Laser Alignment Guide From Cheap Laser Pointer

We were working on joining two fabric like materials for a project, however what made the process difficult was that we needed to place both material
edges perfectly centered on a pneumatically controlled heated bar that bonds the material together creating a seamless seal. it's clear we needed some sort of alignment guide, however we can't put any markers with ink as it will smudge and stain the material so we needed something like a beam of laser to show the center of the heater bar every time. But as always we needed something really really really dirt cheap.

So I remembered searching for Instructables and saw a project that uses an ordinary laser pointer and pointing it to a rotating mirror to form a continuous laser line. I knew that would be relatively easy to do, but then a comment said that I could I achieve the same laser line effect by using glass tubing to project a laser line.

I tested that idea using a glass vial and it works. The trick was to pass the laser beam as tangent as possible to the glass tubing.

Materials for this build will be the following:

1. Cheap Laser pointer

2. glass tubing

3. acrylic sheet 2mm thick (i used up about 8" x 6" sheet.) Includes the housing of the pointer.

4. access to a laser cutter, but this is optional.

5. instant glue

6. batteries for the laser pointer (usually comes with the pointer) I used a plug in DC power supply again this is optional.

7. eye protection or simply just don't look directly on the laser beam

8. sand paper to smooth out edges of the glass tubing.

Let's start.

Step 1: Finding and Cutting Glass Tubing

First step was to find a glass tubing that was small enough and easy enough to cut. I saw a cheap glass tubing that was used for a biology project (you know that project where you use balloons to represent the lungs :)) anyway i cut off a portion of that tubing using a file. (You could probably watch how to do this in youtube.) just make a score around the tubing so you can snap the bit off evenly. Use a towel or cloth when breaking the piece off. Eye protection and safety a must. sand off edges to smooth them out to prevent cuts.

Step 2: Gut the Laser Pointer

Next, was to gut open a cheap laser pointer, the kind that sells for less than $0.25 in your local "everything China made" store.
so i took out the laser components and replaced the push button switch with just a jumper as I wanted to use a 4.5V DC power supply instead of using 3 button cell batteries.

I took a wire and wrapped it around the head of the pointer, this connects to the positive end of the power supply, the other end (the one with the spring) connects to the negative line.

Step 3: Measure and Assemble

To place the tubing as tangent as possible, I decided to make a box for the laser housing and then attach an L-shaped glass tubing holder.

So, I measured the dimensions needed. I was fortunate enough to have access to a laser cutter, that made the job easier and cleaner. Although this could be achieved by cut and glue method with a lot of adjustment and tweaks to get the right alignment. I laser cut the dimensions on a 2mm thick acrylic sheet. I then glued them up and tested it.

The laser line is visible even on a brightly lit room.

Some safety consideration, I later added electrical tape on the contraption to seal off any beams of laser going on any other direction other than that of the intended direction.