When I solder the solder dose not stick to the tip of the iron and it turns black. Are there any solution s to make solder stick to the tip?
Clean the hot tip with a wet sponge before trying to tin it. Are you using flux cored solder?
Russell.
You've let oxide build up on the tip - this is often fatal for the tip.
Its vital to wet the tip with solder as it first heats up - once oxide builds up the only
solution is abrasive, but that rapidly removes the iron coating and once you are through
to the copper the tip is useless (copper dissolves in solder).
Always use flux-cored solder, and extra flux if available to help prevent oxide build up.
Never leave an iron switched on for more than a minute or so with re-wetting it, as the
flux burns off. Flux's purpose is to prevent oxide forming.
Try very fine emery paper to remove the oxide and start again - sometimes a tip
can be rewetted this way, but its tricky.
This issue also seems to happen more with irons that are not temperature regulated. I'm assuming yours is not temperature controlled.
Long long ago we solved this issue by creating a switch box that would switch in a power rectifier in one leg of the AC path when the iron would sit idle. This would effectively cut the average voltage at the heater to near 50% of normal and it would remain warm and not take long to reach usable temperature when switched back to normal (ready to solder).
If yours IS temperature controlled... run it at a lower temperature. (like somewhere around 370 C)