Exhaust hood

Jewelry Discussion
1

I am building my workshop, I have a space of 23’ x 21’, It will have
4 windows, 2 on one side, one on two other sides (one of these has a
door outdoors), and one wall without a window (only a door to another
room), I also will have a 6’ window on the side with two windows, the
two windows on that side are also 6’ each, and the other two smaller
windows on opposing sides is 48" wide. This room is insulated (or
will be this week), it has drywall walls, and it approx 8’ high (no
ceiling yet, but will have one soon). I need a exhaust hood, for
soldering, and lampworking, and I have been looking at the kitchen
variety, but the best I have found in stock at home depot is a 200cfm
one, that is very weak, I would like to find something that is at
least 400cfm. Does anyone have an idea on how I can produce one? I
can get a sheetmetal worker to build the hood, but what can I use for
the exhaust part? I will need to have the exhaust tube go out the
side of the wall, possibly the roof (although I would rather not), my
skills are limited here, I can nail nails, and build simple
constructions. I really need help with this and ideas as to what to
do.

I also need to get a pedestal for my new rolling mill, I suppose I
need to go to a welder and take a template of the holes in the mill
so I can attach it to the floor and the pedestal. What height it the
standard? I am 5’ 6" and my husband is 5’ 7", my daughter is 5’ 3",
we will all be using it.

But here is another question, I have the option of installing a
evaporative cooler or air conditioning. I have been told by other
lampworkers to install the cooler, what effect can this have on my
mill? My metals? Other things? How about my tools? Will they rust?
(Oh, I live in Tucson, AZ), we need something to cool it down.

I am going to paint the floor (concrete) right now, and am trying to
come up with some ideas, instead of just plain? I have seen where
poeple actually do really nice stuff to floors, but have no idea as
to what is involved?

Thanks for any help!

Laura Brito
Beadful Things

2

Dear Laura, I built a beautiful ventilation system for not a lot of
money from Grainger Industrial Supply. I’ll send you the link.
www.grainger.com If you need more help feel free to ask. I can be
more specific. Good luck,

Johnny I

3

Laura, The Grainger Co. handles a wide variety of duct fans and
blowers that will meet your needs. Click this site:
Grainger Industrial Supply - MRO Products, Equipment and Tools and check
item# 5C518. This may be close to what you need. If you live in a
town with a Graingers, visit them and discuss your needs. They
usually have more equipment in stock than they have online…Bob Williams

4

My last one went without my sending it ??? To continue: I can send
sketches of a hood idea doing the high low vent if you ask off line.
Rust should only form if the humidity gets near the dew point and
water condenses. This shouldn’t be a problem in Tucson. Floors can be
stained and finished with a sealer. Check the Fine Homebuilding site.
There has been some on this in the magazine. Look at concrete
countertops finished this way ,not to do , but its another source of
ideas on the same technique.

Jesse Brennan
jkbrennan@ worldnet.att.net

5

Go to Grainger—http://www.grainger.com/ They have store in Tuson and
a monster catalog which they may not give since they pretend to be
wholesale only. Any one in business should be able to get a catalog
. They do cash sales for anyone who has a business . They will have a
fan. A swamp cooler will probably be great as you won’t waste
expensive AC through your exhaust that way. The exhaust will only help
pull cooler air through the swamp cooler and past your work station. I
would suggest you check into installing a radiation barrier above your
insulation . This is just an aluminum foil type thing installer under
your roof. Also use an exhaust fan from the attic space to keep the
attic temp down. The radiation barrier is cheap and is very effective.
Depending if you want to work in front of a window or not will design
your hood. If you work in front of a I would install a flame proof
wall arranged to sweep air across the bench
as well as exhaust up high

6

Laura, Can I move in? Sounds lovely! You have a couple of options
here, one cheap, and one more expensive.

The first cheap one is to look at a blower from either Grainger or
MSC. They are domed with a fan inside. They have them in chicken
coops to circulate air. Ours is this style and has a two step speed
in the motor. You could research the parts and have somebody put it
together for you.

The second more expensive option is to get an HVAC person to do it
for you. We inherited the first style but bought the second style in
our first place at Metalwerx. The beauty of the second one is that
the HVAC guy dissembled it and we are reinstalling it in our new place
for a second soldering station.

The HVAC people are really good and because we are a school, the
insurance agent liked that we had really excellent ventilation. The
fire department was happy as well. The extra money was worth the piece
of mind, but if it was a private studio I might have just opped for
the first and less expensive solution.

-k

7

Looks like you have plenty of room Hood. I would not recommend
building a hood check with a used restaurant equipment place, or look
in the papers restaurants have big hoods that can be fitted before
you put the ceiling on. As far as the exhaust motors or 400cfm that
you want I would look into Graingers there should be one in Tucson.

Rolling mill If you are using manual then the height should be what
is convenient to you. There should be a welding place in town and
they will have the steel too. Use an I beam or a tube 4" and they
could put a base plate for the floor and the mill. The same place
will drill for the holes. (There is Orchidian Dave in Tucson he can
tell you how he motorized his manual mill. If you can do that then it
should be of table height so that you can sit and do your work.)

Concrete Floor paint is available at any paint store usually it is in
Battle Ship Gray. I have been using this for the past 25 years and
repaint every 3 to 4 years. This keeps the dust down and also it is
easy to find things when they are on the floor. There is a
polyurethane finish that you could put over it I have seen that but I
have never used it.

Hope I have been of help.

Kenneth

8 
I need a exhaust hood, for soldering, and lampworking, and I have
been looking at the kitchen variety, but the best I have found in
stock at home depot is a 200cfm one, that is very weak, I would like
to find something that is at least 400cfm. Does anyone have an idea
on how I can produce one? I can get a sheetmetal worker to build the
hood, but what can I use for the exhaust part? I will need to have
the exhaust tube go out the side of the wall, possibly the roof
(although I would rather not), my skills are limited here, I can
nail nails, and build simple constructions. I really need help with
this and ideas as to what to do.

You might check with the (chemical) laboratory equipmen supply
people. See if you can get an exhaust fan such as is used in exhaust
hoods in chem labs. You might want to check on getting an
explosion-proof one.

    But here is another question, I have the option of installing a
evaporative cooler or air conditioning. I have been told by other
lampworkers to install the cooler, what effect can this have on my
mill? My metals? Other things? How about my tools? Will they rust?
(Oh, I live in Tucson, AZ), we need something to cool it down.

It’s possible. On the other hand, Tucson has a dry enough climate
that the moisture may be a boon to your health whild not making it so
damp that you have rust problems.

Cheers!
Margaret

9

Technical Part 400cfm @ 1000fpm (feet per minute) would require an
8.5" round duct (or 4x17,6x10 etc.) 1000fpm or less is the standard
used to keep air noise acceptable in heating and a/c systems for
supply air 800fpm is used for return air (less force because it is
sucked back vs. powered) 9.5" vs. 8.5" It is best to go bigger and use
a butterfly damper to cut back the flow if desired. Use metal pipe and
avoid the flex (slinky) duct. (plastic with wire) Keep the pipe
straight and bends to a minimum. Joints can be sealed with duct tape,
try to get good professional grade tape. A hood is good but there is
also corrugated metal pipe which is flexible and can be fitted with a
damper and an inlet screen I have seen this used in manufacturing
plants with drops down to each soldering station. Side wall venting is
ok but remember to keep it away from windows or air intakes and use a
vent cap designed for vertical venting. An intake to replace the air
you exhaust is an excellent idea remember it must be roughly a size
larger. A backdraft damper on the exhaust is a good idea also (Like
the flappers on drier vents for example)

Practical Part All that said I just dug out my old W.W. Grainger
catalog and looked in the residential fans section. It has listed lots
of possibilities, maybe a kitchen # 4C703 or 4C702 wall fan will be
just the ticket, also I think they can be used with a speed control to
vary the output.

A swamp cooler will raise the humidity level but with your dry
climate I don’t know if that will be a problem. If the humidity stays
below 50 to 60 % it should not cause rust on tools etc.

Lastly, 400cfm is roughly 1 ton of a/c remember this in sizing your
cooling

Email directly if you have further questions

Dan Wellman
danwellman@att.net

10

As far as the ventilation fan, I went with a very powerful remote
fan. It looks like a small jet engine and can be placed anywhere.
People often use them for venting multiple bathrooms on homes. They
have one fan in the attic and it takes care of all of them. Anyway I
used a heating and cooling contractor to make the hood and install
this variable speed fan, its much better than the range hood type.
Its actually in the shop and is not too loud. Mark

11

Try an industrial surplus recycling yard, or “junk yard”. What they
have in their lot, is what they have been unable to sell…equipment
that is likely to be reduced to scrap metal value. They usually have a
remarkable network of other recyclers who can get you what you need.

It should be clear what your exhaust requirement is before buying
anything.

Jeff
Jeff Simkins
Microelectronics Engineer
University of Cincinnati
P.O. Box 210030
Cincinnati, OH 45221-0030

12

You can have a “remote” bathroom fan installed . . . run some 4 inch
sheet metal pipes from your surround, and exhaust through an exterior
wall. My furnace guy did this . . . I love it, relatively quiet (I
can listen to books on tape while working!) No fumes, and since it’s
in my basement where the furnace and hot water tank are (both gas) I
don’t have to worry about the fan sucking out too much air and
causing back flow of gasses that I don’t want to breathe. Oh, the "remote"
bathroom fan will be your biggest expense.

13

Laura–A couple of thoughts about your new workshop.I built a vent for
my ceramic kiln (20-some years as a potter before becoming a jeweler)
using an industrial squirrel-cage blower (looks like a very industrial
hair dryer). I bought it from an industrial distributer, whom I found
by looking in the business-to-business phone book (before the
internet). I don’t know what its capacity is, but it is strong and
relatively quiet, and has worked for close to 20 years, so far. As
luck would have it, the air outlet was just the right size for some
reticulated steel hose (looks like the conduit for electric wires, but
about 3" ID) which I got by looking for “hose” in the B-toB book. This
might be a solution with a sheet metal hood. Should require only some
sheet metal screws and matching bit to hold everything together. Mine
is actually made of pieces of heating duct from Home Depot or
equivalent.If you can’t find these items, you could ask any ceramic
studio you know of–these blowers are widely used for blowing air into
gas kilns. Hope this helps!As for your floor-- when I did mine, I
painted it all white, then sponged it with yellow, then laid some old
square vinyl tiles I had on it in a checkerboard pattern (in sections,
as I had only 15 or 20 tiles), then had fun with a bunch of cans of
spray paint, sprayed erratically in short bursts. I love my floor, and
I’ve had requests to do other people’s, but haven’t cooperated. Oh–I
topped it with a couple coats of polyurethane. Hope this fires your
imagination!

–Noel

14

A simple and cheap high volume fan can be found in old window air
conditioners. One in which the compressor has failed, but the blower
fan still works is what you want. They are usually small
squirrel-cage type fans that run on standard house voltage and are
not difficult to extract from the overall unit. You can scout out
the sides of roads, or check with local appliance or AC companies.
The cost can range from small to free.

    I also need to get a pedestal for my new rolling mill, I
suppose I need to go to a welder and take a template of the holes in
the mill so I can attach it to the floor and the pedestal. What
height it the standard? I am 5' 6" and my husband is 5' 7", my
daughter is 5' 3", we will all be using it.

Take a look at the ready made bases for heavy tools like bench vises.
They usually have a wide range of mounting holes already, and some
are adjustable in height. For your range of heights, the standard
36" counter top height is pretty good for standing work.

    But here is another question, I have the option of installing a
evaporative cooler or air conditioning. I have been told by other
lampworkers to install the cooler, what effect can this have on my
mill? My metals? Other things? How about my tools? Will they rust?
(Oh, I live in Tucson, AZ), we need something to cool it down.

Go with the AC. A swamp cooler and high grade tools usually isn’t a
good mix. Some of the newer wall/window mounts are actually pretty
energy efficient, especially in such a small insulated space

    I am going to paint the floor (concrete) right now, and am
trying to come up with some ideas, instead of just plain? I have
seen where poeple actually do really nice stuff to floors, but have
no idea as to what is involved?

You use paints made for concrete floors. Since this is to be a
workshop, I’d add a topcoat of polyurethane to protect the design.

Ron Charlotte – Gainesville, FL
@Ron_Charlotte1 OR afn03234@afn.org

15

I do torchworked glass also, and wanted an excellent ventilation
system because I apply metal foils to the glass and have a greater
toxic risk than the average glassworker.

I talked to several other glass workers, my electrician, and a sheet
metal person. I ended up buying a Grainger’s exhaust fan which mounts
on the roof. It has a variable speed, but I always use it on maximum,
which is about 550 cfm. I think the minimum is about 200 cfm. The
speed control is on a rheostat. The cost was about $350 for the unit.
The only thing I regret is not buying a two-speed fan instead, because
the variable speed motor makes an oscillating hum at low speeds,
which reverberates and is amplified through the metal ductwork. There
is no hum at maximum speed, but as you turn it down the noise starts
to show up. A two speed motor would not have this problem, and would
also be less expensive. There was an expanded aluminum cage around
the blade which I removed because it vibrated and drove me nuts.
Haven’t had a problem without it.

A sheet metal person came to my studio and took all the dimensions of
what I wanted for the hood. You want to make sure your hood is not
shallow (top to bottom dimension). When you are working glass or
soldering metals, there are heavy-metal elements which can tend to
"roll out" of a shallow hood such as a restaurant hood. You also want
to make sure the hood is deep in the front-to-back dimension. Mine
extends the full width of my 30" table so my torch is completely
under the hood. I placed the hood as low as it would go, without
creating a hazardous metal corner for me when I stood up and leaned
over the table. (I’m 5’4", hood height at bottom rim is 65".) The
ductwork needs to be at least 8". Any smaller and you restrict the
flow at that higher cfm, so you really aren’t getting the benefit of
that fan. Also, you want there to be no elbow bends in the ductwork
if possible, and you want to take the shortest distance you can to
exit your wall/roof. The more ductwork you have and the more it bends,
the less the exhaust “pull” will be. The cost of the hood and
ductwork was about $400.

The other costs were electrical and carpentry to install everything.
The total final cost was under $1000. This is the cost that other
glassworkers told me to expect, and I think I got a great system for a
fair price, plus I was able to design it myself. Hope this helps.
Email me off list if you would like the stock number of the fan. Hope
this helps.

Rene Roberts

16

I was told by one of my instructors/mentors that you needed a minimum
of 600cfm ventilation if you were doing very much soldering. And this
person had the bendable metal ducting that hovered just above where he
was soldering. Very effective. He had his filtered through a water
filter in the attic so he could filter out the particulate and not
polute the air.

Kay

17

If flamibility is not an issue, a 3to6 inch section of the ductwork
can be cut out and replaced with a canvas connector. This will help
to isolate the vibrations from travelling down the metal of the duct.

Dan Wellman

18

I am also looking to install some type of ventilation in my basement
workroom but do not want to spend a fortune doing it. Also haven’t
heard of or seen any system that doesn’t make you feel like you are
soldering in a box. Any ideas for a more open type system? Would be
very interested in knowing more details about your system. You can
e-mail me directly at @tom_grace_stokes if you prefer. Thanks.
GRACE

19

HI Laura,

I have had an evaporative cooler installed in my workshop for the
last 6 years & haven’t had any trouble with rusty tools. The unit is
roof mounted & ducted into the workshop. This style of cooler moves
large volumes of air which has an added advantage of removing any
fumes from the workshop. They work well in hot dry climates but if the
weather is humid they are not very effective. I live in Australia so
the climate is ideal here but we have a couple of humid days a year
where refrigerated air conditioning would be nice. Evaporative cooler
are also cheaper to run.

I have used the smaller wheel around models & had rust problems with
it. Also not very effective.

20 
    I have had an evaporative cooler installed in my workshop for
the last 6 years & haven't had any trouble with rusty tools. The
unit is roof mounted & ducted into the workshop. This style of
cooler moves large volumes of air which has an added advantage of
removing any fumes from the workshop. They work well in hot dry
climates but if the weather is humid they are not very effective. I
live in Australia so the climate is ideal here but we have a couple
of humid days a year where refrigerated air conditioning would be
nice. Evaporative cooler are also cheaper to run.

Actually, a very good point. Being from Florida, anything that adds
moisture to the air is to be avoided out of reflex. The only place
that those evap units are used here are in commercial laundrys and
warehouses. Where she is in Arizona, the swamp cooler should be fine.

 Ron Charlotte -- Gainesville, FL
 @Ron_Charlotte1 OR afn03234@afn.org