Radiator renovation

[DIYspanner]

I’m going to remove a bathroom radiator to clean off the rust that’s flaked the paint off along the bottom seam.
What I’m concerned about is when the rust is removed, any pitting in the skin from rust could cause leaks when the radiator is refitted, filled and pressurised.
If after cleaning the rust off, is filling the radiator with water to test for leaks a good enough indicator that its still sealed?

 

[Madrab]

If after cleaning the rust off, is filling the radiator with water to test for leaks a good enough indicator that its still sealed?

Yes, it will show up any pinholes (leave one of the top valve holes open) what it won't show up though is any thin sections of metal that may give way under 1-2 bar of pressure, if it's a sealed system

 

[Harry Bloomfield]

Yes, it will show up any pinholes (leave one of the top valve holes open) what it won't show up though is any thin sections of metal that may give way under 1-2 bar of pressure, if it's a sealed system

Pressurised air might be a better, easier option, if you can arrange it. Seal all inlets/outlets, find a way to fit a tyre valve, inflate to 3bar and see if it holds the pressure.

 

[Madrab]

Pressurised air might be a better, easier option

Just need to be careful with air, when 3 bar of air goes, it goes with quite a bang.

Better still, wet test. Pressure testing pump, seal 3 outlets, fill with water, attach the pump and pressurise to 3bar and leave, see if it holds.

 

[Harry Bloomfield]

Just need to be careful with air, when 3 bar of air goes, it goes with quite a bang.

Good point, but if there is a leak - air will escape much quicker/more obviously than water.

 

[DIYspanner]

The radiator is removed and the rust wire brushed off but I'm concerned that the rust has crept into the bottom seam and forced the steel sheets apart.

I doubt I'd get all the rust cleaned out. Is a new radiator advisable?

 

[opps]

Aren't radiators galvanised metal? I always though that sanding them "aggressively" was a no no. That said, if they are going to spring a leak, surely they do so from the inside out (in areas not subject to high humidity).

 

[Harry Bloomfield]

Aren't radiators galvanised metal? I always though that sanding them "aggressively" was a no no. That said, if they are going to spring a leak, surely they do so from the inside out (in areas not subject to high humidity).

Not galvanised, that I am aware of. Usual problems in pinholes from the inside to out, due to lack of inhibitor.

 

[DIYspanner]

Inhibitor impedes corrosion on the inside but I'm guessing that the paint finish has not been applied very well over the bottom seam and has flaked off allowing condensation in the bathroom to corrode the bare metal and force the seam apart.

Not leaking to date so perhaps a some silicone pushed into the seam gap or Smoothrite to prevent further corrosion. Otherwise, a new radiator.

 

[Madrab]

Aren't radiators galvanised metal?

Mild steel, cast iron or ally, never seen galvy

The radiator is removed and the rust wire brushed off but I'm concerned that the rust has crept into the bottom seam and forced the steel sheets apart.

I doubt I'd get all the rust cleaned out. Is a new radiator advisable?

get in there with some rust eater and then a screwdriver. To be honest though, once it's at that point then it's a guessing game whether the rust has penetrated or if it's just surface.

 

[DIYspanner]

Rust eater applied!

I've coated all the metal along the bottom where I've cleaned the paint off.

 

[Harry Bloomfield]

Rust eater applied!

I've coated all the metal along the bottom where I've cleaned the paint off.

When it's all done, and back in place - stop her indoors hanging her wet towels on it

 

[Madrab]

Rust eater applied!

I've coated all the metal along the bottom where I've cleaned the paint off.

Excellent, a good clean rub down then and time to get the Oxy/Acetylene out and get brazing

(only joking )