Is the prop for a high speed model? If it is then silver solder is preferred as Dave says.

A propeller for a sedate model is another matter, and one of the harder varieties of soft solder will suffice. There is also the matter of what solder, if any, is holding the other blades in. mixing hard and soft solders in the same job is something worth getting a better opinion than mine on.

I always make my own props for slow models, and use a high temperature soft solder. I've never had a problem.

Chas

Hi Peter, actually I buy mine from one of many Chinese outlets that proliferate here in Spain. I first bought some expecting it to be similar to my favourite electrical solder. It wasn't, as often happens when buying stuff from outlets like this, it isn't what it purports to be, it wouldn't even melt on any of my soldering irons. Soon the penny dropped and I use it with a mini blowtorch for soldering brass, with a little flux. I recon that it must melt at about 225 degrees, as my best iron goes to just short of that.

Now I must do something I hate, trying to talk about something I'm not qualified to comment on. Solders have quite a range of mixes and melting points, I think most electrical solders melt at about 190 degrees, and I'm probably using one around 225 to 235 degrees. A quick look on Amazon shows a big range of solders including some that seem similar so that's a possibility.

I'm hoping that someone qualified to discuss solder will give you better advice, I'm a decent modeler, but no engineer.

Chas.

Hi Peter, Try Comsol a solder paste combined with flux, melting temp. is 296 deg. Silverflo silver solder melts at 630 to 660 deg.that's a bright red in day light and needs easyflo flux. All are available from most model engineers suppliers.

Regards

Eddie.