machining 99.995+ tin

[scottp55]

Hard maple. Made 1.75" children's blocks with 3/16" radius. drilled holes .75,1.0,1.25" diameter and depth (6 blocks) and my father filled holes wth molten tin from his old thin film coating company(purest of pure,did it on the stove with a bottom spout crucible) looks nice and very heavy( 8 oz. for the heaviest block) but the meniscus is .1875" above the surface of the block. a full tray of 13 x 10 blocks on the desktop. How would I program Milling down just the tin(.75" or the 1") and what bit, feeds and speeds. Has any body done anything like the this? Ideas and approaches welcome as I don't even have the machine yet. He has Hundreds of pounds of the stuff and autistic and learning disabled children like weight. He might want to engrave or texture the surface, Help. Odd, but that's why we went CNC router, adaptability and creating out of the box. Thanks to everyone for their help so far. I am over my head, I cannot wait till I can help someone else in the future. Scott

[Brady Watson]

Post some pics.

If you are bent on doing it on the DT, then you'll want to make some V-fixtures that hold the blocks on a 45, all in a row. Two strips mirrored to clamp them together. A cam action clamp (you can machine your own out of maple) can be used to cinch & lock them shut.

...or you can just use a sander like this one: Grizzwold's (http://www.grizzly.com/products/Combination-Sander-6-x-48-Belt-9-Disc-Z-Series/G1014Z)

-B

[shilala]

I'd sit put all the blocks on a smooth surface, make some 1"x1" (or thereabouts) square stock, and clamp up the blocks.
Then I'd screw the whole deal down, clamps and all, centering it on the table.
I'd mic the thickness of the block, then the thickness of the highest miniscus for reference.
I'd measure the outside of the project in x and y, then add 1/2" to those dimensions.
Then I'd create a new project in Aspire, making the project an inch larger on each side than the x+1/2" and y+1/2" dimensions. Then I'd create a rectangle inside the project field the same as the x+1/2" and y+1/2" dimensions.
Then I'd create a pocket toolpath setting the start depth 1/8" above the miniscus, and the cut depth down to within .006 of the top of the blocks. (Zzero would be the top of the blocks.)
I'd use a 1/4" endmill, run at maybe 1.0ips and 10,000 rpm's.
I wouldn't even think of cutting the project until I messed around and cut a lump of tin first. That's show me how to tool it. It shouldn't be a big challenge, I wouldn't think.

Scott, this is a really rudimentary thing. It's good to ask cause it'll give you ideas, other guys might do it different. What I wanted to suggest is to dig into the Aspire videos while you still have time. They are VERY well done and will teach you all the toolpath operations and give you tons of ideas. Even if you don't use them now, you'll remember it can be done and go dig into the videos later.
There are so, so many videos that I wish I could make time to watch them all. I just need to clamp down on myself so I can take advantage of my own suggestion. :)
Good luck, brother!!!

[shilala]

...or you can just use a sander like this one: Grizzwold's (http://www.grizzly.com/products/Combination-Sander-6-x-48-Belt-9-Disc-Z-Series/G1014Z)

-B
I need a good combo sander. Both mine are junk. So much so that I never use them.
More than that, I'd kill for a 24" drum sander. Get me one for Christmas, will ya, Brady? :D

[scottp55]

Brady, not dedicated at all. exploring options, higher weight seems better n initial tests, bismuth might be better S.G. but way more than $2 lb. with stock available on hand. Need to research v-fixtures. My favorite is to weight blocks with 6 pennies in 7/8 x 7/8" hole and cap with plug. nice sensory. Tin was just available, non-toxic, and heavy. It seemed bright and soft and tin oxide appears to the naked eye clear. Scott, thanks. I was wondering if I could do a vector boundary type thing to cut time. Easiest Probably to 6" the whole batch with a rough grit or 4x24" an 18x24" batch. Feeds and speeds and bit for 100% tin or reference to -------------never mind I'll try to look it up tomorrow. Thanks.

[scottp55]

Wow,
2 YEARS ago!! And I'm just getting around to try cutting today and searching for feeds/speeds on Google and this popped up:(
Going to try a VInlay on the 1.25"D block.
Probably a super simple design so I can use my Onsrud 61-040 for clearing(.125" 1F super O) and then probably a 30degree 2F engraving to cut back on material to be removed.
Only air for cooling initially, but after scoping chips out, MAY try seeing if ambient air from DC will work.
Probably start with 360 brass speeds that Brady was kind enough to suggest last year.
First metal cut, and good practice for Brass/Marble ?:)
I'll be the guy hiding behind the plexi shield:)

[scottp55]

Well, it surfaced so well I swapped blocks to the 1" diameter and surfaced that as well and used it for practice.
Read at last minute someone saying Tin was very brittle on CNC forum so ignored Brady's advice:(
Still so nervous though that my feeds were at least 3X too slow and rpm was about 5K too fast:(
By the time I got in the ballpark it was DONE and it was pretty much Toast!
HORRIBLE!
Didn't stick to bit at all though.
Burnished over the horrible finish and recut and STILL needed to go faster.
Should have spent more time setting up as we cut holes in a dozen at a time that day and tolerances built up, and I only eyeballed the calipers with the radiused edge instead of getting the square out, so off center.
Wish I had one more to practice with, but...
Not happy with it, but at least I'm getting closer.

[scottp55]

Happier:)
Only had to go from .5,.1,17K to 2.6,.1,8K to get chips at .01" passes with Drillman1's Kyocera .125" 45 engraving:)
Probably tweak some more but better than it was.
Hey, I was only 200 to 500% wrong on my Guestimate:)
His .0625" 2F up was fine at 1,.2,14K at .02" passes.
Oh well.
To late to set up and cut male for VInlay--Not sure what wood I'll try.
Female here is .02" deep.

[scottp55]

Close ups.
Raised edge was very first pass when I started at 1.8,.1,12K before I S(hifted)> and dialed back to 8K
Tin is a weird critter!
I don't cut my hardwoods that fast!!:)

[scottp55]

Oh, Be CAREFUL with VCP8.014!!!
All I did was duplicate that toolpath/double my pass depth and Z-move speed and got THIS.
Have to see if VCP8.017 does it, but need a downloadable 8.017 for control computer:(
Happened in the Celtic design this was going to be as well, but thought it was a one file Glitch, so changed to the "Fleur".
ALMOST ran it without previewing the "Speed Pass"....THAT would have bummed me out!

OOPS TYPO!
Female .1" deep.

[scottp55]

VCP8.017 on the laptop just eliminated that groove by simply recalculating----So it's a software glitch in the downloadable Shopbot version VCP8.014 on my control computer.
Anybody seen a downloadable Shopbot version for non-Internet computers of VCP8.017 ?
Probably send that file to Tech tomorrow.
Time to look for suitable scrap :)

[gundog]

Scott is it possible the tool won't fit? I have had that happen in the past between vectors if they are too close it will ignore the tool path completely.

[scottp55]

No Michael,
First toolpath previewed fine, and then when duplicated it took that "Shortcut" across. Same exact toolpath on Laptop with 8.017 and it recalculated clean. Took it out to control computer on a thumbdrive and recalculated with 8.014(Shopbot edition) and it showed the same exact gouge again:(
Happened on a Celtic design yesterday also on the control computer.
Made it interesting today cutting the Male for the VInlay:) as I was using scraps and didn't dare recalculate.
Decided to go Purpleheart as Wenge is splintery and can sand uneven.
May not unclamp till Weds as I used Goop to glue it after Dad mentioned how hard bond to Tin would be. Took the tip of my mini-burnisher and managed to get some small upward pointing fishhook burrs into the Tin in a few places for a slight possible mechanical bond advantage.
Cleaned all with denatured before gluing.

Thanks Michael---Yep done THAT:)
Wondering what I'll have when all is said and done with this?

[scottp55]

A couple more. (Notice the extremely efficient high production clamping facility:)

[gundog]

I really like your clamping table Scott.

[Brady Watson]

It is possible to melt the tin and pour it into the incised wood part...then just sand off the top. Viola!

The melting point of tin is around 450 deg F. You could melt it in a toaster over broiler if you had to... I would of course be careful about using any wood more than 8% moisture content. Bad hurty boo-boos ensue from steam...:(

-B

[scottp55]

Thanks Michael. (Although I don't know which one you mean:)
If I'd spec'ed more overhang on the Granite...I'd have 36' linear:)

Got a couple pounds coming Brady, now that G. got me thinking with his Aluminum VInlay.
Yep, Dad wanted me to pocket some 12% Maple blocks and I refused and threatened to Quit:)
You got me thinking of how to do an undercut(Maybe just a little Foredom work), have to see if there's any inherent bond. Maybe pith between growth rings on some species would "Burn out" enough?
Hard telling...Not knowing:)
Going to take some experimenting.
Got a ton of weird shaped TINY HSS burrs for the Foredom that fit my 1/8 collet I might play with for a "keyway".
Needs thinking...this was just a day off on of.
Back to 3D buttons tomorrow.
Thanks,
scott

[Burkhardt]

Fun experiments! As for pouring into the wood, while the tin melts at 450F, you will probably have to heat it up somewhat higher to keep it liquid while pouring and I suspect the wood will brown a little. So, a dark wood may be better for that and look anyway better with the bright metal. To avoid the fuzzy edge when machining, you may want to try the liquid lubrication/cooling. It made a big difference for my aluminum experiments. If you want to limit the mess you can use an eye-drop thingy with 50% IPA/water (I guess cheap vodka would work as well) and a drop of soap. Keep dripping more once you see it evaporating and dry up. I was first worried about the clumps of wet chips that build up but they did not cause much problem with the aluminum.

Since you are using that super pure tin and live in Maine, don't store it cold in the winter or you may get tin pest and it turns into grey powder.

https://www.youtube.com/watch?v=FUoVEmHuykM

[scottp55]

Thanks G, Didn't Know about "Pest" Have to ask Dad as they bought literally tons of this.
Didn't see much if any discoloration on that Maple.
Feel stupid as Dad's old head machinist(still working for Soleras) told me to call anytime for help, and only lives 10 miles away.
Have to give Bill a call! :)
Think Dow Corning(glass division) uses this stuff, but not sure where or how.
Not sure vodka would make it to the bit:) and as it's been 10 yrs since I've seen the stuff...Good riddance:)
Wonder what 3.5-5% added Sterling will do...Looked like interesting alloy. Melting point wasn't Much higher..and this stuff is SOFT.
Got sterling wire and flux, may cast an ingot.
Needs more reading in my metalworking handbook.
Need VInlay wood button first.
Just playing.

[gundog]

This one

http://www.talkshopbot.com/forum/attachment.php?attachmentid=24981&d=1430782815

[Burkhardt]

Think Dow Corning(glass division) uses this stuff, but not sure where or how..
Float Glass (http://en.wikipedia.org/wiki/Float_glass)

As an engineering student in the 70's I interned for a few weeks with Siemens in a rebuild of such a float glass kiln control system for Saint Gobain. Oh my...what a hell hole of a factory. Imagine an acre of red hot tin and glass in a long hall building.

[scottp55]

Thanks Michael:)
Bill Young's design he offered to Desktoppers in #12 on this thread
http://www.talkshopbot.com/forum/showthread.php?19057-Desktop-Jigging-Pics&highlight=desktop+jigging

I just stretched the "apron" a little to hold wider versions of his fences and added a few hundred threaded inserts:)
Mine's the Mach 1 so had to add cutting area MDF so I could surface, but before I made the second one for Northern Desktop, Bob Dodd suggested adding a "recessed apron" so cutting area is raised, and then 1/4" MDF could be glued down when spoilboard gets down there.
Dowels pretty much do the alignment and then Fastenal "connection bolts" makes sure it doesn't budge/lift and really low profile and no washers needed just an Allen key.
Need to make some fences with slots for the bolts so I can retrim fences as needed, also, I love the Shopfoxes, but really limited throw and need a few spacers and shim with tongue depressors. Need to make some wooden cam clamps when I get a chance.
I'm avoiding going back to a "layered" file that's driving me crazy...Can ya tell? :)

VERY easy to set up material, and corner jigs in those files make it easy to reference anywhere in the cutting area

[scottp55]

Don't think so G.
All Dad's company was Thin(Microns)Film Vacuum Coating, Think TiN (Ti Gold back then),CD's,Computer chips, Canadas mylar hologram on their money was Dad's machine, your car headlight.
Pretty sure it was somewhere in their reflective coatings and it would have been a consumable for Vacuum Plasma Coating.
Pretty funky standing in a T-shirt next to one of Dad's(Ulvac NA then) machines and watching Titanium turn into a puddle and then the gas cycloning up to coat my Campagnolo Chainrings:)

JUST called Dad as I was curious, our stuff started as 99.99999% but if it overflows the sprue,or if theres a "spill" then they're not allowed to use it in the line so they remelt and sell huge ingots.
Said this stuff was probably four 9's.
NOT FAR OFF THOUGH:) He said the Vacuum coating machine is only a few hundred feet from the end of the "Float Glass" line(the "closer the better" he said).
Said Tin is 2 layers on the glass(9 layers?) you see on those skyscrapers that look like mirrors/metal.
Said Tin at molecular levels is an infrared barrier that saves on heating/cooling.

[scottp55]

Yep,
Offcenter (but I didn't pour the Tin:)

[steve_g]

Very nice Scott! You’ve got my attention…
SG

[dmidkiff]

Scott you do some good work, always tinkering. I like that.

[scottp55]

Thanks Guys!
Always kicking myself about how I could have done it better. Must be a Human trait, OR possibly hereditary?
Expected an "Attaboy" from Dad, and got THIS in an E-mail last night with him critiquing HIMSELF:)

"In looking closely at the block you used for the Fleur de lie insert trial I see some shrinkage, probably from the cooling contraction of the solidifying Tin in the maple exists in the block.

In a toy block for children this gap could harbor and propagate all kinds of unpleasant bacteria. It would a benefit for a snug fit but how to eliminate it could get expensive.

Tin has an coefficient of expansion (COE) of 23 while wood has a value of 30 perpendicular to the grain. I interpret that as being the direction in the trial block. The COE of wood parallel to the grain is 3 so there is a lot to play with.

It the wood number is higher than the tin, the wood should shrink to prevent any gap. Evidently things are not as they first look.

There are alloys, like type metal that expand when they cool or zero expansion metals that would be gripped by the wood as it contracted. I don't know the alloy mix or cost but lead and/or cost could blow it.

Needs some thought.

mike p"

Leave it to an Engineer:) (Now Me, I'm not thinking blocks for kids at all!!)
Thinking that when poured, surface tension leaves the Tin "Proud" and maybe as it's so soft and malleable, a few "Whacks" with my planishing hammer could force it into the voids AND work harden at the same time?

Funny Steve, Last night I was wondering if it could be poured into splits like your Table, AND mill out a through Butterfly so it would be integral:)
Also wondering about filling loose knots, with or without "TInlay"
Woods can't ALL expand the same, and should be localized anyways?
I guess we'll see.
Like Dad said "Needs Thinking"
Like scott says "Needs Playing":)

[scottp55]

Wonder how it would look on "Wormholes"? :)

[dmidkiff]

Scott, check this out. Not tin. Molten aluminum in wood.

http://www.woodworkingnetwork.com/woodworking-project-photos/woodworker-project-plans/290428911.html#sthash.RAKf4KtT.dpbs

[scottp55]

Thanks David !:)
Not sure I like the legs and the charring(or turning my garage into a foundry:)
But DO like some of her earlier "Putzing"!
Saw some pics of what I was thinking of like Steve's split slab and small knotholes and splits for some Black Walnut I dug out yesterday.
Hoping Tin will get further into cracks than Aluminum and have minimal charring.
STILL wondering what would be a "Product" that Northern Desktop(Vcarve or Vinlay) and Kirk could do without scorching themselves AND the shop and do in a produce-able fashion:(
Found more on her Facebook page:)
I'D be happy just having a piece like that just to look at and touch(Funny, you hold that block and everything is warm UNTIL you get to that face...and it's cool and smoother than the 400G Tung'd Maple...interesting).
Pretty much what I was hoping to see in the pics from Facebook.
Thanks again!
scott

[scottp55]

Duh!
Facebook photo page from her site.
https://www.facebook.com/hillashamia/photos_stream?ref=page_internal

[scottp55]

Just researching a little and thought of BIsmuth shot, now used as the non-toxic shot for bird hunters.
Interesting to read it EXPANDS 3.32% when it solidifies:) Used in PeptoBIsmal---so when pure it can't be too bad.
http://en.wikipedia.org/wiki/Bismuth
Melting point isn't much higher and apparently it alloys with Tin well?
Just interested in what a machined finish would look like?
Still thinking:)
Small quantity/Less pure Bismuth/Tin site I found here(less than $20 and free shipping?), but I'll keep looking.
NO IDEA if they're reputable or not.
http://www.metalshipper.com/
Anybody have any experience with Bismuth?
Looks maybe worth looking into.
https://www.google.com/search?q=bismuth+shot&num=20&source=lnms&tbm=isch&sa=X&ei=LKlMVaXzHujnsASw_4DoDg&ved=0CAkQ_AUoAw&biw=1280&bih=663

[Burkhardt]

Anybody have any experience with Bismuth?
That sounds like a promising idea. Let us know how that works.

No personal practical experience but if you alloy tin with bismuth at the eutectic ratio (57% bismuth, 43% tin) you get a much lower melting point (actually only 284 degrees F) than with the individual metals and not toast the wood. The other advantage of that ratio is that it solidifies immediately into a shiny micro-crystalline metal while most other ratios will give you a coarse crystal mixture that solidifies gradually with a dull texture. I have no idea how it would machine or polish but one special feature of bismuth alloys is that they tend to expand when cooling other than most metals or other substances and they are sometimes used as a cast holding fixture for machining.

I am also not sure how it would hold a polish or if it would oxidize.

[scottp55]

Thanks G.
Good to know.
JUST talked to Dad, and not going to go Bismuth yet, although if we do alloy then he said that was his first pick.
Rereading my Tim McCreight, as my first experiment with the lead solder I used on house copper flashing(had 4 pounds left over) ended in utter disaster as far as metal staying in a shallow VCarve font scrap(.25" Franklin Demi 90degree bit it looked like). May try a simple pocket design .dxf with a bit that gives me a rough pocket bottom next, and enough depth to stay molten till I can slap my charcoal block on it.
Thinking that using a thin (1.4") blank, surfacing, making female with a boundary like "Fleur" so design is raised in pocket, then Cutout with same bit will give me a coin sized female. then cutout Male so the "Coin" will have a full wood exterior border and glue up with a C-Clamp. MIGHT give me something I could store until needed, and then simply place in a project by putting a pocket in.
Just thinking.
Doing stuff like cracks is going to take some more thinking "steam casting" may do it, but think I'd want Bismuth for that due to shrinkage, knots might be easier.
Not quite sure how it would apply to buttons, unless I did like your Aluminum. Wish I'd bought a Jewelers metal roller back when I had money. Came close, but then wondered when I'd use it:)
Glad I'm reading "The Complete Metalsmith" again....One of the dog-eared pages is for Charcoal casting "Work while standing to avoid a lapful of hot metal."!!! Yep, GOT to dig out my 3/4 length leather apron, and get a pair of gauntlet leather gloves!:D

[dmidkiff]

Yea I didn't really like the legs either, but I sure thought the holes and cracks were interesting. Kinda liked the charring too. Mostly thought it would give you something to think about and maybe tinker with. Seems a pain to melt metal in a wood shop.

[scottp55]

Lots of thought!:)
Holes and cracks were my favorite too!
But cracks will be more difficult.
"Seems a pain to melt metal in a wood shop."
That's what they make dirt drives for:)
Also don't have an exhaust hood, so a good seabreeze over my shoulder will be great later this year.
Definitely a seasonal thing to play with for now.
Thanks,
scott