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Air Circulation in Hollow Forms

When a finishing material such as lacquer sanding sealer is applied to the inside of a vessel having a small opening, the drying time is dramatically increased because of a lack of air circulation in and out of the vessel.  Unless the vessel is placed in a draft, the movement of air will be extremely small.

The obvious way to speed up the drying process is to use a small fan to blow air into the interior of the vessel.  Any type of small fan will work, where “small” refers to a fan 6” in diameter, or less.  A larger fan will work as well, but it is overkill.

The fan does not have to direct the air straight into the opening.  A stream of air blowing across the opening will create turbulence and produce enough air movement to reduce the drying time significantly.  This may come in handy if you’re rushing a piece to go to a gallery or sale because it is not “cool” to present a piece having a strong odor of the finish.

A small muffin fan about 3” square (or round) is ideal for this application.  All that is required is to mount the fan so the vessel can be placed underneath it.  

Muffin fans are available on the surplus market and are not expensive.  A web search for “muffin fan surplus” should turn up several hits.  

The fans may require either alternating (AC) or direct current (DC). Typical DC voltages used by the fans are 5, 12, 24, and 48V.  AC voltages listed are usually 115 (or 120) or 220/240 V.  

Be sure to select a fan that will operate from your available house current, 120 VAC in the US.  A DC fan will require an appropriate power supply.  Incidentally, most of the fans used in computers are designed to operate from direct current.

An easy way to include a switch for turning the fan On and Off is to use a miniature toggle switch, one with leads, obtained from your local hardware or big box store.

Connections at the fan can be made using small wire nuts, or whatever method you prefer.  Soldering, with heat-shrink tubing over the connections, is good.

If possible, find a place in your shop where the fan can be permanently mounted in an out-of-the-way spot.  Be sure the electrical wires are secured with no bare conductors exposed. Then when you apply the finish, simply place the vessel under the fan and flip the switch.

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