How To: Cutting out vac canopies

the dreaded vac canopy

Many modellers are wary of using vacuformed canopies due to their fragility. It is so very easy to slip up and ruin your canopy (and the chances seemingly tend to increase when there's only one in the kit). As a result, many people stay away from vac canopies. Doing a vac canopy calls for a bit of care and patience, but not nearly as much as people may fear.

tools and equipment needed

You will need the following:

• 1. A fine point sharpie marker
• 2. A razor knife with a brand new blade
• 3. A pair of fine tip cuticle scissors
• 4. Tweezers
• 5. A coarse sanding stick
• 6. Epoxy putty

getting to work

First, mark around the edges of the canopy with your marker.

Run the tip of your blade along the marked line with just enough pressure so it scores the plastic, but doesn't cut through. Take this step slowly and carefully. Two or three shallow passes are better than one heavy one. Cut in stages instead of making one complete circuit around the canopy.

Then cut the scrap backing plastic with the cuticle scissors until the cuts go just to the edge of the canopy but not into the frame. Be very careful with this step. In the case of this Venom canopy, I've used the Sharpie marker to illustrate where the cuts should go. In highly curved areas make the cuts closer together.

The scored line along the canopy base makes the plastic weaker there. Now take one of the cut segments and carefully bend it down and towards the centre of the canopy. You'll have to bend it back and forth a few times before it snaps off but eventually it will snap off.

Repeat this step until you've snapped off all of the waste plastic from your canopy. Avoid the temptation to rush! Now your canopy is free of its base, but the edges are quite rough. You'll need to carefully sand the edges of the canopy using a sanding stick until it's all smoothed off.

The sanding stick may be used along the edges in order to properly shape the canopy to fit the model. Work slowly and carefully. Remember that it's easier to remove material than add it. If you must add material, add it to the fuselage rather than to the canopy. A nice trick here is to roll a rope of epoxy putty around the cockpit opening and squish the canopy into it while it's soft (Use a little water to make sure the putty won't stick to the canopy). Sculpt the putty to shape then remove the canopy. Once the putty hardens you can paint it, then glue the canopy into place.

Now you have your canopy ready to glue (you may wish to repeat the score and bend steps to open it if it was moulded shut and you want to display it open). Since vac canopies are not made from styrene, regular model cement will not affect it. Glues of choice are epoxy, superglue (non-fogging is best) Krystal Kleer or white glue (PVA. White glue is very good for filling small gaps without damaging the canopy or the model. Apply a blob, then smooth it into place with a wet fingertip). Once the canopy is glued in place, it will be fairly robust, but you should obviously avoid crushing it.

To mask, you can use thin strips of masking tape to outline the canopy panes and then fill in with other small pieces of tape. If Eduard or other manufacturers make pre-cut masks they may be used. Another way is to place a piece of masking tape on the canopy, trace the outline of the glazing on the tape with a pencil, remove it and cut to shape before placing the freshly-cut mask back on the canopy.

conclusion

Doing a vac canopy need not be as intimidating as it appears. Work slowly and carefully to achieve best results. I would put a vac canopy on at the same time I'd do an injection one. Usually the windscreen goes on before painting so the frames get the same paint as the fuselage. If I'm displaying the canopy open, I'll mask and paint it at the same time I do the fuselage but I'll install it last after decalling and weathering.