Cast Iron rads vs pressed steel? Original vs new??

[getcarter]

Hello all. We're about to replace the boiler and some of the rads in our Victorian semi. We are going for "old style" rads and are looking at various ranges.

What I would like to know more about is the advantages (assuming there are any??) of cast iron rads over pressed steel. Are new cast iron "old style" rads better or worse than refurbed originals etc etc.

Any thoughts or experiences would be gratefully recieved.

Ta

 

[Penners]

This is just an amateur point-of-view, but the only clear advantage I can see for modern steel panel rads over Victorian(stye) cast iron is space-saving. The modern rad intrudes into the room much less.

You could argue that thin steel will start to give off its heat more quickly than thick cast iron, but that is offset by the "heat-sink" effect of the iron, which will cool down more slowly after the heat source has been switched off.

You could also argue that old-style radiators have much more historic charm than today's rather clinical steel rads.

You pays yer money....

 

[Penners]

Just one other thought - I don't know how easy or otherwise it is the plumb genuine old Victorian rads into a modern heating system. Could the sizes of threads, tappings and so on be a compatibility problem?

I'm sure someone else will know.

 

[borischarlton]

Hi

We have over the last year installed 8, 4 column cast iron rads. They are Ideal brand and I purchased them all seperately over a period of about four months from ebay and a local rec yard. I then had them sand blasted and powder coated and they look fantastic!! They heat up suprisingly quickly and obviously being cast they retain the heat really well. The rads were relatively cheap, £50 was the most expensive and the least I piad was a fiver. The finishing came to about £1100. So when you compare the cost with somewhere like LASSCO (sp) I did really well. However I did take a gamble because I did not get any pressure tested and one leaked from just about every section!! It was the largest at 25 sections and I didn't have the time to dismantle it so I had to purchase another. You must also take into account the cost of the valves, as putting modern looking TRVs on would really detract from the look. I settled on Chartwell valves and they are about £100 for each rad.

The whole lot did add up but the look is even better than I expected and would certainly do the same again.

Rob

 

[borischarlton]

Penners,
There is no problem at all as it is all interchangeable.
Rob

 

[Penners]

Thanks Boris.

 

[michael]

I’m not an expert on this but I guess reclaimed cast iron coloum rads are ok as long as they have been properly stripped down and refurbished and not just cleaned up and polished. Having said that, new column rad’s can be problematic as well.

I’ve got some relatively modern reproduction cast iron column rads that were installed by the previous owners about 10 years ago. The standard factory made unit was supplied at a maximum of 10 columns and any additional columns had to be added on by the plumber on site.

In my case I have 14 columns on each rad i.e. with 4 additional columns being added to each standard unit. I found that there was leaking not from the factory built part of the unit but from the joints between the columns that had been added on, that is, there was a powdery calcium build up on the joints. This was fixed relatively easily in that the manufacturer was able to supply me with a key for dismantling the columns and a set of new jointing gaskets. I’m not sure if these items would be available for the old reclaimed rads if they started to leak.

As I understand it, the gaskets can fail for a number of reasons but one reason can be corrosive water caused by the two different metals reacting together i.e. copper pipe work with cast iron. My suggestion would be that if you’re buying reclaimed rads make sure that they have been fully refurbished and also ensure that all the jointing components are readily available. Further more make sure that the water in your heating system is properly treated to prevent corrosion. Let’s face it these things are far too expensive to simply throw away if they start to leak and cant be fixed.

 

[michael]

I’m by no means a scientist but this quote from the U.S. Technical Preservation Services may explain some of the cast iron radiator corrosion problems and joint failures if (a) They are installed in a copper heating system without anti corrosive additives and (b) if they are not fully refurbished internally and externally.

“Galvanic corrosion is an electrochemical action that results when two dissimilar metals react together in the presence of an electrolyte, such as water containing salts or hydrogen ions. The severity of the galvanic corrosion is based on the difference in potential between the two metals, their relative surface areas, and time. If the more noble metal (higher position in electrochemical series) is much larger in area than the baser, or less noble, metal, the deterioration of the baser metal will be more rapid and severe. If the more noble metal is much smaller in area than the baser metal, the deterioration of the baser metal will be much less significant. Cast iron will be attacked and corroded when it is adjacent to more noble metals such as lead or copper.”

 

[NT]

Sheet gasket material is available from any car accessory shop, along with hermetite, and IC engines show no sign of disappearing any time soon, so there should not be any great difficulty getting such parts.


NT

 

[AMc]

A pal of mine fitted reclaimed and refurbished cast iron rads in his 2up2down. Some things to be wary of are the heating capacity and standing weight. The units he bought could have heated a house several times larger. Make sure you don't ridiculously oversize your radiators for your rooms or you will have to mess with your boiler temperature and possibly affect your hot water temp to get a comfortable living environment.
They looked great but swallowed a lot of floor space in the small rooms.
They also weighed (almost literally) a ton - it took 4 of us to lift each one and the floor in the back bedroom gradually bowed under the weight which would have worried me.

By comparion a new flat pressed wall hung radiator will take little space, won't weigh much and will cost much less, but it won't look as good either.

 

[CHRIS]

I have just fitted some this weekend (with help from friends) and are very happy with the result, they were reclaimed from a skip and presure tested and sand blasted by a place in Colchester I then got them sprayed in a Pewter colour - they look great.

They have been a bit of a pain with the brass fittings and have to keep a Stilson close to hand and tighten up when I get a few drips (ok after a few times of running the things). I am impressed by how they keep warm after the heating goes off as well.

I have used plastic Thermostatic valves for the moment as the £175 for a set of brass ones will have to wait until later!

 

[another_richard]

You must ensure that the whole system is properly flushed out before running and ensure that your bolier is one of those that can collect the waste pieces of metal using a magnet.

I only state that as a plumber popped round tuther day to explain the benefits/issues of those big chunky rads. They, as will all rads' rot over time and if your boiler and pipes are not flushed regularly, the boiler will pack up.

 

[NT]

They have been a bit of a pain with the brass fittings and have to keep a Stilson close to hand and tighten up when I get a few drips (ok after a few times of running the things).

Sounds a bit of a pain in the brass!


NT

 

[ljn]

I've had a few sets of old cast iron rads. Lasscos will charge a fortune, but will spec up the BTU, which most recalamers don't really do for old rads as different styles differ substantially.

It is important that they are properly flushed internally and pressure tested or they'll kill your boiler- or leak rusty water onto carpets, wood floors and through decorated ceilings.

Interesting post on chemical reactions from michael. I know that my boiler warrenty would be void if the technician can't find a compulsary product in the water. Sorry, but I can't remember the name of the product which is available from plumbing supplyers.

A friend got some reproduction rads and was very dissapointed at how quickley the cool down compared to the caast iron ones.

 

[Aidan]

Advantages; the Victorians only knew how to sand-cast iron. As soon as pressed steel rads became available, everyone stopped using cast iron; unless they wanted a Victorian look.

The threaded fittings will probably be the same, BSP; I'm not aware of any thread form that was widely used. The connections may be fairly huge for gravity circulation systems, 1/2" BSP would be plenty for domestic use.

They won't corrode, if the system is sound and there are corrosion inhibitors in the water. Modern systems are a mix of steel (rads, pipes, boilers) and copper (tube, heater batteries, etc). They will corrode if there is dissolved oxygen problems (leaks, pumping over, air being sucked in, etc.,) or if the water is acidic (active flux residues not neutralized and flushed out). The inhibitors stop galvanic corrosion.

The paint will probably be lead-based, probably many coats.

They will retain heat for longer, since they weigh a ton. It can be a problem if you have a mix and one thermostat controlling all of them. A variable/modulating temperature heating system with steel panels rads will far out-perform CI rads.

You can get steam rads which usually have only one connection. I've never seen them here, they're common in the US where they still use steam heating in old properties.

 

[Penners]

the Victorians only knew how to sand-cast iron.

Are you saying there are other ways to cast it?

 

[Aidan]

the Victorians only knew how to sand-cast iron.

Are you saying there are other ways to cast it?

Investment cast
Plaster cast
Die cast
Centrifugal cast
Roll cast
back cast
worm cast

 

[Penners]

Investment cast
Plaster cast
Die cast
Centrifugal cast
Roll cast
back cast
worm cast

Wow - sorry, but I have more questions.

What's investment cast?
Can you really cast iron in plaster without mould erosion?
What do you make your die from?
Never heard of the last three!

By the way, in case I should sound as though I'm challenging you, I'm certainly not! It's just that - having some limited experience of sand casting - I'm keen to learn more.

 

[MdB]

I was interested too so looked it up

Investment casting: - AKA lost wax casting - Make mold from wax - fill with metal.
http://en.wikipedia.org/wiki/Investment_Casting

Die Casting:
http://en.wikipedia.org/wiki/Die_casting

Centrifugal Casting:
http://en.wikipedia.org/wiki/Centrifugal_casting

Roll Casting: Method for producing thin sheet??
http://www.ocamac.ox.ac.uk/newsletters/Newsletter%205/RollCaster.html
also fly fishing.

Back Casting: ???
opposite of forecasting (yes really). Also fly fishing.

Worm Casting: ???
find them in your back garden?

and a few others:

http://en.wikipedia.org/wiki/Sand_casting
http://en.wikipedia.org/wiki/Lost_core
http://en.wikipedia.org/wiki/Endocranial_cast

 

[Penners]

How about broadcasting: making very wide things out of iron...

and forecasting: making golf warning signs out of iron.