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Camper Vans Part 6: Adding Windows

Posted by Greg Keith on

Sprinter van before adding rear windows

Want to build a camper van? In this series of Campervan HQ blog posts, we'll discuss doing just that. For a more detailed discussion, see my 378-page Sprinter RV Conversion Sourcebook.

Now that you've started your build by getting the interior of the van ready for your camper van conversion, it's an excellent time to add opening for windows, skylights and vents. Terrifying though it is to cut into the metal of your expensive new van with a saw, it's necessary, and it's really not that hard to add windows if you take some care while planning and performing the cuts.


Before you begin: Do not attempt to install van windows in an unheated space where nighttime temperatures will fall near or below freezing. Either install the windows in a heated space or wait until temperatures are warm enough to be suitable for the adhesive to cure properly.

There are several tools you might use to cut the openings (before using any of these tools, make sure you're wearing gloves, eye protection and hearing protection - they all produce a surprising amount of tiny metal shavings and lots of noise):

  • Jigsaw - A jigsaw with a many-toothed metal blade (rather than a coarser-toothed wood blade) is a good tool to use for cutting the openings. However, because of the oscillating motion of the blade, it tends to hammer against the metal (set to to "smooth" if your jigsaw has that option), so you need to take special care to use plenty of tape all around your cut lines, both on the exterior (to prevent paint scratching) and on the interior (to prevent lots of small, sharp metal flakes from being scattered everywhere).
  • Air Nibblers - Air nibblers are another excellent tool for cutting window openings. They can typically easily cut up to 14-gauge steel, produce a lot less metal trimmings, and vibrate less than a jigsaw. However, they can be a little cumbersome to handle, depending on what you're cutting.
  • Center-Blade Shear - Makita, DeWalt and Milwaukee all make center-blade shears which work well for cutting openings for windows and vents on your camper van. This will produce less vibration than a jigsaw, produces a very accurate cut if used carefully, though just as many trimmings.
    1. To start the cuts for your openings, if the exact shape is not clear, you may need to first drill pilot holes or tap outlines with a punch. When you've cut the openings, make sure that you dab the edges of the cut metal with rustproofing paint. You can use a small sponge-like dab tool rather than a brush.
Masking Sprinter van rear door before cutting
    1. Depending on the type of window you're installing, you may have both an exterior seal (created with urethane adhesive) and an inner trim ring:
  • If the window is a new install in a new opening, you may just need to prime the area where the adhesive will go (for example, with CRL 3MTM 864 Primer)
  • If the window is a new install in an existing opening where a window was mounted before, ensure you clean off all of the previous urethane adhesive used with a blade, working carefully to ensure you don't cut too deeply and scratch the van's body paint.
Old urethane outline on Sprinter window opening
      1. Now, unscrew the inner trim ring from the window, using either hand tools or very carefully with power tools, making sure not to strip the trim ring screws.
      2. Fit the window in place in the opening to check for correct fit. If all looks right, pop the window out of the opening again.
      3. If needed, prime the area where the adhesive will go, then lay a thick bead of urethane adhesive all the way around the window opening (CRL Windo-Weld Urethane Adhesive is a good choice for window glue).
Almost finished cutting window opening in Sprinter van rear door
      1. Carefully position the van window in the opening, then press it into place against the adhesive. Make sure all window edges are at a uniform height from the sheet metal of the van body.
Freshly cut window opening for Mercedes Sprinter van rear door window
      1. Once the van window is in the exact position where you want it, mount the inner trim ring back onto the inside of the window and secure it in place with the trim ring screws. On many windows, the screws on the inner trim ring are easy to strip - either hand-tighten these screws, or use power tools for tightening them very carefully.  Do not tighten each screw all the way the first time - rather, tighten each screw partially, moving clockwise, and when you have tightened all the screws initially, do a second round of tightening. Again, check the position of the window edges, you can still adjust the positioning a little if necessary.
      2. If all is good, let the adhesive cure and don't move the van until 4-48 hours have passed. The curing time will differ hugely depending on the temperature and humidity where you are performing the install.
Finished rear Sprinter van windows






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