how to build an acid resistant hood & scrubber _hood_

[4metals]

How is the suction at the hood? It should draw smoke generated at the opening up and out efficiently.

 

[dick b]

I think he is trying to suck against 24"s of water column. Thats much different that drawing air and fumes thru moist media. He needs to go back into this thread and get a better understanding of what the spray nozzles are for.

dickb

 

[2002valkyrie]

Don, did you get yours set up today?
i'm waiting on my sealer to dry. But it looks real good.

 

[eeTHr]

Val;

It works, but the beginning of the holes in the 4" pipe can't be more than an inch under the water or it will make too much suction inside the garbage can, and pull the sides in. It was drawing the air out of the end of the pipe, with no holes in it, with water about one foot up the pipe, but it nearly collapsed the Rubbermaid can.

The air flow will put out a bic lighter at the pipe opening inside the hood. I think that's enough flow to get rid of fumes. It's a 5.5 HP shop vac.

I'm thinking about some kind of reinforcement inside the garbage can.

I'm also wondering if the motor will overheat, because it doesn't look big enough to be a continuous duty motor, as it's very small for a 5.5 HP. I've seen one horse continuous duty motors that are bigger than it is.

I'll have to monitor the heat coming out of the separate cooling fan vent. I hope it has a thermal overload switch inside.

Tomorrow I'll try it in use. :?:

Don

 

[eeTHr]

I added more holes in the 4" down-pipe, at the same level, to increase flow and reduce the vacuum in the garbage can. It worked to some extent. Now the garbage can pulses like a beating heart, about two pulses per second. But it has good air flow at the hood.

The shop vac can take two filters inside, one cylinder shaped going into the empeller opening, and one bag type which feeds directly from the hose inlet and wraps around the inside of the vac. I put them both in.

I already had some holes drilled in the hood door, but now the air flow is more than with the 5" computer fan I used before, so I had to drill some more holes.

I ran it for 15 minutes and the motor fan outlet temperature was steady at 115 degrees.

I also put the box it came in over it to decrease the noise. I cut holes for the vac hose and power cord on one side, a hole for the motor fan outlet on the top and an opening for its inlet on the bottom, pluse a hole for the vac blow outlet.

I ran it for two hours. Within the first couple of minutes the motor fan outlet went up to 110 degrees, and it stayed there the whole two hours just fine. I guess the box lowered the temperature by not allowing sunlight directly on the vac. (Air temperature was 74 degrees.)

Soon after I started the two hour run, the garbage can caved-in a bit, but the lid stayed sealed, so it worked for the two hours.

I need to drill yet more holes in the hood door, because there is still too much vacuum inside the hood (I noticed that when I had the door ajar a little, it sucked the fumes better). This should also help the can vacuum situation a little bit.

Now I need to install a 2" pipe that will take it up above the roof line.

I cooked some A/R at 190 degrees in there, and could smell it a little coming out of the vac blow hole, but it's nothing like when I used to cook it out in the open. Once it gets piped up above, and has a chance to dissapate, I don't think it will be a problem at all.

 

[2002valkyrie]

I cooked some A/R at 190 degrees in there, and could smell it a little coming out of the vac blow hole, but it's nothing like when I used to cook it out in the open. Once it gets piped up above, and has a chance to dissapate, I don't think it will be a problem at all.

That's great news! What did you mix in your drum as a caustic? I have added a 2 1/4" plastic fle pipe on the inside of the inlet port of my shopvac. Then burried it under 10lbs. of charcoal and before the air can enter the foam filter, I put a plastic coffee can over it so that there is a 1" gap it the top. May not last long but it can't hurt. I just need to get started. I am working on getting my exhaust elevated tomorrow.

I am trying to get everything ready to run so I can get started as soon as my melting dishes come in. Then I will be asking more questions on this forum.

 

[4metals]

Something rubs me the wrong way with sucking fumes through a shop vacuum, even with a scrubbing device in the line. I just don't think it will last for long. But some of what I've read here is good. Making a hood from a drum as Valkyrie did is a good cheap start, making the bottom of the door off the bottom by an inch or two is great for spill containment. I would exhaust fumes from the hood with a leaf blower as in the attached sketch. That will give good exhaust but a door that closes over the opening would be a good thing. I would use a hole saw and drill 3 or 4 inch and a half holes along the bottom of the door so air can get in with the door closed. If you get good flow from your shop vacuum you can use the exhaust side to blow up the pipe instead of a leaf blower.

Now there is no treatment of the fumes with this rig. The worst fumes, the red NOx fumes, are the ones we really have to do something about. The bisulfite fumes from dropping the gold can be controlled by adding slowly in an open container and exhausting into open air without scrubbing, the fumes dissipate readily.

To handle the NOx fumes I would exhaust the fumes out of a bucket with a bulkhead fitting towards the top edge connected to 2 erlenmeyer flasks and a vacuum eductor as described earlier.

Only the bucket for the reaction has to be in the hood, the flasks can be mounted outside the hood connected by a hose through the wall so they don't take up valuable hood space. The fumes will be better scrubbed this way and any fumes that leak out if you open up the top to see what is going on will be caught in the hood and pumped up and away from your face. When you change out the caustic from the scrubber flasks you can use it to treat your waste.

 

[eeTHr]

Val;

The flex pipe, charcoal, and coffee can sounds good. Thanks for the idea.

I'll be doing the up-pipe tomorrow, too.

 

[LeftyTheBandit]

This is so red neck I love it.

A leaf blower exhaust fan. :shock:

Who woulda thunk it.

Get'r done!

(time to get the leaf/snow blower out) These two are having so much fun, I feel like I'm missing out!

 

[2002valkyrie]

This is so red neck I love it.

Sorry to take such a great subject and turn it into a "redneck" thread. I am in awe of you all on this forum and hope to join in your ranks someday but I must start with minimal investment which requires me to look around and use what items I have on hand. The only thing I have purchased is gold and I plan to sell it.

 

[jimdoc]

You got to do what you can with what you got. When you don't have thousands of dollars for a fume hood you got to get creative.
If it saves your lungs and keeps your neighbors happy, that is the only thing that matters. I like the barrel idea, it is a great size for
starting out. And they are easy to find, hell I have about a dozen of them already. I think most of us love "redneck ingenuity'
Jim

 

[eeTHr]

Valkyrie;

Sorry, I forgot your question about neutralizer. I didn't add anything to the water, since I was taking the pipe out several times to get the holes right. When I think it's done, I'll use a little Red Devil Lye.

I got a late start today, and am just now going to get the up-pipe stuff.

Don

 

[2002valkyrie]

Yep thats what I used got 2 40lbs. bags at Lowes for $9.00 tax included.

 

[lazersteve]

Valkyrie,

Are you sure you purchased lye, sodium hydroxide, and not lime, calcium hydroxide and magnesium hydroxide?

They both should work, but I've never seen sodium hydroxide lye for sale in a Lowes store in 40lb bags. It's typically sold in 1 lb cans in the plumbing isle if your store carries it. My local Lowes quit carrying the Red Devil lye a few years back, now I use the large bags of lime.

If you definitely got your hands on 40lb bags of lye (sodium hydroxide) at Lowes, which section did you find it in?

Welcome to the forum by the way, it's great to have new members that are as safety conscience as you are!

Steve

 

[Oz]

Did you say you got 80lbs of lye (sodium hydroxide) at Lowes for $9.00?

Please check the bags to see what % and if it is indeed “sodium hydroxide”. If it is high purity there will be more than 1 member going to Lowes.

 

[eeTHr]

Valkyrie;

I assume that you already know that most of the experienced people on here consider lye to be more dangerous to the body than the strong acids normally used in home refining? :shock:

Protect your eyes (end everything else). 8)

Don

 

[2002valkyrie]

Valkyrie,

Are you sure you purchased lye, sodium hydroxide, and not lime, calcium hydroxide and magnesium hydroxide?

lazersteve, You are right, It is Lime not Lye don't know how I got that messed up. But if it'll work maybe I'll be o.k. Thank you for bringing that to my attention.

I plan to order from you on a regular basis in the future if all works out.

 

[Harold_V]

Valkyrie;

I assume that you already know that most of the experienced people on here consider lye to be more dangerous to the body than the strong acids normally used in home refining? :shock:

Protect your eyes (end everything else). 8)

Don

That's absolutely correct.
Years ago, I got a drop of nitric acid in my eye. A direct hit, a drop that bounced from a beaker as I was pouring from a container.

I was seconds away from fresh water, so it was quickly rinsed, but the damage was done. The surface of my eye turned yellowish and peeled off. I was alone, but could see well enough to find help in the yellow pages. I drove about five miles to an ophthalmologist, where I was treated. You may understand that I was very upset, thinking that I may lose the sight in the eye. The ophthalmologist was very reassuring, when he told me, and I quote, "you've very lucky it was acid instead of lye. The human body has the ability to neutralize acid, so while it does damage, it is limited. Your eye will be restored as it was, it just takes a few days. Had it been lye, you had but 15 seconds to eliminate it from your eye, which is not easily accomplished. Unlike acid, it continues do damage tissue, so had the drop been lye, you would have lost the sight in that eye".

Be very careful when handling lye----and wear the appropriate safety gear. Your sight relies on it.

Harold

 

[nickvc]

Sound warning from Harold V please take note all noobies......... As a byline to all of this please be aware that when venting off fume especially when using heat or with strong reactions pms will travel in the fumes so if your system runs for a good space of time make sure that when changing the solutions or disposing of old equipment you check for them it can be a nice suprise( so tight i squeek ),also the exaust fumes will still be acidic after scrubbing so dont pump it over areas where cars are parked you wont be popular!!!!

 

[eeTHr]

Harold;

Wow. I have seen various warnings and potential results before, but your story really puts things into perspective.

Thanks very much for posting that!

Don

P.S. Wow again.

:idea: