View Full Version : I need help to quit smoking

10-06-2003, 11:27 PM
Ok guys I need some good advice on the cheap to solve my current problem. Here's the skinny:
I've got a new habit of casting in aluminum in my backyard using the "lost foam" method, using small amounts of extruded polystyrene shaped to perfection. I really love the results of the method but there is a disturbing amount of smoke from the foam and the oil that is in the sand. I live in a very densely inhabited area and each time I pour metal I expect someone to call the Fire Department. Luckily it is of a short duration and although it does smell like some burning plastic it is not extremely noxious. I would like to use my wet vac and a tin hood to draw the smoke into something, but how can I process it or filter it with common materials? I need to be more low-pro when I cast. Any ideas?

Thank you in advance,


Bruce Griffing
10-06-2003, 11:34 PM
This is a little far fetched, but I can tell you what an industrial solution would be. It is called a burn box. You shroud the casting area and collect the smoke with a fan. Force it through a big steel pipe with a very oxygen rich natural gas flame. The "smoke" generally consists of a bunch of organic junk that is not completely oxidized. A good burn box will do take care of that. Probably not practical for you, but an answer.

10-06-2003, 11:47 PM
"...not extremely noxious." Burning Styrene is not only noxious, it's poisonous. You might try carbon filters in the Vent-a-Hood. I sure hope you've been wearing a mask.

Here's a quote from one of the "Environmental Quality Boards":

"The burning of polystyrene polymers - such as foam cups, meat trays, egg containers, yogurt and deli containers - releases styrene. Styrene gas can readily be absorbed through the skin and lungs. At high levels styrene vapor can damage the eyes and
mucous membranes. Long term exposure to styrene can affect the central nervous system, causing headaches, fatigue, weakness, and depression."

How long have you been doing this?

You may want to reconsider WHERE you do this type of work. It could place you in jepardy of serious liability claims by your neighbors.

[This message has been edited by CCWKen (edited 10-06-2003).]

10-06-2003, 11:57 PM
Try bubbling it through a hookah type device. Not sure what the end product would be though. Styrolitic Acid?

10-07-2003, 12:25 AM
Hi Ken,
Thanks for your input. I've read several resources on the toxicity of this material. There may be some hazard with some polystyrenes but this type isn't nearly as noxious as burning plastic or burning foam rubber. If there is another material that has similar properties, that is that it is easily shaped, firm, and nearly completely sublimates from the mold, and it DIDN'T smoke, and was cheap I'd be all for it.

As far as how long I've been casting with this method it is about 5 times now and I am getting very good results. Sunday I needed a solid metal bracket for a power steering pump for my old Jeep. I mapped out the mounting bolts, designed my part, sanded everything between the bosses smooth and curvy on the foam, put it in the sand with a couple of sprues and poured the metal. I filed, sanded and polished the part, and then mounted my pump. Took about 4 hours and looks beautiful. I'd like to think I did it in HSM style. I didn't have access to my BP mill to machine the bosses exactly, so I just filed it to fit.

Based on Bruce’s suggestion I am thinking of ways to draw the smoke into the intake to my forge. I could introduce some oxygen but I am already getting high temperatures already in my forge and my refractory concrete has a limit that I think is around 2800deg. Hopefully the air in the smoke will be enough. This smoke doesn't ignite much even when molten metal is poured on at 1220 deg. Molten aluminum on wood will sometimes flame up.



10-07-2003, 08:16 AM
(1) Make a friend in the country.

(2)A scrubber type of furnace stacks might work. A high heat, then a mist of water, two stacker.

Let me know the final solution, or at least write me from jail and tell me what they told you in court. One yuppie in ten miles with a chest cold that can point a finger at you. GONE GONE>..

10-07-2003, 09:23 AM
Hah, fuggettaboutit

The dang yuppies around here make more smoke and worse smells running their outdoor "mequite charcoal" barbeques. I can smell incompletely burned petroleum products on the wind at dinner time. Smalls like the airport, or a train station.

I agree that re-burning the products would work pretty well. Maybe a hood with another burner in the exit pipe?

Might be more conspicuous than just disguising the whole works as a barbeque. Let 'em think your metal pouring is just basting the chicken.

10-07-2003, 10:06 AM
Dilution is the solution to polution. You probably don't have a reasonably priced way of cleaning up your byproduct so just "dilute" it by running a good sized fan in close proximity.


10-07-2003, 12:28 PM
I was touring a big Union Carbide plant that made low and high density polyethylene. The high density stuff was a batch process and a big batch happened to start reacting too fast just as we drove our car past the process and they sent the whole mess to the flare. The flare was over 300 ft. high, the rumble and noise shook the car pretty good and may have been one of the loudest sustained noises I have heard. There was a gigantic blast of very black smoke from the flare which was probably over 10 ft. in diameter. The engineers in the car were excitedly telling me to watch the smoke cloud. The plume of smoke shot up but then fell like a blanket back to the ground not far from the flare. They said a good part of the noise was due to steam injection into the smoke. The steam condensed in the smoke and caused it to effectively rain out so that all the exhausted carbon and other chemical products stayed on the Union Carbide property. It was very impressive to see the control it had on a giant cloud of smoke that normally would have drifted for miles. The whole show probably lasted 2-3 minutes to burn maybe 50,000 lb. of plastic. Seems to me that you might rig up a very strong water spray at the end of a longer stack that you turn horizontal or down. The dense volume of water spray might work as well as steam if you have enough flow and you would only have to run the water for a few minutes so it wouldn't take a whole lot of water. Steam would be too much trouble and probably make noise which is more of a problem for neighbors than a little smoke. Another way out is to have a relatively tall smoke stack which will give the smoke a lot of vertical velocity. The idea is to do your casting just after dark when the smoke plume will be hard to see and shoot the smoke high in the air so the smoke and smell is dispersed. You could build the stack so that you can put it up just before you pour and then take it down.

10-07-2003, 01:15 PM
I dunno if Union Carbide would be my anti-pollution model......Bhopal, you know..... http://bbs.homeshopmachinist.net//eek.gif

Still, you need to consider whether the cure is worse than the disease.

You might be better off to get it over with in short order and basically be in "smoke? what smoke?" mode without fancy things to be disassembled etc.

Fancy techie devices simply serve to yell out "I'm doing something that you wouldn't like, right here next to you where your precious kiddies are in terrible danger from it".

I was not kidding about the barbeque idea as a substitute for a casting floor. An old weber or flip-top type grill might be just the ticket. Sand in the bottom to catch spills.

Nobody looks twice at a suburbanite working over the barbeque, no matter what is happening. Looks natural as can be, you fit right in the picture.

[This message has been edited by Oso (edited 10-07-2003).]

10-07-2003, 01:23 PM
Yeah, I like it. You just claim you have clumsy fingers and occasionally drop styrofoam plates on the grill.

10-07-2003, 01:33 PM
RE: "There may be some hazard with some polystyrenes but this type isn't nearly as noxious as burning plastic or burning foam rubber"

Styrene is still one of the worst byproducts of plastic production.

Try wax instead.

10-07-2003, 01:47 PM
I too have thought about building a brick barbeque pit.. Something about turning meat in the saftey gear I wear thou would screw up appearances..

Shoe covers are really important.. Aprons are too. NOMEX overalls, and a blast shield over your face.

I have had two or three molds leak the molten metal out.. NOW< I make my molds on the bottom flask when I can.. MOLD weights?" what ever I need?? SAnd box around the pour area. FOR SURE..

Be careful buddy.. and speak as little about what is actually going on as possible to the neighbors.

I put up a 8 foot board privacy fence.. NOW my problems with neighbors are almost over..

THEY really don't like the drag piped harleys thou. next to the metal building it just directs the noise to them.

10-07-2003, 02:37 PM
Yea Oso,
My forge is built out of a Weber style BBQ and it is still in the original stand with the original propane tank. I have a little blower that blows in from the bottom and a 4" hole in the top. The liner is held away from the shell on 1" concrete stand-offs and the liner is 2" thick. It has some cracks now but it has served me well, and the outer shell remains cool enough to touch. Other than the ductwork it looks original.

These foam models I am talking about are small and light and really represent a very small amount of plastic. The smoke is of a very short duration. It's only a minute or two and I'm not very exposed to it. I think running the smoke into the forge is worth trying and drawing the smoke through a tube with water misters might be something to experiment with. The smoke is nothing compared to my experiments on forging with bituminous coal. That was a nasty smoke that hung over the neighborhood for hours. I'm sure glad we don't heat our houses with that much anymore. Still the world doesn't need any more mushroom clouds either.


10-07-2003, 02:54 PM
Your not trying to remove any toxic fumes, you just need to remove most of the solids from the smoke for low visibility, right?

Make a very thick (maybe 2" or more), oiled (with sticky air cleaner oil) dense foam rubber pad around your Shop Vac filter, maybe even buy a HEPA filter to go underneath.

Make it thick/dense enough to almost pull the vac motor down a little.

You may have to clean it a lot, but how often are you gonna do this?

If the smoke temp. is too high for the plastic shop vac hose, use some of that foil flex hose for a ways to let the temp cool some (even drop a few loops in a barrel of water, if it is too hot).

If there are SPARKS in your smoke, you may torch a good shop vac, though!

Just a thought that would be cheap to try out........


[This message has been edited by Hellbender (edited 10-07-2003).]

10-07-2003, 03:09 PM
Had an even better idea (maybe)....

Put 10"(or whatever, more is better) of water in the bottom of your vac and extend the interior intake vent (with a 90 and length of tube) so the vac is actually pulling the fumes THROUGH the water (bubbling through it).

No filter needed.


10-07-2003, 03:18 PM
Best one yet....

Get a 30 gallon oil drum....

Foil/metal hose (intake from hood) to the bottom of the drum in one bung hole.

However much water depth your vac will suck through.

Hose from vac to other bung hole.

Seal hoses off good at bung openings.

Cheap scrubber....

No heat problems.....


[This message has been edited by Hellbender (edited 10-07-2003).]

10-07-2003, 03:54 PM

That's the hooka idea I mentioned. Probably work, that's how the air cleaner on my Land Rover works except it uses oil.

10-07-2003, 04:04 PM
<font face="Verdana, Arial" size="2">Originally posted by Evan:

That's the hooka idea I mentioned. Probably work, that's how the air cleaner on my Land Rover works except it uses oil.</font>

All my cool ideas are always old news, dangit!

Are you sure your Land Rover Air cleaner actually draws air THROUGH the oil? Most of these types of filters (that I am familiar with) actually use the centrifical force of the swirling air to throw the dirt particles into an oil trap (ie, the air does not actually pass through the oil).


10-07-2003, 04:37 PM
You may be right but I would have to have a look. I haven't bothered with the air filter in years since the Rover is used mostly in the winter and there is no dust in the air in the winter. It never goes on the road since it is not licenced.

10-07-2003, 07:25 PM
The Hooka idea might work, but my own experiments with a bong many years ago proved that the smoke still gets through pretty good. Although it is a little milder. Still it is something to try. Next time I cast I'll have a smoke hood and a duct leading to my forge intake. If that doesn't work well, then I'll try the scrubber tube with water sprayers, and if that doesn't work I'll try the sticky filter. In a month or two I'll have snow to work with as well. It used to work in the bong http://bbs.homeshopmachinist.net//wink.gif
All this just to be a good neighbor.


10-07-2003, 07:54 PM
Duct it off to your forge,but use an overshoot duct so as not to run hot gas through your blower,if you have a charcoal or propane flame going in there it will work fine,so long as the carbon in the styrene smoke is heated to 2100 F,at this temperature the when the carbon hits air it burns completely and produces white ash.

10-07-2003, 08:39 PM

Add a 6" thick foam rubber pad setting in the bong water to break up the big bubbles.......... maybe........??


10-08-2003, 02:13 AM
Your concern is with code enforcement which is generally complaint driven. The key is to not raise the ire of your neighbors. Do your casting during off times when nobody is around, after dark so smoke is not visible, generate an acceptable masking aroma to cover your smells (BO accepted) and remember as Kurt said dilution is the key. A hood with a big fan blowing in a vertical direction should do it. Unless you can generate real high temps reburning the smoke could make matters worse.

Neil Peters

10-08-2003, 10:08 PM
I can just picture Gypsie in his "uniform". Neighbor yells, "Hey! What are you doing over there?" Gypsie pulls out a fork, "Hot dog anyone?"

I think Krawdad has the best idea. My paint booth shoots the "gasses" straight up into the air. The fan is about 10,000cfm though. The paint filters trap the solids (supposidly).

Yea, if anybody saw me in my "space suit", they, for sure, wouldn't think I was flipn' burgers.

[This message has been edited by CCWKen (edited 10-08-2003).]