Tips for protecting delicate miters that nobody talks about

I tried a variation of this last week while I was wrapping some columns with that pre-finished WindsorONE. I didn't have my 2P-10 adhesive handy, so I was relying on yellow glue and a few pins. Using the air hose as a third hand is actualy pretty clever, especally when the drywall is flared out and making the miter want to open up at the face. I found that my old rubber hose works a bit better than the hybrid ones for this becasue it has a bit more grip against the back of the trim. I was working with 5-1/4 inch base and just looped a section of my Bostitch hose behind the long run. It provided just enought tension to keep the joint tight while I adjusted the miter saw for the return. One thing I noticed is you have to be careful with how much pressure you apply. If you have a relly soft wood or thin MDF, you can actually bow the piece if the hose is too thick. I started keeping a few short lengths of 1/2-inch PEX in my bag for the same reason. It has that same springy quality but it is a bit more predictable than a coiled-up hose. It definitly beats trying to hold it with your chin while you reach for the pinner.

Haha, man, been there. I've definitly pinned a hose behind a piece of crown before when I wasn't paying attention. Total nightmare. Nowadays I just keep a handful of those cheap spring clamps or even some blue tape if I'm desperate. But honestly, if you're stuck solo, those miter clamps—the ones that look like little metal rings—are a lifesaver for pre-painted stuff. Saves your hoses for the actual tools and won't leave a mark if you're careful.

While the utility of a pneumatic hose as a makeshift tensioner is undeniable in a pinch, I find that the specific durometer of the rubber significantly dictates the resultant pressure exerted against the rear face of the casing, particularly when one is contending with the inevitable irregularities of a non-planar drywall surface that has been over-mudded at the corner bead. I typically prefer utilizing off-cuts of closed-cell backer rod for this application becasue the backer rod offers a consistent, compressible resistance that accommodates the varying depths of the void created by the trim's profile without risking a structural deflection of the miter face or an accidental pneumatic discharge if a fitting is bumped.

Quick update — after seeing the comment about those spring clamps, I actually tried using them alongside the hose trick on a flared drywall job today. It relly helped with the pressure control. For the guy mentioning rubber durometer, do you find the hybrid hoses or the standard rubber ones give a better 'bounce' for holding that tension?