How do l get moulds REALLY clean?

[Martin Luber]

For both Iron and Aluminum, I had been scrubbing with Dawn and a toothbrush followed up by Brake parts cleaner and preheating on the stove.

But how can l get them really clean to eliminate rounded edges abd get higher quality castings?

Thanks all

[Winger Ed.]

If the edges of the cavities are sharp and crisp, I think your rounded edges are related more towards heat.
Either the mold, alloy, or both aren't quite hot enough. Also, a little extra bit of tin will help them fill out better.

Stains from heat are pretty normal, sort of like a cast iron frying pan being seasoned over time.

I've got a couple of molds that have had hundreds of pounds cast with them.
They look like something that got pulled out of the trash, but the cavities are 'crisp' on the inside & edges,
and I couldn't ask them to cast a better boolit. But I do run everything a little on the hot side.

[Martin Luber]

How hot? Thanks

[longbow]

I pre-heat all my moulds until the sprue plate lube just starts to smoke. That is actually a bit too hot and the sprue puddle takes a few seconds to harden. However, it usually ensures I get good boolits almost right away and after a few casts the mould temp will drop a bit and I can speed up casting.

It is simple and works for me.

Longbow

[GregLaROCHE]

If you are cleaning as you say, your mold is probably clean enough. Molds that haven’t had all oils removed, usually end up throwing wrinkled Boolits. Possibly adding some tin or adjusting temperatures may help. Sometimes getting a mold to do what you want takes a little time until you get the right combination. Also, if your first boolits aren’t coming out the way you want, keep casting. Often things will improve.

[John Boy]

http://www.lasc.us/Fryxell_Book_Contents.htm

The mold and the melt should be heated no higher than it take the sprue puddle to frost in 5 to 10 seconds depending on the weight of the bullet. Example, my 535 gr 45-70 bullets drop out with perfect bases and fully filled out in 8 seconds

[Winger Ed.]

How hot? Thanks

You'll probably do better, and be a little quicker with PIDs, hot plates & such.

I don't have any of that.
I start the pot off with the knob a little past the tried & true 'sweet spot', and the mold laying on top of it.

I start casting and usually reject the first few as the mold finishes getting hot.
When I get a little bit of frost, I back off the heat a little at a time until it stops and the boolits look Chrome plated.

Then I can rock along with more or less no rejects until I get tired or hungry.

[JSnover]

What's your alloy? If your mold is clean and hot and you still get 'rounded' edges you might need a little tin.

[bangerjim]

I nave never cleaned and scrubbed a mold like you are doing in my life!

You may have scrubbed the sharp edge detail off the Al molds!!!!!!!!!!

Don't worry about grease & oil. It will be long gone after a pour or two.

Your problem may be more related to a cold mold and/or under-temp alloy.

And possibly some Sn as said above! Solves all problems I have ever had with lack of cast details.

[gwpercle]

For both Iron and Aluminum, I had been scrubbing with Dawn and a toothbrush followed up by Brake parts cleaner and preheating on the stove.

But how can l get them really clean to eliminate rounded edges abd get higher quality castings?

Thanks all
To get perfectly filled out , 100% perfect cast boolits ... I had to ditch the bottom pour pot and go back to " pressure casting" with a Lyman spouted ladle and 20 lb. Magnum Melter Pot . No amount of cleaning , preheating or 6 cavity moulds would produce the "Perfect" boolits I wanted ... gave away the bottom pour and went back to the ladle and pressure casting . I like to work with two moulds , 1, 2 or 3 cavity moulds .
It may not be an unclean mould ... are you using a bottom pour pot ?
Gary

[Martin Luber]

I can also pressure cast from a bottom pour... but I still wonder about cleaning solutions

[bangerjim]

I can also pressure cast from a bottom pour... but I still wonder about cleaning solutions

You seem to be hung up on this thing about having a "dirty mold". Have you closely inspected the molds under 20-30X magnification? Do you see any dirt? It will be definitely visible. If there, use a pointed hardwood dowel/stick to scrape it off.

Again, I think all your problems are from low mold/alloy temperatures during casting. And possible your casting cadence.....a very BIG factor in quality drops. You need to possibly slow down and give the cavities a chance to fill at the proper mold/alloy temps.

Casting is no rocket science.....but it can blow up in your face! :groner:

Good luck

[brassrat]

I had a new Lee 6 cavity that was dirty with something, or at least my recollection. I cleaned with brake cleaner but it only cleared up after at least one scrubbing with Dawn and not a finish with the brake cleaner.

[cuzinbruce]

As to how hot, most of us probably do not have thermometers for lead casting. Although they are available. Your problem sounds like not enough heat as others suggested. Could be the mold or the metal. Next time you cast, you might crank up the heat until you are getting a frosted appearance. Then back off the heat a bit and see if you like the results better. If your bullets are frosted, the metal and/or mold are too hot. Frosted appearance but well filled out. Solution is to back off the heat or slow the casting. I hope this is helpful.

[Edward]

For both Iron and Aluminum, I had been scrubbing with Dawn and a toothbrush followed up by Brake parts cleaner and preheating on the stove.

But how can l get them really clean to eliminate rounded edges abd get higher quality castings?

Thanks all

It requires compression casting ,learned on another forum explained by a really smart caster , nothing more than mating up the nipple on your ladle or bottom pour to the sprue plate /hold for 5-6 seconds before removing and waiting 8-10 seconds before opening mold. This lets the lead in ladle/bottom pour put pressure on your mold/cavity . The results are amazing especially with 4 to 600 grain bullets as the bases steer the bullet and you could cut yourself on these edges (ALMOST) resulting in more consistent weights and less rejects !/Ed

[Daekar]

I am going to have to experiment with compression casting!

I had a great lesson last night about mold fill out... I was trying a new mold with a different alloy than usual and couldn't get rid of the rounded edges and wrinkles. Waited forever for the mold to come up to temperature and for the seasoning to start, but nothing happened even after I added a half pound of 62% tin solder. I finally realized that the different alloy needed a bit more heat, and after I kicked things up another 60 degrees F it was smooth sailing.

Never assume you know what you're doing... I certainly never will, lol.

[kbstenberg]

Another way to heat the mold to a higher temp. Dip an edge of the mold in the liquid lead.
I normally heat the mold on an open coil heater until the lead is liquified. Then i dip the mold into the lead for a 20 second count. and usually the mold is hot enough to give good bullets rite away. Kevin

[JoeJames]

I am still in the elementary school level, but I have learned a few things on the way. With a new Lee mold I cleaned it with q-tips and lighter fluid, smoked the cavities with a propane long neck lighter, and started casting. Of course all wrinkled starting out. No worry though, kept on casting until I got very good boolits. Just like seasoning a skillet - patience. Dumped the wrinkled ones back in the pot, let the temp come back up good to where the puddle on the sprue plate was good and frosty. O, also per "From Ingot to Target" I always lay the mold - sprue plate down sticking into the melter just above the level of the melt. For experience, albeit limited, I expect wrinkled boolits starting out with a new mold. Sure as the sun rises in the East.

[Moromane]

How often should I need to smoke my molds?

[Conditor22]

How hot? Thanks

I do all my casting between 700° and 720° ( except for pure 750°)
If you're not getting sharp edges your mold may be too cold or you may not have enough tin (pewter) in your alloy. In this instance, many casters just crank up the heat on their casting pot BUT the hotter the alloy the more it will shrink when cool.
I cast pewter (tin) into .5 grain boolits so when this happens I just toss 1 or 2 in the pot and mix it in with a wire whisk.

I preheat all my molds on a hotplate set to 400° with a 3/8" piece of steel on top to evenly distribute the heat. I turn on the hotplate (with the molds on it) the same time I turn on my pot (PID controlled)

With my well-seasoned molds, I generally start getting good boolits on the first or second cast.

I prefer to clean my molds first with solvents then dawn dish soap avoiding any possibility of leaving any residue on them scrubbing them with a toothbrush or denture brush ($1 at the dollar store :) )

[John Boy]

The best cleaning solution for molds is … Micro-90. Free sample on the Internet website. It is a concentrated solution so make a 5% solution. Wet the mold under hot tap water and scrub the mold with a tooth brush and Micr-90 … do it 2x times, rinse with hot water, wipe dry and bring the mold up to temp

It is a laboratory cleaning chemical. Been using is for about 15 years. And once cleaned … don’t smoke the mold just lube the pins with paraffin

[BRobertson]

The info on Micro 90 website states do not use on aluminum!

Bob

[bangerjim]

How often should I need to smoke my molds?

Never.....according to most on here. I used to smoke coat my l molds ONCE when new - using a beeswax candle. Now I do not at all.

(If you feel the need for a high, light up and smoke a mold a day,dude!) HA.....ha!

[jsizemore]

How often should I need to smoke my molds?

Never.

Get your mold to 400degF and your alloy to 700-725degF. I add about 1% tin.

[JSnover]

How often should I need to smoke my molds?

I'm another one who gave up smoking molds a long time ago. I started doing it because they weren't releasing. De-burring will solve most of your releasing problems. If it doesn't, lap the cavities, you'll get nicer boolits that just fall right out.

[Shopdog]

In a previous life.... mid 1970's;

To keep rust at bay,would take a Q tip and put a wee bit of bullet lube(50/50 BW vaseline) in the cavities whilst still warm. This was at the end of a cast,putting them to bed(storage). Then,would warm them just a bit,say halfway to casting temp,and then blast them with brake cleaner. I cast THOUSANDS of really nice bullets that way. Do what you want but,within reason,most make way too big a deal about minor cavity contamination.

These days,moulds live in climate control with several "layers" of desiccant's. Good luck with your project.

[PhilC]

I'm a real rookie, but get good fill and nicely formed boolits from new and used moulds I've accumulated. I clean all new moulds with same lacquer thinner I use in my air powered gun washer to clean my paint guns. Not hardware store stuff, auto paint supply store. Place a mould half in a clean paint mixing cup, pour in a couple ounces clean thinner, brush well with soft bristle brush, and spritz with fresh thinner. Spotless and oil free so you can lube the important parts yourself.

I cast at 725 using a PID controller on my pot, seems to be just right for my use.

[17nut]

Soda blasting!

[gwpercle]

I can also pressure cast from a bottom pour... but I still wonder about cleaning solutions

Acetone soak , and scrub with an old Oral-B Tooth Brush ... Oral - B wont melt .
After a acetone soak , good scrubbing and clean acetone rinse ... it will be as clean as a whistle .
You can substitute Lacquer Thinner for Acetone if you like ...get same clean results ... just as good !
Gary

[AlHunt]

Stop with the brake parts cleaner. If it's non-chlorinated it's probably OK. The older stuff leaves a residue.

Do the Dawn and toothbrush and stop.

Tin may help.

HEAT. Almost all my wrinkly, rounded bullets problems have been not enough heat. I once ran afoul of that stoopid chlorinated brake parts cleaner (of which I used to be an acolyte)

Myself, I run my alloy up around 700 and flux. I've been preheating my mold across the top of the pot. I'll cast the first few throws when the alloy is around 750, while letting it run up to 800. My first 4 to 10 casts are slow to allow heat to transfer to the mold (Though I pop the sprue plate right away so it doesn't get too hard). By now my bullets are looking good and starting to show frost. Frost is my heat check and I start to let the alloy drift back into the 700's. As the mold gets hotter, the sprue will take longer to set and break easier and easier.

I believe antimony is required to get the frost reaction. If you're running pure lead, I don't think you'll get it.

Smoking sprue plate lube is another good heat check.

A hot mold is a happy, forgiving mold.