How to get smoothly-turned burl

[wortmanb]

I just turned an afzelia wood fountain pen, and while the process was highly enjoyable, I think something's missing from my technique.

The pen looks wonderful, but my fingers can make out areas where the pen "ripples", for want of a better term. It's as if the various grains in the burl kept me from achieving a perfect, uniform thickness, and there are instead areas where there's the slightest of dips when you feel the cap or tube from one end towards the other.

I knew there were variations, but I foolishly assumed I could knock down the high points when sanding. That didn't work very well -- mostly, the Abranet just followed the contours and I got nicely sanded ripples.

I'm currently using 3/4 and 1" gouges for pretty much everything, and I've been pleased with the results on most blanks. I occasionally grab a detail gouge for rolling over the ends, but I'm not particularly adept with that or with a skew, so I probably need to practice on some waste blanks to get the hang of it.

What technique(s) should I work on to help avoid this problem on my next burlwood pen?

 

[booney0717]

I'm no expert by any means and i sure that others here will probably be of more help to you than i will but i'm gonna throw my two cents in anyhow. Burls are my favorite woods to work with so far and i ran into the same problem with a few at first. I turn using a mandrel and bushings, others turn between centers. What i do to help is i stop with about 1/8 of the blank left over the bushings and sand down to them. Its given me a nice smooth uniform body to finish over. I also mostly use a ca finish and i lay it on pretty thick. They usually look pretty good that way. Like i said others here wiil probably have some better ideas but i hope this helps out.

 

[Dick Mahany]

The pen looks wonderful, but my fingers can make out areas where the pen "ripples", for want of a better term. It's as if the various grains in the burl kept me from achieving a perfect, uniform thickness, ................

Burl typically consists of varying densities throughout the wood. In addition, the grain runs wildly and in all directions. This means that when the blank is spinning, you are turning side grain and end grain everywhere along the blank which cause his effect.

From my limited experience, I have been able to eliminate all but the most subtle of this by using a SHARP skew and frequently feeling along the blank while it is spinning for the ripples. I use a very light touch and gently shave the high spots. So far it has worked pretty well for me.

 

[Haynie]

I have found that letting some thin CA soak in as you turn even these out. That and a sharp and heck skew with light cuts. I got lucky with some amboyna CA and scraper the last time. Dropped my skew on the concrete, point down of course.

 

[Randy Simmons]

I have worked with a lot of different burl woods, and afzelia is probably one of my favorites. I am no expert with gouges, and I almost exclusively use a skew chisel for my finishing cuts. I would recommend two different things:

first, learn to use a 1/4 skew to make your finishing cuts. Hold the tool as straight as possible, and work from the outside (bushings) into the center of the barrel, taking off little bits at a time.
second, you may want to get a sanding block. When sanding, your fingers tend to just follow the contours, which is nice if you actually WANT to follow the contours of a "shaped" pen. But if you are working on a straight profile, you'll want a flat sanding surface.

Hope this helps,

Randy

 

[George417]

The pen looks wonderful, but my fingers can make out areas where the pen "ripples", for want of a better term. It's as if the various grains in the burl kept me from achieving a perfect, uniform thickness, ................

Burl typically consists of varying densities throughout the wood. In addition, the grain runs wildly and in all directions. This means that when the blank is spinning, you are turning side grain and end grain everywhere along the blank which cause his effect.

From my limited experience, I have been able to eliminate all but the most subtle of this by using a SHARP skew and frequently feeling along the blank while it is spinning for the ripples. I use a very light touch and gently shave the high spots. So far it has worked pretty well for me.

+1 on the VERY SHARP Skew

 

[txbob]

Use a scraper

Any tool where you ride the bevel (like a skew or gouge) will continue to give ridges in a blank with hard and soft spots. The best solution I've found is to use a scraper, which touches the blank only with its cutting edge. Once the blank is ready for sanding, do as Randy said and use a sanding block, Backing the paper with a soft pad or your fingers will create ridges as the soft wood sands away faster.

If you don't have a scraper, turn a sharp skew on its side and make a scraping cut instead of a slicing cut as you normally would with a skew.

txbob

 

[Dan26]

+ 1 on the sanding block.

 

[bradh]

I agree that the uneven surface is from sanding, the grain has softer and harder sections. I counter this on burls and soft wood by stopping my rouging at about 1/8 to 1/16" oversize, soak the blank with CA and let it harden without accelerator. The CA will soak into the wood and harden it. This evens out the hardness and also helps prevent chunks from breaking out, which is a common problem with burls.
Do the final cuts to size with light cuts and a very sharp skew. Resharpen often, burls often have silica in them and that dull tools quickly.
I turned a nice Afzelia burl blank last night and had to re-hone my skew about 4 times just to do the final sizing cuts. There was something hard buried in that wood.

 

[gallianp]

sorry I posted before re-read the original post.

 

[tim self]

Another vote for the skew. Some think the learning curve is to steep but is well worth the results. ALL my pens get the skew treatment.

 

[jbswearingen]

If your blank is a cylinder (no curves) placing your strip of sandpaper on a stiff, flat piece of wood can help. If the blank is curved, it might work. Give it a try.

 

[CharlesJohnson]

I use 1" strips of sand paper on a 1" strip of fun foam when sanding a pen .This evens it out good for me. I use a clean strip of the foam for applying Ca finesh in heavy enough layers for it to even out pretty good. This can easly follow flowing curves too. Good luck and have fun.

 

[Dick Mahany]

Any tool where you ride the bevel (like a skew or gouge) will continue to give ridges in a blank with hard and soft spots. The best solution I've found is to use a scraper, which touches the blank only with its cutting edge. Once the blank is ready for sanding, do as Randy said and use a sanding block, Backing the paper with a soft pad or your fingers will create ridges as the soft wood sands away faster.

If you don't have a scraper, turn a sharp skew on its side and make a scraping cut instead of a slicing cut as you normally would with a skew.

txbob

Agree completely with Bob here..........for my final shavings, I use the skew lying flat and " shave". No bevel rubbing in this mode for exactly this reason. The shavings look like dust rather than curls in this configuration.

Great clarification !

 

[walshjp17]

For the finishing touches, I've had a good bit of success lately with a spindlemaster instead of a gouge or skew. Seems to work well with most woods including burls.

 

[bradh]

Any tool where you ride the bevel (like a skew or gouge) will continue to give ridges in a blank with hard and soft spots.
==trim==

Sorry, I do not agree with this. If this was true, you would never be able to round a blank with a skew.
Changing the angle of the handle left to right will present the cutting edge differently and change where the bevel is rubbing relative to the cutting.
If you present the cutting edge almost vertical, you will get very fine light cuts, but it can also produce ridges.
Once you really understand the skew, the surface finish is great and you can skip the coarse grits of sandpaper. The coarse grits are the ones that remove lots of the softer grain and can make the surface uneven again. Stiff backing for the sandpaper will help, but can also lead to deeper scratches from the sandpaper.

 

[Sabaharr]

I use the skew like a straight scraper and knock down the high points very gently producing only fine dust until it is smoothe.

 

[hard hat]

+1 on the sharp skew. learn to use the skew and it'll never steer you wrong.

 

[flyitfast]

I have found that letting some thin CA soak in as you turn even these out. That and a sharp and heck skew with light cuts. I got lucky with some amboyna CA and scraper the last time. Dropped my skew on the concrete, point down of course.

Hope your foot/toe was not between the skew and concrete!! :biggrin:
Good hint on the CA. This whole thread is a good "mini" tutorial on cutting burl.
gordon

 

[Deadhead]

+1 on the skew lying flat on the rest. A sharp skew laid flat gives me a nice smooth surface, especially on acrylics and resins.

 

[healeydays]

I too have had problem with burls and have found as it is usually a twisted/nasty piece of wood with different hardnesses, some thin CA soaked in toward the end does makes a big difference and then finishing it off with a sanding block does the rest.

Mike B