[Whippetguy]

OK, it's dumb question time. Do most people insulate first, then run wiring over insulation, or the other way around. Also, what do most people use to attach wiring under the dash and to the firewall when you can't put screws through the sheet metal, for obvious reasons? Do the stick-on pads you run zip ties through work OK in an automotive application? I'd like to hear how you folks do it.

 

[docvette]

Doc here, imp:

Always install your wiring over the insulation..the insulation can hold Vapor and wear on the continuity of the harness over time, It can also cause problems if you must shoot screws to hold interior parts.

If you have an area that has no support for Wiring, and can't be secured with screws, Don't use the stick type or plastic bundle fasteners, Heat from the exterior of the body as well as the heater/cooling vents can cause the glue to let loose and the plastic to rot..leaving a harness bundle drooping on your pedal controls and feet..

I advocate getting a 1/8 X 1/8 in piece of aluminum Angle stock, and fixing it between the two nearest supports on the body, and attaching your bundle to it using metal , rubberized Adel Clamps. Use either a threaded 6/32 hole or a nut, star washer, and lock washer at each clamp. For the strut mounting you can use screws, but Pop Rivets are much better.

Doc imp:

 

[pasadenahotrod]

Those stick-on pads for tiewraps work just fine. I used them under the car in a couple places running wires from here to there.

 

[Whippetguy]

Doc, have you ever heard of the sticky back foil insulation coming of the firewall or cowl and falling onto the electrics, such as the gauges? I was thinking of using this type of insulation, but was wondering about that possibility.

 

[docvette]

Doc here, imp:

I'm not for sure, but I don't think that type of insulation is conductive..you can test by putting an ohm meter between the two ends of a test piece..if it reads infinite, its not..if it reads 000, it is..

NO I never heard of it shorting anything out, but I have heard of it getting caught up in your feet, and ultimately getting thrown away..because it falls down.

Usually most insulation pieces are covered by carpet or interior panels..and that holds them in place. You can use a glue that DOES last a long time for that, It's called Pliobond, and you can get it at ACE for $6 a bottle..But don't expect to remove the insulation ever again.

Doc imp:

 

[302 Z28]

On that sticky foil type insulation, if you are worried about it falling down after a period, just spray some 3M contact adhesive on both surfaces then apply it. It is not going anywhere any time soon. Do not use 3M #77 glue though. Go to a good hardware or home improvement store that has a good selection of spray-able glue and read the labels. 3M #77 is not for permanent adhesion IMO. When it gets hot it will let go.

Vince