Strange Issue

[cabezaverde]

I am hoping I can get some input on how to solve a problem I am having with 3 molds over the course of a few years and many, many different batches of WW alloy that work fine in other molds. Different casting sessions months apart.

The molds are all large diameter (44 and 45) Lyman 2 cavity, and all are GC designs.

The issue is that I seem to get boolits that have one side formed well, the other side wrinkly - maybe frosty- in the bands. Of course, this causes them to be ugly (thats OK), and undersized (not OK).

Molds are clean, but of course I will recheck that for the umpteenth time.

I am wondering if these molds might need a little tin added, and possible a cooler casting temp.

My alloy is straight WW, and I am a bottom pour guy.

Has anyone encountered this type of thing? Any fixes?

[GREENCOUNTYPETE]

i don't know about your issue but when i was using strait ww i found tin helped my boolits fill out better , what have you to loose a few dollars in tin sodier.

my first pour they were very wrinkly , for the second sesion i got the mold hotter that helped but still they had some nose wrinkles for my 3rd sesion i got the mold hot and added some tin .i havn't much expeireince but tin helped me.

[caillouetr9981]

Straight WW do make "usable" bullet, but adding some 50/50 Plumbers Solder makes much better ones. Try using 9-parts WW to 1-part 50/50 Solder. This mix works well on most every occaision.

Also, are you lubing your molds at all?

Good Luck...

Reggie

[BOOM BOOM]

HI,
A little tin (bar solder) should work.

[jonk]

Far from a cooler melt I'd say you need more heat.

[cabezaverde]

Far from a cooler melt I'd say you need more heat.

I thought that too at first, but the problem seems to worsen as things heat up.

[leftiye]

The side of the mold that wrinkles is too cool. Try blueing that Half of the mold (or coating with carbon or mold prep). Also, how you pour can cause this with the stream hitting one side of the mold first and causing cooled lead to impact the other cooler half of the mold. If you use a mold heater, you could set the side that wrinkles the boolits so that it gets heated up better. If your boolits aren't frosted on the good side, just cast hotter. Some frosting (not heavy frosting) makes for better fillout. Also a better flux(ing) can also make your lead flow better, and cast well at lesser temperatures.

[singleshot]

How did you preheat your mold? Sounds like the mold may be to cold.

[cabezaverde]

How did you preheat your mold? Sounds like the mold may be to cold.

I put it on a hot plate while the pot is melting - about 1/2 hour. As I said, it seems that the problem worsens the hotter it gets.

[MBTcustom]

Let me send you a couple pounds of solder. It only takes 1 lb. to season a 20lb. pot. I have experienced the same thing you are talking about but I never paid it no mind. However I can almost guarantee that this combination will get you close:
1. mix 1lb. of eutectic solder to 20lb. WW.
2. If your pot has no thermameter buy one and use it. (Notice I said thermometer, not heat setting) its a good investment.
3. Heat your alloy to 650-675 degrees by the thermometer
4. Clean your mold with hopes no. 9 "or some other lead eating solvent" and a bronze brush, (this includes the sprue plate) followed by acetone and a clean toothbrush, followed by acetone wiped out with a clean cotton rag.
5. Smoke your molds lightly with a wooden match.
6. Flux your alloy with a small pea of bees wax. Keep stirring the mix until the sides of the pot are clean and dry.
7. preheat the mold by dipping the forward lower edge in the pot, until the mold pulls out of the lead like pulling out of water. Follow this by dipping the lobe of the sprue in the pot until the same result is seen.
8. Pour the lead into the mold and discard the first two sets of boolits.
9. Go at it and watch your temperature keep it within 15 degrees (that's +-7degrees) of the temperature you like. If the sprue is staying molten for more that 5 seconds after you get a rhythm, back off 15 degrees and keep going.
That is my method and it seems to work every time. I like lees aluminum molds but I still use lyman 2 cavities when it counts.
P.M. me your address and I will hook you up with a couple pounds of eutectic.

By the way here's what I cast today using the above method.

[KYCaster]

44, 45 cal. you say? Is the frosting/shrinkage at the point where the cavities are closest together?

If so the problem is a combination of too much heat and/or poor venting. There is not enough metal between the cavities to conduct the heat away from that area fast enough to prevent over heating....or there is no way for air to vent away from that area.

1) Reduce your casting cadence...allow the mold to cool more between pours.(Sometimes a delicate balance between too hot alloy and too hot mold.)

2) Try "swirl casting"....tilt the mold slightly to one side and let the silver stream hit the side of the sprue hole(gate). This may let the air escape through the opposite side of the gate.

3) With a fine cut file or coarse stone, lightly bevel the top of the blocks at a 45 deg. angle. This will provide additional venting.(Too much bevel and you'll get some flash on the boolit bases at the parting line.)

I have one mold that wouldn't behave till I added a vertical vent between the cavities.

Good luck...
Jerry

[longbow]

My vote goes to poor venting.

I find many moulds do not cast well for me if the sprue plate is too tight. I usually loosen them so they almost swing free.

Also, as per KYCaster's comments 2 & 3:

2) "swirl casting has helped me with some moulds but I am a ladle caster so it is easy for me

3) I have also had to use a fine stone or diamond hone to remove the corners or the mould blocks where they meet under the sprue plate.

I cast mostly with straight wheelweights and/or range scrap with no added tin and all my moulds cast well for me. Some need a bit of help with venting or loosened sprue plate and some like more heat or faster casting but all cast well after I figure out what they want.

Longbow

[adrians]

as longbow said use a swiss file or fine stone to chamfer a very slight angle on the top edge of mold under the sprue DON'T GO CRAZY WITH THE STONE, just a hair is all ya need to give a "naughty" mold that little extra vent it may need , also use a fine scribe tool and gently go along the vent lines ,one or two or more may need "clearing out ".
it might work ,it might not, but it certainly won't hurt either.
at least it's one thing you can strike off your fix list.

[onondaga]

Nice to see the Swirl Casting I frequently post about mentioned. It does remedy hot spots seen as zone porosity or zone frosting and is a classic remedy from before I started casting 50 years ago.

To get a good look Swirl Casting it is a good idea to raise the pot so the pot spout is close to eye level and you can really see your stream entering off center. You can also Swirl with a ladle, it is actually easier to see with a ladle.

Historically the earliest reference I have found on Swirl Casting in America is in the text books of the first Dental Colleges in America as a method used with precious metals for Dental crowns, bridges and metal full denture bases.

Gary

[RobS]

KYCaster has good advise and it sounds like a possible venting problem to me. Run a small scratch awl through the original vent lines first and see if that helps before doing any other mold modifications.

[geargnasher]

Nice to see the Swirl Casting I frequently post about mentioned. It does remedy hot spots seen as zone porosity or zone frosting and is a classic remedy from before I started casting 50 years ago.

To get a good look Swirl Casting it is a good idea to raise the pot so the pot spout is close to eye level and you can really see your stream entering off center. You can also Swirl with a ladle, it is actually see easier with a ladle.

Gary

Yes Gary, it works and I thank you. That was the final tweak to my bottom-pour technique that has allowed me to get the results I always wanted but could only get with a ladle previously. "Swirl casting" evens the heat in the mould, eliminates hot spot spots in the bands, and allows me to cast with much cooler alloy and still get excellent fillout and far fewer air pockets. That, and the addition of a little tin as has also been mentioned should take care of the issues Cabezaverde is having.

Gear

[GabbyM]

44, 45 cal. you say? Is the frosting/shrinkage at the point where the cavities are closest together?

If so the problem is a combination of too much heat and/or poor venting. There is not enough metal between the cavities to conduct the heat away from that area fast enough to prevent over heating....or there is no way for air to vent away from that area.

1) Reduce your casting cadence...allow the mold to cool more between pours.(Sometimes a delicate balance between too hot alloy and too hot mold.)

2) Try "swirl casting"....tilt the mold slightly to one side and let the silver stream hit the side of the sprue hole(gate). This may let the air escape through the opposite side of the gate.

3) With a fine cut file or coarse stone, lightly bevel the top of the blocks at a 45 deg. angle. This will provide additional venting.(Too much bevel and you'll get some flash on the boolit bases at the parting line.)

I have one mold that wouldn't behave till I added a vertical vent between the cavities.

Good luck...
Jerry

Ditto:

With the fat and heavy bullets. It can help to use a ladle with spout like Lyman or RCBS ladle. then use a pressure poor method to force fill the mold. With a Lee bottom poor you can try holding the mould against the spout to force feed it. Although for some reason I have less luck with that compared to a pour spout ladle. You will get rid of that shrinkage that occurs at the center of the mold where the two cavities are close together.

I can get 250 grain 45’s to bottom poor if I’m dialed in within a narrow window. When it comes to 45s’ over 300 grains they get the ladle . I have a few long 30 caliber rifle bulets that work better ladle poored to get the bands filled out picture perfect.

[cabezaverde]

Goodsteel,

PM sent.