Arsenic laced flux?

[Cowboy_Dan]

My parents have finally decided to tear down the swingset on their property before the neighbor's grandkids hurt themselves. It's made out of treated lumber which leads me to believe it contains arsenic. With this in mind, I have a two part question:

1. If the wood is nearly 20 years old, is the arsenic still in it? I have read that oxides of arsenic are gasseous, so it is possible that it has all evaporated.

2. If there is indeed still arsenic in the wood, will using sawdust from it introduce that arsenic into into what I am fluxing? I may end up oxidizing the arsenic, so once again it may evaporate away.

In any event, sawdust makes good flux. So unless this is a bad idea somehow, I think I'll save the sawdust from cutting the parts down for alloys I intend to heat treat.

[fryboy]

i wouldnt even consider it myself - nor would i consider burning it ( for heat,for cooking or even just to get rid of it ) arsenic isnt the only chemical they used in the witches brew for treatment , long term problems with it is why they quit using arsenic as part of the treatment , there's enough much less questionable flux out there in the world for free to not have to mess with it ,heck i think i'd use cow chips before i used treated wood or even grass clippings

[Handloader109]

Agree, would not use treated wood sawdust for this purpose. If you are just casting use beeswax. If you are smelting find another source of wood

[CopperniX]

I am going to have to agree with those above. It is a risk however slight it is still a risk any arsenic left over would be released when burned and there in lies the risk.

[BruceB]

The area of the Northwest Territories where I lived for 35 years is VERY HEAVILY infused with arsenic. It is naturally-occurring in the igneous (volcanic) rock that forms the topography.

The arsenic level in the rock is so high that the lakes show an obvious increase in arsenic levels during and after the spring run-off of snow melt.

One of the major ores in which the gold is found is arsenopyrite.... and arsenic is a MAJOR part of that ore, as one may gather from the name.

Pure arsenic was a byproduct of the refining process, and for some years we were exporting the stuff for wood treatment at a plant in the eastern USA.

The mine where I worked is now closed-down, but there is almost a MILLION TONS of 90%-pure arsenic tri-oxide in storage in old underground workings..... and those old workings are now leaking.

Since the company that owned the mine is now defunct, there is a potential catastrophe which is now the responsibility of the government.

However, I must say that several generations have been born and grown to adulthood in the Yellowknife area without apparent harm from the rather high levels of naturally-occurring arsenic in the environment.... and the drinking water is drawn from those lakes mentioned earlier.

[jsizemore]

The most widely used wood treatment was chromated copper arsenate. Most cautions are not to inhale smoke from burning. I asked chemists, chemical engineers, Ag and forestry PhD's about the hazards from using CCA treated lumber. To a man they said they used treated lumber in and around their gardens and didn't hesitate to feed themslves or their loved ones with produce from those gardens.

[waksupi]

If you get a slight garlic type smell when you put it in the pot, quit using it!

[Toymaker]

There are any number of ways to do the "treatment" on treated wood. All of them involve the use of metallic salts at some point in the process. During the process some of the salt compounds combine to form other compounds, but salts remain. You DO NOT want them in your lead mix. In CCA the copper retards fungus which leads to rot; arsenate (form of arsenic) is a pesticide; chromium binds them together and to the wood. Cut the playset up, use a dust mask, bind up the wood and trash it. Then shower well. Where you leave the sawdust will likely kill the grass.

[RogerDat]

If you need to wear a dust mask to saw it I'm thinking burning it in a melting pot is a bad idea. Not sure but I would think those chemicals could combine with your alloy in unexpected ways. IIRC adding copper sulfate is one way to get zinc out but if there is no zinc then it would pull the tin out. Who knows what CCA would do to your alloy.

[40-82 hiker]

From: http://www.health.state.mn.us/divs/e...s/CCA_fact.pdf

Arsenic causes cancer in humans and has other
toxic effects on the skin and internal organs.
These effects may occur following long-term
(chronic) exposures to small amounts of arsenic.
Arsenic health effects can take years to develop.
Short-term (acute) exposures to arsenic can also
affect health.
Exposure to arsenic from treated wood occurs
when the wood, scraps or sawdust is burned.
Since arsenic is an element, it cannot be destroyed
by fire. Burning CCA-treated wood releases
arsenic, copper and chrome into the air in
dangerous amounts and the leftover ash can have
very high concentrations of arsenic. Arsenic in
ash can be drawn into the groundwater by
rainwater and contaminate drinking water wells.
CCA-treated wood should never be burned.

[1johnlb]

Cowboy Dan great question.
I've heard of cutting corners and being economically sound but that's just plain cheap. My kind of people.

Bruceb
If everybody in town is weird,that makes us normal.
I'm the only normal one in my town.

Pun intended

[MaryB]

Reuse the lumber to build something, toss the sawdust

[62chevy]

Cowboy_Dan I think there are better way to get arsenic in your melt. One would be wheel weights and the other is lead shot.

[Cowboy_Dan]

OK, glad I asked first.

Thanks for the warnings.