by Peter B. Hiatt
|This is an important question to buyer,
sellers, woodcutters, and importers. It is also an area of extreme
disagreement. This article will attempt to show why there is disagreement
and what factors are involved in coming to an agreement. The two general
areas of conflict are how long it takes to properly dry wood and how long
it takes to stabilize wood.
Part of the general area of agreement is that when a blank is slabbed and cut out for curing, the butt sections (end grain) are somehow closed to slow the rate of moisture loss (drying). This is because a blank which dries too fast causes interior cellular damage which can ruin a stock for function as a gunstock. The exterior damage is obvious as cracks develop in the end grain. The interior damage usually does not show up until the stock is being turned. The grain separations and small and sometimes large cracks then often shows up. As a result, the first damage prevention is to stop the unheeded drying by coating the open end grain of the blank with an appropriate material. The most common is wax or paraffin, but there are also other gun sealants such as some paint and other materials. Usually the two or three inches on each end are covered. Now feather also has end grain which comes to the surface, and feather should also be covered with sealant. This can be removed as the stock dries. If the feather starts opening up, it must be reapplied. Keeping a close look at these better blanks is very wise. One does not want to lose an expensive blank.
Next, the blanks must be placed where air can circulate around them. They are sometimes "stickered" by laying them in stacks with thin "stickers" of wood between them to allow air to circulate. It is a good idea to turn the blanks over now and then which helps the wood dry without warpage. In any event, the drying must be done without any sunlight hitting the blanks. Sunlight is a killer in blanks.
How long to dry?
This is a subject of great dispute. My English friends tell me it should be a term of 10-12 years. With their experience, it is hard to argue with them. However, they are on a moist island and air-drying is dependant upon ambient temperatures and humidity. Naturally, there will be a difference in drying time between a desert area and a marine environment. My California walnut industry friends and others like Chuck Peterson of Richards Microfit agree with each other that IN THEIR ENVIRONMENT, English walnut takes a year to dry and black walnut takes 3 years to dry. This time period before a stock is worked because dryness is only one part of the equation. The blank must also be STABLE. If the blank does not have an additional year of stabilization time, the finished stock can still expand and shrink and cause misery to the stock owner. An extra year is required in California for stability. Some areas dry better in the Winter because Summers are so humid. There is a great deal of variation from area to area.
Generally, "dry" in most areas of the US means about 12 % moisture as tested by a moisture meter. In my area, dry means 7-10% depending upon the time of year. It also depends upon the type of moisture meter used. Prong type moisture meters are best avoided.
Another term is important in all this. Along with "dry" and "stable" is the term "temper". If wood is kept in an area that can go through natural changes in humidity and heat, the wood hardens over time and becomes "tempered". Most violin makers won't touch a piece of wood until it has "tempered" for at least 50-75 years. Likely this is caused by the wood grain intertwining as it expands and contracts with the environment. This makes it harder and more stable and affects the tone of the wood. I have worked three very old stocks that were hard as bricks and quite difficult to even sand. They did make exceptional stocks.
What one wants to stay away from is any blank which has been "forced" dry. An example of this is kiln drying. It can simply ruin otherwise good gunstock wood. Another way to ruin wood is to remove the natural internal oils by steaming or boiling the wood. This is practiced in Turkey. The wood is boiled or hot steamed for 24 hours to remove the natural oils. It is then waxed on the ends and it dries in only a few weeks. This quick to market drying technique results in very high internal stresses in the blank and often serious damage. American Gunmaker's Guild members have been complaining about working this wood only to find it often unusable after stock turning. They then have to explain to the customer how his very expensive blank is worthless. The guild members do not like the comments they get from the owners! Moreover, without the natural oils, the wood never truly stabilizes. Moisture flows much easier into and out of the wood as environmental conditions change. In the May/June issue of Shooting Sportsman magazine, David Trevallion shows a photo of a 20 thousandths feeler gauge between the wood and metal of a Fabbri. What David didn't mention is that the wood on this gun had already been changed once for this problem. Fabbri "woolmerizes" their gunstocks which evidently has not solved the problem. I am guessing that this process either pressurizes or vacuums into the wood a natural oil replacement. In any event, beware of Turkish wood. Be sure it is guaranteed in writing in case you also have a problem with it.
The infamous Browning "salt wood" was also a failed attempt to shorten the drying process. There is no substitute for natural air drying.
(Except for posting strictly limited to "www.doublegunshop.com", all rights reserved by the author.)
doublegunshop.com home | Welcome | Sponsors | The Gun Rack | The Book Rack | SxS Video Gallery
Enter Our Monthly Lottery | Order or request more information | Other Useful Information
Double Gun BBS - Question & Answer Open Forum
Updated 02/10/04 DCW - Copyright
(c) 2007, doublegunshop.com