Even pure colophony (could be thinned to reach the perfect visocosity) should work for the initial fixation. Using wick is tedious for removing excess, but as you are already using a microscope then removing any excess solder with the gullwing tip alone should do the job, if a sufficient amount of liquid flux is around.
Edit: means I'd only use a small amount of colophony under the body just to secure the position of the IC.
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The point is not to be afraid of solder bridges in the first place.
When soldering using a gullwing tip, the solder held by the tip naturally shorts a lot of pins together while soldering and also cleans up the bridges when moving along the chip by cleverly using the surface tension of the molten solder to wick away any excess. IMO this is the key for easy and successful soldering of fine pitch packages.
The only type of flux I would recommend is ROL0 or REL0 type as this is not aggressive and does not cause leakage later on.
When soldering using a gullwing tip, the solder held by the tip naturally shorts a lot of pins together while soldering and also cleans up the bridges when moving along the chip by cleverly using the surface tension of the molten solder to wick away any excess. IMO this is the key for easy and successful soldering of fine pitch packages.
The only type of flux I would recommend is ROL0 or REL0 type as this is not aggressive and does not cause leakage later on.
Thanks. The gull wing tip in T12 series is BCM2/BCM3? I am using BC2 which I think is a flat one, not the gullwing one. That may be the reason I am not getting satisfactory results.
Please what is the practical difference between rosin (RO0 - e.g. Amtech NC-559-ASM) and resin (RE0 - e.g. Amtech 4300/LF-4300-TF)? I am looking for the more sticky one, to keep the component placed more firmly. I am using a fake NC559 now, the flux seems to work OK. I would like to get a suitable original to compare - rosin or resin?
Thanks a lot.
Please what is the practical difference between rosin (RO0 - e.g. Amtech NC-559-ASM) and resin (RE0 - e.g. Amtech 4300/LF-4300-TF)? I am looking for the more sticky one, to keep the component placed more firmly. I am using a fake NC559 now, the flux seems to work OK. I would like to get a suitable original to compare - rosin or resin?
Thanks a lot.
I'm not familiar with the T12 series.
The tip with the concave surface is the gullwing shape.
The flat shape is not suitable for this.
I did some research and from the pictures I've seen, I think the correct type is BCM2 or BCM3.
The effect of the concave surface is that it can absorb a bit of tin and at the same time, the tin collected here has enough surface tension to wick away excess solder from the solder joints. The key to get this working properly is the amount of tin on the tip. The way I did it, is that I started with only a bit of tin on the tip an while dragging along the device pins, I fed a bit of tin from very thin solder wire to the solder joint. This way, there is enough liquid tin present to wet the joints, but not too much that would result in bridges left behind. A bit of practice is required. I soldered hundreds of chips this way. To be fair, most of the stuff I soldered was using PbSn tin. With lead free tin, soldering is much more complicated.
Rosin and resin seem to be more or less the same:
"The terms resin flux and rosin flux are ambiguous and somewhat interchangeable, with different vendors using different assignments."
According to Wikipedia.
The tip with the concave surface is the gullwing shape.
The flat shape is not suitable for this.
I did some research and from the pictures I've seen, I think the correct type is BCM2 or BCM3.
The effect of the concave surface is that it can absorb a bit of tin and at the same time, the tin collected here has enough surface tension to wick away excess solder from the solder joints. The key to get this working properly is the amount of tin on the tip. The way I did it, is that I started with only a bit of tin on the tip an while dragging along the device pins, I fed a bit of tin from very thin solder wire to the solder joint. This way, there is enough liquid tin present to wet the joints, but not too much that would result in bridges left behind. A bit of practice is required. I soldered hundreds of chips this way. To be fair, most of the stuff I soldered was using PbSn tin. With lead free tin, soldering is much more complicated.
Rosin and resin seem to be more or less the same:
"The terms resin flux and rosin flux are ambiguous and somewhat interchangeable, with different vendors using different assignments."
According to Wikipedia.
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