Cleaning a mould.

[uncle jimbo]

I was given a Lee 358-158-RF that is a mess. The person that give it to me said he got it in a yard sale box and he told me that it was a mess. If I can get it cleaned, I would like to try it. The dark coloring looks like varnish or laquar and it looks to be baked on. The pictures I took are no real good, but you can see the what I am talking about. An ideas or advice would be appreciated.
Thanks,

paul

 

[Brad]

Give it a good cleaning with bore solvent. Let it soak for a while. Follow that with a good soak in acetone.
I would then give it a go casting.

 

[Rally]

Looks like someone cast with an oiled mould without cleaning it first. I'd do a couple sample cleanings with different solvents to see which one did the best job, then soak it in that for awhile. Then clean it with hot water and dish soap with a toothbrush.

 

[Pistolero]

Looks like somebody did what Lee says and smoked the mold. Yuck.

Scrub with Comet and a toothbrush. Then rinse in hot water.

Bill

 

[dromia]

Yep they followed Lee's instructions and used bullet lube on the mould.

If so then that stuff is a bugger to remove, I find a good boiling with a touch of dish soap works, it will dull the finish on the mould but not harm its function cosmetic only. Acetone is good too although it evaporates quickly, so not much good for soaking in.

Is there any of that muck in the cavities, graphite mould "release" or such like?

 

[Bret4207]

Sometimes, not always, if you get the mould hot and take a swipe at that stuff with 4/0 steel wool it will pull it off. But it's got to be 4/0 steel wool, nothing heavier.

 

[Wasalmonslayer]

You might try wire wheel cleaner from the auto parts stores.
It’s a mild acid.
We use it a lot for detailing older boats it helps take off hard water, deep cleans the grimy galvanized wheels, and take a lot of the dark staining off aluminum.
You must dilute it thou we do not use it straight.
Our mix ratio is 1 cleaner to 4 water.
On the aluminum it will foam just a little.
I have cleaned some real scuzzy molds with this stuff and when finished they look brand new!
Just wet the dry mold and spray down liberally with the solution.
Let is work for 5 min rinse and repeat till it is clean.
After it is clean and rinsed off I hot plate them to dry em out and dust the cavities with just a hint of smoke.

Then heat it up and cast as normal.

I use this method after all other ways have been exausted and you must be careful because it is an acid solution always wear skin and eye protection.

 

[uncle jimbo]

Yep they followed Lee's instructions and used bullet lube on the mould.

If so then that stuff is a bugger to remove, I find a good boiling with a touch of dish soap works, it will dull the finish on the mould but not harm its function cosmetic only. Acetone is good too although it evaporates quickly, so not much good for soaking in.

Is there any of that muck in the cavities, graphite mould "release" or such like?

Yes, the cavities are as black as coal.

 

[Ian]

Yep they followed Lee's instructions and used bullet lube on the mould.

You and Bill nailed it, smoke and bullet lube both per instructions.

My approach would be based on function, not appearance. If it can be cleaned up well enough via the mentioned methods to close properly and make the sprue plate fit, try casting with it and see. A tuft of 6-0 steel wool spun onto a Q-tip is good for polishing cavities with the blocks closed as a last resort.

 

[fiver]

a bullet and some comet mixed with tooth paste will generally clean the cavity's in about a minute, then wash right out in a pan of hot water giving you just enough gritty-soapy stuff for the tooth brush to work.

 

[uncle jimbo]

Thanks for all the ideas. Much appreciated.
So I started by soaking it in a solution of vinegar and baking soda over night. It go a lot of it off. I then used a toothbrush and scrubbed is a paste of vinegar and baking soda. This morning I made a solution of vinegar, baking soda, and Dawn dish soap. Boiled it for 3 hours. That got most of the remaining gunk off, but it made the aluminum turn brown and I can't get that off. I am back to soaking it vinegar and baking soda and using the toothbrush with baking soda to scrub it.
I think I got most of the gunk from the vent lines and the cavities, but they are brown now. If the weather is better tomorrow I am going to try. It is so cold outside, I don't think I can get the pot hot enough or keep the mold hot enough.
I will post a picture of it when I get ready to cast.

paul

On a side note, Chem tool, brake part cleaner or engine degreaser even touched it.

 

[Brad]

Brown I wouldn’t worry about. If it looks better try casting with it. Some of the color may never go away.
I am far less concerned with how my moulds look than how they cast.

 

[Pistolero]

Hmm. Not meaning to be rude, but if you mix vinegar (acetic acid) and baking soda (sodium bicarbonate),
they react with each other, pretty much cancelling each other out, and you have a solution of sodium acetate
and bubbles of carbon dioxide.

It may be sodium acetate is a good cleaner, I don't know .....but I tend to doubt it, it is a salt and most of them
aren't cleaners. I'd think that using either vinegar OR sodium bicarbonate, one is a mild acid, the other a
mild base, would likely work better than both together.

Sodium acetate - Wikipedia

en.wikipedia.org

Lemishine would be good. It is a mild citric acid, you could drink it, but it will tend to reverse any
oxidation of the alumium, making it shine. Try a half hour to hour soak. Available as a dishwasher
additive in the grocery store.

I clean all my new Lee molds with a toothbrush and Comet. Works great, removes oil and very small
burrs, but not any bigger ones.

Bill

 

[uncle jimbo]

Pistolero, how the hell can you be rude. I ask for advise and you offered something that you knew about. That is what I am looking for.
And besides, the day that I stops learning, is the day they screw me into the ground.

 

[Ian]

This is what's so good about bulletin boards filled with knowledgeable, helpful people. Everybody brings something to the table that fills in the cracks.

Somebody correct me if I'm wrong, but iirc vinegar and hydrogen peroxide are often mixed to make a de-oxidizing solution. How something with an extra oxygen molecule can de-oxidize doesn't make sense to me, but it eats rust.

 

[fiver]

airc it gives off that extra O molecule to the air.

 

[Pistolero]

OK, uncle jimbo, I just was a bit uncomfortable criticizing the mix you were using.

Deoxidizing does sound odd, Ian. Acidic solution with hydrogen peroxide....not sure. The acid is
a reducer - will try to reverse oxidation, and then the extra oxygen on the peroxide would try to
re-oxidize it? No kind of real whiz at chemistry, just basic stuff. Maybe the lower pH helps the
peroxide work. It should be good for removing stains - oxygen bleaches out stains well.

Never looked into that one, but have heard of it.

A quick online check says peroxide and vinegar is marginally safe because each OTC is a very dilute
version of what they are. With higher concentration of both, neither readily available, you can get
peracetic acid which is toxic and one source suggests it can explode.

Remember the rocket belts that they used to fly around stadiums and such as stunts?
Concentrated hydrogen peroxide fed into a silver screen catalyst flashes to steam and
that is what the nozzles spew out to lift the guy up and fly him around. Lots of energy
in concentrated hydrogen peroxide.

Bill

 

[Bret4207]

Pretty sure Oxy-clean, which my wife swears by as an odor remover for our stinky barn clothes, is just a powdered form of an oxygenater. She also mixes baking soda and vinegar in the washer after washing dog blankets and says that kills smell and provides some bleaching action. I'm not going to argue with her!

 

[Pistolero]

Bret you might buy your wife a box of washing soda, normally available at grocery stores.
Sodium carbonate. It softens water and helps remove grease and stains and keep them in
solution. It was a common wash day additive many years ago, modern detergents and whole
house water softeners and general loss of knowledge has cut down it's popularity, but it does
work well and you might please your wife if she gets some and likes the result.

It is also great as the electrolyte for battery charger bulk rust remover from tools and
such found with severe surface rust.

Bill

 

[Bret4207]

Been using it for years Bill. Thanks!