Hanging Test Tube Propagation Station | Single Stem Vase

These hanging propagation stations make great gifts whether you do them with a class, or make them yourself.

This is a great intermediate project because it uses a variety of tools for basic and more complex operations. This is one of the projects my advanced wood shop students can choose. These students are familiar with most of the required tools, but I still provide one-on-one support at the table saw and when routing the grooves.

This is a straight forward project, but does requires precision and attention to detail.

Skills Addressed

• Measuring and Marking
• Ripping and cross-cutting on the table saw
• Cutting a stop dado (groove) on the router
• Drilling on the edge of a workpiece with a forstner bit
• Basic glue up
• Basic band saw cuts
• Round over with bearing bit on the router
• Basic finishing

Materials

• 25 x 200mm glass test tubes (about 1 inch in diameter)
• Wood 1 inch thick, 9.5 inches x 3.75 inches
• any species is fine. For this Instructable I used walnut, but in the pictures you will see others we made from Mahogany and Hemp Wood - a cool engineered lumber.
• Cord or String
• I use this Micro Cord which is strong and UV resistant.
• Wood Finish of your choice

Tools

• Table Saw
• Router
• 1 inch round nose router bit
• 1/8 inch round over router bit
• Drill Press
• 1/16 inch brad point drill bit
• 1 inch forstner bit
• Random Orbital Sander
• can also be sanded by hand

You will need two strips that are 1 in x 1 3/8 in x 9.5 in. And one strip that is 1 in x 3/4 in x 1 7/8 in.

If you want the grain to match you can cut all these pieces from a single piece of wood that is 1 in x 3.75 in x 9.5 in.

I have students rip and crosscut these on the table saw.

If grain match isn't important, or if you are prepping materials for students who do not use the table saw, you can rip pieces that are 1 3/8 in and 3/4 in and then allow students to cross cut them to length on a miter saw or by hand.

If grain matching, draw pencil lines to help keep track of how the pieces go together.

With the 1 inch bull nose route bit installed set the fence 1/2 inch from the center of the bit. The easiest way to do this is to raise the bit to full height and set the fence so that it is just kissing one of the cutters.

Next, lower the bit so the top is 1/8 inch above the table.

• This cut it best done in at least two passes, one with the bit at 1/16 inch, and then the final pass at 1/8 inch. On the router lift we have, the fine adjustment knob can be zeroed out before lowering the bit to 1/16. This makes it easy to take a pass at 1/16 inch and then raise the router back to 1/8 inch.

Install a stop block on the fence 7 5/16 inches from the center of the bit.

Install a feather board to keep each piece tight against the fence, and use a push block to make the cut. When you hit the stop block, turn of the router with the paddle switch, and wait for it to stop before lifting out your piece of wood.

• If the groove is perfectly centered on each piece of wood, you can use the same set up for both pieces. Otherwise, you can move the stop block to the other side of the bit and feed from the other direction so that the groove is offset the same on each piece.

There is a bit of variance in the diameter of the test tubes. At this point it is helpful to clamp up the three pieces and check that the test tube slides in easily. If it is too tight, gradually raise the router bit and take additional passes.

With the 1 inch forstner bit installed in the drill press, you will set it up to cut 1/8 inch into the end of the middle piece.

Mark the center line of the piece of wood, and mark 1/8 inch from the end.

Use a fence (I made a simple one by gluing a scrap piece of plywood to a sacrificial piece of wood) to align the bit with the center line of the piece of wood, then slide the piece of wood back so the edge of the bit aligns with your 1/8 inch mark.

The pictures probably make this easier to understand than the description.

Do a mock up to to make sure everything aligns correctly and that the test tube fits correctly.

I use Titebond III here because the darker glue may make a less noticeable glue line with walnut.

Only apply glue to the center piece. Make sure the three pieces are flat (co-planer) when clamped.

Let dry overnight before moving on.

I clean up the squeeze out with a chisel after it has dried.

I have an MDF template for drawing the half circle profile at the bottom. You could also cut out a 3 1/2 diameter circle from paper and use that as your template.

Cut outside your pencil line with the bandsaw, or with a jigsaw (or a coping saw).

Clean up the line on the belt or disc sander.

• This whole procedure could have been done with the MDF template and a pattern bit on the router. However, this can be a little sketchy as this is all end grain. You will have take multiple passes and/or use a high quality bit.

Use a 1/8 inch radius round over bit installed in the router table to round over the outer most edge.

Sand with the random orbital sander or by hand. 120 and 220 grit is adequate.

The holes for the cord can be drilled by hand, or the drill press table can be tilted to 45 degrees.

The hole is centered, and 1/2 inch from the top edge. If drilling by hand, it help to draw the line to help eyeball the drill bits path.

Cut 20 inches of cord and and lightly melt each end to keep from fraying.

Thread through each hole, and tie a double overhand knot in each end.

Any finish is suitable, but a film forming finish, like a polyurethane, may make a tighter fit for the test tube. For that reason I prefer a penetrating finish like Boiled Linseed Oil, Tongue Oil, or a Danish Oil.

Apply two coats and allow to cure before installing the test tube.