The photo is the base of a floor lamp. The material is intended to fill the base and provide enough weight to make the lamp stable. I don't know what caused it to crack apart after these years, but it has. The gray material feels like cement of some kind and the black is a plastic. The base is about 7 inches (18 cm) in diameter and 2 inches (5 cm) high. enter image description hereDoes anyone have a suggestion for what filler material to use for a repair?

  • It is a low grade cement. Fill the base with cement again.
    – RMDman
    Commented Apr 13 at 18:16
  • 1
    it's concrete, not cement ... cement is an ingredient in concrete
    – jsotola
    Commented Apr 14 at 3:43
  • Yep, probably a lightweight mortar of some kind. Could replace with same.
    – Huesmann
    Commented Apr 14 at 15:22

2 Answers 2


You're likely correct that it's cement (of some sort) and it likely broke because the plastic got old and brittle, as it does, perhaps aided by an impact of some sort.

I've seen sand used in lamp bases that will hold it, or you can use any sort of cement/plaster/mortar type material that will harden and remain as a lump if sand would flow out of the base. If trying to cast a new base without the plastic part to act as a mold, you might want to add some reinforcing fibers for cement products into the mix so it hangs together better.

I mean, you could go nuts and fill the base with molten lead, but there's a lot of reasons not to, (burns, toxic fumes, would have to remove the lamp wire to prevent melting the insulation...) and no practical reason to. So give that one a pass.

  • Nothing wrong with casting a lead "washer" about 1" thick and 6" diameter to be held in place by that nut...
    – Solar Mike
    Commented Apr 13 at 19:05
  • Assuming you use correct PPE for casting lead, of course. And maybe glue on some felt so the lead doesn't scrape dust onto the floor.
    – Ecnerwal
    Commented Apr 13 at 19:21
  • 1
    Where is the OP supposed to get a large ingot of lead, as well as have a way to melt it. As opposed to turning the lamp upside down and pouring some cement that is easily available.
    – RMDman
    Commented Apr 13 at 20:47
  • @RMDman and how to mold it, since the base is plastic?
    – Huesmann
    Commented Apr 14 at 15:21
  • I had some old stucco patch, which is a cement product and used that. It worked well. Thanks. The lamp is back in service. Commented May 13 at 20:38

You can buy cast iron weights made for this purpose. You could also buy used barbell weights from local online marketplaces, just find one the right size for your base.

With a barbell weight you'll have to remove the wire from the lamp, pass it through the weight, and reinstall it. The purpose made ones have a segment missing, like a donut with a bite taken out of it, that you can pass the wire through.

Manufacturers use cement because it's "good enough". It's cheaper than cast iron, and being about 4 times lighter is also cheaper to ship. But if you can find used metal plates locally, the cost of them and of picking them up won't factor into it.

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