New Mould Questions

[Steve4102]

  Well, I tried out the mould today.

Sadly I was struggling right from the get go.

Cavity #1(closest to the handle) will not fill out.

I had the mould hot, I had the mould really hot, I had the melt 650, 675, 700, 725, 750 and even 800.  I had bullets that were super frosty, I had bullet that were shiny.

I added tin, I added Mono-Type, I started from scratch with a fresh melt of pure WW ingots, no help, then I  added tin and Mono again, again no help

I poured slow, I poured fast, I poured with the mould at an angle and I poured with the ladle 2-3 inches high.

Nothing I did got all four cavities to fill.  #1 was always less then a complete pour.  I even tried filling #1 alone several dozen times and the results were always the same, less than a full pour.

At this point, I'm at a loss as to what to try next. 

[Ramjet]

I had poor bullets for the first hour or so but after I dumped them back into pot and kept on pouring they got better. When you say they do not fill can you be more specific?

Describe the bullet......

[Steve4102]

  I'll try again tomorrow and take pictures. 

I pour the melt in until it fills up the cavity and overflows the sprue plate.  When I open the sprue plate there is an air gap of about 1/16 inch where the lead did not come to the top of the mould.  Basically the base of the bullet is missing.

[475/480]

Are you pouring lead untill a little bubble comes out the top of the sprue plate? This will help with fillout.
I usually spray brake cleaner in a new mould to get rid of ALL oil, dirt, etc...

Sean

[Yondering]

  I'll try again tomorrow and take pictures. 

I pour the melt in until it fills up the cavity and overflows the sprue plate.  When I open the sprue plate there is an air gap of about 1/16 inch where the lead did not come to the top of the mould.  Basically the base of the bullet is missing.

2 things come to mind here:

#1 - your sprue plate is probably too tight. If it swings freely when warm, that's fine, I like it a little tighter than that but not much. (The tight sprue plate is trapping air in the cavity.)

#2 - smoke your mold cavities with a butane lighter (NOT a wick lighter or a candle). You can't hurt the mold by doing this. A thin soot layer in the mold cavity lets it fill out better, over a wider temperature range. I do this with all of my molds, and most of them will start dropping good bullets as soon as they're too hot to touch. Many of them fill out well enough to see the machining marks from the mold cavities.

[Steve4102]

  Thanks, I'm going to loosen the S plate this afternoon and see if that helps.

[sqlbullet]

I agree that this is most likely a vent issue from a sprue plate too tight and too small vent lines.

[nightal]

Hey Steve, I am having the same problem, none of mime fill out, I am wondering if I have to Patina in the Vents? I was tired when pouring, 1:00am. after about a hr. i just turned the pot off and came upstairs, kind of PI$$ed off.I will try again later, this weekend.
I had one fill out, but could not get it to drop.
I cleaned with Dawn, twice, rinsed, twice, let dry, put it in a SS pan heated for 1hr. let cool down ea. time, then repeated, twice, looks great, but I can't get it to function, like my other mold.

[The_Shadow]

I use a carburetor cleaner to dissolve all solvents a clean the molds.  You guys will need to get those molds hot, pour at about 750-800 degrees, let poured bullets sort of cook off any and residual oils and what ever else is on your molds.  when the bullets fill out and are no longer wrinkled then lower the pots' temp to about 670 degrees.

After the bullets fill out the mold properly and if they stick (that means they are filling out completely) then you can lightly soot the mold cavities, HP pins and bottom of the sprue plate with a propane lighter.

Some tin in your alloy can help fill out.  Pure lead is not going to fill out totally. 
Many newer wheel weights are zinc alloy...If your alloy has zinc in it you are screwed!   Use it for something else besides bullets.

[Steve4102]

Even though I have been having issues with the #1 Cylinder, I still managed to get a few good bullets cast, sized and lubed.

I loaded up a few today with 7.9gr of Silhouette seated to 1.255 +/-.  I found that 1.255 hung up just a little when loading the 6th and 7th rounds in the mag.  I will load a few dummies at 1.250 and see if that helps.  They all feed and fired without issues, 

I set up at 25 yards with a sand bag.  The first mag was a little disappointing, but for me that is really not all that uncommon. 



The next mags was better even with the flier. 



Then I did one without my reading glasses.  This way I can see the target clear, but the front sight is blurry.  Another flier.  Hope these fliers are me and not the bullets?



  So far I like it.  More bullets and more practice and hopefully the fliers disappear.

[Oreo]

You really need to post your experience and questions here:

Results Thread: Mihec 10mm - 200gr WFN / .40s&w - 180gr HP, 4-cavity, Brass

Those are the guys who have the most experience casting with this mold. They can help you diagnose problems better then I can.

[cmemiss]

I wish I could offer some help.  I have 2 Miha molds, this one in 190, and a .38/357.  They both seem to like to run hot, and I preheat on a hot plate while the RCBS bottom pour is heating up.  The HP and shallow HPs drop like a dream, but the flat nose is a bit difficult.  All are slightly frosted.  The .38 mold even drops the Penta HP pretty well.  One other thing.  Have you watched the video on the mihec web site.  That might help if you are new to using these molds.

[Ramjet]

Are you sizing these bullets if so how and to what size?

[Steve4102]

Are you sizing these bullets if so how and to what size?

Yes, .402 with Lee sizing die.

[Steve4102]

  It's running now.  I did a lot of different stuff, so I'm not sure what was the cure if not a little from all of them.

  I loosened the sprue plate.  That alone did not solve the problem completely, better, but not fixed.

  I took everything apart and heated the two halves on a hot plate, very hot.  I took a brass brush and scrubbed the flats of the mold being careful not to f-up the cavities themselves, then let them cool.

  I pressure sprayed the two halves with Break-Clean and let them dry, twice.

  I heated the two halves up on the hot plate, very hot, and let them cool.

  I put it all back together and set it on the hotplate sprue plate down until hot.   Set the melt to 700*.  Poured perfectly as long as I held the ladle up about an inch above the mold.  Cast a couple dozen this morning without a single reject.