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Vapour phase Soldering

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Chris Jones:
I just found these today:
https://www.epa.gov/sites/production/files/2016-02/documents/pfc_heat_tranfer_fluid_emission.pdf
http://multimedia.3m.com/mws/media/122381O/reducing-emissions-of-pfc-heat-transfer-fluids.pdf
https://www.gpo.gov/fdsys/pkg/FR-2013-04-05/pdf/2013-07977.pdf (page 3)
http://www.ghgprotocol.org/files/ghgp/tools/Global-Warming-Potential-Values.pdf
So the global warming potential of Galden seems to be maybe 10000 times higher than CO2 but the estimates vary a lot. If I did buy any Galden then I might feel fairly guilty about letting a lot of the Galden escape or disposing of it in a manner other than passing it on to someone who wants to use it. According to the first carbon footprint calculator I could find with google, a return flight from Sydney to London is equivalent to allowing about 500mL of Galden to evaporate, very very roughly. This would also be about 2 years worth of my car driving.

Given that most people reading this would not be reflowing boards all day every day, and so most of the time the Galden would be just sitting around, and that Solvay's FAQ suggests that it is good at escaping, either a very well sealed lid on the reflow machine or some way of draining down the chamber into a well sealed bottle would seem to be a good feature. (I also think some way of re-distilling the Galden to clean it would be nice.)

[Text below has been edited as I looked again and found that I had failed to notice some things. The addded text is in bold:]
On a related note, at work I found that some bottles of Galden from a few years ago when they were trying various different temperature grades. These were not the original type of bottles from Galden, but smaller ones from somewhere else. All of the LS200 and LS215 bottles seemed to have emptied themselves Some of the bottles were empty, though I can't be sure how full they were to start with as nobody recorded that. But I can't believe they would have bothered to carefully label a bunch of empty bottles and then store them, though the fluid might also have been used to top up the reflow machine without getting rid of the bottles when finished. (And no, I didn't take it!) The non-original bottles that they used don't seal all that well, and I think it evaporated. However, a bottle with the lid screwed on tightly labelled LS215 dated 2004 had a fair bit in it so it doesn't escape as fast as I thought. The LS230 bottle still has some left in it. It would be interesting to weigh that not-yet-empty bottle and see whether it gets lighter, whilst I look for a better-sealing bottle. You can see from the datasheet that the higher temperature grades have less vapour pressure at room temperature, and so it makes sense that they evaporate less quickly.
http://www.solvay.com/en/binaries/Galden-PFPE-Heat-Transfer-Fluids_EN-220543.pdf
Perhaps it would make sense to keep the bottles in a fridge, or keep the whole reflow machine in a chest freezer when not in use. (I am assuming a separate lab fridge or freezer, not the kitchen one!)

helius:
Remember that you are talking about a liquid with a boiling point of 200°C! Unless you operate your line in Death Valley in the summer, precious little escaping vapor will make it into the atmosphere.

Kjelt:

--- Quote from: helius on October 11, 2016, 02:50:32 pm ---Remember that you are talking about a liquid with a boiling point of 200°C! Unless you operate your line in Death Valley in the summer, precious little escaping vapor will make it into the atmosphere.

--- End quote ---

Water has a boiling point of 100oC however my non heating just rotating discs with a fan working Venta passive humidifier can evaporate upto 10 liters of water in my livingroom of 20oC each and every day in the winter.
So evaporation of liquids can well take place at lower temperatures than the boiling point of said liquid.

coppice:

--- Quote from: helius on October 11, 2016, 02:50:32 pm ---Remember that you are talking about a liquid with a boiling point of 200°C! Unless you operate your line in Death Valley in the summer, precious little escaping vapor will make it into the atmosphere.

--- End quote ---
The vapour pressure of galden is around zero in most rooms, so you might be surprised how quickly it evaporates in those rooms, even given its high boiling point.

tautech:
A quick Google for "Galden storage" shows it must be kept in a sealed container.

http://www.appliedthermalfluids.com/home/shop/galden-d02ts-pfpe/


--- Quote ---Galden D02TS Testing Electronic Fluids Shelf Life
Galden Fluids have a guaranteed shelf life of a minimum of 5 years from date of shipment if stored in the original sealed container at ambient temperatures.
--- End quote ---

Others suggest:
Keep away from heat and sources of ignition

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