sanding the drywall compound
 

I've hung, taped, and mudded some drywall and now I'm on the final
sanding, I hope. I have questions about what to look for.

In the old days the edges of the unfinished drywall curved gently inwards.
When plastering, you had to build up the indented area. But the
drywall I got from Rona (think Home Depot with a Quebec accent) has a
sharply recessed edge, forming a shallow flat-bottomed valley for the
tape. Does this type of drywall require a different technique?

Anyway, I did the old, slightly angled buildup of compound in three
widening layers, and now I have a slight, gradual bulge between the
panels, about 14 inches across. I can't see it, but I can feel it when I
pass my hand across the joint. Is there supposed to be a very slight
bulge? How slight, and over what width (say, 1/16 inch over 14 inches?)

Or for this kind of drywall, should I sand back to the valley? I believe
this would leave a narrow vertical band of plaster, flush to the drywall
surface, but I don't know that for sure.





--
"For it is only of the new one grows tired. Of the old one never tires."
-- Kierkegaard, _Repetition_

James Owens, Ottawa, Canada

On 13 Dec 2004 19:45:13 GMT, (James Owens)
wrote:


I've hung, taped, and mudded some drywall and now I'm on the final
sanding, I hope. I have questions about what to look for.

In the old days the edges of the unfinished drywall curved gently inwards.
When plastering, you had to build up the indented area. But the
drywall I got from Rona (think Home Depot with a Quebec accent) has a
sharply recessed edge, forming a shallow flat-bottomed valley for the
tape. Does this type of drywall require a different technique?

Anyway, I did the old, slightly angled buildup of compound in three
widening layers, and now I have a slight, gradual bulge between the
panels, about 14 inches across. I can't see it, but I can feel it when I
pass my hand across the joint. Is there supposed to be a very slight
bulge? How slight, and over what width (say, 1/16 inch over 14 inches?)

Or for this kind of drywall, should I sand back to the valley? I believe
this would leave a narrow vertical band of plaster, flush to the drywall
surface, but I don't know that for sure.

The seam should not be visible at all when properly muded. One trick
that works exceptionally well is to use a trouble light and head
against the wall--you'll see where attention is needed. Do this
before you apply the PVA drywall sealer/primer.

Another tip I discovered as regards dust control (sanding
drywall...nasty nasty nasty) is to get a liner for your shopvac. It
keeps the drywall dust from clogging your filter and from shooting right
out the exhaust. Keeping a clean work area when drywalling makes it so
much more bearable...and it keeps the dust out of the rest of your house.

Phisherman wrote:

On 13 Dec 2004 19:45:13 GMT, (James Owens)
wrote:


I've hung, taped, and mudded some drywall and now I'm on the final
sanding, I hope. I have questions about what to look for.

In the old days the edges of the unfinished drywall curved gently inwards.
When plastering, you had to build up the indented area. But the
drywall I got from Rona (think Home Depot with a Quebec accent) has a
sharply recessed edge, forming a shallow flat-bottomed valley for the
tape. Does this type of drywall require a different technique?

Anyway, I did the old, slightly angled buildup of compound in three
widening layers, and now I have a slight, gradual bulge between the
panels, about 14 inches across. I can't see it, but I can feel it when I
pass my hand across the joint. Is there supposed to be a very slight
bulge? How slight, and over what width (say, 1/16 inch over 14 inches?)

Or for this kind of drywall, should I sand back to the valley? I believe
this would leave a narrow vertical band of plaster, flush to the drywall
surface, but I don't know that for sure.


The seam should not be visible at all when properly muded. One trick
that works exceptionally well is to use a trouble light and head
against the wall--you'll see where attention is needed. Do this
before you apply the PVA drywall sealer/primer.