I am building a laser cutter to cut foam. These foam releases somewhat obnoxious fume so I would like to build some contraption that suck air near the cutting head. I thought of using some duct and dust remover but that is rather loud for my garage. So I thought I would use a few 80mm fan blowing air into a duct.
The amount of fume is not too much, something along the line of a typical house hold vacuum should be able to easily suck out the air.
What would you recommend on the matter?
Only actually safe way to do this is to fully enclose the machine, and have an air extraction system attached to it. Anything else is bound to let some of the fumes/particles escape, and depending on the foam these can actually be quite harmful in the long run.
If in doubt, oversize the air extractor.
What material is the foam ?
I would start investigating, by looking at the websites from companies that specialize in this type of solutions, just to be inspired. Then you know more than before.
Air has to be pulled through a tube as it’s much harder to push it. But have you considered a tube around the cutting head (laser), sealed at the top and having a small rubber tube attached to the side. You could connect the attached tube to a shop vac (one that has a exhaust).
Please take care for adequate ventilation, these fumes under restricted air supply can be lethal
It’s polyurethan foam.
Yes, fumes from that are going to be dangerous, you do need an adequate enclosure, and strong air evacuation, to the outside of the building.
A solution as you describe is inadequate and dangerous, do not do it !
Also, 80mm computer fan are good for high flow, low pressure. So it wont work if you have a restrictive system like a suction duct. You need a higher pressure capable fan like a squirrel cage fan. Just type “dc blower fan” on ebay for an example.
So a shop vac + a water trap? What is water trap? To trap the water?
Search soldering air filter on youtube. There are good examples of what activated charcoal filtering media found at pet stores can do. I would not consider them anywhere near as effective as a true exhaust system, but it is an idea.
I search for water trap and cannot find a vendor that sells them. 
@Dat_Chu Just make one. The “trap” is just a 180 degree pipe bend. The point of which is to close the pipe with water to prevent sewer gases from traveling back up to through a drain.
Eh? Can I have more info?
My google-fu is taking a hit today. Must have been the obnoxious fume :D.