Bending Sides by Boiling:
Bending your guitar sides by placing them in boiling hot water is a method that has been used for many years. When my father and I began guitar building this is the method that we utilized exclusively.
If you want to get into guitar building at a minimal cost, this is certainly one way that you can do it. The only expense you are out is the cost of the boiling vat, the used gas burners and some plywood and hardware for the forms.
You can also purchase these items if you wish. The Everett Side Bender shown in the photo above is available from Luthiers Mercantile for about $225.00, but you can make one for far less money.
Bending sides by the boiling method has several advantages and disadvantages. Listed below is the procedure that you would use to get your sides boiled and clamped to the molds.
Ultimate Guitar Building Unheated Guitar Side Bender
Here is the complete procedure:
Examine Your Wood Sides:
Look for any end checking. This may ruin the whole piece if not found.
Thickness sand you sides to just a whisker over their final thickness.
Try to use straight grained, quarter sawn wood for your sides.
Mark Out Your Sides:
Lay the sides on your workbench in book-matched fashion. This is of utmost importance.
Take a sharp marking knife and cut a fine line along the center of the waist curve. This will be your alignment mark when you first insert the side into the bending jig. Make sure to do this for both sides in book-matched fashion. No not cut this mark too deeply as you will need to sand the mark out prior to your finishing operation. If you feel uncomfortable with the marking knife a heavy pencil line will work as well.
Prepare Vat For Bending:
Your boiling vat can be constructed from galvanized steel. It should be a minimum of 6″ wide x 36″ long x 4″ deep. Place about 3″ of water in the vat. Light the burners and wait for the water to come to a boil. To help facilitate the boiling process, you can place a lid over the top of the vat. When the water is actively boiling, slip the side in the water. There will be a tendency for the wood to float to the top, so you need to hold down the wood. The easiest way is to place wood spreaders inside the vat so that they hold the wood beneath the water level about an inch.
Let the side boil for at least 90 to 120 minutes. At this point the wood should be plastic enough to place on the guitar molds without much concern for cracking.
Inserting Sides Into the Mold:
Be sure to prepare the Mold(s) by having them open and ready to receive the wood. You want to do this swiftly as your window for bending is rather short. It is best to do this with (2) people. With experience you will be able to do it alone though.
Take out your first side, using a pair of tongs, being careful not to burn yourself. You will need to wear a heavy pair of cotton gloves for this operation as the wood will be too hot to handle with your bare hands. Check and double-check your registration mark. Insert the wood into the Mold and center the mark for the waist beneath the waist tension block.
Make sure the side is aligned and parallel with one side of the Mold. Now begin the tightening process on the waist block. Bring it down so that the side is within about 1/2″of contacting the Mold. Now gently bend the upper bout around the Mold and slip on the Upper Bout Tension Block and tighten it so that the side does contact the form, but to absolutely tight.
Do the same thing with the lower bout. Now tighten the waist block down tight. Next tighten each of the bout tension blocks.
Repeat the process with the other side. Set the molds aside in a warm room for about a week to facilitate drying.
Tips and Techniques:
Tags: bending guitar sides, boiling guitar sides, guitar bending methods, how to build a guitar
April 30th, 2011 at 8:03 am
I specialize in tamburitza instruments which are guitar and or pear shaped and made much like an acoustic guitar. I also make mandolins and repair all types of guitars etc. I thought I would give the unheated bending jig a try. I usually use the electrically heated iron in my shop so I have not boiled or soaked wood for your recommended length of time. I have been thinking about this method for some time now and finally getting around to try it. Basically….just how pliable is the wood when boiled using this method? I’m at the point of buying the springs but was wondering just how stiff the springs need to be based on the pliability of the wood to insure tight contact on the jig? I can buy several spring lengths and diameters which of course dictate the amount of pressure the spring will exert. Do you have any recommendations for this?
May 12th, 2011 at 10:00 am
Marty,
The amount of flexibleness of the wood depends on the species. When boiling wood, most woods are VERY easy to bend. If you purchase springs they need to be quite stiff – think you need to use both hands to stretch into place. The unheaded jig is of less importance in that the wood is boiled and it is easier to bend the wood. Also keep in mind if you have trouble with the springs completely clamping the wood in place, you can easily use some helper clamps, which can be pipe bar clamps. I always have a few Bessey 30″ bar clamps in my shop for such emergencies.
I used to use boiling all the time for my side bending. The only disadvantage is that on the darker woods like Rosewood, there is so much resin that comes out of the wood, if it is boiled too long it can change color just a bit and not match the matched back set, which is unboiled.