Structural integrity/Safety question

[Tonegeek]

I would like to reduce the possibility that one of my builds will ever come apart (mainly due to vibration) and short something out. Mainly I am concerned about any screws or nuts coming off inside the chassis. Aside from lock washers which I use religiously, what is the best way to keep this from happening? I have some Locktite but this stuff is oily and messy and you have to remember to put it on as you are assembling each piece. I considered putting some kind of compound (nail polish, silicone) on every fastener after it is tightened down.
Thanks

[Andy Le Blanc]

a drop of enamel paint..... ive seen paint pens with a ball bearing tip for
applying it to various metals... I'll dig a bit.....

[lastwinj]

the loctite gasket stuff works, too.

[Phil_S]

I think nail polish might be too thin and too brittle to do you much good. I like Andy's idea of paint pens. A quick search turned up this:
http://www.pinrestore.com/PaintPens.html
The additional advantage is that you mark what's complete so there is no doubt.

[CaseyJones]

I think nail polish might be too thin and too brittle to do you much good. I like Andy's idea of paint pens. A quick search turned up this:
http://www.pinrestore.com/PaintPens.html
The additional advantage is that you mark what's complete so there is no doubt.

Mil-spec assembly uses a dab of lacquer (otherwise known as nail polish) on hardware to keep it from rattling loose. Mil-spec also sometimes means a lacquer inspector's mark on each solder joint, I'm not up for that 'cuz these are all custom amps and thus prototypes. You're gonna change things. Lacquer on solder joints becomes a wad of crud if you have to change something.

Military ammo uses lacquer on the primers to keep out moisture for long term storage, same concept. It's nail polish from a five gallon can.

Loctite kicks ass! Use Blue if you're going to take it apart again, red if you don't want to take it back apart, ever. The solvent isn't oil. The stuff is oh so similar to nail polish and comes with its own little brush... like nail polish.

I like that nail polish comes in colors of the rainbow. I use purple if I'm dreamin' of hippy chicks, black if I'm thinkin' of goth chicks and bright red if I'm in the mood for Robert Palmer girls.

Oh yeah, there must be turtle puke green available for those Rob Zombie's Dead Girl days!

While we're all havin' a good time... a buddy of mine painted his motorcycle using his girlfriend's cosmetics case. A couple coats of clearcoat and those happy memories are forever!

[skyboltone]

I use nylocks where possible.

[smokin' tone]

I use nylon lock nuts or keps nuts whenever I can.
[img:250:255]http://www.prop-shop.com/g/d/dtxq0422.jpg[/img]

[img:110:87]http://www.northstate.com/fastener/media/kepsnut.gif[/img]

[glasman]

I third the nylocks.

McMasters has a huge selection in virtually any size you need.

[Tonegeek]

Man, I love this place! Or is it space?
Anyway, thanks for the tips. I am using keps/star washers already, but think I will paint them too and next time try the Nylocks.

I was also thinking about something you could paint on the HV connections rather than hassling with heat shrink. Remember that stuff ("as seen on TV!") you could dip your tool handles in to put a rubber-like substance on them (no, not that tool! ) I was thinking about painting something like that on connections around the PS area. It might be a bit overkill, but now that I got friends wanting amps, I just want to make them bullit-proof.

[rfgordon]

+1 on the nylocks

+1 on loctite

Also, I use silicone glue on some threads. A blob of silicone behind the switches before you tighten them down helps them stay put, too.

[dehughes]

Thanks for the McMasters link! I've found a couple of things there for which I've been searching for quite some time! Thanks!!!!

[CaseyJones]

Here's the funny part for me: Buildin' amps tells me how things vibrate. Racin' motorcycles tells me how things break when they vibrate. I can stick the bike on the race stand, whack the throttle and it'll jump backwards two feet! There's nuthin' like lookin' down and seein' sumthin' backin' out down by the toe of yer boot... at speed.

The track requires us to safety wire anything that might get loose and anything that has fluid behind it. Of course Loctite, duct tape and RTV silicone are featured in our pit box full o' magic potions.

Here's one for Skybolt... any aircraft mechanic can tell ya what's gonna shake loose and how to keep it all in one piece.

It's helpful to make friends with a guy who services helicopters. They remove buckets of fasteners then replace them with new, that way you can trust the new bolts to have a full service life. If you're standin' by the dumpster when the old ones get tossed out you're in business! Fine thread aircraft fasteners... pre-drilled for safety wire... are just the ticket for keepin' yer amp in one peice.

[Andy Le Blanc]

rivets

I usually use a toothed washer or even a spring washer on small nut and bolts
I have seen a couple trannies pulled off the chassis but thats because they
failed the "launch from the back of the truck"
or the "flying around in the back of the van" tests
never had a loose parts issue other than that

[CaseyJones]

rivets

I usually use a toothed washer or even a spring washer on small nut and bolts
I have seen a couple trannies pulled off the chassis but thats because they
failed the "launch from the back of the truck"
or the "flying around in the back of the van" tests
never had a loose parts issue other than that

My favorite is "Let's use a Hammond aluminum chassis because it's inexpensive and it's available". Bolt the tranny to the chassis then bolt the chassis to the cabinet. Carefully pack the amp inside a big box of peanuts and ship it across the country. Somewhere between here and there they hand it to the gorilla from the old Samsonite commercial, the customer unpacks it then complains of a bent chassis.

I've seen 'em rip the spotwelds right out of the chassis.

Launching it from the back of the truck is a good idea IMHO.

I was talkin' to some buddies about the old chipboard baffles in '60s Fender amps. One guy brought up a story where he bought a new Twin loaded with JBLs, he paid for it and loaded it into the van. It tipped over backwards at the first light and broke the baffle loose from the cabinet.

[Andy Le Blanc]

I knew a fella once, who told me that his telecaster passed him at an
intersection running a red light...... frost heave just before shook it out of the back
the one bit that I have seen come loose on more than one amp is the nut
around the input jack.. seen a few broken baffles too...... you take precautions
but what actually breaks is not what you imagine.....