Saturday, April 9, 2016

Build It Yourself - Expandable Model Rocket Painting Wand Stand - For Home or Classroom Use

Until recently, I had a rocket painting problem.

To paint a model rocket, you need some way to hold the rocket, while simultaneously not touching the surface to be painted. The solution for most rocketeers is to use some kind of painting wand. The simplest painting wand is made of rolled up newspaper, stuck into the top of the body tube. I usually use dowel rods with used rocket motor casings on top.

Regardless of what kind of wand I was using, the problem was the same: I spray a coat of paint onto the rocket and then wonder Where do I set this thing while it dries? I had a couple of hack solutions which usually worked, but made me nervous.

I would either stick the wand into either the pen holder of my desk lamp, and try to position it so the rocket wouldn't touch the lamp as it dried...

...or I would stick the wand into a large empty food can, wedged in among a bunch of craft sticks, with a large clay weight in the bottom to keep the can from falling over.

Obviously, neither solution was ideal. For one thing, if I were painting more than two rockets at a time, I'd have to find something else. For another, both of these solutions mean that I risked taller rockets falling over and damaging the paint.

I kept thinking I'd need to build some kind of stand. For that, I thought I'd need to get some wood, drill some holes, find someone with some kind of power saw which I don't own, design a stand which would hold X amounts of rockets at one time, and find a place to store the finished stand.

Then, I realized this doesn't have to be complicated - PVC is the answer!

The solution was so simple, I kicked myself for not thinking of it a year and a half ago, when I first got started building.

At the top of the page, you can see what I came up with - a PVC stand which will hold up to four rockets at a time. But the stand is also expandable - you can make one large enough to hold a bunch of rockets at a time, which is ideal if you build a lot, or if you are incorporating rocketry into a classroom setting.

First, let's talk about painting wands

Painting Wands - Paper vs. Wood

The paper wand is a simple solution for your first rockets, and is mentioned in The Handbook of Model Rocketry. You just roll up a newspaper, stick it into the front end of the rocket, and you're good to go.

It does work great, especially if you're painting your first rocket and don't have any used motor casings yet. But there are a few drawbacks.

First, you're holding the rocket from the forward end, which makes painting the trailing edges of the fins tricky, especially with longer rockets. A wooden dowel wand gets inserted into the motor mount on the back of the rocket, so you have easy access to the fins when painting.

Second, there's the problem of where to put the rocket while it dries.

Third, if you squeeze the wand too hard, it will kink and flop over, so you can't hold the rocket upright. This might not be a problem for you if you're an adult with reasonable manual dexterity, but from teaching rocketry to kids, I can tell you that kids get nervous the first time they use spray paint. They tend squeeze the wand so tight, and they might shake and get sweaty palms, and the paper wand just falls apart.

The wooden dowel wand, on the other hand, is sturdy, reusable, gives good manual control (since it doesn't have to be handled gently), and gives you something to do with the dozens of used motor casings you'll soon have on hand.

Making a Painting Wand

This couldn't be easier. Save a few used motor casings, and get yourself a pack of craft dowel rods, about 12-16 inches long.

Craft dowels have all sorts of uses in hobby rocketry, so you will need some anyway. The ones I have are about 5/16 inch in diameter. A 1/2 inch diameter dowel will just about fit perfectly into a motor casing, though you may have to sand the inside of the casing to get all the used propellant out of it.
You need to remove at least some of the soot from the used motor casing. Unless the fit is too tight, you don't have to sand it perfectly clean, but you should at least knock out all the loose black stuff with a screwdriver, so you're not dropping ashes all over the place.

If you are using 1/2 inch dowels, you can then use wood glue to permanently attach the motor casing to the dowel rod. But I prefer to use masking tape to build up the diameter of the rod, and then slide the motor casing onto the dowel.

Sometimes a motor casing will get so caked with paint, you need to replace it. Since my painting wands aren't glued together, I can just take the motor casing off and put a new one on. Dowel rods aren't expensive, but this way I have less to throw away.

Building the Painting Wand Stand

The picture at the top of the page may be perfectly self-explanatory to you. But I never like to assume someone new to rocket building has prior knowledge of tools or materials, or building techniques, so I'm going to show you step by step how to build the stand, and how to expand the stand to hold as many rockets as you need. If you have a classroom with 22 kids and need a place to hold 22 rockets as the paint dries, this might be a good solution for you.
To build the basic stand, you need the following parts, and one tool.

  • A length of 1/2 inch PVC pipe, to be cut into shorter pieces
  • Four PVC elbow fixtures or T fixtures*
  • One PVC cross fixture
  • A tool for cutting the PVC pipe to length

*Note: If you want to build the expanded version of the painting wand stand, you'll need some T fixtures. Either elbows or T's will work for the basic stand, so get whatever is cheaper or more easily available.

You can use a hand saw to cut the PVC, but as in the post where we built a rocket cradle, I find a PVC pipe cutter, available from hardware stores for not too much money (mine was about $12), to be much easier and cleaner to use.

Start by cutting four 3-inch lengths of the PVC pipe, and inserting one piece into each end of the cross fixture.

Cap the ends of the 3-inch pieces with the elbows (or T's), all facing the same direction - 90 degrees from the 3-inch pieces.

Cut four more lengths of PVC pipe, at least 3 inches long. I cut a few even longer, so that larger or heavier rockets would have less wiggle room in the stand when drying.

Insert these into the elbows (or T's), and you're done.

You can cement the stand together with PVC cement if you want to, but you skip the cement, you can take the stand apart for storage, or moving to a new home, or to expand it for more rockets.

Making the Expanded Stand

 Replace one of the elbow fixtures with a T fixture.

The upright piece from the elbow will go into the T fixture. Cut another 3-inch length, and join it to the other end of the T fixture. Then, add another cross.

Add three more 3-inch pieces to the cross, and finish with more elbows and upright pieces.

You now have a painting wand stand that can hold up to seven rockets at a time!

You can continue to expand the stand in either direction, using more T's, crosses, and elbows, to hold as many rockets as you need to. You can even expand the stand sideways, as long as you don't make it so wide that it's hard to reach rockets for adding coats of paint.

This project was so, so easy, and so helpful. I built it a few weeks ago, and have since gotten so much use from it - not only for when painting rocket, but as a good place to keep a few rockets safely out of the way when cleaning my work space, and for when applying decals.

I wish I'd thought of this before teaching a model rocketry camp last summer. This summer, I have an easy solution.

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