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Seam busters (red knives-Swiss knives etc...)

6K views 6 replies 5 participants last post by  Rayn Painting 
#1 ·
Just curious as to the opinions from the commercial hangers here on "Seam Busters" or red knives as some call them. Some hangers insist that they are the only way that you can keep a seam from splitting in the future as it doesn't score sheetrock.
I have found this to be untrue, as I've done redo's on jobs 15 years later where my work looked better than theirs. That being said, some county code calls for it. Any opinions?
 
#2 ·
I have one....somewhere. I don't like them because even that little thin "shoe" that rides under the paper and over the wall will create a small hump when you try to put the seam together after busting it. I just use a snap-off blade and a straightedge to bust seams. If you know how to do them right (don't be heavy-handed and try to cut to China) it should be fine. And I have never seen a city code telling me what tools or techniques I can/can't use.
 
#3 ·
I did a Hampton Inn out by the airport in Atlanta, the contract said that, "due to county code, every seam shall be cut with a red knife." Well, I kept one in my pouch just in case and all, but I didn't use it much. But here in Co... a lot of gc's expect it. So I use it some and straight edge on the wall some. So many hangers don't know how to gauge paste or what consistency is right for what material. It "SEAMS" to me that those are the major causes of seams splitting.

Thanks for the reply pro wall guy.
 
#4 ·
a little more in depth

To go a little more in depth as to the reason some county codes call for it. The theory is that, if there is a score in the drywall, and a fire breaks out, oxgen can travel up the seam more readily than if there is no score.
This is true. I have seen videos made by contract manufacturers (Vicretex if I'm not mistaken) where they built standard hotel rooms and lit them on fire.
It was an effective sales tool and the PDCA picked it up and used it in several seminars for hangers back in the late 80's. They put video cameras in the rooms and lit the beds on fire.
One room would have all of the vinyl cut in the corners and the small wraps behind doors rolled instead of cut to the frame. That's where the open flames went. As well the seams would catch to open flame.
Over all though, type II wallcovering- non expanded vinyl would melt to the wall and not allow oxygen to be sucked through the sheetrock to fuel the fire giveing extra time for escape.

That is why the code restrictions in some areas.
 
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