Fume Extraction - Need more suction

[LuAn]

For a while now I've been thinking of mounting some kind of fume extraction to the head of my laser cutter. To this end I've obtained some nice flexible, and relatively lightweight hose from an aquarium shop (usually used for pond pumps).

I had thought to connect this into the existing fan however, having done a test run / mock up using bits of cardboard and duct tape, I don't think the existing fan can generate enough suction.

Obviously the pathway generated by cardboard and tape is not ideal and a purpose made duct might improve things. However that could turn out to be quite a lot of work just to find that it's not up to it.

I don't really have the money for a proper commercial dust/fume extractor so I'm looking for ideas.

My favourite ideas at the moment are:

1. to obtain something like an Earlex WD1000 CombiVac which, as I understand it, could have a hose in and a hose out. These cost about 50 quid but the down side it that it's quite bulky.

2. to get something like a powerful hairdryer and strip it for parts. The down side with this is that it involves quite a bit of work with no guarantees that it will work or that the fan, which is designed for blowing clean air, will be at all happy about sucking gunk.

Anybody got any bright ideas?

[CalG]

A smallish canister vacuum cleaner (second hand?) can work if you confine the region of generation.
i.e. put an acrylic hoop around the work zone. The smaller the better. and put another hose to vent the outflow outdoors.

You must think of air extraction as volume and pressure. (State side units, not SI ;-)
"suction" is usually indicated in units of inches of water. 32 feet of water is one atmosphere or about 14.5 psi. it only takes a few inches to move a lot of air.

Unless.....

the volume gets to be an issue. CFM cubic feet per minute. A big slow turning floor fan will shove a lot of air out an open doorway, but you can't duct the fan inlet or outlet and expect good performance. Wrong kind of blades for that.

So, pick the correct type of fan, and use it accordingly.

Those import woodworkers dust collectors can be had for around $100 . Hard to beat.

CalG

[LuAn]

Originally Posted by CalG A smallish canister vacuum cleaner (second hand?) can work

That's what I was thinking with the Earlex WD1000 CombiVac but I've contacted Earlex and been told that it won't work. The machine is designed such that plugging a hose into the blow outlet disables the suck inlet. Presumably this is done so that the air being blown is not being sourced via the filter/bin that would collect muck when vacuuming. This makes sense in most applications, but not mine, and I suspect that most machines will be like this. The trick therefore would be in finding the exception to the rule or one that's easy to modify.

So I'm back to asking for suggestions. ;-)

[CalG]

Source a less sophisticated vacuum. Without the interlocks. Eureka,makes some cheap ones, But they cost more than nothing $$ ;-)

I have a couple of fans that would be just the ticket,, but you are there, they are here.

Only UPS would profit ;-(

Cal

[LuAn]

Originally Posted by CalG Source a less sophisticated vacuum. Without the interlocks. Eureka,makes some cheap ones

Had a look at Eureka but couldn't see anything suitable. Maybe I missed the one you meant? I don't mean to sound ungrateful but unless you're aware of a model that will do what I need, there's not a lot of point suggesting I look at any given manufacturer.

The 'feature' I'm looking for is not the kind of feature that a simple vacuum cleaner shop is likely to advertise and would probably (see previous post) be unusual. So I could spend the rest of the year emailing vacuum cleaner companies asking if they have a model that does what I want. What I really need is for somebody here to say "I have an X that would do it, check out that make/model".

I know it's a long shot but please don't send me off on wild goose chases. I can do that on my own. ;-)

(Sorry again that this sounds ungrateful.)

[CalG]

No Problem

Our markets are different. UK vs US ;-) I have no clue what an Earlex WD1000 is!

I'm glad for my extensive scrap box!

Cheers Wish you luck,

[LuAn]

Originally Posted by CalG I have no clue what an Earlex WD1000 is!

It's sold in the UK as a workshop vacuum cleaner but you can also attach the hose to a different orifice to use it as a blower. I thought that with two hoses it might do what I need but as explained previously, this is not the case.

Originally Posted by CalG I'm glad for my extensive scrap box!

I'm jealous. ;-)

[Signmaker]

Luan;

Check this link

You want a decent quality inline fan which has the oomph to suck away fumes quickly so don't waste your money on hacking apart a vacuum cleaner- it won't be powerful enough.

The link goes to quality inline fans which are suitable for paint booth applications so they'll be fine for fumes. The site sells all the hoses, clips and accessories you will need- the smallest 100mm inline fan is 43 quid.

Get a speed controller so you can wind the suction up or down- very handy and only about a tenner.

I have loads of these fans and they are great.

[Pierke]

Hello everybody,

look at this:
http://4volt.com/Blog/archive/2009/0...ir-filter.aspx

DIY extraction.
Hope this can help.

Pierke

[LuAn]

Originally Posted by Signmaker I have loads of these fans and they are great.

Have you ever tried getting one to suck though a tube the same kind of diameter as a vacuum cleaner hose, or less?

I want to attach the suction tube to the laser cutter's head so it needs to be small. I can exhaust through 100mm duct, but I need to suck through something much smaller.

[Litografa]

My suggestion is that for lasering like hobby - DIY filter is perfect. For professional work all my customers buy professional air extracting and cleaning system (which are expensive) and after try to find solution like they can save on filters. Original filters are EXTREMELY EXPENSIVE, but there is alternative suppliers of filters. Activated carbon is available from suppliers to water cleaning. Synthetic filters - from automotive industry. HEPA we buy from ventilation companies and this is more expensive part of filter.
Originally we sell filters from http://www.tbh-online.com Germany and http://www.purexltd.co.uk from Great Britain

[Signmaker]

Originally Posted by LuAn Have you ever tried getting one to suck though a tube the same kind of diameter as a vacuum cleaner hose, or less? I want to attach the suction tube to the laser cutter's head so it needs to be small. I can exhaust through 100mm duct, but I need to suck through something much smaller.

Easy way to do this;

Build a simple duct box which has the fan mounted on one side and the smaller diameter hose on the other. This will allow you to step from 100mm down to whatever you want. You could also build in a charcoal filter to sit inside the box.

You may well find that extraction is more efficient if you simply extract the air above your machine bed. If you attach hose directly to your laser head attachment it's going to place extra loading on the motors and gears.

You could build a simple cowl above your machine and extract up through it.

Whichever way you go it's always better to buy a more powerful fan than you think you need- if you have speed control you can turn a powerful fan down- you can never turn a wheezy little fan up.