Where did I go wrong?

[Random Orbital Bob]

Bob,
Skipping a few grits if the finish off the tool is good is obviously normal and to be expected but what I was reacting to was the suggestion that somehow a starting grit of 240/320 on a bowl was what was reasonable all of the time and anything else was a sign of incompetence.

I was just redressing the balance - Bert Marsh was probably a little extreme in the other direction but if you check his book he says that he always started with 80-grit because he claimed it cut quicker and generated less heat. I was lucky enough to see him in action and indeed I can confirm that is what he did.

Jon

Fair point Jon. Its interesting how many different approaches there are isn't it. Clearly Mr Marsh is a veritable guru and it almost seems rude to challenge that approach. Yet I just cant see the logic in starting with a grit which will actually take the work "backwards" in terms of it's scratch pattern (assuming of course that the tool has left a finish beyond 80 grit). I guess Bert had chosen a "point in time" with his turning when he drew the line between tools and sanding. It's predictable and repeatable and probably very consistent and that's probably what he liked about the method. Almost despite the wood...you know where you are every time.

I think my pathological hatred of sanding has driven me in a different direction

 

[Random Orbital Bob]

But I should clarify...no suggestion of incompetence was intended...I wouldn't dream of it

 

[Mr Finch]

Hi Mick

Many thanks for the reply. You're right, whilst the sanding discussion is not necessarily relevant to me, it is an interesting read and I have learnt from it. FWIW I usually start at 80 grit as I find it can just sort out those few tool marks that I do have a tendency to leave behind.

I also actually (unlike many people apparently) quite like sanding and find it quite therapeutic, it means I can almost switch off and concentrate on the sanding forgetting other woes, at least for that time. I have no doubt that it will change but at the moment I find the tooling of the piece, while very enjoyable, takes lots of concentration and can zap my mental energy.

As far as the wood itself goes, I am glad the I am not 100% to blame (more like 98%!) and that the wood is a harder wood to work.

As I said previously I will try the elm again at some point. In the meantime I have a beautiful 3ft long 10 inch wide 3 inch deep piece of mahogany to play with and a load of green oak to cut up and turn too.

Coll

 

[Random Orbital Bob]

That raises a really good point Coll.

Try turning the green oak. Anything green is much more forgiving than the rasping, dry, brittle experience of more dry woods. The shavings coming off are more like long lengths of linguine

The value of green wood to your learning is that it is much more enjoyable to turn and therefore you spend more time with the various tooling angles and tactics etc.

 

[procell]

I can agree that turning green wood is a whole new experience. I acquired some Eucalyptus and some fruit wood that I have yet to identify and turning both of those was a pleasure compared to scratching away at dry Walnut.

What I find hardest is turning into end grain on small items like a goblet or egg cup. Still not sure if i should start at the center or come from outside to center.

I think my main problem is the tools I have. They are unbranded and do not hold an edge. Even with a jet wetstone system like the Tormek the edge only lasts a minute or two.

I am looking at some 2nd hand tools at the moment. Are Footprint ones any good?

 

[Paul Hannaby]

The tear out looks to be a result of soft areas caused by the spalting / decay. Some form of hardener, glue or even sanding sealer can be used to stiffen the affected areas so you can take a better cut before sanding.

There is an alternative approach - give up on the idea of trying to achieve a smooth, polished surface and put a rotary wire brush in your drill instead. That usually works well with elm but if it needs a little help, get the blowtorch out too.

 

[Mr Finch]

The tear out looks to be a result of soft areas caused by the spalting / decay. Some form of hardener, glue or even sanding sealer can be used to stiffen the affected areas so you can take a better cut before sanding.

There is an alternative approach - give up on the idea of trying to achieve a smooth, polished surface and put a rotary wire brush in your drill instead. That usually works well with elm but if it needs a little help, get the blowtorch out too.

great info, thanks Paul.

I don't own a blow torch (shock!) but I do have a fire pit!

 

[chipmunk]

Sorry for bringing up Bert Marsh again but he used a technique which may help here...
I do read other books and watch other demonstrators - honest.

After each grit he applied thinned cellulose sanding sealer wiped off the excess and let it dry before moving on to the next.
That hardens up any punky areas - it also evens out any open grain and anything.

Paul's suggestion about scorching and wire brushing works ok but isn't a panacea. You can't obliterate a poor shape which doesn't flow or ridges as these will still telegraph through - you'd be surprised. I often find it's best to sand with coarse grits before scorching and wire brushing.

HTH
Jon

 

[Random Orbital Bob]

Bert s.o.d.d.i.n.g Marsh....he's appearing in my nightmares already. This huge monster of a man...firing 20 grit...nee sharkskin sandpaper from an automatic weapon

Seriously though Coll....some great advice in this thread...and don't forget to try turning green wood, you really will be amazed at how much more pleasant the experience is.