Grits

[EnErY]

What is The recommeded grits to sustain the perfect finish before doing the business of the perfect shine some people differ in prefrencce but i'm of the opinion the timber in question that your working with defines where you go on the series of grits used,is this a fact or am i wrong? or is there some dedicated way of achieving the goal?.
Regards
Bill #-o

 

[nev]

IM(L)E its not necessarily the timber but the finish you get from the tool that determines which grit you start with. In my earlier days when using what I thought were sharp tools, but weren't, I would nearly always have to start at 80 or even 60 grit, then work my way through to 600 without skipping a grade. Now I have improved a little I can start at 240 or 320 and finish at 400 or 600 (unless its pens when i go through the micromesh too)

 

[Hesh]

I would agree with Nev altough I do find certain woods easier to sand than others, London Plane for instance I find sands to a very nice finish and I can get away with starting at 240 or even 320, others I may need to start at 180. Sharp tools are definately the way to go in the first instance but I have been known to use a really course grit to shape the odd bead or two..............

Steve

 

[tekno.mage]

I agree that the type of timber affects which grit I start with and how fine I go. For instance, if I'm making a fairly detailed little lightpull out of boxwood, I'd probably start sanding at 240 or 320 grit and go through the grits to finish at 1200 grit. However, an oak bowl will probably get started off with 120 grit and only go to 600 grit. I recently made some small knobs for an accordian maker in a variety of different woods - for most the sanding started at 240 grit and went through to 1200 grit, but the African blackwood ones I started with the 400 grit as the finish off the tool was so polished!

 

[jumps]

an interesting one - mainly for the different 'angles'

fwiw I find the wood will generally define the finish grade whilst, for the most part, my performance (or lack of it) dictates the starting grade. 240/320/400/600 being my norm

I did go through a phase with spindle work and the skew where I aimed to avoid the need for any sanding - but I soon got over that

 

[jpt]

An interesting question on which very few if any woodturners will agree.

Tony Wilson RPT says he always starts sanding at 80 grit as his grindstone is 80 grit.

I start anywhere between 80 and 240 depending on what I am doing and how good the finish is from the tools. All my pieces are sanded to 600 some to 1200 and pens etc right through the micromesh range.

Some turners, chas is I think one of them if not I apologise although I am not having a go, only sand to about 240 on English woods saying anything finer doesnt make a difference. I disagree with this and think the difference is obvious.

john

 

[Paul Hannaby]

Hi Bill,
Don't be obsessed by which grit number you start or finish with because it varies with different types of wood and different types of finish and what you are trying to achieve. Starting at a higher grit doesn't mean you are a better turner - just one with more time to spare! There are a few basic points to bear in mind -

Start with a grit coarse enough to remove any tool marks, ridges or furrows, torn or bruised grain etc. Don't move to a finer grit until all the marks have gone and if your first grit isn't doing the job, go to a coarser one.
All subsequent grits are there just to remove the marks from the previous grit.
The grit to finish at is the one that leaves an acceptable finish. Darker woods show scratches more so they would probably need a finer finish.
My stock of abrasives range from 80 to 1200 grit and all get used at some point.

I would also suggest there is no such thing as a perfect shine. Some things look good with a matt finish, some with a low sheen and some with a deep gloss. Sandblasting and wire brushes etc. can also leave an interesting "unsanded" surface.

 

[CHJ]

.......Some turners, chas is I think one of them if not I apologise although I am not having a go, only sand to about 240 on English woods saying anything finer doesnt make a difference. I disagree with this and think the difference is obvious.

john

Better put that into context, I consider any grit abrasive as just another tool, albeit one with a multi faceted cutting edge and should be used like any other so that there are no tool marks visible when the piece is finished.

Regarding minimum grit and wood types, as long as the scratches you leave on the surface are no greater than the wood structure, and lined up in the direction of the grain, and are not visible to the eye then why go ever lower to polish the high points if the surface coating you are applying is going to provide the gloss.

Now down to the 240 minimum grit statements, I think you will find that the majority of times I make this reference it is to items that are to be sealed (hardened surface) and then buffed through the grades which in effect takes the surface down well below the 600-800 grit level with no detectable scratches, therefore no point in sanding these pieces below 240-320 prior to sealing.

There is also a school of thought that with some surface finishes that too highly a polished base surface reduces the bonding capabilities of the subsequent finish.

I'm of the opinion that if you can't detect any scratches on a finished item regardless as which grit you stopped at then you have sanded fine enough.

Always remember the adage, "Sand with the grain" which with turning subjects may mean doing as much if not more with the lathe stationary.

 

[woodyturner]

I think we all have our own train of thought on sanding I'm one of the old school who thinks that grits are just another tool to achieve your objective when I was making furniture 240 grit was ample we used to call it flour paper.
With woodturning I always stop the lathe after each grit and sand with the grain were possible and find I don't need to go beyond on open grain 240 grit on dense grain 600 grit max but there are as many for as against this method

Acrylic is something else again but I wont get started on that one I hate turning the stuff LOL

 

[EnErY]

Thank you all for the useful tips comments and it has made things a bit clear to me and i think i know which way i'm going to head for its a long winded subject with varying opinions of which i value and also will take onboard for future reference
Regards
Bill