looking for general advice about setting up a test bench area 2

[drewbr549]

Hi all,
I got such great advice in the "concrete as insulation?" post that I thought I'd see what I could mine out of a general question. My situation is that I'm taking my part-time amp repair business from the kitchen table to a "real" test bench, and am coming up with setup/construction questions that I never thought I'd have.
Here's where I'm at right now: I have a bench, approx. 3 ft high (I've always worked sitting down, but thought that standing might be nice for a change - I may change my mind ), and a shelf above the bench that puts my test equipment at about eye level. The room I'm in is concrete on all sides (see thread248-162816). The suggestions I've had so far for flooring are "thick PVC or similar mat" and linkable floor-panel risers. For an insulated bench (assuming that's the route to go), formica has been suggested. It has also been suggested that I install a 10mA, instantanious trip GFCI (I also have an isolation transformer for any transformer-less stuff I work on, though I don't get much).
If there's a consideration that should be in this list that isn't, or if anyone has ANY other suggestions for setting up a test area, I would greatly appreciate them!
Thanx,
drew
p.s. Oh yea - I mostly work on audio gear ( low voltage stuff, but line voltage is there too, naturally, and the occasional tube amp I get in has some pretty high voltages. I do have a pair of KV gloves, but I'm a clutz with them on. Some people say to at least keep one hand behind yer back for HV work, but I hate doing that, too (and it makes me clumsy, and twice as likely to screw something up. One glove, maybe? comments?

 

[IRstuff]

ESD mat surface on the benchtop, along with ESD monitor, along with ESD wrist strap
fire extinguisher
on/off power switch at bench
lots of lighting
lots of ventilation
grounded soldering equipment


TTFN

 

[itsmoked]

drewbr549; You might find this thread interesting.

thread240-154013

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[MacGyverS2000]

Make the bench just tall enough to make standing and working comfortable, but don't forget to purchase a chair that will allow you to sit down and still raise high enough for comfortable working.


Dan - Owner

http://www.Hi-TecDesigns.com

 

[drewbr549]

irstuff,
got everything but the ESD stuff (electro-static discharge, right?). Not too much of that here in missouri, unless you're on carpet, but I'll scope it out more - most of the stuff I work on could easily be damaged by a static charge. I've gotten around the wrist wraps so far by just touching something and grounding myself b4 putting my hands on a board, but this technique probably isn't nearly as effective (and you can always forget). Anyway, thanx! - I'll look into the matting and monitor.
itsmoked,
Awesome list! I've got the basics (ac and dc PS w/ current limiting and isolation, function gen, scope, dmms, etc) but there's a lot of other cool toys on that list, and wow, it's a long one! I got 1/3 way through now, but the kids are waking and today it's back to school in northern MO - I'll check it all out later.
drew

 

[geekEE]

Well, touching something that's grounded does help protect the board that you're working on, but does not protect you. ESD straps have a current-limiting resistor that will allow ESD discharge, but help protect your body from excessive current if you happen to work on a live circuit.

 

[IRstuff]

The issue with intermittent grounding is that it's intermittent. Just turning around to get something may allow your clothing to generate a large enough charge to zap something.

I would think that even in Missouri in the wintertime, there'll be some amount of static generation.

TTFN

 

[drewbr549]

Good idea, macgyvers2000, that would let me alternate between sitting and standing.
GeekEE & IRstuff: you seem to be saying that, given time, I will eventually zap something if I'm not grounded, but that an ESD strap (and possibly a monitor) will un-ground me in a hurry (well, unless I'm grounded somewhere else) in the presence of excess current. This sounds like something I need to look into a lot more - thanx for the heads up.
drew

 

[geekEE]

The ESD strap doesn't un-ground you in the presence of excess current; it just doesn't allow excess current to flow. They typically have a 1meg resistor in series with the grounding wire so that you can't have more than a few microamps flowing through you if you grab a hot wire.

No worries about ESD with a tube amp of course, but a lot of modern audio equipment has DSPs and other things that could be sensitive to ESD.

 

[rtronics]

I like to work on a wooden benchtop surfaced with non-synthetic carpet. (Such as a wool/nylon mix). This can be ESD safe, but also avoids scratching the gear when you move it.
Essential when working on consumer equipment!
DO NOT work on a metal bench. Your business will fail pematurely if you do. (Due to the DEATH of the BOSS).
Valve equipment is dangerous, the advice of working one-handed on live gear, is life saving.
Regards, Ray.

 

[drewbr549]

makes sense - thanks geekEE!
rtronics, scratching definitely is an issue! - I've finally gotten myself into the habit of looking stuff over real good b4 I even touch it w/ a tool, just to avoid that aweful feeling of finding a big scratch later on and wonder, "geez, did I do that?" (paranoia does have its downside)

 

[MikeHalloran]

If you have a US electrician wire the room, he'll put switches, conduit and outlets at 48" from the floor, exactly the level of a 12" riser shelf above a standard 36" bench, so you can't push the bench against the wall. Get the conduit run below the bench or well above the riser.

I like to have an outlet strip on the bench. But anywhere on top, gives you a mess of cords. I like the strip attached to the bottom of the bench, spaced back a bit from the edge.

Re looking stuff over, take pictures. The incremental cost of a digital photo is essentially zero until you print it.



Mike Halloran
Pembroke Pines, FL, USA

 

[itsmoked]

Yes outlets ..lots and lots of outlets.. Sitting here in my lab without getting up I count 49 plugged in plugs.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[ScottyUK]

DO NOT work on a metal bench. Your business will fail pematurely if you do. (Due to the DEATH of the BOSS).

I'll assume that the bench in question is bonded to power earth because it would be reckless and dangerous not to do so in a lab environment. Could you expand on the reasoning for the above observation?


----------------------------------

Sometimes I only open my mouth to swap feet...

 

[zeitghost]

I suppose the other thing to mention is remove all jewellery, such as wedding rings & watches, before working on live equipment.

Short out a large electrolytic with something like that & you'll regret it...

Touch something live with something like that & you won't live to regret it...

 

[itsmoked]

I wouldn't do electronics on a metal bench.. because it... simply... sucks! Regardless of the safety argument.

But to list my reasons:
1) A metal bench must be considered hard grounded. If you are touching the bench with your stomach, elbow, hand, knee, or tongue while working on line voltage stuff the one hand rule is practically pointless. You'll get hammered. One of my electronics profs related a story about a fellow navy tech who died specifically due to this.

2) If any hot lead, component, or chassis touches the bench and A) it's well grounded you get a blast and possibly an ugly permanent local surface crater. B)If thru some freak of nature based possibly on nylon leveler feet, the bench is isolated, you now have a gigantic hot surface awaiting a victim.

3) Metal topped benches are often thin (cheap) stainless steel sheet-metal. This sheet metal has a penchant for lumping up and down here and there. This causes things like all your little bitty parts to roll places unexpectedly or even launch into the air when you lean on or set something down elsewhere changing the chaos-driven plane of the bench surface.

4) The bench can be extra cold or extra hot because it's m e t a l.

5) The previously mentioned scratching. You put some really nasty performance effecting scratches into the service by dragging a heavy chassis across it.

6) You can get reflections and glare off a metal bench. I dare you to find that SM0603 part laying on a well lit stainless steel bench-top.


Pro metal bench: When working consistently with heavy devices like 1HP+ motors, large heavy equipment or mixed systems with oil, hydraulics and other chemicals that will be dribbled and spilled occasionally.

My preference(nae - I shall say requirement): A steel legged bench, with a stained Grade-A 3/4" plywood surface 36" wide, completely covered with a full width light colored static mat, which is connected with a 1Meg Ohm resistor to the local earth ground.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[itsmoked]

drewbr549; Wants to know about setting up a workbench area?

This is what I did. (Note: some pics may not show up occasionally - try later)

Acquired a space.

Partitioned it for the bench/lab area.

Insulate area from noise and thermal gradients.

Finish it in a pleasing manner.

Provide good lighting.

Nice floor and plenty of power (14 duplex outlets on seven breakers)

Add ambiance!

Design and start making benches.

Weld them all.

Finish them.

Add them to the office as planned.

Cover with static mat.

Add a few things.

Put in raised shelves for instruments. Very important!

Arrange things.

Add some book cases and a white board for free thinking.

Don't forget some tunes!



Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[Comcokid]

Itsmoked's bench pictures are great, but it brings up one issue that is always a pain for me. Most affordiable test equipment (i.e. used) is very deep. If you use such things (pulse gens, RF signal gens, RF specturm analyzers, etc) you will find you need a deep shelf over the equipment bench just to keep these things out of your working area. And, such equipment is heavy, so make sure the shelf is strong.

Look at the type of equipment you have and use to see if this will be an issue.

 

[drewbr549]

wow - a lot of amazing help, guys - you're all awesome!

Mike - I'll be running the conduit myself - under the bench definitely sounds better. But, I never thought of putting some of the outlet strips under the bench – sounds like a great idea. When I was doing live/studio sound, we had a fun term for when your cables play twister, but I won’t repeat it bc it has a bad word in it
zeitghost – I’ve heard that one applied to messing w/ car batteries, but for some reason never made the transfer to anything else – thanx! (geez, will my wedding ring even come off??? Sounds like a good reason to go on a diet
itsmoked: You rule! That was an amazing couple of posts. I know it had to take a big chunk of time to put all that up, but I reaaally appreciate it – especially the pics. With that many diverse talents, you’re probably already quite well off, but I wanted to let you know that you could easily add a little text and a few more pics and have a very profitable little ebook/zine (I know bc I have a really lame ebook on guitar setup that nevertheless sells about a copy every day, and the whole process is completely automated – all I have to do is spend the money). Seriously, consider it! BTW – do you (or anyone) know of a good place to buy the static mat (and maybe one of those really cool magnifying glasses)? I mostly shop at mouser and tequipment (and ebay), but don’t know (in the case of the first two) if they carry stuff like that, or if they’re competitive. Anyway, thanx again – you gave me many good ideas.
Comcokid – oh yes, you are so right. I actually made my whole shelf deeper just so my ancient bk scope can fit on it. I’d love to have a new, shallower one, but I mostly just use the scope to trace signals, and can’t really justify it w/ so many other cool things I want. Luckily, though, the shelf is strong (hey, it’s bolted into concrete!). The guy that did my carpentry work claims he actually laid on the shelf to test it
Again, many thanx all for the great advice,
drew

 

[geekEE]

Itsmoked, those are great pics! What a workspace! I think it's nicer than any room in my house. If it had a cot, I'd never leave.