"Mill Spects" building... Questions

[msurdin]

HEy Guys,

So I have been reading about how when companies such as Hiwatt and PEte Cornish build to Millitary Spects its always really high quality, hard to break and a lot better parts.
Is there anyway to learn about building to these spects? Or just better in general? I loved seeing how his boards are held secure to his enclosures and big pedal boards. You know you can just throw it and the board wont fall off like in pedals when they use the standoffs.
The parts are better to arent they?

So I would love to build my stuff much stronger then I do now..

Thanks guys!

Matt

[soulsonic]

There are military handbooks available detailing every aspect of what is required of components and construction practices to meet the military service specifications. I can't think of the name of any of the books now, but if I find them, I'll let you know what they are.

[alanlan]

It's interesting because as an apprentice (at a large aerospace company) I spent some time on wiring inspection and I had to inspect and mark each and every single soldered wire joint with a special green paint (just to indicate that it had passed inspection).  The green paint made all the difference to the workings I was told at the time. The same inspector also told me to go to stores for a long stand and some sky hooks I seem to remember.

[R.G.]

http://assist.daps.dla.mil/quicksearch/basic_profile.cfm?ident_number=67966

[Processaurus]

Dunno if the military does it but on Boss's pcb's I see hot glue on every large component and wire.  The glue on the wires is a very good way to make your builds more durable (though its best to get it working first...) so they don't break at the solder joint if they were nicked a little by the wire strippers.

The glue on the big caps is maybe because with components over a certain size, the solder joint can be damaged by it getting knocked around, from the mass of the component.

[msurdin]

Thanks for the tremendous help guys!

After reading both versions of that mili book i have learned a lot about improving my stuff.

[Dragonfly]

Thanks for the tremendous help guys!

After reading both versions of that mili book i have learned a lot about improving my stuff.

Its amazing what you can learn when you ask the right questions !

[msurdin]

I was wondering about these military parts, where can i get those? How much of a difference would there be in those ones and the parts I order from small bear?

[soulsonic]

Most of the major supply houses, such as Allied and Newark, stock parts which meet Mil-Spec. An example of an excellent Mil-Spec resistor is the Dale/Vishay RN Series.... look for the RN-55 and RN-60 to use in pedals. Many "standard" parts will also list a second set of specifications which corresponds to how they rate up according to the Mil-Spec - for example, the RN-55 resistor is listed as being a Mil-Spec 1/8 watt resistor, but by "normal" standards, it would be considered a 1/4 watt resistor.

[soulsonic]

....The glue on the big caps is maybe because with components over a certain size, the solder joint can be damaged by it getting knocked around, from the mass of the component.

Alot of people do this because it's cheap and easy way to keep large components stabilized, but its a serious faux pas to put a bunch of hot glue around the base of an electrolytic cap. The problem is it seals off the vents of the cap and keeps the gases from escaping which can cause premature failure of the cap. I see this garbage all the time in blown up computer power supplies - you'll see the caps all expanded out and you know it's because pressure was allowed to build inside the cap (among other things...). This is something that's more of an issue with power supplies than stompboxes, but still, using hot glue to hold components in place is not a good habit to get into. I've done it secure a wire before, but I avoid using hot glue whenever possible now.

[the_random_hero]

....The glue on the big caps is maybe because with components over a certain size, the solder joint can be damaged by it getting knocked around, from the mass of the component.

Alot of people do this because it's cheap and easy way to keep large components stabilized, but its a serious faux pas to put a bunch of hot glue around the base of an electrolytic cap. The problem is it seals off the vents of the cap and keeps the gases from escaping which can cause premature failure of the cap. I see this garbage all the time in blown up computer power supplies - you'll see the caps all expanded out and you know it's because pressure was allowed to build inside the cap (among other things...). This is something that's more of an issue with power supplies than stompboxes, but still, using hot glue to hold components in place is not a good habit to get into. I've done it secure a wire before, but I avoid using hot glue whenever possible now.

I've been told a little dab over one of the legs helps tremendously - it allows the gases to escape while the flexible silicone provides shock protection.
We spent a few hours going through high-reliability soldering methods, which definitely would apply with mil-spec stuff. The only problem I can see with it is that it's time consuming (for the soldering part anyway) - it took almost a minute to trim and tin one length of wire.

[Sir H C]

One big thing with mil spec parts is the temperature range they are tested over.  It is wider than for commercial grade parts, and often there is more fallout, so the prices go up.

[msurdin]

I have covered my electrolytic caps on some of my pedals in liquid tape. Am I now looking for trouble? I was told its ok to goop a circuit with...

Thanks for the help... I'm going to try all this stuff out

[soulsonic]

I have covered my electrolytic caps on some of my pedals in liquid tape. Am I now looking for trouble? I was told its ok to goop a circuit with...

Thanks for the help... I'm going to try all this stuff out

Maybe trouble... but there's really no way to say for sure without some kind of QA testing. FWIW, alot of people seem to cover electrolytics and it doesn't seem to cause big trouble. Like I said, this seems to be the biggest issue with power supplies where alot of current is flowing through the caps. If you look at the goop on a Klon, you'll see that the electrolytic caps are only partially covered.

Why did you goop your circuit? My biggest complaint against gooping is that it makes it very difficult to fix or modify the circuit - I don't see any point in doing it on a personal DIY circuit. Are you selling stompboxes and trying to hide the circuit?

[msurdin]

Yes, I have been selling...
I'm going to just put some tape ontop of it to keep the open space un gooped and then just remove the tape.

When people goop it do they goop the bottom, or just to top where the parts are?

[soulsonic]

Klon goops the bottom.

[soulsonic]

What kind stuff have you been selling?

[msurdin]

A rangemaster/ Orange combo booster, triangle, rams muffs, delays, comps, cornish clone stuff, buffer.

soon some custom order stuff

[Paul Perry (Frostwave)]

The glue on the big caps is maybe because with components over a certain size, the solder joint can be damaged by it getting knocked around, from the mass of the component.

There was (years ago) a run of two way radios that were mounted in the cabins of earthmoving equipment & all of them failed because the capacitors vibrated & the joints failed from fatigue. Hell, I even had a CRO (rescued from a university lab) that failed this way. So yeah, glue = +reliability.

[Processaurus]

Wonder if that is why I've had such dumb luck bringing ancient stuff back to life, just by resoldering each joint.  The big stuff rattled too much...