Bus Build: Installing RV Windows for our Bus Conversion – S03E37

After a long period of struggles getting our window support frames the correct size, we had finally reached the time to cut holes in our walls to install our RV Windows.

As first time builders, we have learned to approach the first day of a new project as the learning day.  Once we get a feel for it, we tend to improve and refine our methods. As nervous as we were about this window install, it went really well.

Before we had installed our support frames, we had marked off the perimeter of the window frame on the wall panel so we would know exactly where to cut out our hole.  First, we used a 6” Hole saw to cut out the corners of the window. Then we used reciprocating saw with a 6” metal blade to cut the straight lines.

The straight lines were definitely more challenging to cut.  The vibration of the saw causes the sheet metal panels to vibrate like crazy and it can be very challenging to stabilize yourself as you cut.  The last side being the hardest to cut as you have the large piece of sheet metal that is barely attached to anything wobbling around.

The other challenge was to keep the blade lined up perpendicular to the sheet metal. If they weren’t in that perfect 90 degree angle with the blade, then they would either end up cutting into the support frame or cutting the hole too small and away from the frame.

All that said, we had decided it was better to cut the hole too small as you can always make it bigger after the fact.  The other way round would be worse.

When we needed to tidy up a cut, Don would either clamp the sheet metal down to the frame, to minimize the vibrating sheet metal, or use the angle grinder to shave off smaller amounts and make a clean straight line.

Once we were satisfied with the cut and the window would fit in nice and snug, we applied Sikaflex 252 onto the lip of the window frame and then screwed the window into the support frames and bus beams with 1” metal to metal screws.

We originally thought we were going to use rivets, but were concerned the length of our rivets would not clear the window frame, 16 gauge sheet metal and the support frames.  The screws worked out great and we had a nice bead of sealant around the perimeter on the outside and inside of the window so we felt very confident that this window was well sealed up.

With the first window install going so well, we moved on to the second window only to find that the hole saw blade was already dull and we could not get it to cut the sheet metal. Luckily Don had bought a variety of sizes as we were unsure which size would work best.  We were able to get by with using a 4” hole saw.  Now that he knew what to expect, the straight line cuts went much smoother and the second window went in without trouble. 

Now we just needed to decide if we were really going to go through one hole saw blade per window, or if investing in a more expensive brand would mean it would last longer.


Up Next
We install the rest of our windows. While the installs continued to go smoothly,  we ran into an unexpected problem.

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Sikaflex 252
The original elastic bonding adhesive, Sikaflex-252 offers great adhesive strength coupled with elasticity. This combination bonds and seals at the same time, offers excellent gap filling capabilities and compensates for loose tolerances in the building process. Strong enough to hold sharply reduce or even completely eliminate traditional fastening systems such as weld, rivets, screw and bolts. Excellent Green Strength means reduced clamping time. Bonds to a wide variety of substrates. Some surface prep is generally recommended. Sandable, paintable and NSF approved for incidental food contact. 10 oz. tube.


6” Hole Saw 
6" Hole Saw M42 with Cobalt has a cylindrical cup with serrated edges to cut a clean, symmetrical, circular hole. Bi-metal is for cutting faster and smoother and has reduced vibration due to the variable pitched teeth.


TEKS Metal to Metal Screws
These Zinc-plated steel hex-head self-tapping drill-point screws (100-Pack) provide secure metal to metal fastening and strong holding power without the need to pre-drill.


Reciprocating Saw
This CRAFTSMAN corded reciprocating saw has a powerful 7. 5 amp motor with a 1-1/8" Stroke length for speed of application. The variable speed trigger provides optimal control over a variety of materials With an impressive 3, 200 SPM. The tool-free blade release makes for quick and effortless blade changes. Cut in a variety of positions with the pivoting and adjustable shoe. The contoured over molded handle and grips make using the product comfortable.


Reciprocating Saw Blades
This bimetal demolition reciprocating blade is designed with a unique set pattern for cutting through multi-layers quickly.


By Mela & Don

Mela and Don are sharing their journey as they make conscious decisions to live a more healthy, environmentally friendly life together.

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