What would be the best method to get white emulsion off rough split sandstone and the mortar (cement not lime) joints? The wanted end result being visible clean stone and mortar. There is only about 1 sq metre to do, indoors.
Thinking of a steam cleaner to soften the paint but how to remove the softened paint totally from the gain of the stone? Indoors, so sloshing lots of water about isn't on.
Mechanical with a needle gun?
Any other ideas?
If it's rough stone, then I'd use a wire brush, as the resulting rough surface won't be much different to the original. I cleaned some slate slab that way last week on a decorative fireplace surround that had been cemented into place. Came up nicely.
Needle gun yes, if you want to obliterate the sandstone completely. I'd start with lots of soaking to soften the paint, preferably with a dot of detergent, then a scrubbing brush to remove what it can.
NT
+1
And a manual brush at that, I suspect that a cup or disk brush on an angle grinder may leave unsightly swirls.
I lived in a sandstone building many years ago. A finger nail was enough to cause plenty of surface damage.
NT
It depends on the sandstone. It can be soft as s*it or really hard. The hardest sandstone is in the North of England
I used a circular metal sanding disk on some window sills that we had. You have to be very careful not to go into the stone but it gives a nice smooth finish.
Jonathan
I use something called Enviromose for stripping emulsion (it's one of these benzyl alcohol strippers). It's still a pain to scrape off, but it softens it up very nicely. If I want to remove all traces, I'll follow it up with acetone.
Luxury! We 'ad it hard....
Yes but fair comment, my point was not to dive in with a power tool until it is clear what's needed to do the job. The measure twice, cut once philosophy that we have all learned about the hard way!
exactly. I'd be hesistant to suggest damaging the surface or using something that may well do so without knowing it would be fine.
NT
I think most of us have learnt that you can measure twice, cut once & still screw it up. But it does help the odds :)
NT
Wish to retain the rough split (across the bedding planes) nature of the stones.
SWMBO'd is rather "sensitive" to organic solvents. Not a chance of washing the wall down with acetone. B-)
There are two types kicking about around here, both are fairly hard. One is moderately coarse and when exposed to the weather for a bit will split very easyly (aka fall apart) along a bedding plane. The other is much finer, harder and of "engineeering" grade.
This is the fine hard stuff, has nice colour variation.
Not sure where my manual wire brush has gone... and yes I think a powered brush is likely to be a bit too vicious but a manual brush hard work!
Needle gun ide came from a friend over in the next valley who used one to clean the exterior walls of his place. So I think the stone will withstand it, I'd go gently to start with anyway.
Well, I was thinking more of rubbing, but the resulting smell is pretty much the same :-) But I find that no matter what you do, you're going to get into trouble for it.
I'd try a test patch with caustic soda and a scrubbing brush.
That's a good way of removing heavy scale from steel ...
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