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Forum Index : Microcontroller and PC projects : Backpack 144 from WW
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palcal Guru  Joined: 12/10/2011 Location: AustraliaPosts: 1801 |
Got my Backpack 144 board from WW, and what a good quality board it is. I soldered the PIC in place (with a few solder bridges wich I removed with wick), I have one that went behind the pins and won't come out with wick. If I put more solder on and then use my solder sucker? is that the best way to go. I don't want to overheat the chip. Paul. "It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all" |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 8582 |
Extra solder and then solder wick- a sucker is likely to bend pins Personally I would heat up with a de-soldering heatgun and then a sharp tap on the bench in the direction you want the solder to exit  |
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Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9063 |
That's a clever idea, matherp! I also 2nd the wick concept. The recoil from a solder-sucker will damage the pins as matherp says. Too much solder will go 'Behind' the pins like that, and it can sometimes be a pain to remove. Do you have any really fine solder? 0.5mm or 0.3mm? I use both depending on what I am working on - can send you some if you like - PM me. Big thick 1mm solder is going to cause you a whole heap of solder-bridge problems if that is what you are trying to use, as even a tiny amount of that size will be way too much when soldering 0.5mm pin-pitch. Good luck.Smoke makes things work. When the smoke gets out, it stops! |
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bigmik Guru Joined: 20/06/2011 Location: AustraliaPosts: 2870 |
Hi Paul, Grogs, All, Beware!! I have been using some 0.5mm solder for my SMD stuff for a while and recently bought 2 rolls of 0.3mm `stuff' off a well known Auction site and they arrived a few weeks ago.. DO NOT Buy anything that looks like this picture!  The `solder' leaves a horrible black crusty substance and it also seems to have some impurity as it doesnt seem to melt fully and leaves something like a grey metal residue.. It also cools with a very crystalline look, not unlike Lead free solder looks but it purports to be Tin-Lead.. Basically I have 2 rolls of paper weights now. Just as well they were cheap, I dont know what the chemical composition is but I doubt it is Sn-Pb 60/40 (well 63/37) like it says and the resin is ... well carbonish.. Kind Regards, Mick Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<< |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9063 |
Yes, I agree. I bought something that looked very similar to that from eBay a while ago - biffed it as soon as I tried it out. It was complete rubbish. I get my solder rolls from Element-14, and it is authentic "Multi-core" and "Loctite" brand(made by Henkel) - about $30 a 250g roll for the 0.5mm and about $45 a roll for the 0.3mm - expensive stuff, but you only use a tiny amount, so those rolls last for hundreds and hundreds of board and probably thousands of chips. These solder wires have never let me down, so I don't mind buying the occasional expensive roll every five years or so. Smoke makes things work. When the smoke gets out, it stops! |
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| WhiteWizzard Guru Joined: 05/04/2013 Location: United KingdomPosts: 2794 |
The method I use very successfully (almost daily!) is as follows: First apply more solder to the area of the affected pin(s) resulting in an excess 'solder blob' across several nearby pins!! Then take a liquid flux pen and flood the PCB in the area; and also flux up some fresh solder wick. Apply iron & wet wick to the excess solder blob and watch it magically soak up all solder almost instantly; it will however leave enough solder to connect the pins to the tracks. Inspect the area to ensure the 'issue' is resolved - if not, repeat the process after a short while so that the PIC isn't heated too much. I find the best width wick to use is 1.5mm (1mm is to thin and doesn't absorb the solder as well in these scenarios, and the 2mm+ takes too much heat to warm up first before the 'solder absorption' occurs). I am using a medium size chisel bit to allow a large enough surface area to make contact with the wick to get heat applied quickly. Those pointy tips (or very small chisel bits) don't get enough heat in quick enough (based only upon my personal experience). I find the pins on the PIC144 are very delicate, and for this reason I would never consider to use a 'sucker' as it would probably just bend the pins. Then when you bend the pins back into shape/place, they would probably snap off - not good for the price of those PICs! Hope this helps . . . . WW For everything Micromite visit micromite.org Direct Email: whitewizzard@micromite.o |
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| bigmik Guru Joined: 20/06/2011 Location: AustraliaPosts: 2870 |
Hi Grogs, I checked the Aus Element14 site and the cheapest is $64AU Plus 10% GST and that is LEAD FREE solder.. They do not seem to even stock Tin-Lead anymore.. The Lead free stuff is not good IMHO. Kind Regards, Mick Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<< |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9063 |
60/40 0.5mm 250g - $36 60/40 0.3mm 250g - $42 Smoke makes things work. When the smoke gets out, it stops! |
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| bigmik Guru Joined: 20/06/2011 Location: AustraliaPosts: 2870 |
Thanks Grogs, The second one is actually 0.38mm (closer to 0.4mm) They stock nothing except Lead Free in 0.3mm range. I am not sure its worth it to get 0.38mm when I have enough 0.5mm.. If they had Sn-PB 0.3 I would get some. Kind Regards, Mick Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<< |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9063 |
Yes, it is something of a matter of personal preference to some extent.  I myself use mostly 0.5mm for all the SMD stuff. I also don't really find there is much benefit in the .38 over .5 stuff as you say. Smoke makes things work. When the smoke gets out, it stops! |
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| bigmik Guru Joined: 20/06/2011 Location: AustraliaPosts: 2870 |
G, I have been using the 0.5mm but I thought the 0.3mm might have been better for the 0805 SMD devices as I tend to blob these rather than a nice smooth fillet. Kind Regards, Mick Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<< |
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| palcal Guru Joined: 12/10/2011 Location: AustraliaPosts: 1801 |
I used .5mm and the board soldered no problem except for the blob behind the pins. I have since removed it with a big blob of solder and some wick. Using a bigger chisel bit and a bit higher heat setting and it soaked up really well. Now for the rest of the components. Paul. "It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all" |
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| bigmik Guru Joined: 20/06/2011 Location: AustraliaPosts: 2870 |
Hmm, I found this link on EEVBlog (should have read it before) EEVBlog Solder thread And guess what?? That solder I mentioned before is there in a post from YU2 and he confirms its crap (or is it me confirming his report) Pay peanuts get junk, pay dollars ... Hopefully get good solder ... Anyone know a reasonable place to buy 0.3mm Sn-Pb solder from? Kind Regards, Mick Mick's uMite Stuff can be found >>> HERE (Kindly hosted by Dontronics) <<< |
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| WhiteWizzard Guru Joined: 05/04/2013 Location: United KingdomPosts: 2794 |
As any 'lady' will tell you: Leaded is better than unleaded, and its not the size that matters, its how you use it!  PalCal - glad you got it sorted. Curious if you used liquid flux too. IF not, then can I highly recommend you get a pen as it makes a BIG difference when assembling SMD parts It like anything: once you have used it, you wonder how you ever managed without it. When I have run out in my 're-fillable' pen, if I continue to try the wick method without any applied flux, I nearly always find the wick ends up getting soldered to the area I am trying to clean. Refilling my pen, applying the flux, and all excess solder just gets absorbed up like 'magic'.Let me know if you need any part numbers for the other bits in the BoM - hopefully the email was enough info though. Possibly post a few pictures of your assembly work along the way as others here may be interested in your progress (I certainly am!!) WW For everything Micromite visit micromite.org Direct Email: whitewizzard@micromite.o |
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| WhiteWizzard Guru Joined: 05/04/2013 Location: United KingdomPosts: 2794 |
One thing to stress if using liquid flux; you need to ensure the PCB is thoroughly cleaned after assembly. I use an expensive PCB cleaner spray - also de-ioned water for a final wash. Although I must admit that a 'general purpose household cleaning spray' (designed for glass) works very well too (in fact possibly better than the 'proper PCB cleaner'! Some PCB manufactures seem to 'coat' their PCBs in a chemical that reacts with my PCB cleaner leaving a 'dull' finish. A quick spray with floor polish resurrects the shine and the solder/pads seem to stay looking shiny. The best tool I found for cleaning was a hard bristled toothbrush - but the 'health squad' said that hard bristles were bad for your gums so they are near impossible to buy in a supermarket now  So all the tools you need for SMD work are: 1> A basic soldering iron (no need for expensive temp-controlled workstations) 2> A medium sized chisel bit 3> 1.5mm solder wick 4> A re-fillable flux pen (and a bottle of liquid flux for a life-times supply) 5> Some furniture polish 6> A medium-hard bristled tooth brush 7> Kitchen tissue (for a final wipe/polish) My secrets are no out For everything Micromite visit micromite.org Direct Email: whitewizzard@micromite.o |
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| palcal Guru Joined: 12/10/2011 Location: AustraliaPosts: 1801 |
I use all of the above except the furniture polish, I lacquer my boards when finished with circuit board lacquer. I have a temp controlled iron and use either the chisel or a small conical bit with .5mm solder. I guess the bits are just user peference. Paul. "It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all" |
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| Bill7300 Senior Member  Joined: 05/08/2014 Location: AustraliaPosts: 158 |
@bigmik several years back, I bought a number of reels of Multicore 0.35mm Sn PB, great solder, from Radio Parts Group in Melbourne, and distributed them to various PicaStar builders in Australia and the UK, where any Sn Pb solder was proving hard to source, thanks to the European mandate for lead-free stuff. RPG is a lesser known supplier these days but I assume they are still in business. For some reason Spencer Street rings a bell. Bill Bill |
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| palcal Guru Joined: 12/10/2011 Location: AustraliaPosts: 1801 |
And here you have it solder Paul. "It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all" |
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| WhiteWizzard Guru Joined: 05/04/2013 Location: United KingdomPosts: 2794 |
I was hoping to see a picture of your assembled MMX PCB  For everything Micromite visit micromite.org Direct Email: whitewizzard@micromite.o |
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| palcal Guru Joined: 12/10/2011 Location: AustraliaPosts: 1801 |
It is up and running and the Heartbeat LED is flashing. Here is a picture, still a few sockets to mount (waiting on delivery), the PIC soldering is probably not 'factory' but looks are not everything.  Paul. Edit. A big thankyou to WW for his help and also Geoff and Peter for all the work they do for no return except the satisfaction of helping others. "It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all" |
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