The Dale Maley Family Web Site

Subtitle

Making 28 Wood Screens for Marsh Park Pavilion

In Fairbury, Illinois, since 2004, the North Park has had a screened-in pavilion.  This building is very popular for group events including family reunions.


We decided to create a similar screened-in facility at our older Marsh Park.  Once we had the existing shelter framed and sheeted in, we had to design and make 28 screens, each roughly 4x4 feet.


I studied the design and experiences we have had with the existing North Park facility.  The screens were made of 1.25 x 7/8 cedar frames with an 1/8" groove in the frame to hold the screen and spline. Over the 13 years since these frames were built, both the cedar frames and the cedar stop pieces in the windows have decayed and warped over time.  This building is on the West edge of town and experiences very high winds. The screens come loose from the frames, either through the action of wind or people pushing excessively on the screens. I decided to develop an improved design for the new Marsh Park facility.

Existing North Park screened-in pavilion

One of the City maintenance crew guys told me he added the staples over the spline, in an effort to keep the spline from rolling out of the groove when the wind or people pushed on the screens.  The cedar frame pieces are held together with 2 little trim screws for the corner joints.  The frames are screwed into the sill of the window.

Marsh Park Pavilion

Failure mode analysis of Existing North park screens

Over many years of weathering, both the cedar stop pieces and the cedar frame pieces warp...........so the stop no longer applies any force against the spline when it tries to roll out of its 1/8" groove.  When force is applied from the outside of the building to the screens, the rubber spline rolls out of its 1/8" groove, and the screen comes loose.


To stop the spline from coming out of its groove, my idea was to add another piece of cedar to the frame........which will prevent the spline from rolling out of its groove.........



Since the cedar boards are 7/8" thickness, I made the new strip 3/4" wide, and screwed it to the frame piece about every 6 inches.

I reviewed the design improvement with the City maintenance supervisor, and he liked the idea......so we decided to try it on Marsh Park.

Screen Selection

The Maintenance supervisor and myself selected the Tuffscreen material for this application.  We wanted the mesh to be big enough to let the breezes still go through the building. Tuffscreen is made by Pfifer. I ordered (2) one 100 foot rolls from our local Alexander's lumberyard....48 inches wide.

Trial & Error Design of Screen

I searched the Internet with respect to design guidelines for wood screen design...........and really found very little information. I found nothing about suggested design practices for wood frames.  It was generally pointed out that it requires trial & error to select the groove width and spline diameter........for a particular screen material. So, I made up some little test screens.

I got a selection of 4 different sizes of spline diameters from McMaster-Carr...........

I bought the wood handled spline roller tool from McMaster-Carr also.  It is much nicer than the cheap plastic handled tool sold at Lowes.

My normal saw blade for my table saw is a Freud thin kerf blade, with a thickness much less than the 1/8" wide target.  I searched through my carbide blades and found one from my dado set, but the groove was slightly larger than 1/8".  I tried it and used the largest size spline, but the spline rolled out of the groove too easily.  I then searched through my old steel blades, and found one that exactly made an 1/8" wide groove.  It had a high pitched whine when in use, so I had to wear the ear muffs to deaden the whine!  I summarized my findings in this spreadsheet.........

Here is my small test screen using the North Park original design.  The spline came out of the groove too easily on this design.........


And here is my improved design with the extra cedar board to keep the spline from rolling out........

I used the same size trim screws to make the corner joints.  I had never heard of these little square drive screws before this project, but they worked great and made a nice corner joint. I pre-drilled each screw hole, so I would not split the cedar.  My cedar frames are 1.5 inches wide (I got 2 strips from a standard 1x4 piece of 8 foot long cedar from Menards).


Lots of scrap pieces of cedar in workshop

I bought about 70 cedar boards from Menards in Bloomington and E. Peoria.  I got 1x4 by 8 footers. I ripped them into either 1.5 inch wide scrips for the stops and frame pieces.......or 3/4" wide for the extra retention pieces.  I generated a lot of scrap from my table saw in my workshop!!

I ran the table saw so much, the on-off switch quit on the 1968 sears table saw.  I will replace it with a red paddle switch type switch when I get a chance after the Marsh Park project is done.

Screen Making Set-up at Marsh Park

I used a little Frederick Taylor style work methods analysis to optimize the time required to make each screen at the park.

-used a 4x8 foot sheet of plywood on 2 sawhorses for my work surface.  Since the screens are just under 48 inches wide, this
  worked well 

-put the miter saw and stand close by the work table, to cut the cedar pieces to length

-kept required tools close-by the work area

-unrolled and cut the screen on the other end of the sheet of plywood


It still took 50 to 60 minutes to make each screen by myself.  At the end, with 2 helpers, we reduced the time to 30 minutes each.  I really saw no way to significantly reduce the time required to make each screen.


Once the cedar was ripped, each board had to be stained before it could be cut and used in the frames.  Just once coat of stain was sufficient.


Below are pictures of the screen making set-up.............

Lessons Learned on this Project

  • I could not find any design guidelines on the Internet for designing wood screen frames. I tried to improve the 13 year old design by adding an additional piece of cedar board to keep the screen spline from rolling out of its groove.

  • Cedar knots are extremely hard, with respect to the table saw.  A large knot could "pull down" the speed of my 10 inch table saw, so I had to reduce the feed rate.  

  • When you table saw the spline groove into the cedar, do a visual inspection of the whole length of the groove, and make sure there is not a shallow spot, where a cedar knot forced the wood up.  If you find a shallow spot, saw it again on the table saw.  A spline will not properly fit into the groove if the groove is sawn shallow!!  I had to use the Dremel to fix a couple of shallow spots........which led me to the 100% inspection method.  Although I pushed down on the wood with my hand as it went through the saw blade, I could not feel where the wood was lifted enough to make a shallow groove!!

  • You must do trial & error testing to get the right combination of groove width and spline diameter for a given screen material.

  • Wood screen making is a labor-intensive process with 1 hour required to make each 48x48 inch screen.

  • Once you get the spline material started in the groove to full depth, pull on the spline while you roll it in with the tool.  If you do not pull on the spline, you will have a very difficult time getting it to go to full depth!

  • Because I pulled on the spline material as I pushed it in, I actually had several 25 foot long packages of spline left over when I was done.

  • Do not use the spline roller like a pencil with respect to grip, you will wear out your fingers quickly. Grasp the wood body in the palm of your hand in a vertical position for the least strain on your fingers and wrist.



I guess I will have to wait 13 more years, until the year 2030.............to see if my design is better than the 2004 old design used at North Park :)