Hyn Patty

One of the reasons you are having difficulty with mold release is due to your print lines.  They add a texture that will cause the plaster to grip your 3D printed surface.  So any roughness needs to be filled in, sanded out, or smoothed over.  It doesn't mean that you can't have the texture but at least coat it with varnish or something to help smooth it out and fill in micro undercuts.  All those little places you have plaster sticking inside of the print lines are forming tiny undercuts.  The main problem with 3D printing, IMO, is that there is a TON of cleanup.    I 3D print resins of my horse sculptures and no matter how clean my prints, how much I fuss over no print lines, temperature and other issues still cause so many nit picky things that I can literally spend hours cleaning up a single print afterwards before it's usable for mold making.  
By the way, you can also 3D print originals or mold masters in rubber!  This is super nice for pouring plaster molds and works a lot better than using the hard plastic.  But again, you need super perfect printing because you won't be able to clean up rough areas in rubber as easily as you can with plastic resin.  So as the technology is still evolving and not nearly good enough unless you really, really know what you are doing and that's a steep learning curve.  I've been 3D printing two years now and there's still a ton I'm trying to fine tune.  So mostly I still use the old fashioned methods of pouring rubber and building mold boxes.
Pardon me - I see belatedly that others also pointed this out so I'll just agree with them!    (edited to add this comment)

@Kelly in AK, I became a much better potter after teaching others, and a much better potter also.  I look at teaching ceramics more like coaching, because we are teaching a skill that requires certain movements and body positions along with assembly of parts. I believe shop managers/supervisors of last century were much like coaches also.
 
best,
Pres

The gas/soda kiln (finished work) gets fired 4-6 times a year. Sometimes it’s jam packed, others it’s a little more roomy. I had to scroll through photos to double check my guess. That’s two of us making pots in the studio. No big operation, but steady.
Of course at school it’s different, the kiln’s going constantly, feels that way anyway. Though it’s not my work or kiln I still squeeze some tests in there and things that work for me I’ll use with my kids. It’s been a great opportunity to learn and be a better ceramics teacher. 
 

I fire daily some weeks, and only a couple of times a week other weeks.  But I am often firing my very small Olympic Doll kiln and only have one to three pieces in it at a time.  I only once in a while fire my larger Skutt.  If I'm working on a larger piece then I may fire it a few times a week for a while until that project is done.  Then months may go by without using my larger kiln unless I have a larger load.  A lot of my equine sculpture gets fired several times in the underglaze layers, then clear glazed, then may be fired a few more times with overglazes to build up the complex finishes I am known for on my horse pieces.  Especially if I did any claybody resculpting to the bisque then a piece might easily be fired 10 or 12 times (and in rare cases more).  So that can be a lot of trips in and out of my kilns!  Some days I have both kilns firing at the same time so they each have their own dedicated breakers.
Even with such a heavy firing schedule I have managed after 20 years to keep both of my kilns in pretty good shape.  My Olympic is starting to show wear and tear and needs to be rewired now (still haven't gotten to that yet) but my Skutt still looks shiny and almost brand new.  If I had to make an average over the whole year, I fire about twice a week.  Some weeks I fire every day, some weeks I take off from firing to work on sculpting,  molds or resin casting, etc.  But my art studio is my full time job and I am best known for my ceramics, so...
Edited to add a couple of photos.  This was a larger piece than usual for me, almost 15 inches long.  So I had to fire him in my larger Skutt instead of my little Olympic.  This was a porcelain bisque I resculpted the mane and tail on, made a new custom base for, and then custom glazed.  He was fired, I kid you not, exactly 20 times.  What a PITA!  Not a project I will take on again for a client anytime soon but he did come out very lovely and my client was well pleased!  Took a little extra TLC with packing him too, foam blocked and double boxed of course.  I was firing my Skutt a LOT when I was working on his china painting and enamel layers to build his color.  This is the Cybis 'Nashua' racehorse sculpture by JK Slick.  The brass halter ring was added after firing and due to the sculpture being porcelain, I attached the earthenware base using epoxy rather than trying to attach it in the kiln (and likely recracking later).  So anyway, pieces like this are why I fire so often.  Many layers can be delicate and need to be set and built up with a number of firings.  It took me all year to complete this commission due to various delays & distractions, other deadlines, etc.


I think it would be cool if you all posted a sample of your work with your reply or a shot of a typical kiln load, something!

No worries at all.  If ever in doubt it's always a good idea to double check things and not just take some individual's word on something.  So no harm in calling your kiln manufacturer.  But there are only a few kinds of materials used in kiln furniture and you can tip any of it on it's side without harm.  Firing ceramics, despite our fancy electronic controllers and such, really is an ancient art form and hasn't changed that much even with more modern materials and techniques.  So kiln furniture is pretty basic.  Also, your kiln manufacturer almost certainly didn't make any kiln furniture you got with your kiln any more than they make the fire brick they build them with.  That stuff usually comes from just a few manufacturers who in turn supply all the kiln production companies.   Kind of like china paints - they all come from China but there are only two companies in the USA who import and redistribute it no matter who you actually buy it from.

I second all of what D said above.  While the details may vary it all has to do with properly oxidizing the new elements, whether it is a brand new kiln or simply an element replacement.  In the case of a new kiln it is also about making sure all the kiln body itself is properly seated and set.  People used to think you needed to fire higher than cone 04 but I think the more up to date concensus is that cone 04 is the new standard most people go by.  Congrats on your new kiln!

They are probably using alcohol inks.  Which are FAR brighter than normal inks.  But beware - alcohol inks tend to fade badly with UV exposure over time.  That may be less an issue with the glaze itself to help filter out some UV but you might find that in a decade the ink could use a new application to freshen up the color.  You'd do better to just use the more stable fade-proof inks as you are, or even better, rub that down with thinned china paints into the cracks and then just fire it.  Then you KNOW it's permanent and won't fade or wash out over time.  You can get the color of your choice and simply thin it with alcohol, then dab it into the cracks.  Buff off any extra and then fire to the standard 016 or so, whatever your china paint calls for that particular color.  
SUPER NIFTY alternative for a more Japanese look?  Rub down all the cracks with GOLD or white gold luster, then buff off any external residue, then fire THAT.  Particularly over a dark glaze that looks amazing!  Or use a thinned gold or silver paint if you don't want to deal with the toxic burn off and cost of actual gold lusters.  Trick of course is to get it thinned enough.  Wider your crazing cracks the better.  If they are SUPER fine then you may have a hard time using the niftier alternatives.  But worth a try on a test piece.  Different kinds of crackle glazes can give you finer or coarser crackling.  If the crackle is too fine to get your stain materials into it, try soaking the whole thing in the stain of your choice over night.  Or your crackle may just be too fine to absorb anything but pure inks.
Just be sure if you want to use the items for food, the crackle has to go on the outside ONLY and not inside where food may be in contact.  Crackles will trap bacteria.  Or better still, use crackles for non-food uses, ideally with a fully vitrified clay so there won't be porosity where water can seep in and cause the clay to break your glaze off later like it does with earthenware.

You do know this all predates 'manufacturers', right?  People have been using kilns and kiln furniture for thousands of years and reusing the same basic materials to do so.  But if in doubt just call your kiln manufacturer.  You don't have to take our word for it.

Yep!  Position them ANY way you like.  I often use them on their sides to stilt pieces up off the bottom of my kiln if my equine sculptures are on bases.  Without airflow, the larger bases in direct contact with the kiln floor can retain a LOT of heat where as the slim legs above may cool too fast and cause the pieces to break.  You may also stack your kiln posts to 'build' walls.  I also have an assortment of other kiln furniture that was given to me but here's a really sweet tip.
You can buy materials to MAKE YOU OWN custom kiln furniture and stilts.   I've done this in some cases where I really need special shapes and then added various thickness of Kanthal wire to run up into pour holes or whatever for especially delicate pieces that would other wise fall over during firing.  Or you can skip the specialty materials if you need one use supports custom fitted to ware by making 'setters' instead that can shrink with your pieces, such as used with porcelain bodies.
Anyway, I digress.  No harm at all in utilizing your kiln furniture turned this way and that, or stacked.  I've even used bits of broken shelves that were given to me for nothing and busted them up to the shapes and sizes I needed.  You can even get or make  'kiln beads' that you can box to form customized supports and nestle ware down into.

You do know this all predates 'manufacturers', right?  People have been using kilns and kiln furniture for thousands of years and reusing the same basic materials to do so.  But if in doubt just call your kiln manufacturer.  You don't have to take our word for it.

Yep!  Position them ANY way you like.  I often use them on their sides to stilt pieces up off the bottom of my kiln if my equine sculptures are on bases.  Without airflow, the larger bases in direct contact with the kiln floor can retain a LOT of heat where as the slim legs above may cool too fast and cause the pieces to break.  You may also stack your kiln posts to 'build' walls.  I also have an assortment of other kiln furniture that was given to me but here's a really sweet tip.
You can buy materials to MAKE YOU OWN custom kiln furniture and stilts.   I've done this in some cases where I really need special shapes and then added various thickness of Kanthal wire to run up into pour holes or whatever for especially delicate pieces that would other wise fall over during firing.  Or you can skip the specialty materials if you need one use supports custom fitted to ware by making 'setters' instead that can shrink with your pieces, such as used with porcelain bodies.
Anyway, I digress.  No harm at all in utilizing your kiln furniture turned this way and that, or stacked.  I've even used bits of broken shelves that were given to me for nothing and busted them up to the shapes and sizes I needed.  You can even get or make  'kiln beads' that you can box to form customized supports and nestle ware down into.

Hi @mattb, and welcome to the forum. It would help if you could draw a picture of your plans. Here are some questions I have based on my understanding of the project:
You're making it a downdraft, correct?
What is the btu output of your burners? Powered burners or venturi? Natural gas or propane?
What are you using for a safety system on the burners- Baso valve?
Why do you want to run everything through the electronics bay? Seems like a lot of hassle to work in there, and you'll be restricting airflow for the burners.
How do  you plan to construct the chimney?
Use 16x16 shelves. It needs space to breathe.
You can rewire the control transformer to run the controller on 120V if you want to use the thermocouple. I'd put the thermocouple in a protection tube or it won't last long if you plan to fire in reduction.
You can put the flue opening between the burner ports. Make the flue opening equal to the total area of the burner ports. You can always damper it down.
The bottom shelf will need to be above the burner ports. Have a bag wall for each burner under the shelf. Target bricks can just be a brick leaning against the wall at the end of the firebox, or a brick set upright but turned at an angle to the burners about 2/3 of the way from the burner.

Hello all, 
First post here, but I've been using it as research for a few months now. Little background I've only been involved with pottery for a bit less than a year now, mostly as a way to give my mostly blind wife a hobby (I personally have to many, or maybe not enough, depending on who you ask, as my new phrase has become, my hobby is collecting hobbies). I've been a refractory bricklayer for many years, and most recently I repair and install electric kilns, as well as work for a ceramics dealer, so building my own tools or modifying other ones is not an issue for me. I recently acquired a amaco ah30 kiln and believe this will be a decent donor kiln for converting to gas. Yes I can and could build one however I'd like, but being the frugal guy I am, this kiln seems to fit the bill for my current wants/needs in terms of cubic feet and price (I was paid to remove it). 
As for my plans. I plan to run 2 burners coming in from the right side of the kiln front and back pointing towards the left side with the swinging door in the front, (through the electronics bay) with the flue/chimney in the center (running up through the electronics bay to the top). Since I'm 100% new to gas kilns (although I have done gas forges for blacksmithing) there are a couple things I'd like some guidance on. Firstly, size and location of the flue. I'm thinking bottom center essentially in between the 2 bagwalls from the burners, but how large of an opening is suggested  for the flue/chimney? secondly target bricks on the left wall, just a hard brick cut at a 45?  Thirdly, the kiln has a 20x20 opening between the walls (l/r and f/b), how much room around shelves is recommended? 16x16 shelves with 2 inches around or 18x18 for a 1 inch opening on the perimeter? 
If the controller still works Ill probably rewire it to just use the thermocouple zone control/monitoring since I wont need 240 for running elements. If not I'll do something else for t/c's. I'm sure I'll find something else I need to ask about, but this should be a good start of conversation.
thank you all in advance,
matt

Hi everyone, I fired it according to my schedule, with only three hours at 80C to start with and kept the soak at 30 minutes at the end. 
It turned out well, am very happy with it. 
It's a Japanese style stone tea lantern. they are sold in my local garden centre, they are quite expensive so I made my own!
I've out it in my wildlife garden next to our little pond. 
 

There is some conflicting information about the first firing floating around, both from different kiln manufacturers, for different purposes, and even within the same manufacturer's instructions. L&L's printed manual has long instructed owners of their new kiln to do an initial break-in firing of the empty kiln (but with the furniture) slow bisque to cone 5 (yes, five, not oh-five) with a 3 hour preheat for the dual purpose of seasoning the elements to develop a protective oxide coating and to set the cement used during manufacturing to hold the kiln bricks together. Their newest manual indicates these instructions are for both the Dynatrol and Genesis controllers.
Conventional wisdom by some other kiln manufacturers instruct owners of their new kilns to do the initial firing slow to 04. This is consistent with the recommendation from the manufacturer of the Kanthal elements for seasoning newly installed replacement elements, again to develop a protective oxide coating on the wire. Out on the interwebs, many commenters who own these other brands of kiln will adamantly (but incorrectly) assert that new owners of all brands of kilns should do the initial firing to 04.
And now we have this new video from L&L for programming the first firing on a Genesis controller that instructs a glaze firing to 04 with a 1 hour preheat. However, if one looks around on the L&L website, there is another video for programming the older Dynatrol controller for the first firing that is consistent with the printed instructions, i.e., slow bisque to 5. Is the basic kiln constructed differently for a Genesis vs. Dynatrol controller that it would need a different initial firing? I don't work there, so don't take my word for it, but the conflict seems fishy to me. With 3 instruction sources to choose from (the printed manual and 2 videos), I would go with the 2 that are consistent, i.e, the printed manual and the Dynatrol video. But maybe that's just because I am a recovering accountant...

When my husband started repairing my kilns he would watch the Skutt repair video's just to make sure he did everything right.   My dryer quit working several months ago,  he didn't want to work on it just wanted to buy new one.   We bought  Speed Queens because they were so easy to fix,  I look up a video and check it out.   There is a hidden door on the machine,  open it up and there is two parts right in front of you that could cause the problem.  He went to the supply store and told them what he was working on,  the clerk grabs a part out of big box and says you want one of these they break all of the time.  Fixed the dryer for twelve dollars instead of spending three thousand on a new set.    Denice

I do my best to keep my kilns in tip-top shape myself but I have been VERY LAX at doing replacements and repairs until this past year.  Both of my kilns have performed flawlessly since I got them 20 years years ago  (10  years of that very hard use, 10 years of very little or no use while they were in storage when I was ill) since I got them and I've really had no issues and needed to replace NOTHING, not even a relay.  Two years ago my first relay failed on my small Olympic and that was my first time dipping my toes into replacing of parts. 
Since then I have dived into gutting and rewiring my kilns and replacing just about everything in the electronic controllers except for the mother boards themselves.  I've also obtained patching and recoating materials.  With those efforts and vacuuming them out before every glaze firing, I've managed to keep my big Skutt in like new condition.  My Olympic is showing more wear - cracked floor and  few chips with some discoloration on the outside.  But overall they are still almost good as new, still shiny cases!
No clue how to rate myself in terms of my so called expertise but man, I'm not afraid to dive into just about anything.  As I'm fond of saying "There's a Youtube vidoe for just about everything..."  and it's usually true!  It doesn't matter if it's repairing a home appliance,  your chainsaw,  motorcycle, kiln, or your home, the internet is great to walk you through it.

Hyn  I love the lego's  being used for the walls of your mold.   The old shoe boxes I use don't make a very pretty mold on the outside.   I gave away my son's lego's to a child with learning disabilities.  I gave him all of my son's educational toy's,  I was saving them in case I got grandchildren.    That isn't going to happen so I found a new home for them.  I never new the back end of a horse could be so beautiful.  Congratulation  great work.    Denice

Could be a Dry Lakes glaze - there are several available that have super heavy, thick textures in various colors just like this.  Such as this one:  Luguna Dry Lake Blue
There are also several bead and pebble glazes out there that crackle and crawl and due to the rounded edges I suspect that more than the Dry Lakes - such as this Ritual Glaze Bead and here are some Brain Coral Crawl Glaze Recipes
Here's another one though a little different look to it shown on Pinterest Crawling Glaze
So maybe that will be helpful to you.  I have used this kind of glaze heavily on stoneware before and it's HUGELY FREAKING FUN.  But sometimes it's pricy too.  You can also try layering it on thickly and doing multiple fires to see how it progresses!
I imagine if you texture your ceramic body first and then apply this you can really push it further and that may be what he did.  Good luck!

I can't claim credit for the recycling rubber idea.  I got it from the Tiki Technical videos where he's using Rebound 40 which costs about twice as much as the Mold Max 40 I'm using.  But he's also doing MUCH higher production numbers on his mugs than I do with my equine editions.  
I don't bother with a spread sheet for simple math I can do in a couple of minutes, though people can!  But I am a big fan of using spread sheets for more complicated tracking.  Like for every edition I release I use spread sheets to track what's been cast and what # of the edition I'm on, how many I am getting out of a mold and which mold # I'm on, when a piece has been cleaned, fired, packed, shipping paid or pending,  shipping labels made or not, client name & address for orders, what/how/when they paid their deposit, any monthly payments they are making, special directions for alternate shipping destinations -like if they are in Germany, I'm not set up to ship there so pieces get sent to an intermediary who can forward them on for the client, my total costs per piece, special requests by clients are noted and separate pages set up for those if needed, and so forth.  I suppose I could add the math parts to my already existing note sections just to track it.
Running my LLC is a lot of work so there is a lot to track including taxes, quarterly payments, property tax, etc.  Also lots of notes on the usual stuff like testing new glazes, mixing or overlaying of various brands of over glazes like combining enamels with china paints, how glazes change the look of various underglazes, notes on new slip batches I've made, whatever.  As I get older and my memory less reliable I am having to go back and check my notes more often.  Like to remind myself ... mixing cadmium based overglazes with non-cadmium colors is not a good idea!  
 

Spreadsheet maybe?
I use one for updating my Wordle average each day, another for the running list of used words.
...another for bike miles and bike related metrics.
Another for bookkeeping, with a page/tab for each category.
Several with pottery related stuff. 
They can be handy for repetitive maths.
I'd learned to appreciate Excel through work - so handy for analysis (protocol, messaging, transcription...) as well as repeat stuff (students' grades, energy calcs...)
I like the recycle idea!
We've thrown rocks and cement chunks into fence post holes to save on concrete...

Now lastly for a bit of math.  Yes, MATH.  But this is real simple stuff so no groaning!  If I have six small molds I have clayed up and boxed, I need to know how much plaster to mix up to pour them all start to finish with all of their various parts.  Or rubber!  Rubber is especially expensive, running about $100 to $250 PER GALLON depending on the kind of rubber I'm using.  In this case I'm going with Smooth-On.com's Mold Max 40 (the number is the shore hardness).  These are for my masters, including all mold parts and the positives for making plaster production molds from as well.  So by the time I'm done there will be no hollow parts.  Most people can deduct a little bit based on your rough measurements of hollow cavities you won't be filling.
So, how much do I need and how do I figure it out?  Now I have set up all my mold boxes and clayed up for my first pours I have a pretty good idea how large each finished mold will turn out to be.  So they are roughly the following in inches:  4x4x6, 3x4x4, 3x6x7, 4x6x1, 3x6x2, and 2x2x4.  These are to produce one mini horse sculpture with parts to assemble, as well as my flat medallion sculpted above, and another larger medallion I'm molding of another artist's work whom I've purchased ceramic casting rights from.  I know I just need enough rubber to fill in approximately this much space per each mold and I can pour plaster for extra outer supports to conserve on the amount of rubber I need.  If I multiply the three measurements for each approximated mold I get totals like 96 for the first one, 48 for the second one, 126, 24, 36, and 16 which I then add up to get a total of 346.
What does that mean?  It means that my total volume I plan to fill with rubber (or plaster) is roughly 346 cubic inches.  Then I go pull up a handy converter online doing an internet search with the keywords 'cubic inches to gallons converter' and presto!  Up it pops. (I use online converters all the time for mm to inches, oz to grams, whatever).  Turns out that 346 cubic inches equals just a hair less than 1.5 gallons in liquid.  Yay!   This kind of information can tell me about how about much plaster I will end up using for making all six molds, AND also tell me how much rubber because I'm making the rubber masters for plaster mold production.  Therefor since my choices are ordering the rubber in pints, gallons, or 5 gallon sizes, I'll order 2 gallons.  I'll possibly end up with a bit more than I actually need but that's way better than cutting it too close and not having enough to pour all six.  For plaster your voids may be large enough to measure, multiply, then deduct from your total volume.
Other tips - while this won't help with pouring your plaster molds, you can cut up old rubber molds and use them to help fill in larger volume areas during your pour.  This can also keep your rubber cost down.  So if I cut up a few molds into little cubes I can toss that into a 5 gallon bucket until I'm ready to pour my rubber.  Ahead of time I can figure out about how much of the recycled rubber I'll be using and then I can downsize my order perhaps to only 1 gallon instead of 2!  That could save me anywhere from $100 to $250 per gallon I don't have to order in rubber!  Mold Max 40 runs $114 per gallon plus shipping so it's not nearly as costly as some rubbers.
I eyeball my left over pottery plaster.  I have plenty to mix up a couple of gallons of plaster but with the expectation that I'll have some wastage every time I mix, it may be cutting it close.  Besides, I'll be wanting to pour multiple production  molds of each project anyway.  So to be safe I'll pick up another bag of plaster too.
See?  Simple, basic math.  It can be so  helpful!   

Small update - here is the finished oil clay with a very simple Lego mold box erected around it.  I tend to use Legos (or generic off brand) for tiny things and I made larger mold boxes out of wood or thick acrylic plexi as needed for larger projects.   I have sealed this down with oil wax and then added a bead of oil clay all the way around it on the outside.  I'm about to add a very thin bead of oil clay around the inner edge of the box as well so I can be REALLY sure there will be no leakage.  I will then coat the inside of the mold box and glass backing with oil soap.  I can fill it with water to the depth I want to check for leaks, then pour the water off and measure it to see how much plaster or rubber I will need to make my pour.  
At this point you can see I haven't bothered to lay in a pour hole, sprues for air venting, or even mold keys - but I can!   I'd just want a larger mold box to give me plenty of space to do that, which I have not set up  here.  This pour is set up for a uber simple one sided open mold.  It is otherwise about ready to pour plaster or rubber.   If I did this in plaster I'd want to make a rubber mold of my plaster mold before I started production so I can pour however additional plaster molds I might want or need in the future. 
Another option is I can pour rubber now and skip the plaster.  I can still use an open backed one sided rubber mold to cast a single flat resin.  I pull that out, clean it up and fine tune anything I like, even adding more sculpting in epoxy if needed.   I can get away with undercuts and very thin areas if it's going to be rubber molded for resin production.   I can also cast  a rubber positive master from that rubber mold, from which I can also go on to make plaster production molds.  So there are LOTS options on how to proceed! 
In my case I want to do BOTH so I have to decide which one I'm going to do first, then go from there. 
 
  
 
 

Small update - here is the finished oil clay with a very simple Lego mold box erected around it.  I tend to use Legos (or generic off brand) for tiny things and I made larger mold boxes out of wood or thick acrylic plexi as needed for larger projects.   I have sealed this down with oil wax and then added a bead of oil clay all the way around it on the outside.  I'm about to add a very thin bead of oil clay around the inner edge of the box as well so I can be REALLY sure there will be no leakage.  I will then coat the inside of the mold box and glass backing with oil soap.  I can fill it with water to the depth I want to check for leaks, then pour the water off and measure it to see how much plaster or rubber I will need to make my pour.  
At this point you can see I haven't bothered to lay in a pour hole, sprues for air venting, or even mold keys - but I can!   I'd just want a larger mold box to give me plenty of space to do that, which I have not set up  here.  This pour is set up for a uber simple one sided open mold.  It is otherwise about ready to pour plaster or rubber.   If I did this in plaster I'd want to make a rubber mold of my plaster mold before I started production so I can pour however additional plaster molds I might want or need in the future. 
Another option is I can pour rubber now and skip the plaster.  I can still use an open backed one sided rubber mold to cast a single flat resin.  I pull that out, clean it up and fine tune anything I like, even adding more sculpting in epoxy if needed.   I can get away with undercuts and very thin areas if it's going to be rubber molded for resin production.   I can also cast  a rubber positive master from that rubber mold, from which I can also go on to make plaster production molds.  So there are LOTS options on how to proceed! 
In my case I want to do BOTH so I have to decide which one I'm going to do first, then go from there. 
 
  
 
 

I'm SURE this has been posted on this forum somewhere before but I get asked ALL OF THE TIME to host mold making workshops.  So far I haven't, actually.  What I do with claybody work on already fired bisques and my custom glazing is already plenty to cover and isn't info you can really find online anywhere.  But mold making and slip casting there's tons of into out there if you just go looking!  So here is a GREAT VIDEO by my all time favorite ceramics nutcase himself with one of his many helpful videos.  If you have never made even a simple plaster mold of your own before, or even if you have made hundreds, I'm always learning more!  So give it a whirl!
Small Plaster & Silicone Molds by Tiki Technical Tuesday!
https://www.youtube.com/watch?v=rkf1FR7GsuY&list=PLVz2HhcJdyqgyPYSSeq80qnL-0CNgOJeQ&index=5