over cooked lead?

[Rickf1985]

As for lead vapors being created at lower then boiling point... Does water need to boil in order to evaporate (creating water vapor) and go into the atmosphere?

45_Colt.

No, But, Water is a combination of two gases so there is a big difference. Both Oxygen and Hydrogen are base elements combined to form water. Lead is a base element in itself with no other elements to gas off. Probably not the most scholarly explanation but hopefully you get what I am trying to say.

[farmbif]

I 'm thinking in order to get lead vapors you would need to get it up to something like welding temperature like 1700-2700 degrees depending on process and material , but I'm no expert and its been about 50 years since I was in welding school

[45_Colt]

This discussion has been going on for too long. Lead starts to out-gas at a low temperature. As for water, so when it is evaporating it changes into a substance that is no longer water (more of one element then the other?)?

Here is a better example, a pure element, mercury. Ever heard the phrase "mad as a hatter?" Back in the day (1800's) a "hatter" was someone that made and sold hats. Mostly made of felt. They carved a mold from wood, placed a piece of felt into the mold, then back filled it with mercury.

After a few days the felt took on the shape of the mold.

The only issue was that the mercury was off gassing the entire time, AT ROOM temperature. Poisoning the hatters. The neurological damage turned them into lunatics.

So those that cast, be sure to keep the temperature of the melt under control.

45_Colt

[rockshooter]

does water need to boil to evaporate? well, thinking about my ultrasonic vaporizer, I'd say not.
Loren

[JimB..]

Here is a better example, a pure element, mercury. Ever heard the phrase "mad as a hatter?" Back in the day (1800's) a "hatter" was someone that made and sold hats. Mostly made of felt. They carved a mold from wood, placed a piece of felt into the mold, then back filled it with mercury.

After a few days the felt took on the shape of the mold.

The only issue was that the mercury was off gassing the entire time, AT ROOM temperature. Poisoning the hatters. The neurological damage turned them into lunatics.

45_Colt

Ventilation never hurts, but you and I have different understandings of the old felt hat making process.

The making of felt hats involved wetting the fibers with mercury nitrate as it caused a denser felt than previous methods involving urine. The felt was then steamed and pressed onto forms. The poisoning came from the steaming.

Elemental mercury was not used in the process to my knowledge, although I suppose it could have been available to produce the needed mercury nitrate.

Mercury does evaporate at room temp, all metals evaporate at some rate when they are liquid.

No idea if a casting pot produces enough lead vapor to matter, or if the difference between the amount produced is materially different at 900 vs 700. I tend to err on the side of caution.

[45_Colt]

Ventilation never hurts, but you and I have different understandings of the old felt hat making process.

Interesting, now I wonder if I got bad info, or I'm just plain forgetful. Most likely the latter...

45_Colt

[bangerjim]

Mercuric nitrate (not pure mercury) was the actual substance used to "soften" the felt fibers, not fill the hats. Today hydrogen peroxide is the acceptable safe way to do it. Check out Wikipedia under "Beaver Hat" to see how they were made.

Any metal with oxides or nitrates attached to it will create FAR more health problems than the pure element. Just compare pure lead with white lead oxide for an example.

I would suggest, rather than arguing above one's head on an off-topic on a casting forum, you simply type "mercury used in hat making" into your favorite search engine and read until your eyes hurt!


Most "verbal battles" on here would not even exist if people would just let their fingers do the walking with a search of the net before posting questions or comments. And I DO NOT mean getting "knowledge" from idiots on YouTube!

PS..............if you are afraid of mercury, check your teeth! Chances are you have several silver/mercury amalgam fillings in there! Standard dental practice until they came up with modern plastics to do the job. The mercury magically went away! I had 4 silver filling for 40+ years until the sides of the teeth cracked! No mercury poisoning here. Millions of people have them even today.

[danmat]

#3 on my Lee pot will give me 700 or above at times. It is very inconsistent. That is why I went with a PID on it. I still have the original Lee thermostat hooked up but I leave it set at 7 so if something happens to the PID it will limit the upper reach's of the lead temp. A Lee pot, unregulated, can glow red. And a PID can fail, my temp probe failed and the PID went into full heat mode.

Most pids will have failsafe setting in setup, either hi or lo. Something people using these should check into.

[mozeppa]

i got water to boil at 212 degrees!

[Rickf1985]

Most pids will have failsafe setting in setup, either hi or lo. Something people using these should check into.

The problem with my scenario was that it was not the PID that failed but the temp probe failed. It went to cold temp so the PID thought the lead got cold and called for full heat trying to bring the temps back up. I had bypassed the factory control on the Lee pot not too long before that to see if it made any difference in heat up time, it didn't. I hooked that original thermostat back up real fast after that episode! So now, even if the temp probe fails for the PID the factory Lee thermostat will hold it at around 850-900. Remember, these temp probes are all made in China. And while China has the full capability to make top shelf electronics we certainly are NOT getting them.

[john.k]

Machinerys Handbook---------The open lead bath.......blah ....should not be used for temperatures beyond 1190deg F,as the lead begins to vaporize......blah.....as the temperature increases,lead volatizes and gives off poisonous vapours ........however,with provision of a fume exhaust hood,lead may be used up to 1500 -1600deg F ..(before losses become uneconomic)........of course,the lead fumes were going out into the open air,and doing this today the EPA would lock you up.