how can I drywall a tight radius?

[phil]

I made some crude sleds to try to smooth out the curves.

[Lily left the valley]

*Is still following this progress even though she has nothing of value to add*

[phil]

The pics also show what an ugly mess they made of my fireplace. I'm hoping to break all the tile back off and still show the brick. i got the ones right near the wall off. What were they thinking !

I just picked a cookie tin for the radius , I guess it is about 9 inches.
I cut two pieces of plywood on my bandsaw with the curve in about the middle and flowing into the flat walls on either side. the inside and outside are the same angle so I could use the other piece for the other one. the boxes aren't' quite concentric but that won't matter. I just wanted to get the rough shape and I can probably layer some mud and tape. this was the only part of the room where I had rounded plaster so I thought I'd try to maintain that little feature. all the other corners are square and straightforward.

the aluminum sheet I used was a bit light so I stuck some rags inside and dribbled some epoxy on them to make them a little less flexible. I'm not sure if they will stand up but I will try and see if this helps get the general shape right. I'm not sure if they will just follow the contour or I may need to nail a board to guide one side so it can run in a fairly straight line from floor to ceiling. I'll post pics of progress once I make some.
phil

[phil]

I've been moving forward slowly
I clipped back any drywall that was in the way of my form.
then filled the void between sheets. I use a hybrid blend of mud , with some carpenters glue and some plaster. the glue adds strength, the plaster makes it set up fast. without that the mud will drip away from the wall if you put any considerable thickness on.

First I filled the major gap. then I filled that to flush and taped it.
then I started my fill coats to develop the profile. here it is after the first coat.. I'm not too concerned about rough finish for now. Once I have the general shape right I will worry about finishing. Its best this stuff has some time to cure and shrink since it's quite thick in places so I'm roughing out the shape first. once I near finishing I can omit the plaster and glue in case I want to do any sanding.
It's coming. I have to work pretty fast to get the stuff on and the tools clean when I add plaster it sets pretty fast. 1/2 hr or so of working time.

[Lily left the valley]

I don't know why, but seeing your work light made me smile.

Is the one by there as a guide for your shaping form?

[Mick_VT]

I don't know why, but seeing your work light made me smile.

Me too, I nearly commented on it earlier

[phil]

yea I just temporarily attached a guide to slide the thing against. for the two inside corners I used a piece of that metal corner bead. without it the tool moves all over the place and the idea is to use the tool to help things stay concentric. I could easily round the corner with plaster but to make it concentric from floor to ceiling and to keep the radius even is harder than it first appears. at first my tool wants to stick to the large glob of plaster but as I get towards the shape being right I will use taping mud , which I can sand and thinner layers wont' be such an issue. If I let the plaster/mud sort of half harden and then get the tool wet I can smooth it out a bit without it getting stuck there but at first it's a bit messy. once the tool touches plaster in three places, the middle and two edges it starts to fit the hollow more perfectly. once I have the shape right I can remove the guides and continue on skimcoating everything.

to give an idea of the proportions that seem to work ok. I start with half a cap full of water ( see the yellow cap) to that I add enough plaster to get full saturation, then I add about 2 tablespoons of carpenters glue and a couple of knife loads of mud ( see pic) mix it really well. the plaster changes the properties a lot. it sort of solidifies before it hardens similar to plaster even though it's a small proportion. the glue just makes it hard so it's tougher. This gives me about 20 minutes working time so if I get it on the wall and my tools clean then after it's been on the wall about 1/2 hr I can still work with the shape but it's sort of half hard and slippery.. this is sounding like a cheap porno lol.. Anyway... ahem.. when it gets to that state I can wet my tool and slide it up and down without globs of mud sticking to it. if that makes any sense.

the special drywall looks funny with the brown edges. Its called quietrock , here is their website
https://www.quietrock.com/

I also used this "cetrtainteed silent FX"
https://www.google.ca/url?sa=t&rct=j&q= ... UQ&cad=rja

Here is the green glue which I used between sheets of drywall that I doubled ( on the inside walls)
http://www.greengluecompany.com/



the product on the wall is called quietrock

yea my worklight just junk , I have a few different ones going that I didn't' care so much about. Shades are for sissies

[phil]

Bit further along. I stuck some sandpaper to my form and then skimcoated

[Lily left the valley]

I envy your bay. I always wanted one. The Baker Bungalow doesn't have one, and I just don't think it'd be right to add one.

It seems to be coming along well. Have you hit any difficulties in the implementation of the process?

[phil]

It's just a long job. I've been giving it ample time to dry between coats. Maybe for someone that spreads plaster for a living they might have enough technique to get it pretty even but I've tried this on the past with drywall and found it took many coats before I was happy and if you sand the inside curves just a little too much it's hard to build it evenly. The tool helps as a tool to apply it and as a backer for the sandpaper to keep the curve consistent.
It's a lot of work. There may be a source for corner bead with various radius curves. If one is available it would be a time saver.
I did another coat and applied that after some sanding and it's looking almost perfect now but it's surprisingly fussy work.
I'm almost done with the taping and corner bead so I still have to skim coat all the walls and ceiling. It's coming but I'm looking forward to putting the drywall tools away. At least having a few days off for Christmas is giving me a jump on things.