Range Hood for Casting

[don45]

I just added a NewTone Range Hood over my casting area. Before the add, for a number of years, I've had a bathroom vent fan installed in the bottom of the cabinet directly above my pot. The fan vents directly outside and the pot sits about 14 " below. The hood is now installed directly into the opening into the kitchen fan so that now I'll have two fans running in series.
I use one of three pots, an RCBS ProMelt , an old Saeco, both bottom pour, and a Waage with a laddle, which I use the most. The Waage sits on the bench and the bottom pours sit about 5 inches up on a stand.
My question is how to improve the venting. Should I extend the hood lower with plexiglass or something? Has anyone done this? How? Any other suggestions?
Thanks,
Don

[AFK]

One of the best things you can do is open a window or install a return air system in the room that you are casting. Also the shortest duct run with the least amount of bends is best for the performance of the hood. That should take care of the smoke from fluxing.

[jsizemore]

A little smoke will let you know if your setup is adequate.

[claude]

I'll have two fans running in series.
Which will not double your efficiency, Fans work by increasing the velocity of the air leaving them creating a low pressure system in from of them into which surrounding air flows to stabilize the pressure. Your exhaust fans are probably both running at 1750-1800 rpm, the flow from the first fan in the series is already exhausting at maximum velocity, so the second fan is pretty much just coasting. Add to that the thought that if the first fan in the series is moving air faster than the second fan, the second fan is in fact a blockage, and if vice versa, the first fan is hindering the second fan. Use two outlets and your CFM of airflow will decidedly increase.

[bangerjim]

Do not use them in series as said above. You are gaining really nothing and probably starving the 2nd fan.

Split them and use TWO separate outlets to the outside.

Cheap vent fans in series are not the same principle as a 2 stage air compressor!

banger

[georgerkahn]

If you could fashion "sides" to your casting bench, exhaust may be more directed. I had fans over my pot which seemed to exhaust OK. However, when I put sides on the table -- only about six inches higher than top of my furnace, too -- the efficiency of the setup at the least, doubled. 'Specially noted when I fluxed -- a great more was removed.http://castboolits.gunloads.com/asset.php?fid=108208&uid=32534&d=1414887090
BEST!
georgerkahn

[MtGun44]

I think you will find that sides will help more rapidly evacuate fluxing smoke.

Bill

[Beesdad]

124822Home made hood... Using a high volume computer cabinet fan... I have it connected to a HF exhaust fan flex duct...

[don45]

Thanks for all the input. I already had one fan installed inside the cabnet above so that's how the two fans came about when I added the hood below. I will try it like this and can always remove the extra fan althoughI think it will improve the flow as it goes thru the 90 deg bend. My experience is that you dont need a high capacity vent but just enough to keep the flow going to vent so it goes outside. I am going to try some side skirts, first made of cardboard to check out the design and effectiveness. I have two great new molds just waiting for their first cast...an Accurate and a NOE HP, both 44 Keiths. I started casting boolits in 1959 (350147 for a 71 Win) and very soon after that 358156HP. I've probably crossed the 100K count. Just continue to try to improve safety, ease, and better quality boolits.

Thanks, Don

[725]

I've got a kitchen hood/fan set up and I use back & side walls. Works really well. The kitchen hood even has lights, which help greatly.

[gunoil]

first fan over pot (9" commercial flex tube) and another fan to take smoke out at roof in attic. just pure ingots in pot. ingots made out back sometimes.

http://i1113.photobucket.com/albums/k511/putt2012/null_zpsef5fd415.jpg (http://s1113.photobucket.com/user/putt2012/media/null_zpsef5fd415.jpg.html)