Simple Jig for Cutting Fiberglass Insulation





Introduction: Simple Jig for Cutting Fiberglass Insulation

About: I've been attempting to build a house mostly by myself for the last five years... I finally more or less finished it before the bunker project and after recovering from cr...

I needed to insulate a house I've been building forever and wanted clean cuts so I didn't have any Voids in my insulation.

I made this from some scraps of wood and two hinges. It holds the insulation so it can be cut with a box cutter in a single pass.

Step 1: Assemble Materials

I had some long strips of 3/4 inch plywood ripped six inches wide, but anything handy will do. I made it about 30 inches long so it would do a 23 inch wide piece of insulation without having to worry about centering it.

I used two 3 inch door hinges and some screws and glue.

Step 2: Cut Pieces

From the six inch wide pieces of plywood I cut two lengths 28 inches long, one three inches long and one five inches long.

I ripped one of the long peices into two three inch strips and then cut out a notch so they formed a slot when rejoined.

Step 3: Assembly

I glued and screwed everything together as shown adding a spacer so when the guide was lowered it allowed about 3/4 of an inch for the insulation to compress and this seemed adequate for anything from R-11 to R-30.

Trial and error determined that it works best with the paper side down and with a good blade on a box cutter a single pass will slice through and give you crisp corners for a good fit.



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    5 Discussions

    If you have faced insulation, put the paper side down when cutting, it will cut easier.

    You're right AT. Simple is just using a straight edge but the house was so large and has ten foot ceilings that I had to make quite a few cuts so I drafted any visitors unlucky enough to cross the threshold and in a three minute lesson they could make perfect cuts for me as I did the stapling. I seem to get very few visitors by the way. I dunno why...

    Very nice. I'm not sure I agree with the "simple" part but very nice non-the-less. My idea of simple is a 2x4 and the floor or a piece of scrap plywood if the floor is already finished. :-)