Does hot air gun rework give superior results for surface mount components?  - Page 1
Forum section: electronics / beginners

author: Jim from Chicago
author_rank: Regular Contributor
timestamp: November 23, 2024, 04:39:16 am
content: I was really struggling with some 0402s today with solder tips. Even with the thinnest tips I have I couldn't seem to nail the little buggers. My experience is that if the tips are thin enough to get in there, they don't get things hot enough. And if the tips are thicker to bring more heat, then you can't manipulate the part.After I got sick of trying with the tips, I put the board on a hot plate, put down flux and positioned the 0402 on the pads, then just baked the hell out of it. Cleaned it up and look at through the microscope and it looked good. It looked a lot better than the results I usually get from solder tips.What are your thoughts about getting the best results especially for small components?

author: u666sa
author_rank: Frequent Contributor
timestamp: November 23, 2024, 05:25:57 am
content: With hot air, component reflows into its place. With solder iron you align things, and as usual everything is crooked ever so slightly.

author: Harry_22
author_rank: Frequent Contributor
timestamp: November 23, 2024, 05:29:31 am
content: Hi!When soldering parts of this size I pay more attention to ensuring that they do not jump off like fleas.Often their denominations are unknown. You risk losing more time searching for it. But it, little bugger, just stick to the tweezers!

author: Smokey
author_rank: Super Contributor
timestamp: November 23, 2024, 09:24:42 am
content: I do 0402 size parts all the time. Both hand soldering and on the hot plate with paste and stencil.The secret weapons for hand soldering are:1) Metcal iron with M7CS152 tip (0.4mm tip by 8.5mm length)2) Tiny Solder = Kester Sn63Pb37 0.25mm (no clean)3) Tacky Flux = TF5000I almost never put 0402s on with hot air. If taking them off, easy to flood with some thick solder and just swipe off with the iron tip.

author: Neganur
author_rank: Unknown
timestamp: November 23, 2024, 09:35:24 am
content: from own experience, it is better to have thin solder wire (tin) instead of thin soldering iron tip.with good technique, clean tips, good flux, and proper cleaning, soldering iron work can look just as great as reflow but is typically a lot more work.hot air is great for rework and in my opinion less stress to the pads too. People tend to put too much force on pads with their iron, mostly during to wrong tip size, unclean tips, etc.I would like to believe that there is less stress on the component too, using hot air, since, e.g., both sides of a 0402 are molten at the same time. As opposed to unclean pads (not level), first soldering one side and then pushing down on the component itself during soldering can put uneven stress on it. Then again, uneven hot air also stresses / flexes PCB depending on your copper pours.Still, I would say hot air is a lot easier and more forgiving than soldering with an iron.

author: amyk
author_rank: Super Contributor
timestamp: November 23, 2024, 10:50:48 am
content: Some people are skilled enough to work with SMD parts using a regular iron, but forget about BGAs and other parts with their contacts underneath.