Update Time:

I bought the blower motor today and began construction of the hood. I marked out the center. Cut a hole in dead center and then inserted the suction portion of the blower into the hole I cut just to do a dry fit. It works decent without being complete and obviously is no where the actual CFM due to not being completely connected.

The Blower:

http://i.imgur.com/g6YkrFl.jpg?1

Starting Work:

http://i.imgur.com/3NIFyd4.jpg?1

Hole Cut:

http://i.imgur.com/iVw373d.jpg?1

Assembled:

http://i.imgur.com/9KkjFdw.jpg?1

Oh and I completely forgot about potential noise from the motor. It was quite loud when on. I used an app on my phone to check dB.

http://i.imgur.com/l7X49Y2.png?1

Gonna need to get some comfy soundblocker's

I also had to buy some drill bits to start a hole to cut the hood with.

Today I spent $183.15 on the blower and a set of cheap drill bits. I found a 20% off coupon to buy everything with :).

Running Total: $1739.81

Tomorrow my goal is to open the window and cut my 2x4's into lengths that will prop the bottom sash of the window open. I am then going to seal a board over the window and cut a hole to run the hose through to the outside. I am also going to work on using aluminium tape to seal off the area inside the hood around the hole I cut.

I will also go ahead and drill the holes to put the hardware on (need to still buy) the hood so I can hang it from the rafters.

If I get through all that then (probably won't) Friday is hang day for the hood and testing with flex duct. If I get good results that are near where I want to be then I am going to start measuring to get static metal smooth ducting to replace the cheap stuff.

Next week is the oxy/propane setup :)

You might want to replace the flex duct with smooth walled ducting. Either metal or PVC.

The turbulence that flex ducting has inside can reduce the CFMs down to half or even a third of what a smooth wall ducting would provide.

It effectively reduces an eight inch duct diameter down to to three inches.

You may want to reconsider mounting your fan to the window board instead of the hood. The fan mounted to the metal hood you have will it act like a speaker and amplify the noise from the fan and will direct that sound down to where you are working. Ouch! Mounted to the window board will create less noise, due to being mounted further away and on wood instead of metal. Wrapping the ducting with insulation will also cut the noise a little more.


Have fun

Good idea but the motor in general is loud. Sitting upright on the concrete floor and on it is only like 3 to 4 db's lower, no not much of a difference. It is so heavy it actually stabilizes itself, not much of a "rattle" if you will.

Update Time:

I ended up not being able to open the window as it was painted shut (over 3 layers of paint). I ended up knocking one of the square panes of glass out and then mounting the board directly over the window with a hole cut right where the pane of glass was.

This ended up being a better situation because if my calculations are right, the motor will be perfectly even with the hole now. I am looking at 4' of horizontal duct and 1 90 degree bend to get outside.

Finished board on window:

http://i.imgur.com/26SlIcP.jpg?1

Total cost today: $0 (already had all the materials on hand)

:p

The company I work for was also in the process of clearing out the warehouse so I also picked up 2 massive 4 feet by 3 feet shelves to put in the garage. I can stack finished pieces or park items that are about to go into the kiln. The shelves on the ones I picked up are wood but I can always put a small piece of sheet metal over the ones I want to "park" on.

Update Time:

So this weekend I finished the basis of the hood design.

Final design:

http://i.imgur.com/62wZJWR.jpg?1

http://i.imgur.com/nJKCj1U.jpg?1

http://i.imgur.com/fR2VCST.jpg?1

Here is a shot of the underbelly:

http://i.imgur.com/R7TKzJK.jpg?1


I burned some newspaper under it with it on and it did put the smoke outside. I found that if the newspaper was directly on the table that it "kind of" sucked it up but some did leave the hood area. If the newspaper was held up around 2 feet away from the top of the hood (so 1 foot below the hood) the suction picked up and the flame would actually bend toward the hole.

If I angle my torch upwards to around the tip of the flame being 2 feet away from the hole I believe that will help. In addition to this I believe 2 things need to occur to improve the suction as is.

1) limit the amount of space inside of the hood to move air directly to the hole

2) possibly add curve sheet metal to the sides of the hood that hang down to the table so "add suction"

Ideas are welcome. I believe having the motor near the hood itself was going to provide the maximum suction that would be possible. I am by no means an "hvac guy" so I'm not sure that even mounting the square portion of the motor to the exhaust window and running the ducting to the hood would improve cfm? Again, I'm not sure. I do know, however, in both designs the proposed solutions I put up would add to the overall CFM so I will try and figure out a way to implement them.

From what I remember moving the motor won't make that much difference, the duct work "resistance" to flow is going to be similar whether it is sucking it in one side or pushing it out the other.

Your idea of adding a "skirt" to the back and two sides will help with getting the flow to go more directly to the duct/motor.

Trouble is you are drawing flow from 360 degrees around the hood.
If you can block the source of ''side flow" from the back and at least part of the sides you will increase the efficiency of moving the fumes out of the work zone and into the draft of the motor.
It will also increase the amount of air that is flowing over your shoulder to keep the fume cloud from entering your breathing space.
You only need 5 or 10 % of the air to come over our shoulder but you need to have some thing to keep you from from breathing in the work fumes.

Now that you can see how the smoke does not quite make it to the ducting you can imagine that the heavier particulates that will boil off as you liquefy the glass wont even get captured in the fume flow and they will settle out onto your hands, tools, glass rods and anything on the work bench.

Keeping in mind that a lot of the colorants in glass are heavy metals like lead, cadmium and the like you might understand better why I was so insistent on getting as high a CFM ventilation system as you can possibly afford to start out with.

If your vent flow is weak you will need to constantly decontaminate your hands, tools and bench top if you don't want to spread the heavy metals all over the home where your kids, spouse and pets live.

If you do a little research on the Portland Or. glass maker having to shut down for a while a few years back you will see that it doesn't take a whole lot in quantity to turn an area into a toxic hazard decontamination site.

Getting it out of the house at sufficient velocity to mix with the air out side properly takes more than a simple box fan like some folks mistakenly think.

As a side note: if your rig causes too much noise in the house you can deaden some of it by sandwiching rubber mud flaps between your lumber and the joists as well as tying your chains to sections of firm rubber like old shoe soles.
Anything that can absorb the vibration a little will help a lot.

I have mine suspended from screen door springs.

Update Time:

I went out and bought some roof flashing and decided to build a makeshift rim below the hood. I taped the flashing to the inside of the hood all the way around and did a burn test. I no longer smelled any smoke whatsoever in the garage. I had to walk out in the back yard to smell the burned newspaper so I believe that is a plus.

It improved, but not as much as I would have liked. I took the remaining flashing I had and just sat it around the bottom rim to make up for the small gap between the hood and the table.

This caused the air to pick up quite a bit.

The makeshift hood:

http://i.imgur.com/UxVTMWA.jpg?1

The Inside:

http://i.imgur.com/ajf2xVO.jpg?1

Since the air picked up when I filled the gap at the bottom (the gap piece is not taped to the hood extension yet) I am going to cut the remaining scrap I have left over in halves to tap along the bottom to make it touch the table. After that I plan on taping the outside of the hood extension to the table to seal as much of the air in as possible.

I did a burn test yesterday and unlike the first burn test I no longer smelled any smoke whatsoever in the garage. I had to walk out in the back yard to smell the burned newspaper so I believe that is a plus.

Thankyou for an interesting thread!

Thank you for sharing your journey. I am in the process of setting up my studio, after almost 10 years of not having it. Long story! I will be using some of the information you and others have shared.

Buy an oxygen concentrator. I use 3ea 5lpm units on my small torch head and keep my oxygen tank hooked up to the large burner which I use infrequently. Message me if you want to buy a couple used oxygen concentrators. Best to you.

I have been away from torching about 5 years and like you looking to rebuild my setup since I’ve moved. It was great seeing your progress! Hoping you can post some updates!

I actually ended up not using the entire setup sadly. Even after boxing it in with the sheet metal and taping it I could get all the smoke to vent but the ashes would only tornado in the box and not suck up so fuming and other options are out the window (no pun intended).

This summer I am going to opt for a 2500 cfm commercial hood and install it directly venting out the back wall instead of ducting to the window.

safety first kids!

Thanks for the update!