How fine is your tungsten finish?

[cardiffrob]

I've just seen an advert for reground tungstens and they seem to display an almost mirror finish. Just how smooth should they need to be? Y'know, are yours a bit 'lined' or does anyone polish the surfaces after a grind?

 

[Country Joe]

How fine is my finish?

Hi there,
Not good, as I've just killed my bench grinder.
Think I heard someone before saying they used a flap disc to sharpen them.
I'm a few touch-downs away from doing this, though - as I still have a few sharp ones left.
As far as finish is concerned - they never seemed too bad, but I always kept the finer wheel on the grinder, exclusively for doing tungstens.
If I can get a good shot of one of my sharpened ones, I will - then you'll have a comparison.
All the Best,
CJ

 

[wyn]

I have tried a polished finish once using a polishing disc for grinders. From what i remember it was ok but soon ruined with a touchdown.
What i have found handy is to get whatever type of finish you have, to be consistant. So every time you change a tungsten the arc behaves similar to the last one.

 

[pedrobedro]

As long as the lines run in the right direction it shouldn't affect your arc. Polishing them sounds a bit anal. I do mine on 80 grit fibre disc in the angle grinder sometimes and they work.

 

[Country Joe]

Here are 3 2.4mm tungstens. These look pretty rough, to me - much rougher than I'd imagined, but they seem to work like that.
They're "Multi-strike" (Huntingdon Fusion?), so maybe they come up rougher, anyway. Must admit I've never really studied them (or any other types) this closely before now.
Still much more gouged than I'd have expected!
Maybe I should be ashamed of them, then? But at least the gouges are in the right direction, I suppose.
In the beginning, it didn't really seem to matter much, so long as I had quite a few ground up. Hardly seemed worth sharpening at all, as they'd all tend be contaminated, quite often in under a minute - or so it seemed!
Have you seen the price of tungsten grinders? Horrendously expensive - but why?
All the Best,
CJ

Obviously those were done on the grinder (which is no more) so my flap disc'ed ones will be much better!

 

[hotrodder]

Surface finish does make a difference, smoother/polished is better with regards to tip life (obviously doesn't apply if the tip is melting to a balled/rounded finish with AC) and arc stability- particuarly with low amp work

If you are resharpening tungstens due to touchdowns and the like then it's a waste of time/money to go beyond the finish you get from the finer of the 2 wheels on a bench grinder

If you're usually redressing tunsten due to natural tip erosion then a better surface finish will result in more arc time between sharpenings. For most people, most of the time it's still not worth going to any extra effort as the benfits are minimal considering the time it takes to touch up a tungsten. Exception is low amp work imo when tungsten prep can make quite a difference with regards to arc stability and arc shape

Don't read too much into what's said in these links as they are aimed more at automated TIG, tube mills and the like i.e. overkill for most people, especially while learning...

Everything you ever wanted to know about tungsten (and a lot you didn't)
Effect of tip geometry on arc shape versus stability

Expensive tungsten grinding machines... they're specialised kit, with a smallish market but will pay for themselves in the right circumstances. Could fit out a bench grinder with diamond or CBN abrasive wheels as done by this guy... a bit OTT in many regards but much less mess/dust, diamond abrasives will last virtually forever on tungsten sharpenin duty and won't need constant redressing

 

[Uniqueusername]

I've tried numerous ways and simply because it's usually within reach i just use the BACK of whatever grinding disk is in the angle grinder at the time.........
I'm not a complete animal, i do try to get a decent finish.

 

[Welderpaul]

I've been known to grind tungstens using a flap disc if we're caught out on site without enough spares. Works ok, but not quite as good as using a bench grinder.
We have a really cheapy grinder in the shop that is too weedy to do any proper grinding so never gets the wheels contaminated.
Those tungstens you have ground are fine CJ, the 'grooves' left by grinding help 'channel' the arc to the end of the tungsten, thats whey they should never be ground at 90 degrees to the length.