How Do You Solder without Flux?

Paul, in addition to what john says, you want to make sure the surfaces being joined are clean. Isopropyl alcohol does nicely. Temperature of the iron and time with the iron are important, as well as stability. Too little temp or time and you can get a cold solder joint. Too much and it can be overheated. If the items being soldered move while cooling, such as a shaky surface or being moved by the iron, you can get a disturbed joint. One more thing to note is that if you are using lead free solder, the joint may not be shiny, even if it is a proper, well-wetted joint/fillet.

Thanks to both of you for your help.  I am using an 800 degree iron with appropriate tip for the job and am using rosin-core leaded solder.  I'm wondering if the rosin in the solder ages and becomes less effective.  I've had the roll of solder for several years.  I'm also wondering if there is enough rosin inside the solder.  I've heard that you can get different ratios of solder:rosin.

Any ideas?

Thanks to both of you for your help.  I am using an 800 degree iron with appropriate tip for the job and am using rosin-core leaded solder.  I'm wondering if the rosin in the solder ages and becomes less effective.  I've had the roll of solder for several years.  I'm also wondering if there is enough rosin inside the solder.  I've heard that you can get different ratios of solder:rosin.

Any ideas?

I just looked at the date on the spool of solder - 2005.  Too old?  Hmmmm.....

I don't think it is too old, the roll of solder I am using right now has a date of 02/12/87 on it and the price tag reads $1.98. Back in the early 90's some one was out at the sidewalk sale with a case of 1lb #66/44 solder rolls by Kester and I bought 10 of them. I am down to the last roll and have not had a single issue with them. So I don't think it is age, I would lean towards the iron begin too hot.

Could you take a video of you soldering so I can see your technique? If your joints are cloudy, you may not be holding the iron on the joint long enough to burn all the rosin.