Vapour phase Soldering

[mrpackethead]

Im just getting back into this project again as the crazy time of the year has passed.

I got an email from Hawker Richardson, and they are selling 5kg of Galden LS215 for $AUD 1225 on their web store.   Thats a resonably cost effecitve price.

I want 2.5kg, anyone interested in splitting a bottle with me?    ( I figure in my device, i'll probalby only need about 1kg )..

I'd prefer the 230 degree stuff - used it at work with lead free paste and turned out very well. Due to the finely divided particles that I seem to get everywhere, I'd prefer not to use leaded paste at home if the lead free works well.

Chris

They are also selling the 230, as well, its a little more expensive, but still the cheapest option in A/NZ.

Interested to know what your experience of "divided particles is".

[Chris Jones]

They are also selling the 230, as well, its a little more expensive, but still the cheapest option in A/NZ.

Thanks. Unless someone is doing a group buy I'll leave it until I have the time to build the rest of the thing, and/or lose access to the machine at work.

Interested to know what your experience of "divided particles is".

By "finely divided" I just meant that the solder paste contains very small particles of solder, in comparison to most of the solder blobs that result from hand soldering. I suspect that smaller particles would be more difficult to clean up and more likely to get ingested unless significant precautions are taken. My only experience with (lead free) paste is that I made quite a mess of the bench, though the boards turned out very well.

[IconicPCB]

The finer the particles the more problematic the paste.

A major problem is the shelf life of paste. major contributor to lack of shelf life is ratio of ball surface area to volume of solder ball.

As the ball size reduces the ratio of surface area ( for area read solder dross.. oxidized solder)  versus ball volume ( read healthy virgin alloy material)increases providing for a joint with possible dross inclusions.

[Koen]

Hello, I read the thread (but couldn't watch the videos) and couldn't find an answer to this question : in a homemade setup, Galden in a cooking pot for example, at which point is the PCB inserted ? Is it placed above the liquid Galden before heating up so the PCB will slowly warm up with the air ? Or is it dipped after the Galden turned to vapor and if so, is the PCB warmed up on the side before to avoid a thermal shock ? Thank you, Koen.

[helius]

It doesn't much matter which order, since heating only happens in the zone of condensing vapor. As a practical matter, the PCB is lowered into position first, and then heat is supplied to move the vapor zone up over the PCB, because tighter control of vapor is achieved.

[tautech]

Hello, I read the thread (but couldn't watch the videos) and couldn't find an answer to this question : in a homemade setup, Galden in a cooking pot for example, at which point is the PCB inserted ? Is it placed above the liquid Galden before heating up so the PCB will slowly warm up with the air ? Or is it dipped after the Galden turned to vapor and if so, is the PCB warmed up on the side before to avoid a thermal shock ? Thank you, Koen.

Pretty much as in this post:
https://www.eevblog.com/forum/projects/vapour-phase-soldering/msg596305/#msg596305

[IconicPCB]

Some progress...

Tried domestic induction heating hot plate... did not work... not because the fluid did not get hot  but because the source of heat ( ferromagnetic stainless steel base ) but because the power density was too high.

Had to rethink the heating requirement and limit the input power density. So this time with same power input but from a rearranged source have brought the oven temperature up to 230C.

Need to do some mechanical tweaking in the hope of improving heating rate.

I found that LS230 evaporates at lower temp than the notional 230C. Vapor of some lighter fractions seems to evolve at temperatures around 100C. Do not know what they are but.. it is what it is.

A note of WARNING.. GALDEN decomposes into TOXIC compounds if heated above the typical range of operation be careful to manage power input into the boiler zone.

Next step will be to connect cooling fluid pipes and re run the experiment with the view to containing vapor with minimal losses.

[uncle_bob]

Hi

All of the Galden fluids evaporate if you leave them in the open. The lower temperature stuff goes faster, but they all "vanish into air" if left out for a while. Best to put them in a tightly sealed bottle when not in use. Unfortunately the way we were using them that was not an option. Galden made a lot of money off of us on that project ..... We got somewhat lower loss rates off of the gear with chilled collars on them. In the end it was not clear if the compromises involved in that made sense or not.

Bob

[Kjelt]

Bob do you mean to say that Galden evaporates also at roomtemperatures so you are forced to store it in a tight container after use?

[uncle_bob]

Bob do you mean to say that Galden evaporates also at roomtemperatures so you are forced to store it in a tight container after use?

Hi

Yes, that's exactly correct. They do have a finite vapor pressure (even at room) so they head off into the air. Some of the stuff we used was lower temperature than the 230 so it was what we had the biggest problem with. How tight the container needs to be or if a simple float cover would work ... no idea. We went to bottles. One wise guy suggested a dropping a chunk of lard on top of the hot fluid ...

Bob

[cdev]

Of course when I read the word "Fluorinert", I thought of the Cray-2

A very interesting bit of electronics history...

See http://www.computerhistory.org/revolution/supercomputers/10/68

also

https://en.wikipedia.org/wiki/Cray-2

[uncle_bob]

Of course when I read the word "Fluorinert", I thought of the Cray-2

A very interesting bit of electronics history...

See http://www.computerhistory.org/revolution/supercomputers/10/68

also

https://en.wikipedia.org/wiki/Cray-2

Hi

The stuff is also a "specified fluid" for bubble leak testing to some of the mil specs. The exact mix of this or that varies a bit, but yes, it's all pretty much the same stuff.

Bob

[Koen]

Hello, I bought the asparagus cooking pot introduced earlier in this thread a while ago (at Blokker in Belgium) and it does the job.

I was looking for something unrelated tonight and stumbled upon this which could be better suited and interesting to some of you : Airtight storage bucket for laminating tools (The container is filled up to the sieve with acetone (about 2 cm), brushes and other tools are placed on the sieve afterwards the container is sealed airtight), 20EUR, from Germany.

[Koen]

Hello,

would anyone know of a low-volume supplier of Galden 240 ? Thank you.

[IconicPCB]

Member Jeremy  i think was interested in selling a couple of liters.

[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]

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.

Water has a boiling point of 100^oC 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 20^oC 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]

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.

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/

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.

Others suggest:
Keep away from heat and sources of ignition

[wraper]

I have LS230 sitting in the oven covered with just a lid (not airtight), reflowing small batches of boards once in a while. During about 6 months didn't notice any serious amount leaking away. I actually cleaned the oven, so removed the fluid back in the bottle. Didn't seem that more than 5% was lost

[mrpackethead]

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.

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.

Pratical experience is showing that this largely is not the case.  I've not lost any noticabel fluid out of my tank.. ( its got a stainless steel lid on it but not particaully well sealed )

[Chris Jones]

I edited my post above as I noticed that I was wrong about all of the LS215 bottles being empty. I still think that if one is concerned about global warming as well as cost then it is worthwhile using bottles that are gas-tight (so they hold some slight pressure without leaking), and that it would be worth following Solvay's recommendation on seal materials. Also to minimise evaporation of Galden at room temperature, it might be better to choose the higher temperature LS230 grade rather than LS215, regardless of solder type. My impression is still that it is worthwhile to make sure the chamber lid seals well, like on the Asscon Quicky, because I found that there are drops of Galden condensation all over the inside of the glass lid, even though the machine hasn't been used in the last a few months. I found that the boards are not totally dry when removed from the chamber, and so I think that after soldering, it might be nice to keep the board warm (maybe 100 degrees C ?, e.g. with IR lamps shining through the glass lid) after the board has been raised but whilst it is still in the cold chamber (preferably with the chamber chilled), to recover the last traces of Galden before the board is removed.

[KaneTW]

IconicPCB, did that project go anywhere? I've been interested in building a vapor phase machine but I don't know how much work you've already done. I imagine the most headache would be the vapor cooling since that has to deal with either superheated steam or steam venting.

[SWR]

Tombstones are just painful.  We get the odd ones happening in our reflow oven from time to time.

I know this is an old thread, but just out of curiosity: did you try the notched paste mask (see picture)?