Pitting on sprue seperation

[Topper]

I aquired my first non-aluminum block mold, a Hoch nose pour design.
Took a bit of experimenting to get things rolling, but I did manage to get a good batch of well filled cast.
Problem I'm having is when seperating the sprue, I'm not always getting a smooth flat cut that I'm accustom to, but some pitting.
I'm giving the mold a 10 second count after sprue hazes before seperating and have applied Bull plate lub to both mold face and sprue plate.
Do I need to wait longer?
Is it safe to use a damp sponge to accelerate sprue plate cool down without rish of damaging mold?
Thanks

[omgb]

Use the damp sponge technique..it really works well. it's safe so long as the sponge is damp and not dripping. just touch the plate to the sponge and cut.

[Bullshop]

Topper
A coupla questions first sost I kin help ya. How many cavity, and what is the boolit weight? Multiple cavity with heavy boolits, 300 to 500gn will take a few seconds. Most singles even with a 500gn boolit only takes about two. Could be just the opposite, and your waiting too long. I cut the sprue the instant I see it pull down, which most often is 1 to 2 seconds, unless as I said I am using a gang mold for heavy boolits. If your having to tap on the plate to cut the sprue then IMHO you waited too long.
Maybe not the right way and certanly not the wrong way but thats my way.
BIC/BS

[475/480]

BS hit it right,you are waiting to long IMO.Cut the sprue while it is softer not harder.

Sean

[Topper]

Thanks gents,
The mold is a 2 cavity 300grainer.
Will give it go and report back.

[44man]

Depends on the alloy as to when it can be cut clean and how long to wait. High antimony alloys will fracture (crumble) when still too hot. Cut a sprue real soon and let it drop on a board, take a stick and push on it. It will break apart and so does the boolit base or nose.

[StarMetal]

44man,

Hey, where you been? You're right about what you said in the post. The bullets will crumble when you push on them. Some will even break just from the drop, that is if you're not dropping them in water, but rather on a towel or something soft.

I've found of the spruce doesn't cut, but rather breaks off that mine break off flat. Being they are dang near dead center I don't think it makes much of a measureable difference. I've done some mighty fine shooting with such sprues.

Joe

[jhalcott]

you may be getting your mold too hot.Is there "frosting" on the base? This would indicate high temp of the mold or alloy. Slower casting and/or lowering the melt temp should help.

[Topper]

I will try all the above.
I did crank up the heat due to problems getting the mold up to temp and fill.
Does anyone use a hot plate to speed up the initial mold heat up time?

[boogerred]

topper-i use a hot plate with a steel plate on it to preheat,works great for me.i use a lot of small bullets in lyman DC moulds and find i get a lot of culls trying to heat those big heavy blocks with the alloy. i cast with 5-6 moulds at one time and the hotplate helps to maintain the temp when you need to stop and clear the bench.i have an rcbs mould thats giving me trouble with the sprues.i bought it used and it cast a pretty bullet other than the sprues pulling out.i did all the tricks i learned here and think im going to have to order a new sprue cutter for it.

[44man]

Joe, been busy cutting piles of rough cut oak that I sawed out of downed trees in my woods. Another honey-do to make a pie safe for the wife. Stuffs been in the barn for 3 years and needs cut close to dimensions, stack and dried the rest of the way in the basement.
You're right about not worrying about a little divot on the base, doesn't hurt a thing.
My brother-in-law came down from Ohio. I took him down to shoot my .475 and 45-70 at 100 yd's. I now have enough huge grooves at 70 yd's to plant a field of potatos.

[Topper]

Topper-i use a hot plate with a steel plate on it to preheat,works great for me
I'll pick one up at Wally world.
Great forum ;-)

[Topper]

Update.
Melt is straight WW with 2% tin added.
Tried everything other than changing melt.
Cast at lower temp resulted in incomplete fill.
Cleaned mold, tried again, same issue.
Speed cast at higher temp, pitting on nose after seperating sprue.
What did work was a slow count to 17 after sprues frosted over.
Made for slow casting, but the boolits dropped out well filled with no pitting.
I don't know if this is characteristic of Hoch molds are not, no other Hoch molds for comparison.
http://img.photobucket.com/albums/v342/Topper_1950/P3050018.jpg

[nighthunter]

Topper .... I'd shoot them boolits in a heartbeat. They look good to me. Have you tried shooting them and what are the results? I've had some ugly rifles and ugly bollits that have shot superbly. The reason they are nose pour is to give you a more uniform base that to me is better than a pretty nose.
Nighthunter

[Topper]

Nighthunter,
Thank you for the complement.
Hoping to get out this weekend and give em a test drive in a 14" TC and possibly my Ruger BH.
Will report back on accuracy, but velocities will be no go (partner with chrono in Canada).
Like your signature "All others pay cash" :-)

[Topper]

Update on how these boolits shoot.
Finally mounted a scope versus a red dot on the 14" barrel, thus far best 5 shot groups @100yds run under 2".
Some groups have three touching.
Still trying to put all in tha same hole, but that's ample accuracy for hunting.
Using H110 by the way.

[Ed K]

Looking pretty good now. Which bullet is that may I ask?

[Topper]

The gentleman I purchased it from had it custom made by Hoch. It's a 300gr GC.
Have to really apply a heavy crimp in my 41mag Ruger BH or the bullets back out from recoil.
I mostly shoot them in a 14" TC.

[Phil]

I have several Hoch molds and I don't see a problem with your bullets as shown in the photo. From looking, I assume you are letting the metal free fall into the mold and you are not pressure casting them? I think they will shoot better than you can hold. Mine, fired in my match rifle, will aggregate in the .3 moa range.

Looks like you have some great bullets and they are shooting well for you. Good luck!

Cheers,

Phil

[45r]

For the bullets that show protrusion you can swing the plate back over and tap them flat by not closing the plate all the way.I like that design wish I could get a bore rider for my casull simular to that in OGF.One of these days might order one from LBT.