Drilling into horse hair gyprock?

[echelon6]

I know this is a wood forum but I think many of you would know the answer to this so hoping the mods don't remove this thread

I have a ceiling that's made of drywall that's got horse hair embedded throughout it (the old style drywall basically). I found that it's difficult to cut cleanly through it and the edges always have hairs coming out which is troublesome to remove and I need to reapply topcoat and muck around with all that

Is there a particular technique to do this? Basically I need to drill a few round holes to fit ceiling downlights into them and I want to avoid having to muck around with topcoat and cutting away loose hairs when I make the cuts

[Malcolm Eaton]

That is not what is called " Drywall", you are dealing with old fashion " Pasterboard". Plasterboard is made up from a plaster compound which is layed up on flat tables and reinforced with Sizal. Plasterboard ceilings over a number of years will tend to sag and the surface my begin to craze. Plasterboard ceilings over time once they begin to sag will need to be reinforced by hemp straps with a plaster slury layed over the top of ceiling joists and or batterns.
I would not have thought you would have much of a problem drilling fixing holes through the plaster ceiling and any flaking around the hole could be touched up with Gyprock topping cement or Spakle. If you are attaching light fittings to the sheet I suggest you reinforce above the sheet with timber batterns.
By the way if the sheets are sagging badly watch out as over time they can calapse and full down particular if there is any weight on the sheets.
Check out the renovation forum for advise .
Mac

[SHIPPERS]

Echelon,

In my years of dealing with this material, ( Called many things by many different people ) Plasterglass, fibro though not cement sheet.
There really is no crisp clean way to cut this stuff without producing edges that have hair protruding. I have cut holes using hole cutters in a cordless drill, produces alot of dust.
The benefit is you get a hole the size you want that is also within the margins needed for downlight surrounds.. Unless the old plaster is extremely brittle you should not need to patch.

Shippers