Is this too much for extraction ?

[CRS51]

Evening all, still collecting a few bits for my fume extraction in the workshop and have been looking at various in line fans etc.
Have got a extractor trunk and was thinking of getting one of these to take the fumes away
http://www.ebay.co.uk/itm/Industria...arden_Hearing_Cooling_Air&hash=item4603354f9c
Question is will this be too powerful for localised welding fume extraction via a trunk at the bench ?

Don't know much about the values in cu/m per hour for a trunk system and don't want to be sucking all the argon away from the tig torch.
They also do a motor speed controller so maybe this might be the way forward ?
Any advice most welcomed
Cheers Chris

 

[rtbcomp]

If you need to reduce the flow make a large hole in the trunking on the inlet side of the fan and have a means of adjusting the aperture until you get the required airflow at the workstation.

 

[Welderpaul]

Look for 'dampers', they fit in the tube and are like little shutters to restrict the flow; adjustable from the outside. A standard off the shelf bit of kit.

 

[wheresmejumper]

Youd be surprised at how big a fan you would need to be more of a hindrance than a help.
The speed controller can be fit after if needed

 

[CRS51]

Any of you fellas know the cu/m rating of these trunk units ?
I Think its best to have too much extraction than not enough
Chris

 

[captain-destructo]

a couple of stupid ideas??

howabout an old bouncy castle blower?

or for a small bench extractor howabout the fan from a combi boiler?

 

[chevy2]

I've got an approx 350mm diameter extractor fan in my 24' x 18' workshop and run it through a simple on-off switch,
dont use it much on tig but its great when doing a lot of dirty grinding or continuous mig welding,
keeps the air nice and clean in there, think mine moves approx 2500 m3 per hour?
must get round to fitting a speed controller so it can be left running slowly for general work.

 

[Paul.]

I have a couple of home made set ups using fans salvaged from blown air heating systems, almost identical to the one linked to, modified with a simple spigot to take some 6" flexible ducting they work very well, just put the fan unit outside and make a hood / nozzle for the pick up end, in the summer I use them as cooling fans just lay them on the floor to blow a gale up yer overall leg.
You wont need extraction with tig, for mig just position it above the weld area and it wont bother the gas, useful for grinding as well, if you point the outlet at a box or bin laid on its side about 18" away it catches most of the dust

 

[chevy2]

Just re-read your first post and your concerns regarding pulling the argon away,

My extractor pulls a fair bit more air than the one you intend to fit and i never have any argon sheilding issues,
mines wall mounted about 7' from the floor and about 5-10' from the bench depending on what end you're working at,

one thing i did do is mount the fan at the opposite end of the workshop doors which is where the clean air will be pulled from and then it'll be more efficient by removing the dirty air first before replacing it with the clean air from the other end.

 

[CRS51]

Thanks for the replies. Regarding the flow rating, are the ratings in cu/m before you attach a duct/arm ? I have been looking at various types and some mention 'free air'
So if you had say a 1000cu/m per hour fan would this be starved by attaching a duct/arm of say 4 or 5 inch diameter of would the suction / flow rate be increased ?
Hope this makes sense ?
My garage is 90 cu/m in volume.
Cheers Chris