Metal polishing: what's in those Josco crayons?

[rsser]

I've sent them an email asking but no reply.

I want to hone/polish HSS woodturning tool bevels, taking them from the 80g bench grinder wheel to 1000g or better, using power honing with an array of wood discs used on edge on the woodlathe.

It would be helpful to know what the particle sizes are to plan the steps.

I'm a complete newbie at this kind of thing so go gently if I'm off with the faeries :wink:

[Grahame Collins]

There must be a Josco MSDF for the crayons.
it will be must likely there.
Grahame

[BobL]

There must be a Josco MSDF for the crayons.
it will be must likely there.
Grahame

I had a bit of search a couple of years ago and couldn't find anything so I also contacted them but they never got back to me either.

I did find a "components" listing from somewhere at work and from memory they had a range of Silica/Al/Fe oxides plus some animal fat like tallow, and some other waxes in them. Maybe we should try again to contact them again?

[rsser]

There are no data sheets on their website unfortunately, and as posted above, they didn't bother to reply to an email.

[malb]

Hi Ern, from a few years of metal polishing, I suspect that you are pushing the proverbial uphill.

There are a range of compounds available, which are basicly a wax impregnated with abrasive dust and pigments to colour code them. For general polishing of mild and stainless we worked through belt grits to 600 or higher or trizact A10 (btn 1200 and 1600 grit), then used a dark grey compound on a stitched cotton wheel, followed by a green compound on an open cotton mop and then a white compound on an open cotton mop. I believe that the abrasive in the white compound was white lime.

Have seen so called polishers buff from 120 grit using the same procedure. They could develop a nice shine but couldn't get rid of the 120grit channels in the metal, they just highlighted them and made them stick out.

My concern with your approach is that whatever you use for your wheel stack will have a much coarser grain than compunds that you use, and this will be the dominant feature on the finish. The only solution whould be to set leather strops around the periphery of the wheels to eliminate all grain effects, flexible mops will spread and round the faces, destroying the effort of getting the cutting edge straight and square.

I figure a three stage system would be adequate, but once again the result is in the prep, not the polishing.

[rsser]

Thanks for sharing your experience Mal.

Yes, jumps btwn grits that are too big has been a concern; will see if I can get sil.car. grit to stick somehow.

Some carvers have had success with green crayon (chrom oxide) on MDF disc edges. But that's around 5 microns I think and a loooong way from 80g.

And yes, some leather is on the way as an alt've. Used for hand stropping and by Tormek etc for honing tool edges.

[Harry72]

Autosol paste is pretty fine, it will shine like a mirror.(better than 2000g W&D)

[rsser]

Thanks Harry.

There's no shortage of compounds at the fine end:

Flexcut Gold ... 'down to' 0.6 micron but many particles much larger; from the website: "Its blend of aluminum and titanium oxide provide a balance between aggressive removal of hardened tool steel and offering a high-color polish." Trying to source some of it ATM.

Veritas Green .... '0.5' micron - they don't confess what the range is

Tormek paste .... mix of 3, 2 and 1 micron alox particles

[hughie]

many years ago I used collect edged weapons and restore them to close to their former glory.
For the most severe effected I used to start with fine valve grinding paste on a felt buff, progressing up to coarse( not sure of the grit I think 250 } lapping and fine ( 500grit )lapping compound. Final polish with jewellery's rouge on a cotton un-stitched buff.

It was lot of work but it did produce a very fine finish

[rsser]

Thanks Hughie.

[Greg Q]

I have used the Veritas green stuff before on a very hard felt wheel. Works well enough. The best results were from Autosol on a leather strop, plus it's cheaper, available everywhere and does not dry out*

*assuming you don't lose the cap like I always do.

I note that you can get diamond lapping compound in a lot of ten tubes of various grits ex china on ebay. I have some, but I think it's all 8 micron.

I don't know if there's any intermediate sort of compound...the different colour joyco sticks seem to be for different metals mostly.

Greg

[rsser]

Thanks Greg.

Yes, diamond paste is available - don't know how much to order. They're 5 g tubes, and an 8" x 3/4 disc is about 19 sq in on the rim in old money if my maths works. Assuming a leather coating, care to guess how far a tube would go?

The ebay seller didn't care to guess.

[Greg Q]

A little of that stuff goes a very long way. I reckon a two pea sized glob would coat the wheel, and less to recharge it.

The more I think about this the more I wonder if your plans could include a few sandpaper lined discs? That way you could at least get past 1200 grit before trying compounds. I have only ever used waterstones up to 8000 grit* before honing.

*which is a different grit standard, but I am too rushed to look it up right now.

[rsser]

Yes - seems there are a range of options. eg http://www.woodworkforums.com/f10/diy-gouge-hones-99350/index3.html

ATM I'm committed to disc edge approaches, on a lathe arbor, ultimately with a 12mm rod mounted in front to take Tormek etc woodturning tool jigs. Just proof of concept - that you don't need a $1200 Tormek with HSS tools

PS will send you that steel bar for the TCT scraper today Greg.

[Greg Q]

What are we doing up so early?

I have to go on another trip Monday, so it'll be later next week anyway before I get a chance to do the carbide thing.

Greg

[rsser]

LOL ... insomniacs rue!

No rush at all. I'm recovering from a broken wrist.