Safe Insulating Materials?

[Steve Mavronis]

What materials are safe to use in a stompbox to protect 'both sides' of a floating circuit board while it is powered on. I don't want anything that sticks to the board itself, but the inside of the lid would be okay. Just need suggestions for a electrical non-conductive barrier between the board and other metallic parts (pots, lid, etc.) of the stompbox interior.

[John Lyons]

Asbestos?

[Steve Mavronis]

Asbestos?

LOL John, not fire protection!

On second thought I'll just wrap thin black packing foam around the board. Thanks.

[R.G.]

The industry likes "Nomex", an insulating, dense card stock that's prepped for high temperatures, toughness, and fire retardency. Think of it as high density brown paper on steroids.

[amptramp]

An item you may still see around is called fish paper, a bluish-grey paper stock that was used as insulation for receivers, transmitters and power electronics almost as long as there have been tubes.  But what I would use (if I was going to ever use a floating board) is duct tape on the lid and chassis.  It stays in position, can be trimmed to size and is reasonably puncture-resistant.  Like the force, it has a dark side and a light side and it holds the universe together.

More modern people tend to use phenolic or epoxy-glass as an insulator, but it has to be glued in somehow.

Floating boards will always present a problem with motion of the board stressing wiring.  This is especially true if the effect is used in front of a speaker operating at high output - the board will vibrate inside the chassis and break wires.  I would mount a plate between the pots and the chassis that can take countersunk screws for standoffs.  Some people attach standoffs to the inside of the box with JB-Weld or epoxy.

[caress]

a piece of soft foam works well.

a big chunk which is held in by the force of the lid screwed into the box
or
you can take 2 pieces, put them on the top and bottom of the circuit and wrap a bit of tape around it to keep it together.  even boss pedals and the like use this method...

[Tony Forestiere]

A big piece of vinyl "Duct Tape" across the pad side?
A "temporary" solution (of course).

I don't want anything that sticks to the board itself, but the inside of the lid would be okay.

Sorry. I missed this. Wrapping in  layers of paper is good.

 But what I would use (if I was going to ever use a floating board) is duct tape on the lid and chassis.  It stays in position, can be trimmed to size and is reasonably puncture-resistant.  Like the force, it has a dark side and a light side and it holds the universe together.

Bwahahahaha... I missed this too

[ayayay!]

I use craft foam.  2mm.  JoAnn, Hobby Lobby, etc.  Also available w/ adhesive backing.  A sheet usually sets me back $.69.

http://www.joann.com/joann/catalog/productdetail.jsp?pageName=search&flag=true&PRODID=xprd1131950

[Steve Mavronis]

For now I cut out a 1/8" thick peice of black foam 2.25" wide by 5.2" long with notched corners and with one end under the PCB the rest folds over it held down whent he lid is on.

Those other materials sound interesting. I'll have to check them out when re-furbishing pedals like this old MXR one.

This is why I don't like 'floating' boards and use PCB mounted pots in my own clone projects instead, but I understand they are not for everyone.

[jasperoosthoek]

Plexiglas withstands 200kV where PVC will start to conduct .

[johanp]

[Steve Mavronis]

I noticed the new re-issue CSP-028 Custom Shop '76 Vintage Dyna Comp still use foam. My foam appears to be the same stuff:

[stringsthings]

For now I cut out a 1/8" thick peice of black foam 2.25" wide by 5.2" long with notched corners and with one end under the PCB the rest folds over it held down when the lid is on.

Those other materials sound interesting. I'll have to check them out when re-furbishing pedals like this old MXR one.

good job, mate! ... although a floating board is not the sturdiest method of construction, it does get you one step closer to the "ideal" pedal ... ( it's a quick-and-dirty technique for those one-off prototypes that won't see the live stage )

[familyortiz]

Of course, if just lining a surface like a chassis lid, from nearby terminals, components, etc. some electrical tape works nicely.

[MR COFFEE]

May I suggest a material you can get for FREE and keep out of the landfill that lasts for longer than any stompbox you are likely to build?

Think about all those rigid clear plastic packages that hang on hooks and make it hard for people to steal products. You know, those packages we all curse because we have to get out scissors or a knofe when we get it home from the store just to get the product we bought out of the %$$# package.

The plastic is insulating, easily cut to the needed shape with scissors, stiff but not completely rigid, thick enough and tough enough to not be punctured by the pointy cut off leads that protrude from the bottom of pcbs, and did I mention FREE?

AND you are keeping the stuff out of the landfill.

How could you want to use anything else? <grin>

mr coffee

[PRR]

Maybe you have seen 20-30 year old foam. It rots. It gets completely disgusting.

For a one-off, this %$#@! pilfer-proof pack my new tub-spout came in is, as Bart says, otherwise useless but can be cut and will probably outlive us all.

Transformer "fish-paper" is old and traditional but vanishing as improved materials with flashier tradenames come onto the market. "Nomex" might be used in very hot transformers but better known for racer's fire-suits. Such materials are hard to find in one-off quantity.

Duct-tape IS prone to puncture on wire-leads, and WILL crap-out in 5 or 10 years. (BTW, that's why it isn't legal for ducts.) I used a lot of it on short-term projects. I would never want to use it for a long-term application, not if the users knew who built it.

Electrical tape, other than as many-layer wrapping, is sure to make trouble down the road.

[Steve Mavronis]

I've wondered about thin plastics but thought they are prone to static discharge. Maybe that's a myth unless just certain types are. Temporarly I have foam in my repaired MXR Dist+ but I want to change it out. Need to find some rubber sheets to cut out or maybe a wide enough roll of that 30mil 600V insulating Templex stuff that I used as a barrier between my 250-OD clone's PCB trace side and pots because of tight clearance. I could fuse a few 1" strips together to make it 2.2" wide but that would look ugly at the seams.

[jasperoosthoek]

Static charging only occurs when there is friction with air or and another material. I've been using thin transparent plastic sheets for years in all my pedals. No charging and other problems, nothing. It works like a charm .

[John Lyons]

May I suggest a material you can get for FREE and keep out of the landfill that lasts for longer than any stompbox you are likely to build?

Think about all those rigid clear plastic packages that hang on hooks and make it hard for people to steal products. You know, those packages we all curse because we have to get out scissors or a knofe when we get it home from the store just to get the product we bought out of the %$$# package.
AND you are keeping the stuff out of the landfill.
mr coffee

+1
You can get more than you'll even use for free. Boss uses the same stuff, They just crimp it little to keep it straight.
I have a small stock of it for when I need it.

[MR COFFEE]

Thanks to all who share my enthusiasm for this material for this use.

Pat yourselves on the back for also keeping this "does-it-ever-deteriorate?" material out of landfills where future generations will need to mine for the stuff when our "petroleum-is-readily-available-and-always-will-be" generation is long gone and reality finally sets in on our civilization.

May we all learn to appreciate the wisdom of re-use, recycling and conservation of our resources for generations yet to come.

My parents were  young adults just as the "Great Depression" set in, and I have absorbed their values and wisdom about avoiding waste and valuing what materials Mother Nature has provided us with, and I have come to echo their recognition of the value of those materials. (Sorry if this sounds preachey; I guess I've taken it to heart and it's my values now)

mr coffee