Create A Tiffany Style Lamp Form and Pattern

Example 2: An “inside” lampshade form

Why this example?

I mentioned in Example 1 that I also wanted to create, and describe the creation of, an “inside” lampshade form.

If you are planning to solder a cap to your lamp or, if you’ll be using a ring and want it to extend above the outer surface of your lamp, you’ll probably want to put a recess in the top of your lampshade form. This will be covered in the section that follows this example.

Step 1: Brasses

There’s not much to add beyond what was said in Example 1 – Step 1.

Step 2 : Create a full-sized paper profile

The following is the profile that I plan to use for Example 2. It’s a simple shape that will allow me to demonstrate what I want to demonstrate.

Example 2: Paper profile

One thing that is very different here is the pivot point. As you’ll see a little later, the wood profile that we’ll be using to shape our form, pivots around a length of PVC pipe that stands in the middle of the form.

In Example 1, that pivot point was very high and the pipe was well supported by the surrounding Styrofoam.
In this example, the pivot point will have to be very low, no more than 1/2” above the lowest point on the paper profile. A higher pivot point would be unsupported by the Styrofoam and would be unstable. Even with keeping the pivot point low, I’m going to want to set the PVC pipe into a block of wood.

The low pivot point forces some changes to our profile. I’ve drawn some vertical lines at the sides of the paper profile. They indicate the profile that I would like my final lampshade form to have. I need to be able to rock the wood profile up and down on the pivot point so I can chop away the excess Styrofoam. If I were to cut my wood profile with those straight sides in mind, that rocking motion would do great damage to the upper parts of my lampshade form.

The arcs that I’ve drawn from the upper corners out to the baseline indicate the shape that the wood profile will have to have so it does not do damage to the upper parts of the lampshade form.
I still intend to have the straight sides. I’ll just have to cut them by hand.
I created this design as follows:

I drew the top horizontal line. Since we’re drawing the shape upside-down, this actually represents the base of the lampshade.
I used my framing square to draw the vertical centerline.After determining what the height of my lamp will be, I drew the middle horizontal line.
The distance between the middle and bottom horizontal lines indicates how thick the Styrofoam will be in the center of the form. I decided to make those lines 2” apart because I want to have room to embed the wood block that will help keep the PVC pipe vertical.
After determining what the radius of the lampshade will be, I marked both outer edges on the top horizontal line.
Because I like to have the lampshade form go a little bit beyond the edges of the pattern, I measured out an additional 1/2” on each end of the top horizontal line. From those points, I drew the right and left vertical lines.

Step 3: Prepare the Base

For Example 2, I decided that my lampshade form would have 10 repeats. I started out exactly the same way that I did in Example 1. Once I had my quartered circle, the next step was to divide the circle into 5 even segments and then bisect them.

Five segments

The process for segmenting the circle was exactly the same as the process in Example 1. The one exception was that I set the adjustable angle tool to 72° instead of 120°.

Bisecting the segments was easier than I’d expected. In the preceding drawing, you may notice that the top segment is already bisected by one of the quarter radii. All I had to do was set my drafting compass to that distance and step it out around the circle.

Ten segments

The task of drawing a circle with the same radius that the completed lampshade form will have proved to be a little bit more difficult. Again I got the measurement from the bottom horizontal line on my paper profile. I mentioned earlier that I wanted my lampshade form to have straight sides. The measurement that I was looking for was the distance between the vertical centerline and either of the vertical lines on the sides (not the curved lines.

The complication was that this was a larger circle than I could draw with my drafting compass. Fortunately, I discovered a neat little trick.

I had noticed that my metal ruler had a hole on one end (probably so it could be hung on the wall). After measuring out the radius of the circle that I wanted to draw, I put a tack through that hole into the center of the circle. Holding m pencil against the ruler on that radius point that I had already measured, I was able to swing it around the tack. So long as I kept the pencil against the same mark on the ruler, I came our with a nearly perfect circle.

Ruler Trick

Completed drawing on paper

Transferring the drawing from paper to wood was done as before except that I had to use my ruler trick again to draw the circle.

Before I cut the base out, I did one additional step that I think is more important for an “inside” lampshade form than it is for an “outside” lampshade form. Starting with the lines that I drew earlier to quarter the circle, I drew a grid to indicate where the base of each of the Styrofoam bricks will sit. The reason for this will be apparent when I start gluing the brick to the base and shaping the Styrofoam.

Finally, I cut the base out.

As in Example 1, I used my trick with the holes and pins (brads) to make sure that my base won’t move around on my 1/2” piece of plywood.

Cut out the base

Holes and pins (brads)

Again, I found it difficult to align the holes and pins was very difficult. As before, after aligning the holes and pins, I outlined the base I drew a mark to indicate where the radius with the hole should line up.

Also as before, I marked ends of the repeat radii on the edge of the base.

Step 4: Prepare the pivot

Preparing the pivot Example 2 was very similar to Example 1. The primary difference was that the piece of PVC pipe was much shorter. I explained the reasons for this back in Step 2.

In step 2, I also mentioned that I was putting extra Styrofoam at the bottom so that I could embed a wood base for the PVC pipe.

Measuring for my pivot:

I again took my pivot pin measurement from my paper profile. This time, I wanted the top of the piece of PVC pipe to be an inch or so above the lowest point of the bowl. I took my measurement and cut the PVC pipe.

Next, I made my wood block. I cut a 2” square piece of wood and drew lines from corner to corner. At the center point (where the 2 lines intersected), I drilled a hole that was slightly larger than the outside diameter of my PVC pipe (I didn’t have a bit that was the exact size). Using my gridlines, I glued my block to the exact center of my base.

Note: This came loose on me later on so I recommend putting a couple of screws through the bottom into the block.

To make up for the hole being a tiny bit large, I wrapped just enough tape around the PVC pipe so that didn’t wobble but it still went in and out easily.

Block to support PVC pipe

Finally, I made the same final revisions to my paper profile that I made in Example 1:

I made a new horizontal bottom line 3/16” (the thickness of my plywood base) below the old bottom line.
I centered my pivot pin strip over the vertical centerline and drew a vertical line on either side of it.

Revised paper profile

Step 5: Make the wood profile

The Example 2 process was nearly identical to Example 1.

Transferring the profile

Tweaks to the profile

Note: There’s one thing that I did by accident here but found to be very useful when I got to shaping the Styrofoam. In the Assembled profile photo, you’ll see that the top and outside edges of my wood profile are straight and square to each other. See how I took advantage of this in Step 6.

Assembled profile

Step 6: Glue and Shape the Styrofoam

As with Example 1, I started with the four central bricks, fitted around the PVC pipe. This step had two main differences from Example 1:

Because the PVC pipe was inserted into a wood block, I had to make a cutout in each brick so it would fit over the block.
Because of the shortness of the piece of PVC pipe, it was essential that I cut away much of the extra Styrofoam before I glued the four bricks together. If I hadn’t done this, it would have been next to impossible to get the pivot pin into the end of the PVC pipe.

When creating an “outside” lampshade form, the shaping motions tend to push the Styrofoam bricks toward the center line (the PVC pipe). This is what would allow me to shape the central bricks, then add the next tier of bricks and shape them, etc.

In creating an “outside” lampshade form, it was immediately obvious that the shaping motions were going to push everything away from the center line and, most likely, blow the lampshade form apart.

To counter this, I glued all of the Styrofoam bricks to the base and to each other (using toothpicks liberally). Once the glue had set, I turned the whole thing upside down and trimmed off most of the excess Styrofoam.

Starting to trim

Trimming completed

In the note at the end of Step 5, I mentioned that the outside edges of my wood form were straight and square to each other. This was fortuitous because I was now able to use those edges to shape the outside of my lampshade form. Setting the base onto the pins that I created in step 3, I was able to scrape away at the sides until I had a cylinder that had the same diameter as the base.

Trimming completed

With that done, I tied the whole thing together with duct tape (I put paper under the duct tape so I could remove it later).

Tied together

Finally, with everything tied together, I started the shaping process. This was the same chopping/scraping process that was used in Example 1 (with a very gentle touch). Vacuuming out the debris was a nearly constant task since it all collected in the bowl.