Author Topic: Fume Hood - Casting ingot and bullets  (Read 7867 times)

Offline idelphic

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Fume Hood - Casting ingot and bullets
« on: November 02, 2009, 12:12:04 PM »
Happened to have the chance to do some casting over the weekend,.. even with a draw fan going, and the garage doors open,.. the smoke got a bit thicker then I'd like...  This was my first exposure to casting, so I'm thinking ahead to the next time.

Has anyone considered building a fume hood setup to cast ingots and bullets?  To cast the ingots we used a camp stove and a pot and dipped out the scrap steel, and then ladled the lead into molds.

To cast the bullets, a standard electric pot was used.  While not nearly as hot,.. it still off gassed.

I wonder about using a high draw fan over the work area (pot) into a HEPA filter to prevent 'extreme' exposure.

Offline cohutt

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Re: Fume Hood - Casting ingot and bullets
« Reply #1 on: November 02, 2009, 09:07:44 PM »
I smelt ingots outside, period. too much mess and smoke funk is generated cleaning the lead.

With my clean ingots,  I cast bullets in my shop with a box fan pushing air in and a makeshift vent hood drawing out directly over the pot.  I salvaged a bare fan from a kitchen renovation years ago - made the hood out of thin panelling scrap and cardboard and shot it 2 feet directly out of the shop with no filter.
It is hardly an air tight shop - a single basement garage slip dugout with ill fitting bard doors on it.

Offline CountryRootsCityJob

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Re: Fume Hood - Casting ingot and bullets
« Reply #2 on: December 09, 2009, 11:11:26 AM »
Everything I remember about casting with my dad says dress up warm, get a bunch of hot chocolate/coffee/apple cider, and fire up the camp stove on the back porch... preferably when it's not too windy.  Doctor bills cost too much to take the risk of doing that inside any enclosed area in my book... I may be paranoid, but if you take that route, you aren't going to be wondering if your filter got enough trash out of the air or what-not...

Then again, I live in zone 6...

Offline Orionblade

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Re: Fume Hood - Casting ingot and bullets
« Reply #3 on: December 12, 2009, 01:15:01 AM »
Quick tip for a "fume hood" - get a laundry sink - or a surplus any kind of sink that's about 2 feet square-ish. Metal would be better, but the big plastic laundry sinks aren't bad.

Long story short - get a shop vac, hook it up to some fittings and attach it to the drain port - you might enlarge the drian with a PVC floor flange to accomodate more flow rate. Put a grate of some sort over the top. The one I saw at a wood working shop used what I think was a gas grill or oven grate, fastened with some little plumbing/wire clamps around the edges.

You have to size it so there's not a HUGE amount of dead space - I would imagine a large electical conduit junction box would work as well - with a side outlet so you might have more height-appropriate mounting options.

Anyhow, if you want some design help, let me know, but there are commercial options available. The best part of this is that it's reasonably portable and exhausts the junk wherever you put your shop vac, and it also sucks junk DOWN away from your face, instead of up or to the side. Commercial fume hoods that I would reccommend for use with lead or other heavy metals, run about 1500 bucks even on eBay.

Later,
Orion

Offline quietmike

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Re: Fume Hood - Casting ingot and bullets
« Reply #4 on: December 12, 2009, 05:54:18 AM »
I rigged a HVAC register boot to be above my pot and attached an 8" axial fan and duct work to pipe the fumes through the wall.

Works well and is quiet and cheap.

Offline r1kk1

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Re: Fume Hood - Casting ingot and bullets
« Reply #5 on: August 04, 2010, 08:31:54 AM »
If I'm fluxing then I wear a respirator. When I'm casting I do not. I have my lead levels checked every two years. My baseline is negligible, and recent tests have not shown an increase since the first baseline was taken some 30 years ago. I do not eat or drink when working with lead and wash my hands frequently. I would recommend that everyone get a level drawn at their next physical. I cast outside in a garden shed with a huge opening. Winter time is casting time for me.

take care,

r1kk1 

Offline copdills

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Re: Fume Hood - Casting ingot and bullets
« Reply #6 on: August 05, 2010, 12:32:46 AM »
in the winter time I cast in building outback, I use an old range hood with  the built in exhaust fan pulmed to the outside , works ok so far

Offline dicko

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Re: Fume Hood - Casting ingot and bullets
« Reply #7 on: September 05, 2010, 01:43:13 PM »
The report of raised blood lead levels by 423 aaron, is related to this.   It is well known that lead poisoning never leaves the body and accumulates over time with repeated exposure.   It is of course very damaging.   The question is whether bullet casting carries a risk of lead poisoning, and if so, how much risk.   423aaron's report is not the only report of elevated lead I have seen, so I take it seriously.  But I have seen very few such reports.   As a commercial bullet caster, I cast more bullets in a year than most home casters will cast in a lifetime.   Being self employed, I have a medical check up every year, including blood tests.   Because I handle lots of lead, I get tested for lead every two or three years.  No elevated levels have ever been found.

I can't explain why I don't get poisoning while others do.   I can only describe my practices, in which my safety precautions are more directed to avoiding burns than poisoning.   There are two possible causes of poisoning, absorption through the skin from handling, and breathing fumes.   Pure lead and almost pure lead is soft, and certainly rubs off onto the hands, sufficiently so that I don't handle soft lead with bare hands.   To be exact, I will  the occasional piece because it takes more than that to be harmful, but that's all.   For the most part I wear gardening gloves.   

It is of course not practical to wear gloves for lubricating.   Fortunately the bullets are not soft lead, they are hardened with antimony.   I handle them in the tens of thousands, and have never seen lead coming off onto my skin.   What makes lead fumes so dangerous is that they are colourless and odourless, and thus undetectable.   However, lead does not fume below about 900F, which is so far above casting temperature that it should never be approached.

I do all my casting indoors with no artificial ventilation.   For one thing I don't want to get rain in the melted lead.  In any case my equipment is bulky enough to make it impractical to move outdoors for the day's work then indoors afterwards.   My conclusion ?   There is no need for fume hoods, extractors and the like.



 
       

Offline Orionblade

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Re: Fume Hood - Casting ingot and bullets
« Reply #8 on: September 25, 2010, 05:32:35 PM »
I would point out that all liquids have a nonzero vapor pressure, no matter the temperature - what that vapor pressure IS, is another question. I can't really comment on it, but I would say that for the average home caster, since you're not going to be as experienced as a commercial casting shop, just get a little fume hood or "solder smoke sucker"

I just found one of these and I'll be ordering it soon, since I have my shop almost complete and will be building a TON of circuits very shortly for a variety of projects (to include a CNC unit for my 3 axis mill)

http://www.howardelectronics.com/xytronic/426dlx.html

60 bucks seems steep, but for the peace of mind, I'll take it.