How can I avoid grain tear out on a wood bowl and get a good smooth final surface?
Wood bowl grain tear out can be frustrating. There are many ways to address this issue including using sharp tools, cutting with the supported grain, speeding up the lathe, changing angles, and even treating the surface.
This article will cover, in detail, numerous approaches to solving the wood bowl grain tear out problems that might be plaguing you.
What Is Grain Tear Out?
When we turn a side-grain wood bowl, we are basically turning a bundle of linear wood fibers, kind of like a block of straws. These “straws” run across the surface of the wood bowl blank.
With each rotation of the lathe, the end-grain or ends of these “straws” will pass by twice, once for each end of the tubes. These tube or fiber ends are known as end-grain.
It is this end-grain that can rip, snap, or simply break off and that creates grain tear out.
Typically, side-grain or the longer parts of the wood fibers cut smoothly and don’t bend or break as quickly as the end-grain.
The Problem Lies Deeper
When grain tear out occurs, at first glance, it may appear to be only a few small pock marks in the wood bowl surface.
The first thought might be, “perhaps a little sanding can fix the problem?” Not quite, these pits are more than they appear.
With closer inspection, the damage is revealed. The end-grains have been broken, snapped off and jostled around. The pockmarks are gaps or holes where some end-grain fibers have been ripped out completely.
To fix and level the surface, clean cuts must be made down to the deepest areas of these voids. I’ve seen these be as much as one-eighth to one-quarter of an inch deep in some cases.
Until all of the grain tear out area is removed with precise cuts, the tear out will remain, and sanding will do very little to remedy the problem.
My Grain Tear Out Story
When I first started turning, I was lucky you might say. At the time I had no idea, and I guess the fortunate thing was I didn’t know I was lucky.
Let me explain.
I love wood and woodworking. It was only natural that a friend of a friend’s Facebook plea for help with a fallen limb came to my attention.
The branch fell in the night and barely missed the edge of their home. Aged, dead, and rotting, the wood still had to be good for something, I thought.
I didn’t see the wood as dead and rotting, I saw spalted pecan! It didn’t matter that I’d never worked with this type of wood before, I knew it had to be good.
The idea of milling it into boards vanished when it became apparent we had no way to haul the massive sections out of the tiny fenced backyard. Logs it was. So we bucked the limb down to manageable chunks and loaded it on my trailer.
It was a good thing I got that wood when I did. Numerous neighbors stopped by and were eager to use the essence of that beautiful pecan to smoke various animal carcasses. That still makes me shake my head.
The logs were stacked in a dry place and sat to wait for their fate. This was about the time I decided to join the local turning group.
Hey! I have my own wood, I’ll bring that and turn it into bowls.
So, I did just that. Log after log produced bowl after bowl.
What I didn’t know, because I hadn’t turned any other type of wood, was that pecan is notoriously punky and problematic for producing grain tear out.
Ignorance Is Bliss
I turned and turned, or instead, ripped and ripped that pecan over and over. Everyone and their brother at the turning group gave me tips and advice on how to lessen the grain tear out.
Luckily, nobody said, “turn a different wood.”
Being a newbie, I thought that the rough surface was just because of my inexperience. How was I to know? LOL
Slowly over time, my bowls got smoother, and the grain tear out diminished. I learned to use a variety of techniques to tackle trouble areas.
It wasn’t until my pecan stash was almost depleted that I turned a different type of timber.
One day, with a sycamore bowl blank, mounted and a few rotations of the lathe I stopped, and my mouth dropped open. The sycamore cut like a bar of soap.
Oh. My. Goodness. Why had I been turning that rough punky pecan all this time?
Well, I’ll tell you what, it was pure luck that I turned that pecan first. I was lucky enough to get the best possible lessons for how to deal with grain tear out first and foremost.
Looking back, I’m so glad it worked out that I acquired that beautiful, yet challenging to turn wood first before turning an easier wood.
I learned so much more than I would have imagined from those persnickety pecan fibers. Now, let me share my knowledge with you.
14 Ways To Avoid Wood Bowl Grain Tear Out
1. Start with a sharp bowl gouge
A sharp bowl gouge might seem obvious, but it is the single most significant factor in reducing grain tear out.
Imagine the end grain fibers like little hairs. If those hair get hit with a dull bowl gouge edge, they will fall over and bend. Instead, we need to shave the wood fibers, much like using a razor.
Return a sharp edge to your bowl gouge as frequently as possible. And remember, if you’re wondering if you need to sharpen, the answer is YES and now.
For details about sharpening a wood bowl gouge, see my bowl gouge sharpening article for more information.
2. Supported wood grain
Cutting “with the grain” is a confusing statement, as I detail in the article about making supported grain cuts.
After sharpening the bowl gouge, nothing contributes to the reduction of grain tear out more than cutting in the proper direction with supported cuts.
This technique is so important that my article about Supported Grain Bowl Gouge Cuts really needs to be the next article you read if you haven’t read it yet.
3. Use Traditional Grind Bowl Gouge
The fingernail grind is the bowl gouge grind I prefer for most of my turning purposes.
However, with that being said, a more traditional standard grind offers better results when confronting problematic end-grain.
I can’t tell you why for sure, but it just works better. Perhaps it’s the steeper bevel angle or more bevel surface.
Whatever the reason, a traditional grind bowl gouge is excellent for making the final few passes, especially on the bowl interior.
Here is an article specifically about the angles of the bowl gouge bevel, it’s an important read.
4. Fine tune the curves with a negative rake scraper.
Aggressive scraping, in general, is not a great idea when dealing with grain tear out.
However, fine-tuning areas with tool marks or hills and valleys can be accomplished with light focused passes of a sharp negative rack scraper.
Another great option is to use a round nose scraper and “cut” instead of scrap the surface. Here is the link to all the details about cutting with a round nose scraper.
5. Increase the lathe rotation speed as needed but within reason.
You might think that 300 to 500 r.p.m. is super fast, but I’m always amazed how I can feel the bowl gouge dipping in and out of tool mark grooves at these “slower” speeds.
Turning up the lathe speed makes it more difficult for the tool to repeat bad behaviors and instead it will start to create new clean cuts.
In general, I never turn faster than 1,000 r.p.m. and much slower than that for pieces larger than 12 inches in diameter.
There is a lot to know about the lathe speed, read this article next that covers this issue.
6. Slow down the tool speed
Think about drawing a sharp knife across a sheet of paper. If the blade is pulled slow and steady, it will make a smooth cut. If the same knife is rapidly pulled through the paper, tears will most likely form.
Moving the bowl gouge through the wood fibers is very similar. Take your time and let the sharp bowl gouge edge make a smooth cut.
Quickly forcing the bowl gouge across the surface will usually result in grain tear out.
7. Make lighter deliberate cuts
Heavy, aggressive cuts usually result in grain tear out. Be deliberate and make more controlled less deep cuts.
The depth of each cut is not what is essential when dealing with grain tear out. We are most interested in clean-cut fibers with each pass.
Several clean cutting passes are much more valuable than a single deep, damaging pass.
Lighter, slower cuts are the hallmark of making great finishing cuts. Want to learn all about finishing cuts? Read this article next.
8. Stay on the bevel.
Riding that bevel is critical. So critical that I have an article solely devoted to understanding and learning to ride the bowl gouge bevel.
If the bowl gouge tip is not supported by the gouge bevel, tool marks and torn grain are sure to form. Think of the bevel as the guide that controls the cutting edge of the bowl gouge.
9. Angle the cutting edge
When cutting with either a bowl gouge or negative rake scraper, angle the tool cutting edge to reduce force. Experiment with subtly different angles.
By angling the tool edge, the sheer force of the metal to the wood is reduced, and a cleaner cut occurs.
Think of an old-school paper cutter. The blade drops down at an angle and makes a clean cut. If that same blade were lowered parallel to the table surface, the paper would probably fold and rip. This also happens to the wood fiber ends.
The angled cut is especially important when using a negative rake scraper. A more gentle and cleaner cut is made, rather than the scraper meeting the bowl surface at a flat 90-degree angle.
This technique is described further in my round nose scraper article, check it out.
10. Shear Scrape
Shear scraping is a bowl gouge technique that feels foreign and odd at first but is incredibly valuable for creating a smooth finish.
Incorporating the gentle approach of a steep cutting angle as described above, this bowl gouge finishing technique can produce results that rival beautifully sanded finishes.
Shear scraping can cleanly cut the wood bowl end grain while eliminating grain tear out.
I encourage you to learn more about shear scraping by reading this article about perfecting the bowl gouge shear scraping cut.
11. Wet the fibers
Occasionally, depending on the species and age of the wood bowl blank, wetting the surface can help to raise fibers.
Like little limb hairs, some wood end grains need a boost to position them for a clean cut. Wetting the wood surface can raise fibers and allow the sharp bowl gouge to make a clean pass.
When I worked with the problematic punky pecan I mentioned above, I’d often run into areas that were soft and spongy.
No matter what I did to try to achieve clean cuts, there always seemed to be areas that tore and ripped out.
At this point, if no other tips are working, try applying a layer of shellac to the whole bowl or just the trouble areas.
I mix my own shellac using shellac flakes and denatured alcohol. Mixing your own shellac is far better than any “shellac” product in the store.
The shellac will harden the soft, loose fibers and present them better to the sharp bowl gouge. When the cuts are made, instead of falling over or breaking off, the wood fibers stand tall and are cut clean.
Want to know all the steps for making the best shellac available, read this next.
13. CA trouble areas
Just like the shellac technique above, CA can be used in specific areas to solidify the wood fibers and make them easier to cut.
CA works great for particular issue areas like knots or bark inclusion areas.
Although CA can be used on the whole bowl surface, I find shellac is better for that purpose.
14. Specific sanding
Sand any trouble areas still remaining with focused attention. Do not sand with the lathe on as this will only increase any tool mark hills and valleys. Instead, find the trouble area, usually along the end grain, and sand with the grain to remove any tell-tale marks.
Sanding by combining lathe rotation and detailed with-the-grain sanding (lathe off) is the ideal way to achieve a smooth final finish on your wood bowls. I have an article all about how I sand my wood bowls. Check it out.
Grain tear out can be discouraging, but with persistence and patience grain tear out can be a thing of the past.
Take your time and experiment with one or a combination of the above tips to eliminate the tear out on your wood turned bowl.
And if all else fails, try turning a more forgiving wood. Ha!
On the other hand, if you really want to learn (or torture yourself) find some old ratty and punky pecan (or similar wood) to turn. The resulting bowls can be beautiful if you don’t make yourself crazy in the process of overcoming all the grain tear out issues. 🙂
Check out these other important articles as well:
• FINISHING CUT – WOOD BOWL TURNING BEYOND THE BASICS
• 5 WORST TENON SHAPE WOOD BOWL
• 13 WAYS TO RUIN A WOODTURNED BOWL
• 9 STEPS TO SHEAR SCRAPING PERFECTION BOWL GOUGE TECHNIQUE