Some of our plaster walls have cracks. It seemed counterintuitive to fix hairline cracks by making them larger, but just spackling them didn’t work. The cracks reappeared in the new paint. So, I will widen the cracks and use setting-type joint compound instead of spackle. On some DIY pages they apply plaster adhesive before filling the crack. When is this necessary?–or should I always use plaster adhesive, just to be sure? Janet
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I'm not sure what it is the
I'm not sure what it is the DIYs are calling ahesive, but I would use a bonding agent made for plaster.
This does two things. It seals the raw dry edge so that the old does not suckthe moisture out of the new too fast before it cures. When that happens, you are left with flaky powder right at the point where you need a good bond the most, in that crack.
The other thing t does, is leave a slightly tacky surface for top coats to stick to.
There are several reasons for dragging a crack wider before repairing, that I don't have time to get into, but just do it.
Can you post some product names? Are they available at Home Despot, or do I need to go to a more serious store?
I know a very good plasterer, and he uses a product called "Plaster weld" it is rolled on large areas, and brushed in cracks that have been cleaned out. It is a reddish liquid and stays somewhat tacky.
I think you need to go to a drywall supplier to locate it, I don't recall seeing it in any Big Box or small mom and pop hrdw. store.
That's good stuff.
It stays
That's good stuff.
It stays slightly like a gummy latex to keep some flex in the joint so less likely to telegraph a hairline crack, and the pink lets you see you have things covered.
In a pinch or a small job, white PVA glue or TiteBondIII will do the job
That's good stuff.
It stays
That's good stuff.
It stays slightly like a gummy latex to keep some flex in the joint so less likely to telegraph a hairline crack, and the pink lets you see you have things covered.
In a pinch or a small job, white PVA glue or TiteBondIII will do the job
>> There are several reasons for dragging a crack wider before repairing, that I don't have time to get into<<
No need, as one of the reasons soon became obvious. I saw only the surface cracks, but the fissures were actually more extensive. The plaster beneath was crumbly, in some place all the way through to the brown layer!
I had been wondering how much to widen the crack, but this discovery answered the question. I dug just enough to remove the crumbly section, leaving a groove less than 3/8" wide.
Janet