Casting resurrection and soldering on

[Rik ShawParticipant @rikshaw]

On the second hand and part machined casting set I am working on at the mo someone has machined one side of a steam chest about 1.5 mm to small effectively scrapping the poor thing. Rather than spend +£10 on a replacement casting I thought that tomorrow I will try and breath new life into it by soldering a strip of sheet metal on and re-machining it.

The simplest option open to me is to maybe use some of this which I have a pot of:

**LINK**

Not sure if it will be fit for purpose though given that it needs to bond steel to cast iron and it says nothing about using flux on the lid.

Has anyone tried doing anything similar using this stuff?

Rik

Edited By Rik Shaw on 21/04/2019 17:29:05

[Rik ShawParticipant @rikshaw]

[Anonymous]

Reading the blurb the stuff is a lead free solder paste (including flux) intended for surface mount electronic components. The flux will be non-corrosive and/or water soluble. In other words not very effective!

I doubt the paste will work on cast iron, and any resulting joint will be weak.

Andrew

[JasonBModerator @jasonb]

I think it may even be just the flux, certainly look slike it as most pastes containing solder are grey. PDF on Silverline site looks like it is zinc chloride and no mention of any metal content.

You could silver solder it though it is not easy to CI as you need to drive the carbon off the surface first. I'd whip out the JB Weld and stick a bit of over thickness steel to the casting and then machine it.

Edited By JasonB on 21/04/2019 17:45:05

[Rik ShawParticipant @rikshaw]

Thanks Jason . It never occured to me that JB would stick a strip of metal to a casting, I've only ever used it for filling blowholes. I'll try it tomorrow and let it cure a few days before machining.

Rik

Edited By Rik Shaw on 21/04/2019 18:14:55

[John PurdyParticipant @johnpurdy78347]

Rik

I had a similar problem a few months ago with a cyl. casting for a ST #1. The side of the valve face opposite the exhaust port had a large chunk knocked out of it well into the valve face. I machined it back by about 3/32" and using JB Weld fastened on a piece of 1/8" steel held on by 2 countersunk screws with the heads well below the surface, and filled with JB Weld. Then machined the surface back to the correct dimension. Once painted the fix will be invisible.

John

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