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Vapour phase Soldering
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mrpackethead:

--- Quote ---It looks like the Galden LS series is a mixture of perfluorinated polyethers of varying chain length, varying molecular weight in the 700-1000 range, it's not just one chemical.
So, basically, they can just separate it into whatever boiling-point range is desired by fractional distillation, just like distillation of hydrocarbons at an oil refinery.

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Im with you on this conclusion now.  and maybe even you get a mixture of different chain lengths, which average out to give you a specific temp?


--- Quote ---Galden HT seems to be similar but with a higher BP range, higher than soldering will need, targeted as a chemically-stable coolant for specialist applications, eg. CVD, ion implanters, plasma etching and stuff at applicable apparatus temperatures, especially where chemicals or reagents are involved that may react with a non-perfluoro coolant (uranium enrichment, for example, is one application they mention). The chemical formula is the same, but the typical length of the polymer, the average "m" and "n" numbers in the formula, will be higher. And the CAS number is the same because it's the same general family of chemicals with one CAS number as a group.

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HT and LS grades are avaialable over the same range of BP's..  You can get LS230 and HT230.. Both have a nomial boiling point of 230C.   Theres LS200 ( which would be good for lead solder i guess ) and an HT200.

I have two suspicions.   

(a) the product may in fact be the same thing marketed at two different products, for two different end uses.. one has a higher price tolerance than the other
(b) the LS product is 'refined' more accurately than the HT, so the actual BP, may be sitting in a smaller range than the HT.

I've seen quite a number of commercial machines specifying HT grade, and the DIY projects we've seen all seem to use HT.   

Its less than half the price..   If we have a temp range that is just a wee bit wider, does it actually matter, provided its not too far out?

helius:
perfluoroalkylamines like Fluorinert were used as blood substitutes because of their ability to dissolve oxygen. This is not desirable for soldering because oxygen reacts with the metals, making a duller joint that wets more poorly.
jeremy:
Thanks Luke for the tips. I agree, after reading the patents they seem to just make a big batch of perfluorinated polyethers of varying chain lengths (get polyethers, add fluorine, bake at 180C until golden brown, etc) then distill it into the different boiling points. It's interesting that HT is so much cheaper, and potentially not necessary for vapour phase. If weller recommends HT, I trust them with all my other soldering gear, so I don't see a problem.

It's kind of strange that the other manufacturers use LS actually...

I found a guy in australia who sells quite large diameter and length borosilicate tubes. Also, you can get a 4L beaker with a ~160mm ID on Amazon for not too much. This plus a stainless "induction interface disk" (google it) seems like it could be a decent way to start. Now I'm trying to think about how to raise the board gently when potentially the balls are still liquid. Or perhaps since it is a hobby system and I only need one board, just turn off the heating and wait for it to cool. Suggestions welcome!

Edit: I was also thinking about just putting some ball bearings in the bottom of the beaker. What do you all think? Galden has basically no chance of exploding, so I can't see a problem there.
free_electron:

--- Quote from: mikeselectricstuff on January 23, 2015, 07:41:42 pm ---
--- Quote from: free_electron on January 23, 2015, 05:42:46 pm ---
--- Quote from: jeremy on January 22, 2015, 08:53:12 am ---free_electron: nice pic. what did you draw it in?

--- End quote ---
Altium silkscreen layer  >:D

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So I'm not the only one that does drawings in PCB software because I can't be arsed to learn a proper CAD package then...!

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Altium pcb has almost everything regular 2d cad has. Corrdinate system, multip,e layers , lines arcs polygons , you can place dimensions , rotate stuff, there is a library system for often used symbols. You can load and save dxf to be compatible with the rest of the world.
And you dont have to learn some awkward tool. Works perfectly fine for me !
langwadt:

--- Quote from: mikeselectricstuff on January 23, 2015, 07:41:42 pm ---
--- Quote from: free_electron on January 23, 2015, 05:42:46 pm ---
--- Quote from: jeremy on January 22, 2015, 08:53:12 am ---free_electron: nice pic. what did you draw it in?

--- End quote ---
Altium silkscreen layer  >:D

--- End quote ---
So I'm not the only one that does drawings in PCB software because I can't be arsed to learn a proper CAD package then...!

--- End quote ---

I've done it :) but now I use http://www.plm.automation.siemens.com/en_gb/products/solid-edge/free2d/

free and extremely easy to use



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