Lead free. High temp neede to melt it. Gerald
On Tue, Mar 24, 2015 at 9:23 AM, Harvey White <[email protected]> wrote: > On Tue, 24 Mar 2015 00:03:54 -0700 (PDT), you wrote: > > >Hi Harvery, > > > >700 dgree can melt lead-free solder *directly* very well -- that's how I > >adhere a layer of solder to connector pins. Then I put connector on top of > >P2 on the board and heat the pins for making the solder melt and connect > >joint just like the video. > > This is called (or was) "sweat soldering" it does work, but may not > be the best at times. No problem though. > > >But the solder between pins and P2 won't melt > > What may be happening is that the solder on P2 is protected by a layer > of something, either oxide, or solder mask, or the like. I'd take a > small xacto knife or equivalent, and gently scratch one of the pads to > clean the surface. You want to stay in the plating area (assuming > that this is solder plated. Did you use flux? Liquid flux is > generally very useful in this kind of situation. You should be able > to melt the solder and let it flow onto the board land (the contact > area), without a pin there. If the solder just beads up, then you're > not getting any heat transfer to the pad, or the pad is protected. > > I've had badly oxidized pads not take solder, and some plating on > boards will not accept solder (nickel, if I remember it). In that > case, some very gentle abrasion of the plating may expose the copper. > This is a crude solution, though. You could also try cleaning the > pads with a pencil eraser. It's quite abrasive and should not be used > for edge contacts (it will remove gold plating very easily). > > >and none of it will adhere to the P2 even I heated 4-6 seconds in 700 > >degree. Note that I cleaned the solder iron with tip tinner and brass > >sponge before this step. > > Generally, what you do is avoid the tip tinner unless you're losing > the tinning on the tip (solder won't adhere to the tip itself). I > normally don't use it or need it. Then you add solder, just a bit, to > the tip, use the sponge to clean it (and any oxides) off, then solder. > You can add a tiny bit of solder to the tip, which forms a tiny drop > there, and when put to a joint, will help heat transfer. > > The steps are generally 1) clean the tip, 2) do the joint, 3) put the > iron back (it doesn't need to be cleaned at this point, the excess > solder actually tends to protect the tip). > > > > >Another way is just like you said (hope my understanding is correct) to > >heat some solder and let it flow to the pin and wet the joint. I tried. > But > >the solder flow won't adhere to the P2 but just accumulated on the pin > till > >bridge with adjacent pin. > > Then there's something there that the solder won't wet. There might > be a coating over the connector. > > > >Do you have any comment on this situation? > > > Just did, it's an odd situation, since most of the boards are > manufactured to enable you to solder to selected areas, and the pads > for such a connector site would be ready to solder to. > > Mine's a circuitco board, so I can't help with trying. > > If you have some leaded solder, I'd try that. I'd also get a tube of > flux, you want the Kester RMA flux, which would be available at places > like Mouser or Digikey or Avnet (not sure about Jameco). This flux is > quite helpful for doing surface mount soldering (I do that a lot...). > > Harvey > > >Thank you so much! > > > >On Monday, March 23, 2015 at 8:37:46 PM UTC-7, Harvey White wrote: > >> > >> On Mon, 23 Mar 2015 19:46:19 -0700 (PDT), you wrote: > >> > >> >Thank you Tom and Harvey! I'll try again with higher temperature (800 > or > >> >even more higher till it melts) as well as adopt Harvey's suggestions. > >> >Result will be reported in this thread. > >> > >> Ah, no, more temperature is not always what's needed. > >> > >> Too cold and it never melts. Too hot and it damages the board and > >> what you're soldering. For leaded solder, 600 degrees is fine for > >> small sensitive parts, 700 degrees for standard parts, and you almost > >> never need 800 degrees. > >> > >> Try a few joints with the solder and just solder a few pieces of wire > >> together, say 22 gauge or so. That gives you the practice you may > >> need for lead free solder (behaves differently). > >> > >> > >> > > >> >I used lead-free .022 in 700 degree. Temperature is one of a few > factors > >> I > >> >haven't adjusted in those attempts for not damaging the board. > >> > > >> 800 degrees is a bit too hot. There's a bit of a touch to it, as to > >> how to solder and how not to. You want the solder to "flow" and to > >> "wet" the joint as if it were water. > >> > >> I'd see what the melting point of your particular lead free solder is, > >> and then see what the recommended iron temperature is as well. > >> > >> Harvey > >> > >> >Also I've found CircuitCo version in Jameco Electronics. > >> > > >> >On Monday, March 23, 2015 at 5:25:56 PM UTC-7, Harvey White wrote: > >> >> > >> >> On Mon, 23 Mar 2015 16:56:58 -0700 (PDT), you wrote: > >> >> > >> >> > > >> >> >> > >> >> >> > >> >> >> > >> >> >> > >> >> > > >> >> >I just checked my settings. I have my iron set to 430C / 806 F and > >> >> haven't > >> >> >touched it since soldering that JTAG connector last week. Yeah. So > >> very > >> >> >hot. Don't leave it sit on the board at that temp. I figured a fast > >> dab > >> >> at > >> >> >high temp is better than letting it sit at lower temp though. Maybe > >> I'm > >> >> >wrong. Like I said, I'm not a pro with the soldering, but it worked > >> for > >> >> me > >> >> >on the first try. Before I got my nice soldering iron I had problems > >> >> >getting connectors soldered onto another board because my iron > wasn't > >> >> >getting hot enough. I don't have that problem anymore. :-) > >> >> > > >> >> >My solder is Kester 44 Rosin Core Solder 60/40 .031. > >> >> > >> >> OK, several things here: > >> >> > >> >> 1) 63/37 is eutectic for solder, and has the lowest melting point. > It > >> >> goes from liquid to solid and does not have a plastic phase (good). > >> >> > >> >> 2) 700 degrees is normal, and 600 is used for sensitive devices. > >> >> > >> >> 3) the amount of power that your tip can deliver (not necessarily the > >> >> temperature) determines the size of the joint you can heat and > >> >> successfully solder > >> >> > >> >> 4) clean is the key, a freshly tinned tip (clean and can transfer > heat > >> >> well) is much better than an oxidized tip. > >> >> > >> >> 5) better to use a brass sponge than a wet one. Less thermal shock > to > >> >> the tip. > >> >> > >> >> Harvey > >> >> > >> >> > > >> >> >Tom Olenik > >> >> > >> >> > >> > >> > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- Gerald [email protected] http://beagleboard.org/ http://circuitco.com/support/ -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
