Author Topic: HP 1670D LA broken trim - mystery plastic  (Read 148 times)

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Offline TerraHertz

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HP 1670D LA broken trim - mystery plastic
« on: June 11, 2021, 02:48:52 am »
A while ago I bought a cheap HP 1670D logic analyzer. For reasons not worth going into. Shipped from the USA, it wasn't packed well (what a surprise.) All the minor damages were easily repairable, until I got to the last one...

The plastic edge trim around the front of the machine. It was cracked in two places.

Then I discovered that HP used some quite tough but brittle plastic, that does not soften with any solvent I've tried. MEK, acetone, polystyrene glue... nothing. Worse, the MEK has a bad effect, making the surface shrink, resulting in nasty looking surface crazing. See last pic.

I'd just assumed of course MEK would work, jigged up the pieces and squirted MEK into the crack. Some flowed onto the outer surface of the plastic. The cracks developed some time after this failed attempt to glue it.

Does anyone know what this plastic is? Is there any known solvent for it? There's no type identifier markings I can see.

Probably the only method of repairing the breaks would involve heat welding it then surface profiling the mess. But for that I'll need some of the same type and color of plastic. I don't suppose anyone has an unwanted one of these trims, broken or not?

Oh btw, the missing knob is since repaired.

« Last Edit: June 11, 2021, 02:57:50 am by TerraHertz »
Collecting old scopes, logic analyzers, and unfinished projects.

Offline james_s

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Re: HP 1670D LA broken trim - mystery plastic
« Reply #1 on: June 11, 2021, 04:44:55 am »
It may be PC-ABS, I've tried gluing that with solvent without much luck, especially when it gets old and the plasticizer leaches out. I'd try cyanoacrylate rather than solvent, you can fill in cracks and gaps with baking soda and then soak them in a bit more glue and it forms a rock hard material. If you manage to get it all back together you can spray paint it so it looks good.

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