How to Read your Sandblast

Biz News - I've just finished and added three new Ligne Bretagnes to the catalog, one of which is going to be used in the examples below. Check them out!

"This blast isn't even on both sides!" How many times have pipemakers and vendors heard that line, usually in reference to a pipe that's simply not cut inline with the ring stacking? After the popularity of my last article on sandblasting, I thought I would do another devoted solely to explaining just how grain and growth rings are arranged in briar, and how to "read" the surface of your sandblast to learn more about it. Let's start with how grain affects, and is affected by, sandblasting. In the pic below you can see sketches of a typical briar block:



Imagine you are looking at the block end-on. Grain rarely actually goes straight up from bottom to top (Wouldn't that be easy?), so I've drawn in figure A some more typical curved, slightly sideways grain lines. Laid through the block are also the briar's age rings, which are shown as shaded horizontal bars. The age rings curve and bend with the shape of the wood. Also, note that they tend to be more widely spaced deeper down in the block, and to tighten together considerably the closer they are to the outer plateau surface.

Figure B shows what you would get if you sandblasted that block - a surface where each age ring creates a pronounced ridge. But this only shows age rings, not actual grain. One can picture a briar block as a stack of slices of cheese, with each slice of cheese representing one year's growth. Punching down through these stacked layers are the lines of grain, like long needles pushed down through our cheese slices. They resist sandblasting ferociously, and limit the degree to which one can achieve sandblasted depth between the layers of cheese.


Blasting at higher pressures can only help so much - the more you blast, the more the total surface of the wood will sink in, as shown in the drawing above. It's the bamboo branch effect - One can easily snap a single branch, but bundle fifty of them tightly together and Hong Kong Phooey would have a hard time punching through them (particularly if his cat wasn't along to help). This is why very tightly-grained briar tends to render less interesting sandblasts - the tightness of the grain itself resists all but cursory ring depth. Drawings C and D, below, are a typical comparison of the difference in surface depth between a block with wide-spaced, loose grain lines (C) and a block with very tight grain lines (D):



Now that we've got a handle on just how rings are created and what they are, let's take a look at a typical bowl. Getting a "ring grain" - meaning a stack of vertical rings - is actually no great challenge if one has the capability to drill blocks at off-angles inline with the grain, but sometimes this isn't possible (particularly in machine-made shapes and middle-grade handmades, for reason of production labor costs), and sometimes the pipemaker doesn't even want this effect because he's bored by it (me). The problem is that the effects created are sometimes misunderstood by collectors unable to visualize how the grain in their pipe flows. For example, take bowl E, below:



There we have a nice crosscut billiard-like bowl, seen from the front, with grain flaring across the bowl and producing a lot of bird's-eye on the right side. Picture F shows what this same grain arrangement would become after sandblasting - The rings show horizontally to the direction of the grain fibers. I once heard someone complain that a pipe's grain was "sagging on one side" when in reality it was as above, simply a factor of the sideways tilt of the age rings in the bowl.

The disadvantage in offset ring stacking like this comes where there is a lot of bird's-eye - the "end points" of the grain fibers. Bird's-eye looks totally different after blasting from grain blasted from the side - It won't blast deeply and there are no growth rings to see, because you are essentially looking down at the stack of cheese from the top, rather than being able to see each layer from the side. This is where folks will sometimes mistakenly think a pipe isn't "blasted evenly" - of course the pipe is blasted evenly, as in to equal pressure, equal attention, etc - but the surface created is completely different.

Let's look at some real examples. If we take that blast in F, above, and look at it on both sides, we'd see this:



And here is the same arrangement on a real pipe! First, let's look at this grain layout on a smooth example:



And here is a nearly identical grain layout in sandblast version - First the side that matches the bowl above, and then its opposite side:



(And how does everyone like this finish? It's new... or rather, it's the end result of a LOT of gradual experimenting and developing. No name for it yet, but I think it looks very nice, showing off the blasting detail with great highlights and all without having to buff the edges off. Some pipes with this finish are currently queued for shipment to P&P and to Israel)


(BTW, the above pics WILL enlarge for a more detailed inspection if clicked)
Now that we know how to recognize the layout of the grain in the bowl, we know what we're looking at and how to recognize it. You can see the age rings, the lines of the grain passing through them, and every individual "stalk" of grain from the top point down, on the side that is all bird's-eye. That swirling miasma in the second photo is the result of looking directly down into the grain of the wood, as if you were looking onto the outer skin of plateau.

I'm fond of unconventional grain layouts, personally. I like it when every pipe is NOT necessarily a stack of growth rings from top to bottom. Probably my personal favorite of unusual grain layouts is the back-to-front seen in the sketches below:



This is where the grain starts on the back of the bowl, the part facing the smoker, and expands outward over the bowl and shank. I find this look particularly appealingly craggy for some reason, probably because it so perfectly illustrates the radial fan of grain that existed in the original block of wood. Here is a great example of this layout in smooth:



And here is a very similar layout after sandblasting (This pipe, #08-45, is posted in today's catalog update, if you want to see more of it)



I hope this has helped a bit to explain why various sandblasts look like they do!

Sandblasting - Circles and Shanks

Sandblasting stirs up lots of questions. Thankfully, I have my buddy Nick to actually ask the stuff that would make good blog topics! I thought it would be worth addressing because while there are lots of fans of "extreme" blasts out there, there isn't a great deal of knowledge of just how various effects are arrived at, and the design trade-offs that must be made along the way in order to produce various effects. Many times I have seen someone criticize a blast, claiming, "It's not even on both sides", when in actuality, it's perfectly even - It's just that the grain isn't the same. Other complaints often involve out-of-round bowls, shanks, etc... seemingly not really understanding that high pressure, deep blasting deforms by nature, according to the grain & hardness of the wood. Let's look at some bowl examples:



Bowl A is your classic top-down view of a smooth pipe bowl, looking down into the chamber. Light sandblasting, as is done by the majority of blasters, retains this roundness and shape easily, as can be seen in B. It just doesn't take off that much wood, leaving the shape very defined and obvious. This changes when we start doing the sort of very deep, very intense sandblasts that I and others do on our higher grade pipes - One literally begins to sculpt the wood by nature, altering it to nature's inner shape (think of a "skeletal" structure within the wood), as seen below.



Pipe C is a good example of a deep blast and how it changes the bowl. Note that the bowl has actually shrunk from its previous outside diameter - When planning to do a very deep blast, I find I must usually oversize the bowl initially so that the outcome will be closer to what I want. Some people don't like this look - It's a matter of personal preference - but it should be stressed that this IS the natural result of a deep blast. You're literally looking down at the strongest parts of the wood. I make most of my blasts this way because I like and appreciate the natural look. For me, the natural "chaos" of the result is the whole point, in a creative sense - I enjoy starting with a billiard or whatever and seeing what its inner architecture will reveal. However, there are ways to do a deep blast and still provide a more-or-less round shape. One method is to use extremely fine nozzles to allow the blasting to be very precisely targeted in order to retain the overall shape while opening recesses, but this is rare - I know of perhaps three or four pipemakers on the planet who do this sort of work. Another method, more common and simpler, is just to do your deep, high pressure blasting, and then sand across the exterior to bring the shape back to a more precise circle, then lightly blast over the pipe again. You can retain the deeper grooves while providing a full sandblast finish.

This gets much trickier when we move to the stem & shank. One can blast the hell out of the bowl because it has nothing to compare to - nothing it must join to - but the shank must join the stem in lines and visual bulk. Remember, heavy blasting actually makes the wood shrink, so a stem & shank join can quickly look awkward. Probably the most common approach to this is to tape a masking ring around the wood that joins the stem and then blast lightly down the shank, producing a result like A, below.



Picture B is the challenge for all pipemakers - If you carry the same pressure and aggressive blasting from the bowl down the shank, you will end up with this look, which I term "shrivel shank". The shank gets noticeably smaller than the stem. The blast is deep and dramatic and even with the bowl, but the lines of the stem-to-shank join are spoiled. Many collectors are fine with this, and prefer the "all over even" blast depth to a varying blast depth, but it bugs me, personally. I like consistent, smooth lines from stems to shanks. Of course this varies sometimes - If I'm going for a particularly gnarly, battered appearance, I'll often do this purposefully, in order to enhance the overall look of the pipe being really weathered.

I suppose what I'm trying to explain is that all these effects are trade-offs in one form or another. There's no such thing as "perfect", there are just different options.



What I have been doing lately is avoiding the masked-off shank briar ring altogether, and simply fading the blasting intensity down the shank, as shown in C, above. Blast carefully, with an eye towards not hitting anything hard enough to start seriously shrinking the shank. The shank nearer to the bowl can be left a bit thicker and blasted deeper, but I reduce the pressure as the blasting approaches the stem join. This retained that stem/shank line I love so much - one even, connected line top and bottom, rather than a shank with a stark "drop off" where the blasting begins. Matter of personal choice, really.

One other option is to make the whole shank fatter to accommodate a heavy blast to match the bowl, but this doesn't work so well in action. It's hard to get the stem-to-shank join flat, for one, and the higher, harder portions of the wood will remain even after blasting, poking out beyond the stem line I desire.

I hope this helps collectors by providing a bit more of a full picture regarding how and why various sandblasting decisions are made!