# flat box



## killerjune (Jun 18, 2011)

12-14 inch or 10-12 inch for the flat box 

thx


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## cazna (Mar 28, 2010)

8-12 for walls 10-14 on ceilings for me, Your need more than an inch of cover each side, The edges are so fine you easy sand through to edge of next box under, Then that line can show after paint. Sometimes.


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## Lovin Drywall (May 27, 2016)

I 10 ich then i 12 inch rough sand that edge and center lightly then 14 inch and on ceilings it gets checked for flatness with a 16 inch trowel and coated wider whereever it needs it because flat ceilings will look lije garbage if not checked and this happens when the 14 inch coat is still wet so theres no flashing


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## Lenny (Jan 20, 2018)

First coat over tape must be a 7” or 8” box to properly reduce crown. Most finishers I see today think they need to start wide which is the wrong concept. The first fill coat cannot over fill the shoulders of the Sheetrock. Running anything larger than a 7 or 8 will produce crowned shoulders and concave center which is the absolute worse thing a taper can do. 

I prefer a 7 box than 10 and final with a 12 box, never hand knife!


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## endo_alley_revisited (Aug 9, 2016)

Lenny said:


> First coat over tape must be a 7” or 8” box to properly reduce crown. Most finishers I see today think they need to start wide which is the wrong concept. The first fill coat cannot over fill the shoulders of the Sheetrock. Running anything larger than a 7 or 8 will produce crowned shoulders and concave center which is the absolute worse thing a taper can do.
> 
> I prefer a 7 box than 10 and final with a 12 box, never hand knife!


A 10" box works fine for fill coat. If you adjust the box properly and constantly check how accurate you are filling the bands, they should dry absolutely flat to the wall. If you are overfilling your bands, then you are simply not paying proper attention to your work. If you keep the blades and shoes properly adjusted there should be no edging to worry about later. A 10" box allows you to fill coat the butt joints while you are fill coating the bands. A 7" or 8" box is useless for coating butt joints.


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## Mur-Wall (Mar 18, 2018)

*Flat box*

Buy a 10 or a 12 and skim with a 14 trowel tight.
Builders in Quebec prefer a hand finish.


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