Creative Woodworks & crafts 2001-03, страница 26

SLAB SAWING

by A! Caldiero

A man and his slab. Al Caldiero has made a name for himself scroll sawing unbelievably large pieces.

Should you decide to attempt it, slab sawing could very well prove to be your biggest, and most rewarding, scroll saw challenge.

Before ] start, let me warn you that slab sawing may prove to be your biggest scroll saw challenge—you may even be aeeuscd of having a chemical imbalance or a gene deficiency. Hut once you have completed your first slab project, nol only will you find it financially rewarding, but it will give you a whole new outlook on scrolling. Mere is how I go about it:

Tooling up

The saw I prefer for my slab projects is a 20" DeWali. Used in conjunction with a spiral blade, it allows me to saw a slab up to 40" wide. I also need at least two roller stands to support the workpiece while sawing. Because my saw is mounted to my bench, the roller stands don't have lo be very tall. I adjust them about 1/16" higher than my saw table so that when moving a slab right to left, there is no resistance from the saw's table top and I do not have to worry about overly stressing the machine from the weight of the slab. The slab should never touch the 's table top. I use both the standard

saw

roller and roller balls, but let me warn you, the balls may become liung up in your cutouts.

Blades

For any slabs 1-1/4" or thicker, I use a No. 2 Olson spiral blade. The key to using this blade is having it extremely tight in the saw. 1 have tried using No. 4 blades, but noticed my saw arms bending. I feel that using the No. 4 blade here may cause damage to the saw—it is just too much blade. I would rather go through more blades than wear out my saw. You may find spiral blades difficult to use at first, but it is the only way to saw a large slab.

Wood selection

Selecting just the right slab is half the battle. I have spent many hours searching saw

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When sawing a large slab, using roller stands on either side of the saw to take the weight of the wood is a must.

preparing tne stock is an important part of the process. Glue any loose bark back in place.

mill after saw mill looking for ideal lumber. 1 usually look for slabs with some kind of character, maybe a special kind of grain pattern, or one that still has the bark on it. All the slabs I use are kiln dried.

Slab preparation

The 1-3/4" thick slab of red elm that I selected to use for the Last Supper and the Crucifixion of Christ look me a day to prepare before I could adhere the pattern. I start by checking for any loose bark. When 1 find some, I glue it back on. What works best for mc is to carefully pry the loose bark away from the wood with a toothpick, spreading it just enough to slowly drip glue in between. .1 then use another toothpick to work the glue into the gap. Try not to get any glue on the outside of the bark. I then clamp all the glued areas and allow the piece to dry.

After removing the clamps, 1 turn the slab over so that the bottom side faces up. On this particular piece, I noticed a hole in the slab that was approximately 1" deep and 1-1/2" in diameter. There were also several drying cracks, or checks. These problems were easily rectified by using a Dremel Moto tool, slowly cutting away any soft wood and debris. For the checks, I worked the Moto tool back and forth following the crack down about two thirds of the thickness of the slab. Once I the cracks grooved out and the large hole cleaned out, 1 used an air compressor to blow out any loose wood chips. Then I mixed up a batch of 5 minute in a paper cup and poured it into the grooved cracks and large hole. Even though it's called 5 minute epoxy, I let it stand for an hour or so. That way it sets good and har d. Then I sanded the cured epoxy down lo the surface of the wood with a belt sander using a 100 grii belt.

After such prep work is completed, I'll sand the entire slab (both sides) with 150 to 180 grit sandpaper. This usually