making wires on circuit board immobile but able to be removed later?

[snip]

Silicone. Lots of different brands & formulations (RTV, Goop, etc.)

Dab a small bit on an unused corner of the board and let it dry, to see if it can be peeled off cleanly.

HTH

Not great advice, as most silicones cure with acetic acid, which corrodes circuit boards. If you must use silicone, use one that is specifically safe for electronics. There are only a few.

=======================

** Just get one labelled " Neutral Cure "

These are safe to use with metals like copper and tin.

..... Phil

Cyanoacrylate with accelerator. It sets fast, cracks off really easily and can be cleaned up with acetone.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC / Hobbs ElectroOptics 
Optics, Electro-optics, Photonics, Analog Electronics 
Briarcliff Manor NY 10510 

http://electrooptical.net 
http://hobbs-eo.com

Hot glue will soften when heated with a (controlled) heat gun, before the electronics get damaged. Wires can easily be removed then. Just experiment a bit on some old PCB.

Arie

From the literature:

3M 3748 Hot Melt Overview The 3M 3748 is a unique hot melt adhesive often used in electronic assembly because it provides excellent thermal shock resistance and is non-corrosiv e to copper. The 3M 3748 also provides an excellent bond to polyolefins. T he 3M 3748 also comes in a self-extinguishing version that meets UL 1410 re quirements, 3M 3748VO.

Good stuff. And if you want to crack it off, a few minutes in the freezer m akes it very easy to handle.

Peter Wieck Melrose Park, PA

[snip]

If you're gluing to a bare board and bare traces that may be true, but it's rare to find a board that isn't conformal coated nowadays.

Conventional RTV silicones outgas acetic acid for some period up to days - long after it is 'cured' for practical purposes. And that acetic acid will attack exposed metals of many types, including 304 and 316 stainless steel. And, worse, if that silicon is in a confined area such as an enclosed chas sis, the damage could be inches away from the source.

Peter WIeck Melrose Park, PA

Candle wax?

--
Adrian C

NO! Long ago (50+ years) I used that to stabilize selfwound RF inductors. The copper rotted away within a year. It may depend on the wax type, bees wax is supposed to be less agressive.

Arie

I would think that candle wax would have dyes and perfumes added. Lots of coils, capacitors, transformers, etc. were potted in wax for decades without issues. I guess pure beeswax would be the safe bet though.

I use beeswax for repotting some 1970s flybacks on old GE TVs that we use in some classic video games made by Nutting Assoc. Works great and hasn't led to any further trouble after upwards of ten years...I made a simple silicon mold to hold the old core and just warm up and pour the wax in.

John :-#)#

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(Please post followups or tech inquiries to the USENET newsgroup) 
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I should add that beeswax is likely too soft to hold the wire suspended for any period of time and it melts at lowish temps, it would probably be of no use to the OP for his application.

John :-#)#

--
(Please post followups or tech inquiries to the USENET newsgroup) 
                      John's Jukes Ltd. 
MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3 
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                      www.flippers.com 
        "Old pinballers never die, they just flip out."

coils, capacitors, transformers, etc. were potted in wax for decades witho ut issues. I guess pure beeswax would be the safe bet though.

Carnauba wax (plant-based) Beeswax and Paraffin wax all have their negative s. Carnauba wax and Beeswax are both highly acidic, albeit with 'weak' acids - but will attack bare copper and untinned copper wire over time. You will n ote that old waxed-paper caps used tinned copper or iron leads, not bare co pper. You will also notice than when wax 'leaked' onto the chassis, there w ould be a permanent stain on the chassis - from the acids in the wax. The m ix on the old paper caps and coils was, typically, 80/20 paraffin to beeswa x - the admixture was more stabile than either alone, and easier to work th an either alone. Paraffin wax oxidizes, is highly flammable - more so even than beeswax- and while hydrophobic is sufficiently lipophilic as to attract fat-based conta minants out of the air - such as cooking odors, nicotine and so forth.

Transformers back in the day were 'potted' in either an asphalt-based tar (equivalent to modern non-plasticized hot roofing tar - that which is melte d in tar-wagons), or in coal-tar pitch (awful stuff!). Both of which are st abile over a wide temperature range. Some few things were, in fact, potted in wax, but today that wax would be called "Jeweler's Wax) which, when cold is machinable and quite hard.

There are 'archival' waxes that are both acid free and self-extinguishing, but at $8 - $15 per ounce, not cheap.

I keep archival glue-sticks, electronics-safe glue sticks (compatible) and conventional glue-sticks (not compatible). I need two glue-guns as the chan ge-over is quite wasteful otherwise.

Peter Wieck Melrose Park, PA

... specifically safe for electronics _and/or aquariums._

[Sorry - the first attempt went email...] Jonesy

-- Marvin L Jones | Marvin | W3DHJ.net | linux 38.238N 104.547W | @ jonz.net | Jonesy | FreeBSD * Killfiling google & XXXXbanter.com: jonz.net/ng.htm

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Interesting. Not to change my own topic here, but I have a 125 KV high voltage generator that I made myself fifteen years ago for demonstrational purposes. The design is not mine, but uses two auto HEI

coils in opposite phase. To get the voltages needed and not destroy the

coils, they had to be placed under oil. However.....

Three years ago, after the device had been stored away for almost a decade, I removed it and its storage container (I always keep any oiled components in an extra container to contain possible leakage later). Well, good thing I had the extra container as there was some leakage. Not much, but enough that I decided to drain and switch out containers. Done and restored.

Another option at the time of the original build was, instead of using oil, to place the coils in wax. I never did this originally, but decided to make a spare HV section (which only contains the two coils). This time, I used white canning wax with no additives. I did this last year. The year before, I was worried that the canning wax might crack upon exposure to heat and cool, so I poured a block and placed it into an environment with a lot of temperature extremes for a year. No cracking after a year, so that's when I decided to pour the wax spare generator section.

Now, just as a precaution, I'd never take the unit in a hot car, warmed up from summer heat let's say, for any length of time as I'd be concerned that the wax might start melting, so that's where the oil filled one would be used. Where the wax one is stored might vary from

15-100 F, so confident at those temps.

Oil can sure creep right through and out of things! I have another homemade device, a high voltage probe, consisting of many resistors in series. It can measure up to 100 KV and uses a standard multimeter with

its very high resistance. I made it 20 years ago. However, being stored on the shelf above me right near where I sit here, I noticed some

suspicious spots of what I thought was water at first on the rug this past summer. I was perplexed at first and thought my roof might be leaking until I decided to finger the wet drop one day and rub fingers together to see if it was in fact water. I then knew for sure that it was oil. Turns out that when I made my HV probe, I exited the resistor PVC enclosure with a piece of HV multi-stranded TV wire of the kind often seen coming out of TV flybacks. Well, although I sealed around the wire to PVC exit, I didn't properly seal the strands themselves. It

took 19 years, but oil made its way through that wire and was dripping from the end plugged into the meter. It's not much, maybe five drops in

several months, but definitely a leak. Not having time to get to this yet to remedy, I covered over the wire end with a plastic bag and had this hang out over the shelf side to contain any further leaking. As of

today, the bag probably contains an ounce of oil.

As for the circuit board, I probably won't use wax to hold the wires. I

like the hot glue idea, which I have in abundance here, and I can always

reheat later to the wires come right back off the board. I just have to

be sure not to get any of the glue on the soldered traces themselves.

What would be wrong when using conventional glue sticks?

Conventional glue-sticks have a much lower plastic temperature than the oth ers - Anything lower than about 120 F should be fine. But understand that t he melting point is about 175 F. Archival glue-sticks melt from 250 F to 3

80 F depending on the application. Electronics glue-sticks are designed for hot-temperature application or 350 F to 380 F. In a solid-state device wi th low voltages and (always) low ambient and operating temperatures, conven tional glue-sticks should be fine unless labeled otherwise. Low-voltage un less the sticks carry a UL-94 listing.

Peter Wieck Melrose Park, PA

Ok, thanks because I wasn't sure. That part of the circuit won't be under heating so I'm going to go ahead and use the sticks I have.