I started this particular topic in my previous blog post on 'Kiln Repairing Glazed Ceramics' so this is Part 2, continuation of the kiln repair of a Hagen Renaker 'Sherif' Arabian foal.  In this post I will talk about after the kiln repair of the already glazed piece.  If all I were doing to this earthenware foal was repairing it, I'd simply add white underglaze to match the body with a little grey shading, fire that, then clear glaze so that the entire body had the same sheen.  Tada!  All finished!  But as refiring any piece in the kiln will render it no longer truly 'original finish' then we may as well save OF pieces for cold repair techniques, and instead use kiln repairs to set up a piece for customizing.

After firing the leg repairs I wanted to push forward to also reshape the hooves to have nice, sharper edges, sand the bottom of the feet so the piece stands perfectly without any hint of wobble, resculpt the missing ear so it's flipped backwards, and redo the mane & tail to have more style!  This is the same 'Sherif' fired to repair the legs but without any glaze yet added to the bisque repairs.

Here is the other side showing her or his missing ear reculpted and flipped back.  I have used the same techniques to score the base of the ear deeply with toothy cuts so the new clay can grip & interlock with the already fired ceramic.  Then I also did the same to the mane and tail.  Already glazed, I simply cut deep toothy scoring into the mane & tail or I could have removed them entirely to add new replacements with or without using Kanthal rod to help me shape the tail.  Again I used bisque mender only here but I could have applied it initially for it's greater strength as dried greenware and then added regular earthenware clay right over it.

Here is a top view to show the mane and tail resculpting in progress before firing.  DO remember to wear protective mask suited to working with silica clay if you are at any point sanding or shaping DRIED clay or bisque mender.  Otherwise always work it while it's still damp or wet so there is no clay dust.  Here you can see I have added & detailed the mane but not yet detailed the tail in this shot.  If it cracks when drying, simply fill in any cracks as you go because the clay will shrink.  After bisque firing it, more cracks may appear as the clay shrank again while fired.  Fill those cracks in as well then you are ready to proceed either onto over glazes, or clear glazing.

Contrary to popular belief, YES you can add underglazes right over top of an already glazed piece!  If the glaze is also low fire then the underglaze will simply sink right into the glaze when you bisque fire it to cone 04 to mature the underglaze.  Work it as normal to lift, etch & otherwise prep each layer.  Fire as if it were a regular earthenware bisque.  As long as the underglaze you are adding isn't super thick it'll be fine & sink into the glaze layer below it.  If you apply the underglaze TOO thickly then it may form a crust that cracks rather than sinks into the glaze.  If that happens you can also repair it but better to not add too super thick a layer in the first place. 

Now we have the same Hagen Renaker 'Sherif' foal with the first layer of underglaze fired!  At this point the leg & ear repair are pretty hidden.  I continued on with the next layer of underglaze to detail the mane with hand painting.  Push everything as far as you need to in steps, add all the details you want, then bisque fire one more time.  After that you are ready to add your clear glaze and do what may be your final firing to cone 06 as normal, just the same as if this piece had been a bisque & not already glazed.

Tada!  This is the completed kiln repaired, resculpted & reglazed Hagen Renaker 'Sherif' Arabian foal to a soft baby 'black'.  Black foals are often grey or get sunburnt brown before they shed out their baby coat for a true black adult coat.  My client was thrilled with this piece and I am too.  Alternatively, if you overglaze, I could easily then continue working to custom glaze this piece to push it further.  Or if you don't work with underglazes, skip that stage to move right into clear glazing and then overglazing.  The actual kiln repairs can show however if you don't cover them with opaque colors so keep that in mind to build up layers or use specifically opaque rather than transparent over glazes such as opaque enamels before you progress to transparent china paints.  Have fun with it!

Watch out for future posts on how I actually resculpt a bisque or glazed piece to add a new mane & tail from start to finish.

I posted a step by step on how I kiln repair damaged bisques using a Dante as my example.  His legs being too thin to use Kanthal rods, or if your porcelain or fine bone china proves too difficult to drill out.  But what if the piece you want to kiln repair or resculpt is an already glazed piece such as a damaged Hagen Renaker?  Is it even possible?  Why yes!  It doesn't matter that it is already glazed, porcelain, earthenware or fine bone china - you handle it just the same as if it were a bisque.  That may sound risky, but pieces I have done using these techniques decades ago are still in perfect condition.  What better than the test of time?

Back in 2022 a client sent me a Hagen Renaker 'Sherif' Arabian foal with two broken legs and a broken ear.  It was already glazed a light grey-white in it's original finish.  This client had seen me resculpting & reglazing other already glazed pieces for decades.  She challenged me to repair and resculpt this foal, then custom glaze it to a whole new color.  Challenge accepted!  So the first thing I did was drill out the earthenware legs on both sides of the breaks so I could set Kanthal rods into the leg repairs.  I've done leg repairs both ways - with & without rods.  I'm not really sure which method is better, though obviously some pieces are easier to drill out than others.  Material and the thickness of the legs may determine drilling them out to be impractical. 

It is important to note that you can't just use any kind of drill bit.  It must be a diamond coated drill bit both so it doesn't leave metal fragments in or on your ceramic piece that will discolor, but also regular drill bits aren't going to be up to the task of drilling through ceramic.  I prefer to use a hand drill rather than a power tool as you need to go very slowly so not to shatter the thin leg.  The diamond coating also chips & wears off quickly so replace your bits as often as you need.  They are inexpensive because the 'diamond' coating isn't actually diamond of course.

Here you can see the legs of the earthenware ceramic foal have been drilled out to fit in the Kanthal rods.  Now it's time to rough up & score the ceramic so it is as deeply toothy as possible.  Just like slip sticking two pieces of damp clay together, we need the newly added clay to /interlock/ with the already fired clay so it will have a lasting grip even when temperatures or humidity change over time.  Otherwise slick pieces won't hold up and the clay would flake & crack in due time.  The same should be done when joining any two materials really, such as epoxy to plastic or resin because the coeffifiency (expansion & contraction rates) of the two materials may not match. This is what makes it possible to repair even porcelain or fine bone china using a lower fire clay like earthenware!

Again the tools I use, be they files or dremal bits and cutting discs, are all 'diamond' coated.  In the case of cutting deep toothy score marks into the ceramic pieces I wish to join together, I can either do it by hand, or use a power tool.  Unlike drilling down through a thin leg, I don't have to worry about shattering it when I'm just cutting toothy slices through the already fired clay.

Each broken piece is deeply scored using files or cutting discs so that when the new clay is added (first using bisque mender) it will have something to interlock and grip.  The same applies to the Kanthal rods I will cut and insert into the legs.  If they are slick the clay won't necessarily keep a grip on it so I rough up the rod pieces with a file and wire cutters to make it as toothy as possible as well.  You could try using Nichrome wire instead but in my experience the Kanthal works much better and doesn't flake apart like the Nichrome sometimes does.   The two resistance wire types also fire to different Orton cones in the kiln so I prefer the higher firing Kanthal myself.  It is the same wire used in most kilns for kiln furniture, kiln elements, etc.

Once I have 'glued' the leg pieces back together using the rod inserts and bisque mender then I am ready to add regular wet clay over this to build out the leg.  Or you can just use more bisque mender.  As I make my own bisque mender it is cheap and I have ample amounts of it.  With the various additives like gum Arabic to make it stick & dry stronger than regular dry greenware clay, it has some advantages but may be trickier for you to detail once it's dried.

Each leg gets a bit of Kanthal rod inserted and then it is 'glued' on using the bisque mender.  I like to set my pieces upside down so the leg I am working on can be straight up and not angled off to one direction or another.  Use a heater fan or hair drier to help set it up fast.  Don't worry about cracking.  Newly added mender or clay will shrink as it dries, and again when you fire it.  So just fill in the cracks & keep going, don't worry about it.

After drying, the broken legs are then ready to sand & shape up!  At any point I can add regular clay over the repair now if find it at all difficult to work with the bisque mender.  Any cracks are filled and the fine tendons are carefully carved back in.  If you find the legs are too fragile & you keep knocking them off, use bisque mender only.  Sand & shape them, then fire and add details like tendons after the repair has been bisque fired.

Now we have a fully repaired Hagen Renaker 'Sherif' foal all ready to go into the kiln.  I fired this baby slowly to cone 04 as if it were a bisque - simply ignore that it is already glazed.  Firing to cone 04 won't hurt the glaze.  If any cracks appear after the bisque firing just fill them in & sand again.  Complete any detailing using your diamond coated tools if you need to and then you are ready to clear glaze the leg repairs.  Any piece like this that is kiln repaired is no longer technically original finish but it will then be all set for custom glazing!

This concludes PART ONE.  I will continue this blog post in Part 2 - Customizing an Already Glazed Ceramic.