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How To Fire A Knife Handle Without A Nonglazed Area


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#1 Janet McCampbell Harper

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Posted 24 June 2014 - 08:08 AM

I have a student who wants to fire a knife handle but without any non glazed spots.  I fire to ^6 so the small metal stilts won't work.  

Any advice would be appreciated!

Janet

 



#2 Chris Campbell

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Posted 24 June 2014 - 09:41 AM

Why won't the stilts work? Mine can handle cone 6.

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#3 ayjay

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Posted 24 June 2014 - 10:59 AM

Assuming there is a hole for a tang.   I fire small pendants on home-made stilts, I make them from small s/s nails (about 30-40 mm long)  pushed through a wodge of clay - there is a small hole at the top of the pendant (later covered by the finding) which allows it to slide onto the nail.

 

You'd need to scale it up for a knife handle, make the clay base larger and find some  3 - 4mm thick s/s, (I use builders wall ties) they will withstand firing to ^6.



#4 Chilly

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Posted 24 June 2014 - 11:07 AM

I make home-made stilts using stainless steel ex bicycle spokes.  They last at ^6 for a few firings.


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#5 Benzine

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Posted 25 June 2014 - 08:53 AM

Why won't the stilts work? Mine can handle cone 6.

 

I was always told, that the metal stilts would fuse to a glazed bottom, at even Cone 6.  I never tried to disprove this.


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#6 Chris Campbell

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Posted 25 June 2014 - 10:01 AM

They stick and make a little mark that is easily sanded off to leave a smooth surface.

Maybe it depends on what level of wire you have in the ones you buy?? I just put mine in assuming they would work and they did. :unsure:


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#7 Benzine

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Posted 25 June 2014 - 10:33 AM

Even at low fire temps, the stilts will make marks on glazed bottoms.  I was led to believe, that they would pretty much melt into the glazed bottom at anything hotter than low fire.  

 

Maybe it's just one of those bits of misinformation, that gets passed on as fact.  Like how air bubbles in clay cause explosions.


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#8 High Bridge Pottery

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Posted 26 June 2014 - 08:37 AM

I have fired to cone 10 electric with home made element wire stilts and they left little marks but only took a slight pull to unstick them from the glaze. Porcelain with a transparent glaze.


                                                                                                                 1384226_215924051918490_1181728069_n.jpg


#9 schmism

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Posted 26 June 2014 - 02:32 PM

for home made stilts. Tungsten has a melting point of 6000+ F

TIG welding electrodes are tungsten and are used to weld stainless. eg: they will last a LONG time at 2400F

$10 at amazon
http://www.amazon.co...ngsten tig rods

Instead of a one piece handle, suggest a slab handle build. VERY common in knives.

eng4.jpgeng5.jpg

Bisque the halves then have him/her lap the flat sides that need to mate on some sandpaper so they are nice and smooth. They can also check fitup on the knife tang and make adjustments to the profile so that the 2 halves fit/feel good together.

then glaze the outsides and leave the inside unglazed and simply lay them on a shelf (or block them up with little tabs)

You could forgo the pins in the handles as you dont want to crack the brittle grip slabs and just rely on the epoxy to do its job. (which will be plenty)

when glueing the grip slabs to the tang use hose clamps, cable ties or at least wrap the handles in tight tape to act as a clamp.

If they want to do a full tang style were you can see the spline of the knife the handle slabs are the basicly the same. Generally they have some way to physically attach the handle slabs (as in small internal pins) but again epoxy alone would suffice.
fire-full-tang.jpg

#10 Benzine

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Posted 26 June 2014 - 03:45 PM

schmism, 

 

That's great info on the tungsten.  I currently only low fire, but I would imagine that if I made low fire stilts, they'd last a lot longer, than those I purchase from a supplier.  I wonder what they use?


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#11 Chantay

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Posted 26 June 2014 - 05:22 PM

I have many times used the small stilts.  Doesn't work well on plates though, they sag.  A new stilt will have a finer point.  Using thin glaze will create a smaller mark.  After firing, if the stilt stuck to the glaze just pop it off.  I then use a polishing stone to smooth out any little burr or bump left.  Is undetectable.


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#12 Janet McCampbell Harper

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Posted 27 June 2014 - 12:13 PM

Thanks for all the info....now you have me wanting to make knife handles too!



#13 Tyler Miller

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Posted 27 June 2014 - 12:51 PM

Just a word of caution about the rabbet tang construction in schmism's illustration.  It's a deceptively difficult to design to pull off well and I think the design is unsuitable for ceramic.  The stress of use will fall directly on to the ceramic material in a way that it isn't strong.  Even if using the "frame tang" version of the same design, the stress will be applied to the handle in a way unsuitable to ceramic.  It's also just a fiddly, time consuming handle method that takes a lot to get right.  Lots of sanding/milling to get things right and if you've got to fire the components, even slight warping could ruin hours of work. 

 

Slab handle is the way to go.  Either lots and lots and lots of pins to spread stresses across the ceramic slabs, or none at all and a good strong epoxy.  I know of a guy who uses marble, and his designs generally use pinless slabs: http://www.bladesmit...showtopic=24768

 

http://www.bladesmit...showtopic=21793

 

http://www.bladesmit...showtopic=24858

 

A few use pins, but I've noticed not in the past few years:  http://www.bladesmit...showtopic=21900

 

I've made a number of knives over the years, but I've never made ceramic slabs.  Neat idea. :)






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