Safe adhesive for internals of tube gear?

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rjd2
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Safe adhesive for internals of tube gear?

Post by rjd2 » Sat Feb 01, 2014 12:00 pm

i'm building out a pair of RS 124's at the moment, and the output trannies are about 1cm too high for my 2U case. i need to find a way to house them safely, and properly.

there is enough room for me to properly zip tie them to the pcb, however, it seems potentially half assed, if the zip ties were ever to fail. as a secondary securing method, would epoxy or gorilla glue be acceptable, as the unit does have tubes and will generate heat? there's pcb room to safely adhere it, i just don't know if that would be both for integrity of glue, and fume-wise, a hazard.

is there a safe adhesive i could use internally, or should i really attempt to find some way to secure it using metal-only? (probably much harder, but possibly feasible). thanks.

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Nick Sevilla
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Post by Nick Sevilla » Sat Feb 01, 2014 10:17 pm

I've seen many trannies zip tied to boards over the years.

Just don't put the zip ties close to any real hot components, if possible, and you'll be fine.

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vvv
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Post by vvv » Sun Feb 02, 2014 10:12 pm

Seems obvious unless it don't occur to you, but sometimes when I lack zip-ties, I use insulated wire and twist-knot it.
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The Scum
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Post by The Scum » Mon Feb 03, 2014 5:43 pm

Without seeing the exact assembly itself, it's hard to really make strong recommendations. Any chance at some photos?

Adhesives can be problematic.
  • Some of them soften when heated.
    Some of them are extremely hard to undo, if things ever have to come apart.
    The long-term chemistry may be unpredictable, especially in a warm or damp environment. You wouldn't want something that turned out to be a super-slow-acting acid, for instance. Or that reacted to some specific portion of the item in question - like the enamel insulation on a transformer's windings.
That said, adhesives are used every day, in many applications. You may need to understand the overall chemistry in sufficient detail.

If things are such that zip ties will work, they're easy to apply, undo, and chemically reasonably inert. If you're running them through hols in metal, you might want to make sure that there aren't sharp edges that might gnaw away at them.

Real metal fasteners (screws, bolts, straps, star washers, etc) also meet some of those requirements, and are also reusable, after they've been undone.

Seems obvious unless it don't occur to you, but sometimes when I lack zip-ties, I use insulated wire and twist-knot it.
I once saw a similar solution fail pretty spectacularly. Someone was wiring up the banana plugs on the back of their speaker, and somehow secured the thing with a baggie tie. Eventually the paper on the tie somehow peeled up, and shorted the output of the amp.

With a new fuse, the amp was OK. But it scorched the woofer and tweeter. I'll never forget the sound of that woofer voice coil trying to jump out of the cone.
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Post by Orpheus » Sun Mar 09, 2014 7:41 pm

I do know from personal experience that gorilla glue has a breakdown voltage below the B+ value of 6L6s. It will melt, burn and actually spatter all over the place kind of like if you leave fork on your plate when you put it in the microwave....cleaning up pasta sauce off the ceiling of the oven.

The black zip ties are made to be more UV resistant than the white/clear ones, they might be better for temperature.

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GussyLoveridge
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Post by GussyLoveridge » Mon Mar 10, 2014 1:48 pm

I'm also looking for suggestions on how to mount filter caps inside a tube amp. I've tried hot glue as I've seen some folks do, but I can't get it to stick.

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Post by substitute » Thu May 22, 2014 4:46 am

RTV Silicone. I used to work for a pretty famous pro audio manufacturer, we used it for mounting filter caps to the chassis of tube mic press. It helps with micro phonics as well.

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Gilroy
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Post by Gilroy » Sat May 31, 2014 8:43 am

GussyLoveridge wrote:I'm also looking for suggestions on how to mount filter caps inside a tube amp. I've tried hot glue as I've seen some folks do, but I can't get it to stick.
I just built a Pultec clone from RecPro and I zip typed all the filter caps together in sections and that worked fine and easy. Home Depot has some super tiny ones.

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GussyLoveridge
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Post by GussyLoveridge » Sun Jun 08, 2014 6:31 am

Just wanted to say thanks to everyone - the RTV silicon seems to be the bee's knees for what I'm looking for - awesome!!!

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