Static when sanding

[Mark A]

When using my belt sander connected to an old vacuum cleaner via a DIY "dust deputy" (traffic cone, 15l paint tin and a load of duct tape) I get static shocks when I touch the hose - one shock made my entire arm numb for about an hour. If I don't discharge the static on myself for a while I can actually see the sparks when I look down the hose and can hear it crackle a bit. Any thoughts on how I can prevent this??

Thanks

 

[NetBlindPaul]

mark,
Please provide a little more detail about your install.
My first instinct is that you are luck to still be alive!
Wood flour is highly flammable and can be explosive!
You need to look at the hose/duct you have used.
Perhaps you need to look at steel spiralled hose and earth the suction end to the main earth terminal of your electrical installation by suitable means.

 

[theartfulbodger]

That sounds dodgy given the flammable nature of sawdust. I guess that very very fine dust is explosive when mixed with air?

Can you run an earthing cable to ground? Even if that means sending the cable to a plugged in metal-bodied machine?



edit

What he said ^^^^

Pics of the DIY traffic cone cyclone dust trap thing would be good as well!

 

[Mark A]

My first instinct is that you are luck to still be alive!

I usually don't have good luck so thats a bonus!


Here's a picture of my contraption - it does look like something out of scrapheap challenge but it works ok

The belt sander has a slightly larger spout than the hoover nozzle so I improvised with a cut-down aspirin bottle, a 1" plasterboard screw and some packaging tape - all of which are right next to my hand while I hold the sander

Could this be the culprit? or should I somehow earth the hose?

 

[theartfulbodger]

Prossibly the hose? Netblindpaul will give you a firmer answer.

You should feel proud of that scrapheap challenge inspired extractor! I'm thinking about bodging something similar together from old hoovers and scrounged air hoses.

edit

just re read your first post. yup definately look to earth the hose! I guess static is building up due to the friction between the air and dust and the hose.

 

[miles_hot]

do you get it with any other tool? Do you get it from just vacuuming? i.e. see if it is the air movement / dust friction theory. My concern would be that it might be the tool itself, especially if you don't get it with other items or you don't get the same effect from just vacuuming up the dust.

I'd be dead scared of seeing sparks inside the dust collecting system! Either way I'd stop using the system till you've got some earthed bare copper wire inside the tube connected to earth. Then do the lottery

Miles

 

[mailee]

NO WONDER! Look at the name on the sander. :shock: :lol: Sorry couldn't resisit that.

 

[Hudson Carpentry]

hay wheres my post gone?????? I made the joke about the name of the sander to :roll: (hammer)

Anyhow there's now 2 unfunny members on this board

The helpful part to my invisbile post went something like.

Spark hits dust and dust goes bang. DO NOT use it. Try connecting the hover direct to the sander and don't use parcel tape (parcel tape is very prone to static). I suspect the traffic cone and paint tin.

 

[barkwindjammer]

The static is caused by particles brushing all the plastic parts, you should remedy this immediately before doing any more sanding as you have unwittingly made a vandergraaf generator combined with a flour bomb :shock:
an easy fix is to earth your device by running a thin copper wire from the end of the hose that connects to a tool (your sander) to an earth strap in or near your workshop, route the wire through all the hose to the collector tin and to the strap.

 

[Mark A]

NO WONDER! Look at the name on the sander

I was waiting for someone to say that!!! =D>

I haven't had this when the contraption has been connected to any of the other tools I extract the dust from (router, mitre saw, plunge saw, jigsaw, orbital sander), but this could be because my hands are not close to the hose while I'm using it, I usually do not run them for a prolonged period as I do with the belt sander and the amount of very fine dust produced by these tools is generally less.

When I vacuum up dust I'm holding the nozzle in my hand so am I earthing it?

Incidently one spark passed through the fleece, the jumper and the thick padded coat I was wearing when I touched it with my forearm - I thought it was a shock from the mains!!

If I run a copper wire through the hose, would the metal shed I almost blew up be a suitable earth (my grasp of electrics is quite limited)

Thanks

 

[barkwindjammer]

I'm guessing here, your sander will be almost all plastic construction and double insulated, other tools may have metal parts where the static will be dissipated, yep the metal shed will dissipate static as its a fairly 'flighty' beast, static can be very high in voltage (60,000v) is not unheard of, the killer in electrickery are the Amps-the stuff contained in 'bought for' electrickery i.e. mains, static will 'go to ground' very easily.

 

[NetBlindPaul]

Its volts that jolts but amps that kills.
Voltage causes you to smart, or jump, like static electricity, but it is the current that kills, i.e. the amperage flowing, e.g. from the mains.
The metal shed "may" dissipate the static, in any case this metal work should be connected back to your incoming mains supply earth terminal to comply with wiring regulations, this is by the way NOT a business requirement it is a requirement for all electrical installs.
Before someone else jumps on me for apparently scaremongering.

 

[studders]

I think it might be your Hoover generating the static. I used to get some real belts from a Dyson I used to have.

 

[Mark A]

Unfortunately there are no mains supply installed in the shed - I use an extension cable plugged into a socket in the kitchen. We have recently renovated the house and with hindsight we should have got the electrician to wire an outside socket.

Thanks

 

[NetBlindPaul]

mark,
This may be one of your issues, please check that you have a "suitable" earth at the end of that extension lead to comply with BS7671, this could be another way of saving your life.

By the way it sounds like you're a good man do get the next lot of lottery numbers off, got 6 winners for me please?...

 

[jimi43]

OMG...that has to be the funniest setup picture I have seen in a long while.... :mrgreen:

Simply brilliant!

You made my night...I am going to bed chuckling out loud!

Cheers!

Jim

 

[Erasmus]

Looking at that unbelievable setup makes me think I'd rather just attach the dust bag that came with the belt sander. Emptying the bag periodically has to be preferable to tripping over Heath Robinson's worst nightmare every 5 minutes. Get yourself a proper workshop hoover and a qualified electrician before you take out the entire county power grid :lol: :lol: :lol:

 

[Mark A]

OMG...that has to be the funniest setup picture I have seen in a long while.... :mrgreen:

Every time I look at it I laugh - although by the seriousness of these posts, not any more!!

The contraption is quite efficient in collecting chips and the larger particles but the tiny hoover filter gets blocked continuously by the fine dust. For now on I think I'll just reserve any sanding I have for outside, using the dust bag which came with the sander.

Anyway I was thinking about upgrading the "dust extraction system" to a proper wet-n-dry workshop vacuum or a vacuum extractor like this

http://www.axminster.co.uk/axminster-axminster-rdc100h-vacuum-extractor-prod794272/

but that'll be tomorrows topic! (after I buy a lottery ticket)

Thanks for the warnings :lol:

 

[jimi43]

Oh, getting a VAX is simple...

Bootfairs! There are literally hundreds of them...I see at least two at every fair and they go for no more than a fiver. I have three. The filters cost more new but there is a guy that sometimes comes who has them for a few quid.

I usually put on a respirator and blow them out way down the garden with air pressure.

Jim

And you can probably find bigger traffic cones that that on the way out! :mrgreen:

 

[dibs]

Interesting topic...My own set-up is a detached garage (workshop). I had the mains plumbed in by my prospective sun-in-law, an electrician, Part "P" etc. The mains runs from my home fusebox via a large gauge armoured cable. This runs to a small fusebox with seperate switches for lights and sockets. I don't know the rating, but prospective s-i-l knew what type of equipment I use.
Dust masks aside, my only "collection" is an Earlex workshop Vacuum Cleaner, which is mainly for hoovering round. I do connect it to my table saw, and, only recently, to my orbital sander-I try to sand outside as much as possible. The point is, the Earlex has a long plastic hose, so, should I be looking at potential static hazards, especially when sanding, when I hold the sander and hose at the same time.
Thanks for your thoughts. Rick.