Extractor for belt grinder- advice needed

[adrspach]

I would like to ask for an advice and tips what to get after all this misfortune is finished.
I have small workshop garage for metal and wood work therefore extraction of grinding dust is for me essential that I do not contaminate my wood with metal.
I am also aware of fire risk with grinders.
What should I look for which would work with metal grinder. Ideally I would like it working for both wood and metal but it is probably impossible due to fire risk.
Thank you.

 

[TFrench]

I don't have extraction on my belt grinder (sorby pro edge). It just leaves a lot of black fluffy dust in the bench. If I have to use an angle grinder I just go outside.

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[Rorschach]

Most knife makers etc seem to use a bucket of water hung under the grinder platten.

 

[Sideways]

I put a small, shallow aluminium box (half an electronics project box) below the bottom roller of my pro-edge, and a powerful 40mm square flat magnet underneath it. This helps catch metal dust coming down off the belt and there is less to hoover off the bench. Every once in a while a spark will ignite the filings and they burn out slowly like a glowing cigarette ember. No harm done, but don't use a plastic container, those melt.
By contrast, using a CBN wheel with no extraction throws metal dust all over the floor.

I think if I was trying to extract metal dust, I'd want to suck it into a cyclone separotor or something first before my shop vac. That might give time for any sparks to burn out. Use a metal drum not a plastic barrel and don't mix wood and metal in the same system. Fine metal mesh screens are sold for some extractors that may be exposed to sparks. You could investigate where and how exactly those are used.

 

[Inspector]

I wouldn't use aluminium in any dust collector or dust container because it and iron basically make thermite. I saw small aluminum cyclones for sale from China for not much more than the plastic ones. I suggested it on another metal forum and was quickly corrected.

I would have two separate cyclones. One for the wood and the other, made of steel for the metal grinding. Can you put the DC's in a shed/lean to outside the shop.

Pete

 

[Hornbeam]

Thermite is only going to create a reaction when both iron and aluminium the particles are in very fine powder form as it relies on large surface contact area and often an external heat source to get it started. Any solid aluminium container will also have a thin layer of aluminium oxide preventing any reaction

 

[Sideways]

Aluminium and it's alloys have a melting point of 660 C or higher, and the oxide layer has a significantly higher melting point as you find out when you learn about welding the stuff.
There's no way a few grams of smouldering iron filings are going to get an aluminium tin hot enough to be a problem.

Thermite reactions commonly uses a very high temperature source to get them going - magnesium ribbon like you used to get in school chemistry lessons is popular.