Questions on used HVAC blower...

Zinci · #1 2011-06-10, 11:38am

I'm yet another newbie and hoping one of you kind and knowledgeable folk can help me find the Forest in the Trees. Sorry if this is much too wordy!!

I'm running a HotHead/FW type torch for the moment but plan to be upgrading at the end of the year to a different torch with an OxyCon & bulk propane (properly piped through the wall from the outside)

I'm working on building a barley box and getting proper venting in place so I can stop working outside on my porch. I luckily have several friends/business acquaintances in HVAC businesses and plan to try and source my fan/blower from them for free or at least verra cheap, but want to ask them smart questions to make sure I get what I need.

When I'm asking about obtaining the blower what exactly am I asking for? I need to be able to wire the fan for a standard plug - or at least have an electrically inclined friend do it that way. Do I need to make sure it's a particular voltage? Should I be asking for the whole blower assembly? I'm sure there are other things I should ask for/about but honestly don't know what those things might be.....any suggestions. I can build things from wood and metal pretty well, but electricity and mechanics confuse the bee-gees-us out of me!

Oh, in case you need to know, the barley box I'm building will be about 3' H x 3' W x 2.5' D with a baffle on the front so the opening is about 2'x3'. I plan to mount the fan to the top center of the box. My box will be mounted to the back wall of the garage so the exhaust pipe length should be very short - 2 feet or less I think since i'll be venting right out that back wall and can cut the hole for the vent pipe where ever I want it to be.

Thanks for your thoughts!!!
Melissa

Dale M. · #2 2011-06-10, 7:17pm

You need a fan of about 600-750 cfm, it needs to be 120V AC.... And you need a way to attach fan to fume cabinet and to duct work to get exhaust air outside...

Something like this will do very well...

or...

Top fan is referred to as a "squirrel cage" fan... Lower picture is a "vortex" style used in hydroponic or green house environment...

Dale

cheng076 · #3 2011-06-10, 11:04pm

I'll add some comments to Dale's post.

I have used and still use a free 3 speed free furnace fan and have set up several others for friends. Mine has been in operation for 4 or 5 years now.

The top fan Dale shows also comes in a style that has air intakes on both sides. Most furnace fans/blowers will be rated well over 600 to 750 CFM and will be 2 or 3 speed. But more is better than not enough. These fans come in both 120 VAC and 220 VAC. 120 VAC is common household current without a special circuit and wireing. The fans have color coded wires that are standard and it is easy to follow. They can be wired to only use one speed if that suits your needs. Ask your friends to get you a 'blower assembly, 120 VAC'.

The bottom fan Dale shows is easier to hook up to ducting and the ones of that type I'm familiar with run quieter than a squirrel cage type but they are more expensive. Free is always better for me.

PJH

Zinci · #4 2011-06-11, 10:36am

Thanks so much for your response Dale and PJH! I think I get it now. I don't know why mechanical things intmidate me, but I'm sure I can make it work - especially now that I have a better clue what I'm asking for!!! I am hoping the fan will be "more" rather than "less" as I'm paranoid enough about safety to need to at least have the ability to overcompensate

I've spent a huge amount of my "lurking" around here revewing the Safety forum to make sure I set this up correctly , which has made me pretty paranoid about the safety side of things for lampworking - enough that i'm now working on venting and air conditioning our rather oven like detached garage so I can build my set up in there instead of trying to set up in the basement. My new husband thinks I'm going a bit overboard, but bad luck follows me, so i'm trying to make it really hard to damage the house LOL

Thanks again for your help!

cheng076 · #5 2011-06-13, 10:36am

Good for you!

It's always better safe than at risk. I do find that in unfamiliar situations most rational people tend to go a bit overboard and that's a good thing. Knowledge is the key and there is a lot of it here on LE. Gather your knowlledge, think it through, apply it to your situation, make a plan and execute that plan and you will succeed.

PJH

Lorraine Chandler · #6 2011-06-14, 11:31am

Melissa, I have a 4' area side to side and I find that I am kinda cramped with the longer rods of glass.

If you have only 18' on each side of the torch, well about 16 inches because of the torch, you might find yourself having to pull your rods out towards you when torching and it leaves you no room for pulling stringers or twisties while working them in the flame.

When I move my rods away from the flame I move them to the side so if you did that you would hit your barley box.

LyndaJ · #7 2011-06-25, 2:05pm

You can build a larger box, more like a fume hood, and keep the open area smaller so that your fan size doesn't have to be too big.

My set-up is shown here. The hood is 3 x 8, enclosed, with the fan pulling from the top. I have the right hand 4 sq ft section closed off with plexi to reduce the face area of the hood. My fan is 1250 cfm.

Zinci · #8 2011-06-28, 6:51pm

Thanks Lynda! I love that set up and the metal wainscotting is great looking! You're the first Cincinnati bead maker I've seen

I'm wondering if you use a speed switch on your fan at that CFM or do you just run it full on?

LyndaJ · #9 2011-07-12, 8:36pm

I just have an off/on switch. There aren't too many of us in the Cincinnati area. Maybe more as Brazee Studio keeps training new ones.

cheng076 · #10 2011-07-13, 9:55am

If you have restricted room you can reap most of the benefits of closing off the side areas of your torch station by using what I'll call semi-sides;

I can remove these side panels and set up more torches as I have quick connects for them under the table top and the fan is sized to adequately vent the area on speed 2 or 3.

CSimi115 · #11 2011-08-20, 7:17am

I'm also a newbie looking for a free fan. lol Am I correct in assuming that the first fan shown can be obtained from a HVAC person but the second is not something they use or are getting rid of? Also, can you just have the vent pipe above or do you need the box?

Thanks
Chris

PS This will be going over a 4 x 8 table that I also use for stained glass.

Dale M. · #12 2011-08-20, 8:36am

A fan is a fan for most concepts, any fan that can be adapted to ducting easily can be adapted (within reason).... Main issue with fan is ability to move air and your ability to adapt it for use....

You do not need to have over head hood, BUT its a lot easier to build system with a hood from the standpoint of performance, a capture area (hood) rather guarantees you will remove bad elements out of studio where just the end of open duct may capture most of what you are trying evacuate but there is no guarantee... Also open end of duct will probably require larger fan to capture elements they a hooded system,... Larger fans means more power consumption, more mechanical noise from fan, and more noise for air flow....

You can probably dial back (speed control) fan for stained glass work because fumes produced by soldering process are quite a bit less then with melting glass.... But ventilation designed specifically for stained glass work will probably be wholly inadequate for hot glass work....

Dale

LarryC · #13 2011-08-20, 10:18am

Remember that you often get just what you pay for in this world. Free does not always translate into economical.

CSimi115 · #14 2011-08-20, 10:22am

Thanks Dale for your answer. I realize that with the fan for the torch work I will get a "two for one" with being able to use it for the SG which now I just use a small fume extractor which really seems to do nothing. I know I've seen some 3 speed furnace fans like the one in your examples so I thought that might be good. Already have the hole in the wall to the outside and a booster fan on there for now with flexible vent pipe (metal) til I get the new fan. I figure something is better then nothing at this point. The open end pipe seems to work for me since I have flourescent lighting above my table so my lighting isn't restricted.
Any more advice? I appreciate it.
Chris S.

Dale M. · #15 2011-08-20, 10:34am

Quote:

Originally Posted by CSimi115

Thanks Dale for your answer. I realize that with the fan for the torch work I will get a "two for one" with being able to use it for the SG which now I just use a small fume extractor which really seems to do nothing. I know I've seen some 3 speed furnace fans like the one in your examples so I thought that might be good. Already have the hole in the wall to the outside and a booster fan on there for now with flexible vent pipe (metal) til I get the new fan. I figure something is better then nothing at this point. The open end pipe seems to work for me since I have flourescent lighting above my table so my lighting isn't restricted.
Any more advice? I appreciate it.
Chris S.

IF you decide on large hood/collector over work table, you can always put lighting under hood....

Dale