How do you cast with a mihec mold?

[milsurpcollector1970]

I got one of the MIhec 311410 130 gr hollow point molds.

I just fired it up yesterday. When I get it hot enough to fill out the boolits crumble when I open the mold if I let them sit till they are solid the next ones I pour are wrinkled.

I have 3 good boolits out of 20. I am using the long hollow point pins if that makes a difference.

I haven't used tin in years with any of my other molds Does a brass mold need tin more than aluminum or steel?

This is the first time I have cast with a brass mold.

Not sure what my melt temp is I have the 4-20 pot turned up to 8. I plan on building a PID next week when i'm back from vacation.

I tried preheating my mold on a heater I made from my old lee pot, didn't seem to help.

[runfiverun]

I'd stay away from the tin in a brass mold unless you absolutely need it.
the mold does need some break in time to develop a patina in the cavity's you'll see it turn a brownish color.
this is a little bit of insulation similar to smoking an aluminum mold.

your second paragraph is your clue as to what's happening here, brass is between aluminum and steel it needs heat of course.
it doesn't retain it quite like steel will but retains it somewhat better than aluminum does.
you just need to find your rhythm of when to open the sprue and dump the boolits.
you might have to open a little sooner and then hesitate before dumping.

[Jupiter7]

All my mihec brass molds usually have a 1st cast break in. I do some heat cycling on ceramic stovetop after a soapy water toothbrush cleaning before 1st casting and also preheat on hot plate.

[Dale53]

Hollow point moulds require a bit more help from the operator. I have several Mihec hollow point moulds. Recently, my good friend, the Green Frog, was visiting and he brought his new Mihec 314640 hollow point for us to "break in". The mould was a typical Mihec - more like a work of art than a bullet mould. In examining it, I noticed that it wouldn't quite close. It is the new design where the hollow point pin shafts run through BOTH mould blocks. The blocks were binding on the shafts not allowing the blocks to complete close. It was a simple matter to loosen the shafts about a 1/4 turn (they are screwed into the hollow point pin). Use the allen wrench supplied with the mould (they are metric). The mould worked perfectly after that little operation.

After carefully scrubbing with an old tooth brush and Dawn Dishwashing liquid followed by a HOT tap water rinse and pat dry with Kleenex (no lotion on the Kleenex) I placed a single drop of Sprue Plate lube furnished with the mould on the shafts at the OUTSIDE of the blocks. The single drop of oil will wick inside properly lubing the shafts without contaminating the casting surface of the mould (the cavities). Then we carefully heated the mould blocks on a hot plate (slightly over medium on MY hotplate - YMMV).

I ALWAYS use tin when casting hollow points. I do what the old masters who hunted LOTS with hollow point bullets did - use 20/1 lead/tin alloy for proper expanding (that's what you use a hollow point for:razz:). Others have successfully used WW's+pure lead (50/50) with the addition of 2% tin to the final mixture. That expands well and also casts well with a hollow point mould.

The Green Frog and I got terrific results with the new Mihec mould (as expected) after two or three moulds full. I am careful to NOT overheat a brass mould when preheating as it could warp, ruining it. I pre-heat so it is just below casting temperature. When it takes a few seconds for the sprue to solidify, then you know it's the proper heat for the mould and the metal. I run the metal a bit hotter than when casting solids. 750 degrees rather than 700-725 (checked with a reliable thermometer) gives me what I want with hollow points.

The new mould style pulls the bullets out of the cavities when the mould is opened. I neglected to mention that we also pre-treated the part of the hollow point pins that makes the hollow point with mould release before starting casting. That way, when the mould is opened the bullets fall off the pins without whacking the mould. Easy-peasy!

The Green Frog is VERY happy with his new mould. It was a downright pleasure to cast with it.

Hopefully, your experience will be the same...

Dale53

[RED333]

Yep, get the pace right, brass likes to run hot.
The first time I ran a brass mold it took close to 30 mins before I got the hang of the pace.
Now I can get boolits out in the first cast.
Try counting, helps me.
Fill the mold, count to 3, open the plate, count to 3 open mold and dump.
Start again, works for me.

[Beagle333]

Cast faster. Start off with alloy at 720° and cast like a madman and then you can back alloy temps down once block gets hot and boolits either start frosting heavy or breaking when you dump them.
After a while, you'll get the "feel" of where your alloy needs to be, to match your casting speed and the temp the blocks need to maintain.

You could start out with 690° alloy and cast like mad until they stop wrinkling, but I have found this to take longer and be more frustrating than working down from a hotter alloy. Your choice.
I always use 2-2.5% tin with HPs.
Good luck!!

[dragon813gt]

While alloy temp is important. The mold temp is more important. Preheat the mold on a hotplate. Alloy temp needs to be a little higher to keep the pins hot. Once up to temp keep going and going an going. They never cast well the first few times. At least they haven't for me. But after a few sessions they are broken in and run like a champ. Cadence is really important when casting hollowpoints. Brass molds have a small temp margin where they work well. So if your cadence is off you will have problems.

[tomme boy]

Sell it and buy a Accurate mold. At least you will be able to cast with it.

[Blanco]

Good advice here
I got my first MiHec mold about a month ago. There is a learning curve, and a brass mold has a break in period. Brass molds seem to like to run hotter. Some tin in your mix will help fill out the cavity, just don't get carried away. Once you start casting don't stop to inspect, keep up as fast a pace as you can to saturate the mold with heat. Once the temp comes up, the magic will happen.

[zuke]

I bought one last summer, a 32 HP/WC design. After googling it and youtubing it and finally email mihic and getting no response what so ever from them I sold it and bought an Accurate mold.Now I is a happy camper.

[dragon813gt]

I bought one last summer, a 32 HP/WC design. After googling it and youtubing it and finally email mihic and getting no response what so ever from them I sold it and bought an Accurate mold.Now I is a happy camper.

I don't understand this. There is plenty of info about casting w/ them here. And overall they aren't hard to use. Hot mold+hot lead=bullets

[44man]

I only used brass once, beautiful mold. Really was a work of art but I found the mold needs to be hotter and it cools faster. As big and heavy as it is, you would think it would hold heat.

[HangFireW8]

When I had issues with a Mihec HP mold, the GB Honcho was a big help and Mihec took a little while but stood behind his product. I've bought more since.

[white eagle]

without reading all the other advice you got I will ad my 02
sounds to me like you need to set aside more time with the mold
brass molds seem to have a longer break in time that say aluminum might be it takes longer to heat up
they do however hold heat real well once you get them where you want so watch your alloy temp
wrinkled boolits to me mean mold not at temp or mold not broken in
to me MP hp molds are a beautiful thing and make wonderful boolits

[longbow]

What Beagle333 and dragon813gt said... get a good rapid casting cadence going to keep the mould hot and keep casting! Don't stop to admire or check boolits.

I have the same mould and have no problems with it at all. I pre-heat until the sprue plate lube just starts to smoke (you want the mould hot but don't overheat it), then start casting with hot alloy. If boolits stick to HP pins then a light smear of sprue plate lube on the pins will help but mostly keeping everything up to temperature is most important.

I mostly cast with range scrap or wheelweights so no fancy alloys. I sometimes add some 50/50 bar solder but not normally unless I want a malleable boolits as Dale53 mentions. If I am popping milk jugs full of water, which is what I have done for the most part with those boolits so far, plain old range scrap works for me (for plinking) and is cheap and easy.

Do not overheat your Mihec mould! Two reasons ~ 1) appareently overheating a brass mould can cause it to warp; 2) if you get the mould hotter than the melting point of the lead (or very close) not only is there a high likely hood you could get tinning but you will have to wait while the alloy cools before you can drop boolits or they will be brittle (possibly part of your "crumbly" issue).

Follow the advice everyone has given you (except for selling the mould!) and try again. Once you get the hang of it you will love your Mihec mould.

Longbow

[44man]

I got good boolits right off after pre-heating to 500* but had to go a faster pace.

[YunGun]

I've got that one too; it was my first-ever custom/brass/HP mould & definitely a different animal from the cheap Lee 2-cav (non-HP) moulds I'd used previously.

The most important thing when casting HPs is that the pins needs to be HOT, & the larger/longer the pin, the more heat seems to be needed. Alloy & mould temp of course play a large part as well but those can be fine & casting otherwise great bullets, but if the HP pins are too cool you'll get lots of wrinkles & boolits will stick tight to the pins. HEAT is the solution to pretty much ANY/ALL problems with HPs in my experience; I find it easiest to just bump the alloy temp up & vary the speed of casting to offset any overheating like you're describing. The trick is finding that happy medium between too cool & too hot.


When I get it hot enough to fill out the boolits crumble when I open the mold if I let them sit till they are solid the next ones I pour are wrinkled.

That was one of my problems too - after learning that the brass moulds needed quite a bit more heat than I was used to with the smaller aluminum moulds, that went a long way towards resolving my problems but then I ran into the 'crumbling' issue you mention. This is simply due to the alloy not having cooled enough yet when you open the mould. You can slow your casting tempo to allow a bit more time for the mould to cool between casts but, as you mentioned, this may allow the mould/HP pins to cool TOO much... Some suggest using a fan or even cooling the mould on a wet/damp cloth, etc. to 'speed cool' the mould which does help the boolits 'freeze' faster in the cavities but it's pretty easy to overdo it & then you're constantly chasing the mould's temp sweet spot... I've tried all these methods & while they have their advantages, I found it very difficult to maintain a reasonably constant temperature.

I haven't had time to do much casting for the past few months while working on the house, & I've been chomping at the bit to get back at it.... I made a little time to prep & heat up my new MP 402-170 mould (http://castboolits.gunloads.com/showthread.php?246856-MiHec-10mm-40s-amp-w-170gr-150gr-WFN-HP-4-cav-Brass) & threw a few bullets after it arrived a couple weeks ago, but hadn't had any real time to cast. During that first run I was attempting to cast a mix of the deep HP & penta HP pins but was having a HECK of a time getting them to drop from the deep HP pins since I hadn't allowed enough pre-heat time. Ultimately just swapped to all penta pins & continued without issue for the short time I had available...

Finally made some time this weekend to do some casting with my new MP HP mould & a couple of newer-model Lee 2-bangers (312-185 & 311-1002r) & was determined to get some deep HPs made up... This time I spent a good bit more time heating the pins & mould before starting & things went much smoother, but I was still struggling to get good, consistent results from the deep HP pins.

Remembering my previous brass mould lessons, I realized more heat was called for, but I use a Lee 4-20 bottom pour pot, & the thermostat setting only goes to 9. So I broke out my 'majik marker' & corrected the label so it goes to 11! Now all my boolits come out great! :kidding: Ok, sorry, I couldn't resist!

Seriously though, I found that simply resting the freshly-filled mould for a few seconds on the lead ingots waiting patiently to find their way into the pot worked wonders!! They make an AWESOME heat sink that'll suck the heat right outta the bottom of the mould to help the boolits solidify faster without cooling it too much & even seems to help maintain a more constant mould temp if I let it set for a moment too long while messing with another mould. If/when the ingots start getting too warm & it starts taking longer for the sprue to freeze, dump those in the pot & simply rotate in some cooler ingots, with a judicious application of cooling fan, etc. as needed....

[44man]

Remembering my previous brass mould lessons, I realized more heat was called for, but I use a Lee 4-20 bottom pour pot, & the thermostat setting only goes to 9. So I broke out my 'majik marker' & corrected the label so it goes to 11! Now all my boolits come out great! :kidding: Ok, sorry, I couldn't resist!
Stop making us spit coffee on the keyboard! :bigsmyl2:

[OuchHot!]

Back when dinosaur poo was still steaming, "everyone knew" that you couldn't cast good boolits from an aluminum mold. Being a curmudgeon in training, I ordered an aluminum mold. Whew! It began to seem like "they" was right. The wonderful founder of a wonderful mold company (Walt, RIP, of NEI) and I had a good long talk. He told me my dial thermometer was likely inaccurate (it was) but good enough for comparative purposes. This is what he had me do: Start by finding the melting point (liquidus) of the alloy in question. Set for about 100 degrees higher and start casting. Change tempo systematically until good results show. He was plaintive that I was messing with too many variables at once. Once you have a tempo, you might find that 120 or 80 degrees gives a broader window but you should be able to get a good boolit from his initial condition. I started doing this with everything from several 1-2cav molds used in sequence to 5 cavity brass molds and have always been able to get a good boolit from the right tempo. Then, and only then, I adjust other parameters. I did not find switching tow Mihec molds a challenge except that sometimes I use a micro torch on the hp pins to get started.

[kbstenberg]

Has anyone figured out how to cast flat points with the Cramer molds? I have 3 Mihec Cramer's and I will be danged if I can get bullets to drop from the molds when I am using the flat pins.
All 3 molds drop HP's like a dream but when I put the flat pin in, the bullets just won't release.

[dragon813gt]

Has anyone figured out how to cast flat points with the Cramer molds? I have 3 Mihec Cramer's and I will be danged if I can get bullets to drop from the molds when I am using the flat pins.
All 3 molds drop HP's like a dream but when I put the flat pin in, the bullets just won't release.

The mold is not hot enough. Once it is the bullets will release just fine.

[bangerjim]

Mine work just fine. You need to get it hotter! Use a hotplate. Works for all types of molds.

And hold your mouth right!!!!!!! HA......ha.

bangerjim

[tomme boy]

I can't get them to release either. And the molds are hot enough. I have kept cast at a very fast clip and kept turning the heat up for an hour straight till you had to wait about 30 sec to open the mold before the lead would not pour out. Then started to turn down the temp and kept going. They would never drop the flat points unless you BEAT the mold. I understand tapping them. Almost every mold you have to tap a little. I have broke a couple of handles trying to get them to drop the flat points. Now I just cast the hp's and never the FP's. I have had two versions that were NON-HP and were the same way. Beat them or don't use them.

[Beagle333]

I have a few that have the 90° lube grooves. True, they might be a little feistier than the HPs (since you are actually nudging the boolit out with the HP pins), but when they get seasoned and I learn how to use that particular mold.... they all work just great. I have never had to sell a mold because it wouldn't drop boolits. 8-)

If you need to whack it til you get it broken in, and also yourself..... get a 8-10" soft pine furring strip (feels like balsa wood). You can beat that thing until it turns to fluxing sawdust or your arm hurts and won't damage either mold nor handles.