how to avoid burn-out when soldering?

[diy001]

I have some soldering experiences on 1/2" and 3/4" pipes with propane. I am confident my skill on them.

Today I just tried 1" with MAPP. The first joint is a 1"x1"x1/2" tee. It turned out a nightmare. It was burnout. I have to redo it.

It seems that when the temperature reach to the point needed by the lead-free solder, the flux is also burnout. I am using #95 tinning flux. All materials are bought from HomeDepot.

Or I applied the solder too late?

How do you avoid the burnout? Is there a way to repair the burnout joints?

 

[frodo]

the body , the shoulder, the cuff, what a fitting's parts are called

but your torch, the tip of the blue flame, on the back of the cuff at the shoulder
establish heat, roll the heat around the fitting.
on the opposite side of the fitting, touch the solider to the cuff. as the solider melts, back off with the heat

iif you heated the fitting correctly, you should see the solider travel around the fitting.
the solider is "pulled" into the back of the fitting by the heat, it is called capillary action.
which means the solider will follow the heat.
when solidering a 1x1x1/2 tee, i solider the 1" sides first. then the 1/2" last.
most of the time,you will not need to heat the 1/2", it is hot from the 1" being heated.
after you solider, using a dry rag, wipe the excess flux/solider off the pipe
wiping your fittings is like wiping your butt. you aint finished till its done

 

[Mr_David]

I have seen to many guys use an excessively hot torch. I try to tell them it's like cooking. You don't fry and egg with the flame on high. turn it down, move it around. the small gap between the pipe and fitting causes a slight delay in heat transfer. an excessively hot flame will burn the flux before the pipe inside the fitting gets hot enough. Bigger pipe I preheat the pipe a little before I do the fitting but not to much you don't want the solder running down the pipe. you want it to suck up into the fitting. control the heat. Like Frodo said pull the flame away when the solder starts to melt. It's an art.