Advice requested

[Maurice D]

Hi folks, I am new to the forum having been turning for about 12 months.
I would appreciate a little advice in relation to end-grain on bowls.
I have been trying to turn a Bubinga bowl but I am having trouble with the end grain on both sides of the bowl. I have sharpened my gouge, cut from base to rim and rim to base, and tried without success to sand it to an acceptable level but without success. I have been left with considerable pitting.
I don’t know if I am not working correctly or if it is the way the blank has been prepared, (it was a bought blank) or if it is just one of those things. I have decided not to turn the inside at the present. Your advice would be appreciated.

 

[cornucopia]

hello and welcome

end grain can be very problematic-some woods are worse than others and dry wood is always worse than fresh/wet wood. you should be cutting from rim to base and the gouge should be like a razor to get the best results- if you still have problems try applying some of the intended final finish of the bowl (i.e oil or wax) onto the problem areas and try again to see if that helps reduce the problem-if all else fail's power sand with 80 grit!!!

 

[wizer]

Also try some shear scraping techniques.

 

[CHJ]

You could try coating with cellulose sanding sealer before trying again, make sure your bowl gouge cutting edge presentation is creating a slicing action as opposed to a strait cross cut chopping action.

On the outside of the bowl you should get best results from going from base to rim as you are slicing towards the ends of the exposed grain, if you go from rim to base you are cutting into the end grain. Of course if slicing towards the ends the cutting edge is blunt it will pull the fibre out.


On the inside of the bowl you should get best results from going from rim to centre base.
Think of sharpening a pencil or think of the wood grain as a bunch of straws and how you would slice them with a knife.

This 'normal' approach can go very astray though dependant upon how the grain orientation presents itself in a particular blank.

By your description you are getting pulled grain ends due to 'Blunt Cutting' something the best turners are quite capable of doing, the only answer is as George says get the tools razor sharp, stiffening the fibres with cellulose sealer or lightly wetting the surface with water to swell the fibres and lubricate the surface may well help if you want a lubricant alternative to oil. Wet Shave :lol:

 

[Happy amateur]

One of the problems that beginners to woodturning do not always appreciate is the importance of rubbing the bevel when using a gouge.
It does not appear to be emphasised enough. Perhaps the experienced turners take if for granted.

It may or may not be the cause of trouble with tearout.

Fred

 

[Maurice D]

Many thanks for the replies, I would never have thought of wetting or applying sanding sealer.

 

[CHJ]

You're welcome Maurice, that's what the bulk of the membership is here for, to discusss and help with problems. Most turners have their pet method of fighting end grain problems but as George said if all else fails use 80 grit. As long as the article is finished well you will be the only person that knows and given time and experience the need will diminish.

As will the knowledge build that tells you that sometimes it's just not worth the aggro' to 'do it the politically correct way' and resort to 80 grit straight away.

The main thing to watch if sanding is to keep the form contour and use rotary sanding if possible, either friction drive, which I prefer, or power sand with a drill. One advantage of power sand is that it allows localised attention to a troublesome spot whilst stationary, just need to watch you don't spoil the flow of the curve doing this.

 

[Paul.J]

Hello and welcome Maurice
You found your way back on here then

 

[Maurice D]

Hi Paul, yes I had to create a hotmail account and a new user name but I got here in the end

 

[Deejay]

Also try some shear scraping techniques.

A bit late, but have a look at

https://www.ukworkshop.co.uk/forums/tear ... ight=shear scraping

Cheers

Dave

 

[guyandzoe]

I hope this isnt too controversial but rubbing the bevel is an art for the spindle turners. In the past too many spindle turners have taught and written about bowl turning.

In bowl work really 'rubbing' the bevel a la spindle turner inevitably leads to bounce (on the end grain usually) and other problems such as excessive vibration and the horror of cross hatching.

For bowls one needs to caress the wood with the bevel or even just have it there waiting to support the cutting edge if needed. If you get bounce then positively relax the back hand to take pressure off the bevel and go again. Practice by stopping the cut and listening to the sound made by the bevel alone. It should be fairly quiet and tickling the wood not pressing (rubbing) on it. It is preferrable to press down on the tool rest rather than force the gouge onto the wood when getting into such problems.

Richard's guide to using the long grind in Deejay's post above is very good. But I would also add the slicing cut - for the bowl's outside only - which is used flute up at 12 o clock cutting on the wing (not the tip) with bevel support and a horizontal gouge. DONT try it with a shallow gouge!!!!

And practice by turning by hand first - its probably not a beginners cut. The resultant catches in inexperienced hands can put any skew to shame.

Torn grain is often the result of scraping (not shear scraping) rather than cutting the wood.