Soldering brass

[vrossi85]

Hi all, I have a problem i need help here. I have tried to solder brass to my white metal parts but having great difficulty. I suspect its maybe the solder wire material problem as well as my skill..... Well, therefore i hoping anyone out here is willing to give me a tutorial on how to solder brass onto metal parts and also any recommendation on which solder material should i use for it? Thanks in advance!!

Ro

[sjelic]

The problem is with temperature difference, white metal has very low melting temperature while brass, specially if it is thicker has higher "adapting" temperature. Try to heat brass first and then join white metal part. From my experience you should just glue it
But maybe I am also doing something wrong.

[mike@af]

White metal does not like to be soldered, I have lots of trouble in the past trying to solder white metal. Soldering brass to white metal is going to be even more difficult due to the different properties of the materials as Sasa said. I'd just epoxy it.

[MPWR]

When I've tried it, the white metal melts before it solders successfully.

[vrossi85]

Hi thanks all for the reply. But i came across several modeler that they used either brass or maybe tin sheets to do modification to their metal kits. For example F1 metal kits, they usually will solder the front or rear wings before painting, or cut out incorrect white metal portion before attaching metal sheets to them using soldering. I'm wondering what sort of solder they use.

I have went to some hardware shops and they too tell me that the normal solder for joining wires onto circuit boards are actually unsuitable for brass or large surface, they told me I should use some metal that's for welding. I was confused since they also cant tell me where i can find those. But it seems like many metal kit modelers doesnt face these problems and they are able to solder the parts and sand them nicely into shape. I really hope to learn this technique from somewhere or someone.

Ro

[CrateCruncher]

Ro I understand your frustration having been there myself. I suspect your not tinning or fluxing sufficiently but I'll go over my process from the beginning.

There are many different kinds of solder and each has a different melting point. The lowest melting point is good old 60/40 tin/lead ratio and the stuff I use. Why? Because, as others have mentioned, the white metal being mostly tin, also has a melting point in the range of most solder so keeping it from getting too hot is the biggest problem.

Since there is no risk of melting the brass do as much work as possible on it before you get anywhere near the white metal. I like to coat the brass with rosin soldering flux, then "tin" the contact surface with my 60/40 solder until it has a silver shine.

Next I coat the white metal surface to be joined with additional flux. Then I add just enough solder to the tinned brass part to make the joint before offering the brass up to the white metal.

Here is the tricky part! Only add heat to the brass with your soldering iron. As the heat builds in the brass it will transfer into the white metal, slowly at first, then rapidly as the contact surface grows and the transfer rate increases. When the joint has grown large enough to hold the parts together remove the iron from the brass and cool the assembly down.

This takes practice so try it on some discarded parts first. Try to hold the white metal piece in a vice so it can't squirm around. Use an electricians soldering tip (looks like a rod with the end scooped out) for wire and a flat tip for strip brass. Don't try to join a large surface area because by the time the edges are hot enough the white metal closest to the heat source will be a puddle of tin. .... And don't be surprised if you need a bit of putty to fill in around the weld.

[cinqster]

The previous advice is good -definitely 'pre-tin' the brass parts first and then allow the solder attached to the brass to flow on to the white metal which is pre-fluxed.

A good trick to avoid having to use too much heat on the brass is too grind away any large contact areas on the brass eg. leave a thin outer wall on the brass - helps quicker heat transfer and less chance of destroying the white metal.

I use Powerflow Flux and low heat lead free solder. You could also use a heat sink material on the white metal to stop too much heat transfer - have a look for it at jeweller product websites.

http://www.fernox.com/?cccpage=powerflow_flux&sub=9

At best, soldering white metal even on it's own is difficult and needs lots of practice. Here's a piece I made from soldered sheet pewter...drove me mad trying to get it right!

[vrossi85]

Thanks for the really good tutorials! I learn something new now. The key is that i did not use soldering flux. I don even know there exist such a stuff for separate application!! Because i think most of the soldering wire in my hardware shops are already mixed with flux in it. This is what i learned when i google search somewhere too. Well, i need to buy the flux and try it out again.

And cinqster, the pewter workpiece is an art!! really makes me envy of your soldering job! I must work hard to achieve that... Thanks for all the replies once again!

Ro

[cinqster]

Cheers Roland,

BTW, I had a good look at your website - really nice and very well designed mate!