dhaig Posted September 22, 2022 Share Posted September 22, 2022 I recently undertook fabrication of a set of louvered ventilators for the three side windows of our LEII, following the excellent design posted by @csevel. I want to share some lessons learned for others who may want to fabricate a set for their Ollies. The window vent consists of two main parts, a purchased louver ventilator and a custom made acrylic mounting plate, shaped to fit a partial window opening, into which the louver is mounted. I executed the fabrication a bit differently from @csevel. Since I wanted to produce a set of three louvered ventilators, I made a template using 1/4" medium density fiberboard (MDF) for the mounting plate. I, too, used one of the window screens as a guide for the edge contours of the template to match the sliding windows and frames. The final mounting plate template is 16-3/8" tall and 6-5/8" wide at the midpoint. The rectangular opening is 3-½" wide x 12-1/16" tall. After tracing the screen contour for the vertical edges of the template, I clamped the window screen to the MDF and used the screen as a template for my router to follow, to cut the shape. Cutting external edges of MDF template I had purchased the White Water Plastic 5-Slotted Louvered Ventilators from Amazon, although they are now shown as unavailable. I recommend searching for other sources, such as West Marine. It appears the same product is sold under multiple brand names. I used one of the purchased louvered ventilators to determine the size of the rectangular opening required in my MDF template and centered the outline for the opening. Note the rear of the louvered ventilator is tapered, so the opening needs to be large enough to accept the entire rear projection through the MDF mounting plate template, with the flange of the louver meeting the mounting plate. The rear projection also has two reinforcing ribs on each of the long sides and one each on top and bottom, which require notching the sides of the opening for clearance. To cut out the rectangular opening in the MDF template, I first tried to use my router, but found it very difficult to control the router and tried various guides, unsuccessfully. Achieving accurate cuts freehand with the router was also very difficult. In retrospect, using a router table to cut the opening rectangle would not be too difficult if done with straight outer edges, prior to cutting the outer edge curves. Frustrated by my lack of skill with the router, I switched to using a scroll saw to cut the rectangular opening in the mounting plate. This requires drilling a starter hole inside the rectangle, then inserting the scroll saw blade. The scroll saw proved very useful in making accurate cuts to make the MDF template. I tried to cut the rectangular opening as accurately as possible, which was relatively easy to do. If a scroll saw is not available, I recommend using a high quality hand held jigsaw as another option. After cutting the outer curved edges and rectangular opening in the template, I sanded the edges smooth and inserted one of the louvers into the template to test for fit. I used blue painter's tape to hold the louver in the template while testing the fit in the window opening. Test fitting the MDF template and louver I inserted the MDF template and louver into the window opening to verify the curved side abutting the window fit closely, with as small a gap as possible. I made slight adjustments to the template with a belt sander mounted upside down on a work table. I also verified the template could be inserted into the window track while inside the trailer, without requiring removal of the window shades or screen. While inside the trailer, position the mounting plate and louver through the window opening and tilt the top topward the upper screen track. The mounting plate is first inserted into the upper track of the screen, then placing the bottom of the plate into the lower window track, then moving the top of the mounting plate from the screen track into the window track. Sounds confusing, but works easily after a few tries. When the mounting plate template is inserted into the window track and pressed against the window edge, there is space above and below the plate and the window track. Once the mounting plate template is in the window track, it should be lifted slightly as the window is moved to shut against the plate. This should result in the curved edges of the mounting plate mating closely with the curved outer edge of the window, top and bottom. Closing the window against the mounting plate secures it in place, seated against the vertical edge of the track and the edge of the window. After several trial fittings and minor adjustments to the template, I was satisfied the template mounting plate would fit snugly to minimize the chance of water leaking in at the junction with the window. I did all of the trial fittings on the street side window above the bed. Only then did I test the template in the other two similar windows, which is when noticed the edges of the three windows are not uniform. The street side aft window had some black sealant projecting from between the two panes of glass. On the other windows, the sealant material does not extend from the edge of the two panes of glass. When fitted against the outer pane of glass in each of the three windows, the mounting plate template proved to be a snug fit, when carefully inserted. As a final test of the fitment of the mounting plate template, I tested to verify each of the window screens would close. Initially, they would not. The rear of the louver ventilator projects one inch from the rear of the front flange, causing interference with the screen and preventing its closure. Since the louvers do not have any screen built in to prevent entry of insects, operation of the standard window screens is essential. @csevel indicated her screens would close with the louver in place. I suspect my louvers and hers may not be exactly the same depth. Or, since our trailers are five model years apart, there may be differences in our windows. My solution to resolve the screen interference issue was to reduce the rear projection of the louver ventilator 3/8" by: Removing 1/8" off the rear projection of the louver ventilators using a table saw; Fabricating spacers from 1/4" thick acrylic sheet to insert between the mounting plate and the front flange of the louver ventilators. Removal of 1/8" of depth from louver ventilator 1/4" Spacers dry fitted to rear of front flange of louvered ventilators In the photo above, all three louvered ventilators have had their depth reduced by 1/8" and 1/4" spacers dry fitted prior to cementing in place. The spacers are 9/16" wide, surrounding the rear projection of the louver ventilators. (The protective paper coating is still in place on the spacers in the photo.) Side view of spacers bonded to rear of the flange of a louver ventilator The spacers were bonded to the rear of the flange using acrylic cement applied using a small application bottle with a needle applicator (from small box in photo below). After dry fitting, I cemented the spacers to the louvers, starting with the top and bottom, while the side spacers were in place loose, without cement. After the top and bottom spacers were firmly cemented, I cemented the side pieces. I found using spring clamps to hold the spacer pieces in place worked well while the cement set. I test fitted the louver ventilators inserted into the template mounting plate to verify the interference problem with the screen was resolved. The screens cleared with very little space to spare. Fabrication of Mounting Plates Having completed the mounting plate template, I next made a copy of the template, also from 1/4" MDF, as a backup in the event I damaged the master template. Making a copy also served as a dry run for routing the acrylic sheet. Using double sided woodworking tape. I fastened the template copy to a sheet of 1/8" black acrylic sheet, in preparation for cutting the first mounting plate. (Use the woodworking tape sparingly- 6 pieces 1 inch in length is sufficient. Otherwise, it can be difficult to remove, with adhesive left behind.) MDF template on acrylic for routing From experimentation cutting scrap acrylic sheet with the router, I had found the router bit would quickly melt the acrylic sheet. To avoid melting the acrylic sheet, I removed the excess acrylic material from around the template and the rectangular cutout, leaving only 1/16" to 1/8" of material to be removed by the router bit. I was then able to obtain smooth edges following the template for final trimming with the router. With the template attached by woodworkers tape to the 1/8" acrylic sheet, I used the scroll saw to cut the acrylic, keeping the saw kerf 1/16" to 1/8" away from the template. This freed the first piece of acrylic from the larger sheet and removed excess acrylic material from around the template. I mounted my router, with a 1/2" flush trimming bit, to a small router table. I then proceeded to trim the remaining acrylic sheet from around the template, both the outside edges and the rectangular cutout. After routing the first mounting plate, I repeated the same steps two more times, attaching the template to the acrylic sheet, trimming away the excess material using the scroll saw, then making the finish trimming using the router mounting in the table. When I had routed all three mounting plates, I lightly sanded the edges of the acrylic mounting plates to remove the sharp edges. Assembly of louver ventilators to mounting plates The louver ventilators with spacers attached are dry fitted to the mounting plates. Once satisfactory fit is verified, the parts are ready to be cemented using the acrylic cement. NOTE: The louver ventilators for the Street side windows are oriented opposite those for use on the Curb side. Position the mounting plates properly to abut the windows and insert the louver ventilators with their louvers on the outside and the louver openings facing down. I found it easiest to start by cementing one of the short ends of the louver ventilators to the mounting plate, using a couple of spring clamps to hold the parts together until the cement formed a firm bond, which takes about 5 minutes. Proceed to cement successive sides of the louver ventilator to the mounting plate, one side at a time, applying spring clamps until the cement cures. Use the needle applicator to apply cement at the intersections of the parts. Allow the cemented parts to cure overnight. The acrylic cement is very effective at welding the acrylic parts together, producing a very rigid assembly. Completed set of louvered ventilators and mounting plates After assembly, I added the same rubber edge trim recommended by @csevel to the edge of the mounting plate which meets the window edge. This trim seems to conform well to close any gaps between the windows and the mounting plates. The completed units are quite rigid and nest reasonably well. I set the width at 6-5/8" for two reasons: To yield three mounting plates from a 24" x 24" sheet of acrylic To keep the mounting plates and louvers as small as possible to facilitate storage in the trailer. I made a pouch to contain the louver ventilators to make it easier to store them without concern for damage to them or to other parts of the trailer. I had leftover car headliner material, which is relatively thin, with a foam backing, to which Velcro straps readily attach. Summary This project, which I first thought rather simple, provided several challenges. I spent much more time than expected to achieve an acceptable result. Given the extended drought and high temperatures in Texas, I have not had an opportunity to test the effectiveness of the vents, nor how well they keep rain out. In a week we depart for a two and a half week trip to Colorado to photograph fall color. I expect we will encounter some test conditions in the mountains. I hope this information is useful. Please feel free to contact me with questions. Regards, Don 2 11 1 2 North Texas | 2022 LEII, Hull #990, delivered 2/17/22 | 2014 BMW X5 35d Link to comment Share on other sites More sharing options...
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!Register a new account
Already have an account? Sign in here.Sign In Now