapping procedure just don't overdo it and use very fine grit lapping compound.

Here is some info I saved to a Word file on the subject of lapping. It was posted here by GBO members.

Lapping molds
                       Posted by Billy Marr
                     Mon, Oct 23, 2000 at 12:54
       In another forum I read a way to lap molds that is
       different from what we have discussed.
       First you need a bullet that has been cast in that
       mold.

       Second cut off the portion that you do not want to
       lap.

       Third drill a small pilot hole in the bullet and
       insert a small wood screw.

       Fourth coat with valve lapping compound fine will
       work.

       Fifth insert in mold hold mold in hand excerting
       enough pressure to let bullet spin but still lap keep
       putting pressure until bullet spins freely.

       Sixth cast a few and messure repeat as needed.

       I tried it this weekend it works great.





Posted by Leadpot

Will.
You can lap a mould but you must be careful with a aluminium mould if that is what you have, when you lap, for it don't take to much to go to far.
This is how I do it. I drill a hole in base of a cast bullet were the sprue was cut that fell from the mould you want to lap. I use a 1/2" or 9/16" #7 or 8 sheet metal hex head screw and screw it in the base of the bullet. Next I use premium buffing compound, like dico it comes in a stick. I scratch a little off the stick on to a glass plate and mix it with a little cutting oil till it is a smooth past next I roll that bullet in the compound just hard enough so some inpregnates into the lead a little then put that bullet back in the mould and just roll it with your finger a little to settle it in and get the mould coated with the compound re coat the bullet again if you need to and put it back into the mould and close the blocks.
Now you can use a nut driver and spin that bullet in the closed mould till it gets a little loose then use a drill with a driver and spin that bullet in the mould. but you want to take car you don't slip off the base of the screw or you might damage the cavity base edge.
The compound I use is dico E5 emery for cutting and SCR to polish.
Or you can use pumice or rotten stone and oil. I use this for lapping barrels with a lead core. you can get this in paint stores.
Remember if your blocks are aluminium they lap fast. I hope this will help you.
I have used this method for out of round moulds and taking some tool marks out.
Kurt

And this on the topic of Lee-Menting. I do not know the source of this or how I came by it. Just noticed it below the above document in my files. Didn't realize I had it.

Sure-Fire Lee-Menting Technique (Aimoo Post Revisited)
________________________________________
I'm not trying to repeat myself here...however, by request...

The title and following text are a copy of a sticky post I made on the old Aimoo Cast Bullet forum on 03/20/2004.

...well at least for my 6 Lee moulds.

I lik Lee molds for their price and light weight...and in general their bullet designs (most are well tested copies from over the years). I have disliked them because they've never dropped bullets to my satisfaction and frequently suffered from poor fill-out. One was so bad I resorted to prying the bullet out of one of the cavities with an awl applyed to the bullet base. I checked for burrs, smoked it, cleaned it, used mold release, all I could think of...to no avail. I was ready to throw it, when I discovered the following solution quite by accident. That was three moulds ago. I now apply the following lee-ment to every new mould. It's worked every time. Bullets drop as well as they do from my RCBS and Lyman molds...first time, every time.

In my opinion, Lee moulds suffer from three main flaws...bad cavity finishing, poor venting, and bad handle to block fit. Higher end moulds don't...but the extra finishing and quality control adds to cost. So...expect to spend a little time to improve the Lee mould

Those of you who've given up on Lee moulds, I recommend you give the following a try. In addition to usual tools, you'll need a carbide tipped scribe and an aerosol graphite mould release (not for the reasons you suspect), and "Comet" cleanser. Several of the "lee-ments have been described by others and I used their experience in developing it. It's an hour well-spent to avoid "Lee frustration"

1. Look for any obvious burrs in the mould cavity and remove them with a sharp knife. Clean and lube the mold per instructions, smoke the mould if you wish, and begin casting. If your bullets fill out drop as advertised, consider yourself lucky, you need read no further. If not, cast 4 well filled-out bullets(hopefully the handle bolt pounding trick will free them) and save them (you'll likely need only two, the others are spares). While the mould is hot, carefully loosen the spue plate screw until it falls free under it's own weight. I've found that if I do this cold, it's too loose while hot. It you back it off too much, you need to tap a screw to hold the spue plate screw in place. Carefully (you don't want to drill the mould), place two bullets back in the mould and using about a 3/32 bit, drill a hole about 1/4 inch deep in the bullet base.

2. Clean the mold again. Now spray the entire cavity and mould face with graphite mold release. Let it dry and spray a second coat. The surfaces should be black. Remove the bolt holding the handles together so you can easily get at the mould faces. With a cloth, and "Comet" clean the block faces. The fine venting lines will stand out...filled with graphite. Take the carbide scribe and run it down each vent line, deepening and widening them (not too much but enough to be noticeable) between the mould cavity and the edge of the block. Put the handles back together. Fill-out problem solved.

3. Screw a 1 to 2 inch long screw into the hole in one of the bullets, wet the bullet, and sprinkle some Comet on it. Place it into the bullet cavity and with a drill at slow speed and the mould closed on the bullet, rotate the bullet in the cavity. Continue until the mould fully closes on it. (Comet as a polisher is another board members idea...don't remember who...but thanks...it works). Repeat a second time. Use another bullet for the other cavity, if you have one, and repeat. Now rinse the molds and with a toothbrush clean them. Carefull inspect the mould cavities. Burrs and high spots that were previously unnoticed will be seen easily as bright spots surrounted by black...depressions as black surrounted by white mold metal. With a sharp knife, scrape the burrs off and smooth any sharp depressions that represent an imperfection. Go back and repeat the Comet trick twice more for each cavity, clean and inspect the mould for burrs once more. Most of the graphite will be gone, some will remain but will be highly polished, and will help fill the inperfections...it is an aid...not a hindrance so leave it. You now have a polished and repaired cavity...it will drop bullets with the best of them. I don't need to smoke the mould...my old "impossible mould" now works beautifully...it had several imperfections in one cavity that I couldn't spot without the graphite trick. I found it by accident, In desperation had tried the mold release (don't use it for its advertised purpose...bad release problems lie elsewhere), but discovered its real value while trying the Comet mould polishing trick. Bullet release solved.

4. I use a 6 gallon plastic bucket when casting. I fill it with water and place a cloth with a four inch slip in it for water-quench bullets. For air cooled, I fill it with rags as a cushion. However, I lay a flat piece of wood (1X4) across the back half of the bucket. Most Lee moulds have bad handle alignment...especially the double cavities. They frequently don't meet squarely when opening or closing. This wears the block face as the two rub together ...eventually wearing off the vent lines. If you lay the rear of the mould blocks on the flat board when opening them, they will open squarely...same for closing. This saves the mould and aids in bullet release. Handle alignment solved.

Sorry about the long post...however, thought it might be of use to those of you who've given up on a Lee mold. If you're not satisfied with the performance of your Lee, I suggest you give it a try. I've had 100% success to date...it works!

[us920669]

I had thought about doing exactly that but got nervous.  Now that I see its been done, I'm going to try it.  Of course, I'm cast iron, so I've got even less to worry about.  I'll probably cast tomorrow, I'll let you know what happens.

[us920669]

Well, I just Leeabated my NEI mold with valve grinding compound and I'm a believer.  There was yellow crud, now cut about 50%.  I'm going to try it like that for now - I've screwed up a lot of things in my life by overdoing it.  I'll cast tomorrow for sure - hope I don't make airplanes. Drilling out a lead bullet is kind of tricky - some hints: Make your starter hole with a soldering iron, and use clean-up  braid if you have it. Drill while the bullet is hot - it's like butter.  I used a 9/64 bit and a downspout screw.  Clip off the tip so the threads start right away.  When the bit hits cold metal it might seize, so use a reversible variable speed drill.  I used a socket and tee handle to lap, no power.  Your first couple of twists are with the mold open a scoch and all the compound will scrape off and end up on the flats near the edges, so stop and push it back down into the cavity.  Any compound on the flats will hold the mold open and you will be opening up the sides of the cavity, not the bottom.  This seems like a great tip, but I would say only do it if you have too, and take it easy.[size=78%] [/size]

[geezerbiker]

I bought a lee .430" mold with the intent of lapping it out to .433 for the oversize bore on my .44 Mag Handi rifle. 

I mail ordered both 300 and 600 grit lapping compound and after a lot of lapping with the 600 grit, the mold was very smooth inside but I only picked up maybe .0005" in bullet diameter.  I moved on to the 300 grit and I put it aside when what seemed like a lot of work and I still hadn't increased the size by .001" from when I started.  What I'd do was lap for a while, wash the mold with soap and water, then dry with a hot air gun before casting test bullets.

This mold now drops bullets easier than any other Lee mold I've ever used.  When I get around to it, I'm going to lap all the rest of my Lee molds and maybe a few of my Lyman molds...

Tony

[us920669]

I'm glad to hear that lapping doesn't remove too much metal because I've still got work to do.  I must have softened the yellow crud up yesterday because it's on the move, still causing problems.  Today's melt wasn't a total loss, I got some real beauties, but also quite a few dogs that went back in the pot right away.  Inspecting as they drop is a good idea for this rig, since it keeps the mold at a good temp.  This mold always was a good dropper, but after just a little lapping it's even better.

[Land_Owner]

My concern in lapping is the reduction in the "sharp edged" characteristics of driving bands and lube grooves.  You will be reducing the amount of lube, by a tiny amount, that the grooves will hold.  Also, the once sharp edges and features will become more rounded.  These characteristics may be good for mould release and fill out, but do they affect accuracy or the potential for leading?  I am really-really tempted to go this route with a few of my "problem" moulds.

[us920669]

I worried about that too.  I haven't been able to shoot any of them yet.  Obviously, the delicate parts of the mold will come down first.  Comparing sized bullets visually doesn't tell you much.  I put the goop in the mold carefully to only hit the areas I wanted to, but the bullet squished it around some.  First application I didn't use much compound and it pretty much stayed where I wanted it.  Once you get it to where the mold will close all the way, it doesn't take too many turns for the lap to spin pretty freely, since the bullet reduces very quickly.  I dragged my finger over the cavity edge real gently, like you would do a knife blade, and I think there was a slight burr on the leeward side, where the lap came up out of the cavity.  That might have been left over from manufacture, I didn't check it before, and the side where the lap entered the cavity still felt sharp, but there's no question it got abraded some.  I'm going to do it again, since it definitely helped my yellow crud problem, but I might look for a more gentle compound than straight valve grind.

[us920669]

I worked again last night with Permatex VGC and I'm down to mostly bare metal in the cavities.  I think I was so cautious on my first effort that I only started to remove the yellow crud.  The mold is soaking now and I'm going to try the brass brush pretty soon to get the rest of it out of the corners.  I refined my process pretty good, so I'll share what I learned.
Use the hardest alloy bullet you have.  You will twist the lap clockwise so the screw doesn't back out of the bullet, so lay a thin bead of compound along the right edge of the cavity on both blocks.  Put the mold back in the handles and close them as tight as you can and still have the bullet turn and give it a half turn.  This will spread the stuff over the whole surface.  Then open the handles, wipe off any compound on the flats and do it again.  After a few times the handles should close all the way and you can give it maybe a dozed turns before the bullet gets so reduced that it's no longer cutting.  This will start to make sense as you do it and see what I am talking about.  Be aware that as the bullet reduces, it will move deeper into the mold, so it will be abrading only the rear facing surfaces.  You might want to have several bullets prepared.
Of course, everything depend on what you are trying to do - remove stubborn contamination, like I am, or smooth out the surfaces for better bullet release.   

[Land_Owner]

I put aside a dozen or more 380 ACP bullets from a Ranch Dog aluminum 6-cavity Lee mould that is "not quite" what I want by way of definition of lube, driving bands, and fill out.  I know I have to be extremely cautious as aluminum will cut a whole lot faster than steel.  Also, some of the moulds problems might well be ME.

How do you get the machine screws centered in the bullet?  I have a drill press, but no alignment or holding arbor.  I was thinking of drilling a 0.360" (+/-) hole in a block of wood, lightly pressing the 0.356" bullet inside, and then drilling the bullet center just smaller than the diameter of the machine screw. 

Might work, might not depending on the friction between the drilled wooden block and the lead bullet.  If the drill press is advanced too quickly, the centering drill too dull, or the wooden block friction too low, the bullet is going to spin before the drill advances into the lead.  That will probably mar the bullet and deform the necessary grooves and bands.

[us920669]

I decided not to haul out the DP with so much else on the bench.  I just clamped it in the vise with leather pads, very gently, and used the soldering iron for the starter hole.  If you drill the bullet hot it goes right in, especially with a big starter hole.  The drill did spin the bullet a little, which was OK since it proved the bullet was not squashed.  Actually, none of my holes are centered, but it doesn't really matter with hand lapping.  Bit seizure is a problem, just go slow.  With your smaller diameter I guess you've scaled down bit and screw size and a soldering iron hole might be too big.  The ace set-up would be to get the screw real hot and just push it in, but that's starting to get complicated.
I'm very pleased with what I see now.  You never know how dirty something is until you clean it.  I could do more but I'm going to try to cast again and see how it goes.

[geezerbiker]

I just left the sprue plate open and drilled the slugs in the mold.  I could have used my drill press but that would have meant that I would have to get up and go to it when the hand drill was right there... 

I have #8 self-tapping screws on hand so I drilled the hole for them but I don't recall what size bit I used.  The bit seizing is problem so like it was said before go slow.

I've only lapped aluminum molds so far and I haven't had a problem but I did mail order my lapping compound.  Valve grinding paste is too course in my no so humble opinion...

Tony

[Czech_too]

An alternative to using a screw to turn the boolit would be to pour some, placing an appropriate size nut on top of the mould cavity.  This is with the sprue plate open of course.  Make up at least a few of these because as stated, the boolit/compound will wear some.

[us920669]

This thing is still kicking my butt.  I made one change - I put the mold in the oven at 200 while the metal melted and that did save me some time, but the "boolits" (I like that) still have some surface roughness, most of which can be wiped off with just a dry patch.  I took the mold out in the sun and yellow crud is back!  I think casting sucked more old grease out of the pores.  Maybe I shouldn't worry about it, they size fine and I'm sure they will shoot fine.  One thing, lapping has given me a smoother, glossier bullet, so the imperfection stands out more.
I don't think lapping has damaged the mold (yet).  On an NEI, the bottom of the lube groove is not cut square, but with a nice beveled surface.  Of course, that's a raised area on the mold.  Looking at the mold with a glass and checking some of the first casts I made, I can see it is getting more rounded - not by much, but we all know VGC will do a number of ferrous metal.  The only thing I got now that's more gentle is Metalglo, which is pretty soft.  Where do you go for something in the middle?

[geezerbiker]

I bought one of the lapping compounds I use from Midway.  It's used to lap locking lugs on bolt action rifles.   I think this was something like 320 grit but I'd have to find it or look it up and I'm not in the mood to do either.  The 600 grit I got off eBay and I think it was sold for lapping engine cylinders.

I bought the finest grit lapping compound Midway had and I was concerned it would be too coarse.  They had 2 or 3 coarser grits compounds and I wish I had bought one of those instead of the 600 which is way too fine for all practical purposes...

Tony

[us920669]

I really appreciate all the comments and tips.  I'm being quiet now because I'm not sure what I will do next.  I'll keep you informed.  I did make some 44 pistol bullets with the same alloy and furnace and had no problems at all, except I did realize how punky a good RCBS mold seems after using the big block NEI.

[us920669]

I think I'm out of the woods.  I found out I had some 220 material in my scope lapping kit and I did the most careful, gentle lap yet - no more yellow crud.  I did just a little casting last night and it doesn't seem to be coming back.  I had another idea too.  There may still be a little dirt up in one ogive area, so I made some half-bullets - just a quick flip to the valve - and a few are perfect, just down to the crimp groove.  They come out with a pig tail down one side to hold on to, so I'm going to try to work with the mold open and spare the bands any more cutting.  There were some machine marks in the ogive and I've been watching them.  They are a lot softer but I can still see them, so I don't think lapping could do much to the actual dimensions of the mold, at least with cast iron.
I also benefited from reducing the metal temp.  I never got a thermometer, I have always just melted at 7 on the 1 to 10 dial, cut back to 6 and then down into the 5 area as the level dropped, but I'm sure it takes the metal a long time to respond.  I'm going to try lower numbers all the way for a while.  Thanks again for all the interest.

[us920669]

Half-bullet idea isn't really very good.  It cleaned up the nose area some, but there isn't enough room for your fingers and working on a mold half, the lap tries to climb out of the cavity and that would damage the edge.  I'm sitting pretty good as I am now.