Question about the tape sticker on the seams
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If I understand the question correctly, paper drywall tape is just embedded in a thin coat of joint compound. So yes, gypsum. I'd imagine there are other ways? But that is the industry standard - everyplace I've ever been, anyway.
Can you give a link or a photo to it? The fact is that when we put the tape in the seam in Russia, and close it with plaster putty, it subsequently dries and swells. I don't have a photo of what it looks like right now, I'll try to simulate the situation at work and show how it looks
Paper joint tape in North America is generally adhered and embedded with drying type joint compounds which are primarily limestone (calcium carbonate) w/a PVA binder, not gypsum, but can also be be adhered and embedded with gypsum setting-type compounds.
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YouTube is your friend:
Good thing I'm not a drywall guy, then. I always thought your run of the mill drying compounds were gypsum based.
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I do not do a lot of drywall, FYI. And I can't comment on that particular product.
But nothing should swell when it dries. Bulging often comes from leaving too much mud under the tape - meaning you need more pressure on the knife to squeeze out the excess.
Gypsum setting type compounds expand during curing which can sometimes result in joints becoming visibly proud which initially weren’t.
Edit:
I might note that gypsum setting type compounds can either shrink or expand depending on the amount of calcium sulfate hemihydrate in the formulation, being that the calcium sulfate dihydrate expands during the setting process via forming crystals which are less dense than the actual slurry.
Edit:
I might note that gypsum setting type compounds can either shrink or expand depending on the amount of calcium sulfate hemihydrate in the formulation, being that the calcium sulfate dihydrate expands during the setting process via forming crystals which are less dense than the actual slurry.
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I don't want to open a can of worms, and this is a hotly debated issue, but do you guys like mesh or paper tape? I've only ever learned to use mesh well to be honest. But, I've also torn out a decent amount of failed mesh tape over the years, too, so I do understand the downsides of it. The debate I've heard is that mesh is fine as long as you use a setting joint compound, but it will almost always fail and crack/etc eventually with normal drying premix joint compound, so whenever I've set mesh tape I've always done it with USG Easysand or Durabond hot mud(or in the case of tile backerboards, thinset) at least for the first pass, but because even Easysand doesn't sand that well I do second and third coats with premix.
I used the paper once, and set it with some hot mud that was setting off too quick for me to work with and got some blistering, and generally found it awkward to work with (was trying to make a ceiling corner) so I really don't want to use paper tape, but I've always heard it was stronger overall compared to mesh, and my bet is that mesh with setting compound still will end up stronger than premix plus paper?
I used the paper once, and set it with some hot mud that was setting off too quick for me to work with and got some blistering, and generally found it awkward to work with (was trying to make a ceiling corner) so I really don't want to use paper tape, but I've always heard it was stronger overall compared to mesh, and my bet is that mesh with setting compound still will end up stronger than premix plus paper?
What is the essence of our paper tape sticker method? 1. Apply a layer of UNIFLOTT putty. 2. The next day, after soaking the paper tape in water (1-2 minutes), we glue it to the PVA glue (not an expert in American chemistry, the glue that glues dense cardboard). 3. The next day, we go through another layer of UNIFLOTT putty. All. Then, at will, we either cover all the SHEETOCK, or we drill the seams and paint. That's something like that
Why would you be soaking the paper tapes in water? I always apply dry over drywall compound.I like paper tapes best, BTW.
I do not know an analogue of PVA glue in the USA, we glue thick cardboard with it
I like paper tapes best, BTW.
Looks like the compound is setting off too quickly…an old-school plastering trick is to add some cream of tartar which will retard the setting off time and allow the vinyl acetate in the compound to wet & bond better to the paper. You can also add additional vinyl acetate to the mix. I’ve also soaked paper joint tape in water when working with faster setting type compounds. It’s also best not to coat over the tape with a heavy layer until the mud and tape is set…just a super thin layer over the tape immediately after embedding.
Edit: Tough to tell by your pics, but if I incorrectly assumed the paper was lifting off and not adhering to the compound, nix the above suggestions.
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PVA Glue isn't known by PVA in USA, but usually it's sold as wood glue.
Also, if you buy Concrete or Plaster Bonding Agent, it's usually just PVA glue thinned down.
He adds glue to his compound sometimes, and does a lot of drywall repair videos if you're interested. Some people do dislike/critique him, but nonetheless he's showing his work.
To me something I thought about with my experience with paper tape doing something like that (I usually use mesh but used paper for a corner...) when using setting compound that had almost set off, if you're using setting compound it could just be too close to setting off and can't bond anymore. If you're using premixed drying compound (ie, from the bucket wet, not mixed as powder) it could just be that it needs some more water to help the tape soak up some water to bond. Or you could add more PVA glue to the mud directly, but even plain water and a thinner mud could potentially fix the problem. From the look of those joints, it looks like the mud is too thick to cleanly wipe it down with your knife/trowel, you should not have mud be as "proud" (ie, sticking out/upright) from the joints like that. However, you need a thicker coat for prefilling your joints, or a setting compound, but on your subsequent coats you could definitely thin it.
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