Concrete standard lamp base powdered/perished...

RainbowsInTheSpray

... very suddenly and without warning. Totally crumbled and left a nice carpet hoovering job.

This is the concrete filler added to the underside of the round metal base of the lamp to give weight and therefore stability.

Can anyone suggest a fix..?

stuart45

Have you got a photo?

Martin_the_Unjust

Probably any wall filler or similar would do the job.

Eldi_Dos

Putty and then a felt pad cut to size?

RainbowsInTheSpray

stuart45 said:

Have you got a photo?

Looks more or less like this:  

https://www.dunelm.com/product/everett-floor-lamp-base-1000253651?defaultSkuId=30921616&utm_source=google&utm_medium=cpc&utm_campaign=Lighting_Lighting-PMax_[GOO-PLA-LIGHTING-LIGHTING]&gad_source=1&gad_campaignid=19815176331&gbraid=0AAAAADGqyX1iOh0fIuCBWfaM8LFlubWND&gclid=EAIaIQobChMIttfm-pG9jgMVvphQBh1cpjZuEAQYASABEgK2V_D_BwE&gclsrc=aw.ds

The metal base was filled with concrete as a cheap stabilising weight. We're talking a couple of kg...

stuart45

It might be worth adding some SBR to the mix to help it bond to the metal.

BlueonBlue

Many have a plastic base weight held on by a nut through the middle ...that can fall apart.
These are filled with concrete or sand or something similar thats heavy.

If you can find a old broken lamp take the plastic weight out and fit it to yours.

WIAWSNB

You still have the 'concrete', RitS?
Two basic ways to do this, I think; one is to reuse the stuff you have, by mixing it with SBR or builder's PVA. Spoon it back in, tamp it down repeatedly and firmly, and it'll need leaving for a good few days.
Pros: you use the old stuff. And you have a useful tub of SBR/PVA for other tasks. Cons, it'll take an age to dry...
Or, buy the smallest pack of 'ready-mix' from Screwfix or similar; eg postcrete, patching mortar, powdered filler, basically anything to which you add water and then 'sets' chemically. 
For the first solution, add the SBR/PVA to the crumbled mix to make the stiffest paste possible - the least liquid as possible - and spoon it back in. Tamp it down repeatedly and firmly, and ensure it's level so it doesn't stick out beyond the bottom. Allow to dry.
I'm imagining you can undo the base for this, and turn it upside down... Almost certainly it'll have a large nut on the underside, and if you undo this, it should slide down the cable, and allow you to remove the base - slide that away a good metre or so too, and then set it upside down on a couple of equal-sized books, so the cable doesn't interfere. Then fill, ensuring the cable isn't affected.
If you want faster results, then just buy a bag of 'setting' stuff. Bear in mind this will still take days to dry out, so don't stand it up until done, or else you may get a damp patch.

Section62

RainbowsInTheSpray said:

... very suddenly and without warning. Totally crumbled and left a nice carpet hoovering job.

This is the concrete filler added to the underside of the round metal base of the lamp to give weight and therefore stability.

Can anyone suggest a fix..?

Are you sure the material is concrete?  Concrete doesn't normally crumble like that.

It is heavy though, so if you are replacing the material with something else you need to make sure the something else will give you enough weight in the base for the lamp to be safe to use.  Fillers and plaster are usually lighter.

GDB2222

Just thinking laterally a bit: 

Buy books from charity shop 

Pile books on base of light

So, you have supported the charity, your light is secure, and people will think you’re intellectual (which explains why the room looks untidy with the books piled up). Win, win, win! 

WIAWSNB

https://www.screwfix.com/p/no-nonsense-mo42-multipurpose-mortar-grey-5kg/452hn

Section62 said:

RainbowsInTheSpray said:

... very suddenly and without warning. Totally crumbled and left a nice carpet hoovering job.

This is the concrete filler added to the underside of the round metal base of the lamp to give weight and therefore stability.

Can anyone suggest a fix..?

Are you sure the material is concrete?  Concrete doesn't normally crumble like that.

It is heavy though, so if you are replacing the material with something else you need to make sure the something else will give you enough weight in the base for the lamp to be safe to use.  Fillers and plaster are usually lighter.

It'll be concreteish. Fine, so more like filler.

I even had a sellotape dispenser that had this material in its hollow base in order to give it weight and stability - until one day it crumbled and started to pour out past the bottom rubber cover.

I tapped out all the loose stuff, and brushed PVA into what was left behind to bind it, and then added as much as I could of the stuff that had come out, mixed with more PVA. It was dead easy, and worked, but obviously on a smaller scale than this job.

Hopefully RinS still has most of the stuff that came out, in which case it's best to reuse it. Mix stiffly with PVA (perhaps slightly diluted - 10% water), and press it into place. Tap tap tap. Jobbie jobbed. Add anything obvious like sand to make up any shortfall.