In my Alde 3010 caravan heater the thermofuse is gone. It is soldered on a printcard, and I wonder if there is any tips regarding soldering a new one on the printcard. The fuse will hold only 92°C so I'm afraid it might get a little hot.
Will there be any help if i put the fuse in the freezer and take it out the moment I solder?
Usually they're intended to be crimped, but I see they have actually soldered this one (with longish leads) and it's a one-time melty-type fuse. Image from eBay:
Easiest thing is to use a Hemostat/forceps (image from Amazon) and clamp it on the lead you are soldering (leaving your hands free to hold the iron and the solder) before you solder it. Then move it to the other lead and repeat.
They come in handy in all kind of non-surgical work anyway, from electronic to mechanical assemblies and are not expensive.
Besides using hemostats, alligator clips, or a heat sink clip like the one pictured below (common in the 1970s); you can also use a piece of toilet paper soaked in water and wrap the wet TP near the body of the component. I used this technique in high school when money and availability of tools was not readily available.
You can also take advantage of the latency of heat (energy absorbed during phase change) for solder. Melting the solder just above the tip between the joint and component will reduce the temperature on the lead between the soldering iron and the component. A handy technique when tinning wires with insulation that readily melts, a bit fidgety to do when soldering a component on a circuit board (requires tacking the part on the bottom and applying heat to bottom of board, feeding solder on top of board).
Image from Jameco web site (100378).
The clips sold in the 1970s had notches for the lead which increased contact area.
This I have learned in the Navy Microelectronics training. Use one of those alligator clips on the lead that you are soldering. The alligator clip will act as a heat sink for the thermal fuse. You can add more clips in series if you need to.
The soldering iron tip must be at least 700F or about 360C for the and assuming you have a broad chisel-type tip not a pencil pointy-type which are not ideal for through-hole vias to begin with.
With the alligator clips drawing heat away from the thermal fuse, you should be good to increase the soldering iron temperature for the ideal solder wetting to prevent cold-solder joints with the via hole.
Good luck!!
Some other options:
Soak the fuse in isopropanol while soldering.
Thanks to enthalpy of vaporization the temperature will stay below the vapor point of the liquid.
On the other side, this seems to be an easy solder job.
A short touch with a hot (!) iron should give a proper joint while keeping the temperature low (you don't want to work on that joint for seconds with a mid-hot iron).
I suggest to touch the fuse while soldering.
This adds some extra thermal mass and you have direct temperature feedback.
