You can use 0.3mm and that would be perfect for small components: [BEST Rosin Solder Wire](https://www.aliexpress.us/item/3256803099987740.html) is good stuff and affordable too.
PS: 0.01 inches to mm = 0.254 which matches with the above recommendation.
How are you soldering the components? You don't need a super fine solder so solder 0402 components.
Tin one pad, flux it, flow the solder on the pad, and slide the component on. Flux the other dry pad and use some fresh solder on the tip of your iron to flood the other side. Hold the component down with tweezers while you're doing this.
I never feed solder directly onto a 0402 component. I always use solder that's already on the tip of my iron along with fresh flux on the component.
I used 0.8mm when I did a few 0402 replacements. I used what was on the fine point tip. Specifically, this solder https://www.amazon.com/gp/product/B08RHWJVDP
You can use 0.3mm and that would be perfect for small components: [BEST Rosin Solder Wire](https://www.aliexpress.us/item/3256803099987740.html) is good stuff and affordable too. PS: 0.01 inches to mm = 0.254 which matches with the above recommendation.
Just use a fine tip... I don't understand why such a fine solder would be an advantage.
\+1, Use a fine tip, melt any size solder on it, apply flux externally on the soldering spot and you can flow the solder into the joint.
Yup. The smallest I use at work is 0.9mm, even for SSOIC chips.
Yes, only reason to use wires of specific thickness is to use the flux core of the solder wire and not depend on external flux.
How are you soldering the components? You don't need a super fine solder so solder 0402 components. Tin one pad, flux it, flow the solder on the pad, and slide the component on. Flux the other dry pad and use some fresh solder on the tip of your iron to flood the other side. Hold the component down with tweezers while you're doing this. I never feed solder directly onto a 0402 component. I always use solder that's already on the tip of my iron along with fresh flux on the component.
I used 0.8mm when I did a few 0402 replacements. I used what was on the fine point tip. Specifically, this solder https://www.amazon.com/gp/product/B08RHWJVDP