Salvage with heat gun?

Oldbitcollector (Jeff)

I was doing some reading last night that a heat gun can be useful for salvage of electronics.
Since I just happened to have one, as well as some boards, I put the concept to work.

I'm curious.. Do components such as caps and SMD parts survive this process, or is it a waste of time?

Oldbitcollector

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The comments and code above are proof that a million monkeys with a million propeller chips *could* write Shakespeare!

Phil Pilgrim (PhiPi)

Although you don't have a lot of control over the actual temperature when using a heat gun, you can rest assured that SMD parts can survive temperatures above the melting point of solder. Otherwise there'd be no way to install them in the first place. So if you work fast enough, you should be able to free them without overheating. Just remove them with tweezers as soon as the solder melts.

-Phil

Forrest

Just a word of caution - I wouldn't try to remove batteries. If they get too hot - they could explode.

LCD displays and long connectors are also tricky - if overheated the glass can crack and the connector will melt.

You can shield these heat sensitive components with aluminum sheet stock or aluminum foil before using the heat gun on nearby components.

kjennejohn

I do lots of rework for SMT stuff using a hot air station. This is basically a fancy heat gun, but with custom nozzles and close control of air temp and air flow.

I have gotten into the habit of fluxing the parts before removal, as this seems to make the solder melt quickly and evenly, allowing me to remove parts quickly. Installing new parts with this station (using a fresh application of flux)·is a toss up: straight digital parts, like 74- series and comm chips like MAX232s, reinstall OK with this method. However, we use analog ADCs and MUXes, and these don't survive the process well. I end up wicking off the solder on the pads, applying flux and then hand soldering these parts back on.

The moral is: you can probably use your heat gun for sizable through hole and surface mount discrete parts, and maybe for most digital ICs, but if not sure, expect failure.

Yours,

kenjj

P.S the animated emoticons drive me nuts. Any way to stop these?

Phil Pilgrim (PhiPi)

kenjj,

Most browsers will let you disable all GIF animations. Just check your "preferences" (or somesuch) menu item.

-Phil

LilDi

Keep in mind that the max temperature while soldering a component is for a one time shot. Any subsequent heating of the component is likely to do damage. You may not notice it, but the life span of the component has been shortened and its electrical characteristics have likely been changed.

bobledoux

Just heat the board and rap it against a table to knock the components off.

Mightor

Oldbit,

If they no longer work, you can always turn them into something like this, and probably sell them for 10x as much!
More here (and a howto).

Gr,
Mightor

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| To know recursion, you must first know recursion.

Bean

LOL Mightor, That's just not right [noparse];)[/noparse]

Bean.

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Teacher: What is the difference between ignorance and apathy ?
Student: I don't know and I don't care
Teacher: Correct !
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Post Edited (Bean (Hitt Consulting)) : 8/21/2007 12:34:28 AM GMT