Ahh..... THERE it is...Darivs:
It was kind of hard to look for a microscope and zoom a bit closer but I did.
So here is the atom picture you ask for.
View attachment 219151
Using the principle that the solder will follow the flux, I use a paste type and apply it with a sharp toothpick end to only where I want solder to flow. Then I cut off a very small piece of the solder and with tweezers place it where I need the solder. Each piece needs to be firmly held in position so I use my small multi-arm device with the alligator clamps and additional clamps as need to grasp the parts and hole them in place without movement. OK . . now the flux followed by the solder piece are put in place and my small pointed soldering iron is applied gently touching the metal either under or beside it. The very small piece of solder quickly melts and goes where the flux was placed with very minimal overflow which makes cleanup very easy. Just my approach which I worked into from sloppy over soldered early attempts to the much smaller and cleaner result which will hopefully improve with more use. You may want to try this and see how it works for you. Good clamping is essential though so that things stay in place. Rich (PT-2)A couple of comments on soldering.
There are basically two types solder. Lead free (RoHS) solder requires higher temperatures ~215C and requires that all parts to be soldered are very clean and grease free. Lead based solder requires a lower temperature ~185C and is more forgiving on cleanness. You can also get by with a smaller soldering Iron with lead based solder. As for flux do not use acid based flux most of the paste type fluxes are acid based and needless to say the acid will cause issues with the models wood. Look for water based fluxes. In the photo the heavy coil of solder looks like 50/50 Plummer's solder. Don't even think about using it unless you are soldering copper pipe.
As for Lead free solder there is some evidence that this type of solder will "grow" whiskers over time. There is also evidence that the lead based solders have a much longer life. NASA does not use RoHS solder on anything that goes into space.
Jim
A couple of comments on soldering.
There are basically two types solder. Lead free (RoHS) solder requires higher temperatures ~215C and requires that all parts to be soldered are very clean and grease free. Lead based solder requires a lower temperature ~185C and is more forgiving on cleanness. You can also get by with a smaller soldering Iron with lead based solder. As for flux do not use acid based flux most of the paste type fluxes are acid based and needless to say the acid will cause issues with the models wood. Look for water based fluxes. In the photo the heavy coil of solder looks like 50/50 Plummer's solder. Don't even think about using it unless you are soldering copper pipe.
As for Lead free solder there is some evidence that this type of solder will "grow" whiskers over time. There is also evidence that the lead based solders have a much longer life. NASA does not use RoHS solder on anything that goes into space.
Jim
Using the principle that the solder will follow the flux, I use a paste type and apply it with a sharp toothpick end to only where I want solder to flow. Then I cut off a very small piece of the solder and with tweezers place it where I need the solder. Each piece needs to be firmly held in position so I use my small multi-arm device with the alligator clamps and additional clamps as need to grasp the parts and hole them in place without movement. OK . . now the flux followed by the solder piece are put in place and my small pointed soldering iron is applied gently touching the metal either under or beside it. The very small piece of solder quickly melts and goes where the flux was placed with very minimal overflow which makes cleanup very easy. Just my approach which I worked into from sloppy over soldered early attempts to the much smaller and cleaner result which will hopefully improve with more use. You may want to try this and see how it works for you. Good clamping is essential though so that things stay in place. Rich (PT-2)