MP mold HP pins sticking

[Drew P]

Been having trouble with bullets sticking to the hp pins on my 9mm mold. Tried two stoke oil, wax, even spray mold release and nothing works for more than a couple casts. Any suggestions before I start buffing on them?

[minmax]

Buff them. No polish them.:smile: I just got an MP 30cal mold, same thing on my new mold. They slide like butter now that I cleaned them up a bit.

[BK7saum]

Yep, remove the pins and polish. Round pins i use 800 or 1500 grit paper and spin the pin in a drill. For penta pins, I smoothed the pins with fine or extra fine EZlap. No more sticking.

[Gamsek]

https://www.mp-molds.com/tips-tricks/70-general-advice-for-using-brass-hp-hollow-point-moulds

I never polished any of my pins on MP molds, (yes, it can help too) but rather also pre warm mold on a hot plate really well so the pins get hot enough too. To maintain temp of pins it helps if you cast with alloy that is a bit hotter. A new mold needs prepping or at least 3 casting seasons to develop some patina. No sticking after that. Glen Fryxell said that "hot pin is a happy pin"

[tomme boy]

Yep after your 4th or 5th session it will start to work better. It takes a long time on a hot plate to get a even temp on the pins. Mine usually takes about 5-6 pours before they are dropping freely. I would rather have them a little bit cold than too hot. If they are too hot the HP will get mangled. Especially the hex. I have more rejects with it than the round pins. And the round pins usually shoot better also. For me anyway.

[Gamsek]

Yep after your 4th or 5th session it will start to work better. It takes a long time on a hot plate to get a even temp on the pins. Mine usually takes about 5-6 pours before they are dropping freely. I would rather have them a little bit cold than too hot. If they are too hot the HP will get mangled. Especially the hex. I have more rejects with it than the round pins. And the round pins usually shoot better also. For me anyway.

Yes, you are totally right. It's better to start low and heat pins with pouring then to start extra hot. Had exactly the same experience as you when I tried with mold and alloy that were to hot.

But when we find that sweet spot and everything is just right, those beautiful hollow point boolets start to fall out...

[Beagle333]

Shining them up does help. Sometimes a little graphite (shade the tips good with a pencil) will help too. But heat is what makes it happen. The buffing and any release agent just helps you get along until you find your temp, then you won't need those tricks anymore.

[minmax]

Yeah, I forgot about the heat thing. Yes, absolutely find YOUR temperature, the mold likes.

[Greg S]

As stated above; season the mold, pencil graphite on the pins and find the correct temp.

[C. Latch]

Buff them. I do this with any new HP pins before I ever install them. Period. You'll never, ever find one that can't benefit from a good polishing, because the makers can't afford to hand-polish every pin they send out.

Then coat them with pencil graphite. Coat the shafts (not the pin, but the shaft it's on) with a bit of 2-cycle oil. Very light. Wipe on, wipe off.

Then get them hot. Really hot. I've never got one too hot, but I guess it's possible.

[Moonie]

I make sure the pins are very hot and use mold release on them.

[Drew P]

Wow thanks okay. Yeah I've been playing with lead temp all over the place on this mold and have had a hard time determining what is best. I'll turn it down and it seems to be happy for a few casts, then starts messing up, I'll turn way up and then also seems better momentarily. Fast tempo, or slower, it's all just mixed results. I've also had problems with tinning on this mold and have done a lot of pencil work and wax removal and such. I did heat cycle the mold a lot to start but with all the timing I eventually tore it down and soaked it in vinegar and hyd peroxide for a while to get a good color going. I'll do some buffing and see where that leads (pronounced Leeds)

[tomme boy]

You'll get it. These brass molds just take a while to figure them out.

[Drew P]

I can certainly agree with that ^^!!

Well I spun the round pins in the drill on some steel wool. They got nice and shiny and seemed slicker than snot. Spritzed them with Frankford graphite spray stuff and got to work. Seemed great at first but then as usual started sticking again. Seemed even worse than before. Oiled them and would get a few more casts but ultimately they would start sticking again. Too bad because it seems like they are really on the verge of being perfect.
Am I rushing the sprue cut? Should I be fan cooling the mold a little? It does seem to be more reliable if I pause and slow down pace a little, but I hate to slow down!

[tomme boy]

I run my lead from 675-725 depending on the mold. I don't think you have the mold up to temp yet. Or you are casting too slow. You are still going to have to tap the pivot pin on the handles lightly to get them to drop.

And your pins are backed out 1/2 turn also right? Because if the 2 guide rods are tight, they will stick every time. Just back out the rods a 1/2 turn.

[Beagle333]

Tomme boy was right about having the guide pins just a little loose so the HP pins can wiggle just a touch.
And I also agree on more heat. I often start out very hot 725°-735° and get em started frosting and then back the heat down until I get the look I want or the boolits start to stick. Sometimes I might cast em all at 725° and sometimes I need to back it down to 680° or so to keep the frost from getting too much.... depending on the mold.
You could go either way, but I just find it easier to back it down than to work it upward.

[Drew P]

Yah I used to run a little hotter with the steel and aluminum molds. For some reason this thing seemed to like a little cooler.
So tonight had the best session today yet with it. It does seem like the lead is a little cool but the mold seems to get a little hot. I started resting it on a wet towel while the sprues cooled if I had one stick and it seemed to free it up for a couple casts. I dunno why I tried this. Either I read someone did it or someone said never to do it. Didn't get any lead smearing on the blocks or tinning so that's good. So maybe I need to implement the fan or slow down rate?

[dragon813gt]

Pins are to cold. They need to be hot to release properly. I run MP hollow point molds at 750 or above. I know some people preheat the pins w/ a torch to get them to final temp. I solved the sticking pin problem by not casting hollow points anymore. The fad faded quickly and I was tired of lower production numbers. I know this doesn't help w/ the problem but many others have done the same thing.

[Drew P]

Yeah it's my first hp mold and sort of just wanted to see how they work. It's neat but yeah, I'll probably cast a bunch and then put it away forever or sell it. I have the RN version coming and am looking forward to that experiment.
I hear you on the pins temp but being buried in a block of brass I don't see how the pins can be appreciably differentiated in temp from the brass that surrounds them. So, maybe my whole mold is too cold.

[dragon813gt]

They are dissimilar metals that gain and lose heat at different rates. The pins will lose heat quickly when you open the blocks to drop the bullets. I run the lead hotter than normal to keep the pins up to temp.

[Gunslinger1911]

I have had great luck with Bullplate lube. You should have gotten a small bottle with the MP mould. Put some on a q-tip, smear a little on the HP pins. Maybe helps with the "patina"? I dunno, but lead does NOT stick to Bullplate !

[RugerFanOH]

I was having trouble casting with a "mystery" wheel weight alloy, tried a known mix: Hardball Bullet Casting Alloy Metal (2%-Tin,6%-Antimony,and 92%-Lead)It made a world of difference, maybe the tin makes it better?