One of the frustrations in the electronics assembly world can be when your soldering iron tip cannot be tinned. Tinning is a necessary step for all new tips. By tinning the soldering iron tip, you can keep the tip from oxidizing. The fine coating of solder that is applied to the tip is critical to the soldering process, as the tip transfers the heat from the iron to the joint that you are trying to solder.
The real secret to tinning your soldering iron tip lies in the timing. You need to get the coating of solder on the tip before it gets hot and begins oxidizing, which can make this process a challenging if not impossible one. To prevent this oxidation you need to act quickly and efficiently applying the solder.
Your soldering iron tip also may not be tinning if there is an oxide layer. In this case you will need to first clean this oxidation off of the tip before the tinning process.
Another sign that there is a problem and that you will not be able to tin the soldering iron is if the tip keeps turning black when you try to solder. Less expensive soldering irons will have a tip that is more likely to get black carbon on it, contaminating your tip with this in turn. If this is a reoccurring problem, it may be worthwhile to invest in a higher-end soldering iron which will save on productivity, not to mention operator frustration, in the long-run.
Weller is a popular manufacturer of soldering irons that can help to eliminate this problem. The Weller TCP12P Controlled-Output Field Soldering Iron is a great choice.
KIMCO Distributing offers a wide range of soldering irons, including those from Weller. Visit http://gokimco.com/search?form_key=OhbYqHgT3MbeEp53&q=soldering+iron to browse the soldering irons available.