# Curved corner installation



## fulcrum (Sep 13, 2010)

Installation of curved corners by one of our customers


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## rhardman (Jul 7, 2009)

In my early 20's I did a 3 coat plaster (interior) column about 12 feet high with a skip trowel finish. I started with a card board tube for pouring cement for the general shape, wired it up and built it up from there. It took forever. 

What sort of composite material are you using? Is it rough so mud will attach mechanically or do you need glue? Does it need a skim coat before texture? Will it take a texture?

The columns must be 2 piece semi circles, how to you attach and finish them? Screws? Tape and finish?


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## silverstilts (Oct 15, 2008)

I have done them both ways the columns that were poured concrete in sauna tubes stapled wire mesh around it and finished with plaster, finished concrete pillars after the tubes were removed there I just skimmed out, also in the late 80's I was doing a mall remodel where they had the composite 1/2 circles. They sat on a base, stacked 2 high and had a top, all of which were in half sections. They had clips on the inside which were fastened to with screws from the outside & glue on the inside. It was a real pain because when they were put together none of the screws would recess. The Framers did not really get everything lined up perfect so it made it very difficult to finish especially where the second section sat on top of the first. I was to use taping mud and perfatape to tape and finish. There were a total of 16 of these over 20 ft high. They were a real pain to do but after 30 years they are still there and holding up just fine. I did some columns in a bank about a year ago same composite but small diameter 12" they were even tougher because of being so small in diameter.


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## fulcrum (Sep 13, 2010)

*Curves*

Actually the curves were originally made to produce 90 degree corners for a local architect. Then we added the 180 degree bullnose sections for finishing wall ends. We really weren't thinking columns at the time. The columns were produced by our customer using four 90 degree sections. Now I'm thinking columns - two 180 sections would be a lot less work for everybody.
So if we made column 'kits' what size would you want to see?
The surface is drywall paper - When we first started to do this we tried dozens of different surfaces, both to ensure a good bond with mud and to have a finish that was compatible with the standard drywall beside the curves. After many abortive attempts we finally figured out that the right answer was to use the same paper that is used on standard drywall (DUUUH)


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## rhardman (Jul 7, 2009)

I think the diameter of the column I did was around 20 inches but Silver could offer a more experienced suggestion.

One thing I would definitely do is recess those seams and then have a rounded knife made to conform to 1/4 of the circumference of the column (so it's an easy "up and down" finishing process). If you rely on straight knives, they will round the seam horizontally and it will get wavy...and take too long to finish. Any metal shop could form the "knife" for you. It would cost almost nothing. Some long strips of sandpaper (24 inches or so) would be nice so they could sand it all down like shining a shoe. _That would be a great kit._ 

My $0.02 :thumbsup:


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## fulcrum (Sep 13, 2010)

*Curves & columns*

Thanks for the advice. On our 90 degree corners we offer the option of tapered edges to match the taper on drywall long edge. The corners have a 2 1/4" straight section coming off the curve to make finishing easier but there is no reason we couldn't put the same taper on the edges of a 180 degree section.
I like the idea of putting the curved knife & 'shoe-shine sandpaper' in to make it a complete kit. 
Just need to figure out a couple of diameters that folks would want & we'll get right on it:yes:


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## silverstilts (Oct 15, 2008)

rhardman said:


> I think the diameter of the column I did was around 20 inches but Silver could offer a more experienced suggestion.
> 
> One thing I would definitely do is recess those seams and then have a rounded knife made to conform to 1/4 of the circumference of the column (so it's an easy "up and down" finishing process). If you rely on straight knives, they will round the seam horizontally and it will get wavy...and take too long to finish. Any metal shop could form the "knife" for you. It would cost almost nothing. Some long strips of sandpaper (24 inches or so) would be nice so they could sand it all down like shining a shoe. _That would be a great kit._
> 
> My $0.02 :thumbsup:


The 180 degree columns or 1/2 circles that you put together are somewhat recessed but not much, however if they are stacked you still have that to contend with because they are not recessed on the ends. I bent a 8" & 10" knife to finish the verticals but still ended up rounding them out even more by troweling horizontal so they wouldn't look egg shaped or oblong with bulges. No matter how you do it it is very time consuming to make them look perfect. I did as you mentioned with sand paper buying a roll and using it to buff around the column. Then I sponged it with a damp sponge (to eliminate any sanding marks) because the composite is smooth as glass.


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## fulcrum (Sep 13, 2010)

*Curves & Columns*

Agree with the stacking comment - for our normal corners we produce 8' & 10' lengths. This eliminates the issue of stacking joints nearly all the time. No reason we couldn't make them longer except that then shipping starts to be a pain.


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## fulcrum (Sep 13, 2010)

*Easier way to make columns*

OK, what if we made columns like this
We produce two half circles with flats on the end like in pic 1
The flats allow the two half circles to be screwed onto strips in the center of the column - pic 2 (will vary according to what's inside and what framing you use)
Once it's all screwed in place then the flats give you a recess to tape and mud over like in pic 3 - the recess would be pretty much the same size as when the taper on two long edges of drywall meet. Make a curved knife with the same radius as the column to finish.


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## rhardman (Jul 7, 2009)

Looks good. My first thought was an "over and under" seam where one side sits over the top of other side (with the overall joint still recessed) so you would only need a single row of screws down one side of the seam. Might add too much to the mfg. costs and on the jobsite, there would probably be breaking prolems unless your material is very sturdy.

I would suggest that your knife be wide enough (and a thick enough gauge) to track evenly down the seam, Too narrow and it will wave right and left. Silver's right (of course) that they will need some horizontal knife work, but if you make a good verticle knife, most of the issue would be taken care of initially.

Talk to DeAnne at Advance Equipment about the knife, their shop can create anything and inexpensively. Their Cool Grip handle would add quality to your kit at a minimal cost.

Nicely done! :thumbsup:


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## silverstilts (Oct 15, 2008)

I have a really good design but unless I get some profit off of them it will be a secret..:thumbup: actually a couple dang I should have been an inventor.


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## fulcrum (Sep 13, 2010)

*Column Kits*

Following our discussion we prototyped a column. What do you think?
We just fastened them to a couple of strips of 3/4" plywood - obviously they would be going on to wood or metal studs. The flats at the seam will make it easy to finish. This one's just taped - waiting for a curved knife before finishing.


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## silverstilts (Oct 15, 2008)

:thumbsup: Looks pretty good..


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## Capt-sheetrock (Dec 11, 2009)

Yeah, what he said ^^^^^:thumbup:


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## fulcrum (Sep 13, 2010)

*Column Covers*

Here's some pics of our columns installed by Thorne Assocs of Chicago.
Altogether they put in 60 of these in remodelling a big commercial building


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