FIRE SALE!

[jim stephens]

I agree.  Most devices are expected to be heated briefly to soldering 
temperatures, not heat soaked at that.

Temperature in this case is much different than heat.  The designers of 
the devices must take into account what temperature is require to do the 
solder assembly function, and minimize the amount of heat the device is 
exposed to.

On wave soldering machines the heat was quite low, and these would have 
been assembled then.  Even with current radiant oven techniques, the 
parts would fall off if there was an extended heat exposure.  They do 
that often enough now with heating problems with devices, with open 
circuit failures happening.

If you're lucky and have a quick fire department response, the setup 
time on the equipment is at least 4 or 5 minutes.  Unless there's 
physical danger and the building involved may have people trapped, they 
take time to assess the fire, the propagation and there's more time 
before they attack.

I've seen a couple of events and a couple of full exercises, it doesn't 
happen quickly.  Fire departments are sadly known for letting buildings 
burn into the basement if it saves life or property of other nearby 
structures.  You'd be lucky to get this out of a burned out building in 
most cases.  Once the fire is knocked down the heat will be present for 
quite some time afterwards, as they let it cool and clear flash fires, 
and take care of nearby property.

thanks
jim

On 10/11/2020 7:21 PM, William Donzelli via cctalk wrote:
> How long do you think those poor machines cooked? I bet far, far
> longer than the soldering temperature spec. likes.
>
> --
> Will
>
> On Sun, Oct 11, 2020 at 10:06 PM dwight via cctalk
> <cctalk at classiccmp.org> wrote:
>> Most components can stand soldering temperatures. It is clear that it was only hot enough to melt plastics. That isn't even hot enough to damage boards. It is wasn't powered at the same time, it is unlikely to have been harmed. I've seen cases where there were flames in the board area and parts were not damaged. These were mostly wrapped in their cases. Melted plastics most likely protected the boards from dangerous temperatures.
>> Dwight
>>
>> ________________________________
>> From: cctalk <cctalk-bounces at classiccmp.org> on behalf of jim stephens via cctalk <cctalk at classiccmp.org>
>> Sent: Sunday, October 11, 2020 6:49 PM
>> To: William Donzelli via cctalk <cctalk at classiccmp.org>
>> Subject: Re: FIRE SALE!
>>
>>
>>
>> On 10/11/2020 6:34 PM, William Donzelli via cctalk wrote:
>>>> I suspect much of the electronics is fine. It would be good for someone wanting backup cards.
>>> You must be joking. Those cards are done. Any chip that is still
>>> operational will likely fail upon or shortly after power is applied.
>>>
>>> --
>>> Will
>>>
>> I agree.  Especially the ones heated high enough for the melted plastic
>> or scorch damage.  A radiative and convective heat soak is pretty damaging.
>>
>> Consider the flow temperature of the materials inside.  Unless the fire
>> was  flash fire, the entire thing would have been heated for some amount
>> of time (15 minutes minimum usually, to 45 minutes) due to response time
>> of the equipment.
>>
>> Not evident in the photos would be possible contamination from either
>> fire suppressant materials or water to extinguish the blaze.
>>
>> Like I said, Ethan is looking for a cabinet for an 11/70 stripped out of
>> such, and these probably are okay for that.  Maybe some of the other
>> bits after inspectiong, but I'd not trust the boards up front.  It would
>> be a project I'd want a solid shop of parts to do testing for every
>> board involved to certify they work.
>>
>> Most people I know have one system in their basement, lab or garage, and
>> I'd personally not want to put boards from a source like this into such,
>> unless i had nothing to lose.
>>
>> thanks
>> Jim