Casting Fume Box

[mark james]

Due to allergies, this project came into being. I suspect it may be useful for anyone who may develop sensitivities to resins after they have been casting for awhile and may want to try to continue, so there may be more application. Additionally, it may be useful for those who use PR (which I do not) as I've read that the odors can be strong.

I started with a Harbor Freight 40 lb sand blasting cabinet. (May, 2014: $299; sale price $210; additional 20% off = $168). Extras: silicone caulking, 3/4" gasket tape; 6 LED puck lights; copper fittings; blue flex tube for air vent; Air vent/duct for garage wall; a battery operated air mattress pump; various fittings to reduce hoses and pipes from the box, to pump, to wall junction; probably a few other minor things.

My objectives:

1. Sealed as well as possible to prevent exposure from fumes on my skin.
2. Have a slow continous air draw out from the box venting through a wall.
3. Be able to have enough inside work space to mix and cast and store
all supplies.
4. Pass inspection from SWSBO!

Inspection went as expected... I failed!

Last 2 items required: Better gloves. The included gloves are actually deemed very good, but may be gas permeable are questionable, so SWSBO will order me some of her preference . And it was suggested to have a 1 3/4" air hose for air in from the outside wall, and seal all last junctions and the hole in the back where the compressor hose has bee threaded. I had thought that all forward joints were sealed directly in front of me, and that the back accesses could be OK to allow air in and help with the continous air draw... This was not acceptable.

If this is of any interest - ask any questions.

I need to wait a few more days to test and do some casting.

 

[plantman]

Mark; Now this is a case where thinking inside the box makes life a lot more enjoyable for you and others who are sensitive to fumes. Great idea, designing, and exacution on your part !! Nice photos to show how it was done. How are the gloves to work with, and is that an explosion proof motor ?? Jim S

 

[mark james]

Mark; Now this is a case where thinking inside the box makes life a lot more enjoyable for you and others who are sensitive to fumes. Great idea, designing, and exacution on your part !! Nice photos to show how it was done. How are the gloves to work with, and is that an explosion proof motor ?? Jim S

KABOOM




Explosion proof motor....???? Me THUNKS NUT...

Hi Jim.

It is a simple battery operated inflatable air mattress pump with an inlet hole and an outlet hole. I was not sure it would suffice, but I was VERY happy with the draw - the air coming out was very acceptable to me before final installation with a silicone seal. IT WILL CLEAR THE AIR FROM THE HOOD.

Gloves... My wife is looking into that and will order what she deems best...... I have been banished from the hood until it is "wife approved." Which actually is fine with me; when you have an "ace in the hole"...use it!

Unfortunately, she travels to England for 10 days, so unless she gets gloves ordered in the next 2 days (she won't), I won't try to cast until late in May (unless...).

I have some leads on gloves, so we'll see.... Although for me, fumes are the crucial issue (not splashes), so I want/need gloves and seals that are good for gases/fumes. ("Nitrile coated").

But.. Hope the thread was useful. Ask any any questions as this is a work-in-progress.

 

[MikeL]

"allergies, the mother of invention". Maybe that's not how the quote goes.

I think it is a great idea. I have definitely become sensitive to CA and am now wondering if I am getting sensitive to latex or maybe it is to resins. Not sure. But your fix could be something others may need.

 

[plantman]

Thanks for the added info Mark. Reason I asked about the gloves is, I know I would ever be able to open small containers (CA) with the thick rubber gloves that came with my sand blaster, it's hard enough trying to hold small parts with them. The reason for asking about the motor of cource was for safety reasons, but what you have and the way you have it set should rase no issues. Great job !! Jim S

 

[mark james]

"allergies, the mother of invention". Maybe that's not how the quote goes.

I think it is a great idea. I have definitely become sensitive to CA and am now wondering if I am getting sensitive to latex or maybe it is to resins. Not sure. But your fix could be something others may need.

Take some advice: (not from me necesssarliy)... Woodturners/woodworkers have attested for many moons that once you are "sensitized", it does not go away, and it will get worse unless true precautions are taken.

I had severe reactions to Paduk; never touched any Rosewood; had reactions to several other woods, so I'm certainly in the "TAKE PRECAUTION" class.

I have a JET ceiling mounter air filter, a Jet Dust collector, use a full respirator when warranted, and STILL have occasional problems.

Be mindeful to what YOU need. And do it! It's worth it!

 

[TimS124]

Great concept and love that the execution includes solid quality control. Thank you for sharing your project and your wife's expertise. Hope it works out for you.

 

[OOPS]

You may feel that your pump is sufficient, but consider this:

College chemistry labs have fume hoods, but they are not sealed in the manner you describe. The hoods are open about 6-8" above the counter, so that any number of people can put their hands in under the hood simultaneously and pour or mix chemicals. There are no noticeable fumes coming out of the hood because of the size of the fan, which sucks air from inside the room, through the opening and up the vent. The fans have to be explosion proof (which I don't believe you need here) but they move an impressive volume of air through the unit, so if you have 15 cubic feet to your unit, a bathroom or kitchen fan that pulls 180 cu.ft. will make sure you don't smell anything. Also make sure the line between your box and the wall is as straight as possible to prevent inefficiencies of air movement.

I like your idea, so these comments are just for your consideration. I hope this helps.

 

[mark james]

You may feel that your pump is sufficient, but consider this:

College chemistry labs have fume hoods, but they are not sealed in the manner you describe. The hoods are open about 6-8" above the counter, so that any number of people can put their hands in under the hood simultaneously and pour or mix chemicals. There are no noticeable fumes coming out of the hood because of the size of the fan, which sucks air from inside the room, through the opening and up the vent. The fans have to be explosion proof (which I don't believe you need here) but they move an impressive volume of air through the unit, so if you have 15 cubic feet to your unit, a bathroom or kitchen fan that pulls 180 cu.ft. will make sure you don't smell anything. Also make sure the line between your box and the wall is as straight as possible to prevent inefficiencies of air movement.

I like your idea, so these comments are just for your consideration. I hope this helps.

GREAT SUGGESTIONS! I'll check those fans for possible replacement of mine! I just want to make sure I don't PULL in garbage/dust/etc as my main purpose is clear casting Alumilite for stamp blanks; I have about 35 I would like to do for family at Thanksgiving. But I am very open to improvements!!!

 

[TimS124]

Home Depot carries a 50 cfm bathroom vent fan for about $14. If you want to move more air, the price goes up, but that's a pretty cheap starting point...

 

[mark james]

Finally ran a test cast earlier yesterday. :wink:

Went well! I believe I may have a reasonable solution for those of us that have allergies!

Final tweeks: I used the gloves supplied from Harbor Freight.
I abandoned the mattress pump for an unused small shop vac.

I casted 2 sierra blanks - Alumilite. 40 PSI, 55 minutes. These were stamps on tubes that I owed attendees at the Ohio IAP meeting a month ago (sorry for the delay...). The members made the blanks and I was to cast them and send them home!

Just a thought... These may be great blanks for Service Pens!!!

But, back to the box! It held pressure well. A smoke test indicated that all air was going out of the box rapidly!.

I practiced 2X with water to see if my "dry box" technique was OK - I did fine.

I was able to mix the alumilite (clear) within 3 minutes, and pour into the cast, drop the lid and tighten, pressurize, all within 5 minutes.
(I had 7 minutes for the Alumilite to set).

Pressure was still at 42 PSI at 55 min.

I purged the tank out the wall of the garage. Turned on the shop vac to vent all latent fumes for 5 minutes. Opened the pressure pot and let sit/air for 5 minutes. I then turned off all air/compressor, and let the mold sit for 10-15 minutes.

The molds were rock solid! A few "clouds" on the upper perimeter - should be no issue after turning!

A day later... No allergies (The entire reason for this post!!!). I'm REALLY HAPPY!!!

It may be a small victory, but I want to cast small amounts just for personal use for stamps, steampunk, hopefully watch parts; this is encouraging!