Fusing Tips

I'm confused with the anneal 9999. I've read many posts, but don't understand the 9999.

@ When filling a casting mold with frit, some bubbles are likely. The finer the frit, the more tiny bubbles you are likely to entrap - therefore when you want the best clarity possible, it's best to use coarse frit, or even nipped up chunks of glass. If you wish to eliminate as many bubbles as possible, you may want to essentially introduce a "bubble squeeze" in your firing schedule. For castings of this thickness, this may mean you reduce your ramp rate once you've reached 1000 degrees F to a rate of 50 degrees per hour from 1000 degrees until you reach 1200 degrees, then you can return to a faster ramp rate until you reach your process temperature.

@robinsnest69 Fusing has some additional "rules" that don't exist when creating stained glass and mosaic art. It is important to ensure that all the glass that is used in the project is tested compatible (all 90 COE or all 96 COE). Van Gogh glass is not tested compatible for fusing (the COE is unknown) and the special color coating is not rated for heat work, meaning that it will burn off, and could release harmful fumes when fired in a kiln. The cracks are a result of glass incompatibility which causes stress as the glass expanded and contracted at different rates during heating and cooling - it has essentially pulled itself apart. I hope this explanation helps you to get the results you desire in your next firing.

Hello. I did my first firing the other day. It am definitely hooked. I see some cracks in my piece and am guessing that came from the annealing stage ( coe 90 glass) I used some Van Gogh tiles in my piece, in silver and Purple, but all the color is gone. Did I fire too hot? Please help.

@ Using pattern bar slices as a design element can create some unique and stunning art. If you wish to create a center motif of pattern slices with a border, there are a few considerations to make. First, how thick are the pattern slices? If they are about 1/4" thick, when full fused they should remain approximately the same dimensions. If they are thicker, the glass will flow outward a bit, or if they are thinner, the glass may pull in a bit. Many artists opt to cut slices a little thin, and position them on a layer of clear fusible glass to help stabilize the size and shape. Additionally, for the border the glass needs to be stacked approximately 1/4" thick, if you use a thin base glass, you can simply add a layer of color border over top to achieve this. If you wish to avoid using a base layer of glass, you will want to stack 2 layers of the border color to help ensure it fuses evenly with the center motif.

@ Boron Nitride spray works well as a release on stainless steel molds. Make sure you shake it well before use, and keep the can upright while spraying. The first time you treat the mold you will want to apply several coats of release.You do not need to use a kiln shelf in your kiln, however it is often recommended. The kiln shelf will protect the floor of your kiln by ensuring that if glass sticks to a surface, it's the removable and replaceable shelf that is damaged instead of the floor of the kiln. If you wish to fire without a shelf, be sure to use a fiber paper to protect your kiln floor.

@lisagw To use a curved surface draping or slumping mold such as the table lamp mold you mention, you will want to make sure glass is centered and balanced on the mold. It is easiest to do this by placing the kiln washed mold on your prepared kiln shelf, then positioning the glass. If your glass is un-evenly weighted (maybe it has extra decoration only at one side) it may not sit level, but as long as it is correctly placed by measurement it should form nicely. Hope this helps - and happy fusing!

Hi! I'm confused about where to place the glass when using a table lamp mold (item#80685.) Do I balance it on the top of the mold (won't it fall off?) or do I center it and lean it against the mold (won't it melt funny?) Thanks, Lisa

@gatormichals like ovens, kilns vary and sometimes small adjustments need to be made to accomodate the kiln size, where the elements are, etc. Based on the results you got I would shorten the hold time at the highest temperature. Maybe try 30 minutes. We tested a mold like this and we found that we had to watch it as it started dropping to be sure we weren't going to fast. You don't want to open your kiln up much, but it's okay to open it just enough to peek in. Good luck!

I need advise, I made the system 96 Poppy sundae dish; I used COE 96 glass I followed all of the instructions and the firing schedule to the letter, however when I fired the dish the drop section for the bowl dropped way too much and melted down or the foot. The throat / neck portion of the bowl was way to thin and ended up braking, I believe it was because it couldn't support the weight on the top lip of the bowl. What happened, what did I do wrong? Can a Delphi expert or some one with more experience can offer assistance.

It depends on the effect you'd like to achieve. Generally we'd recommend a clear base with strips placed across it. Firing strips in a mold will only tack fuse the strips to the base layer, however, so you'll retain a lot of texture. If you'll only have two layers of glass you can simply place strips on the base and fire to fuse and then slump. If you want to place strips on their edge and create a thick slab with added depth, that will require the use of a damn mold. It will definitely require some experimenting to get the desired result.

Can I place strips of glass on a mold and directly fuse them together to make a large plate? Or do I have to fire them in a dam and then slump them?

@comments2 Thank You, that makes sense!!!

@Bonnie1021 Annealing is the process of slowly cooling your glass back to room temperature. If the glass doesn't anneal properly - even after a tack fuse - it can cause stress and breaking in your finished piece. I think adding 30 minutes or so of annealing time to your firing may solve your breakage problem.

sorry, my problem is that . I tack fused 2 pre-cut jewelry pieces together and when I tried to wire wrap them the the base or larger piece broke apart. I have never tack fused anything before. I have a small Jen-ken kiln and the glass was system 96. Shouldn't it have annealed during the tack fuse?

@Bonnie1021 you anneal small jewelry pieces the same way you anneal large pieces. After your full fuse segment add another segment. Assuming you have a tabletop or a small studio kiln you can cool the kiln as fast as possible to either 900 F (90 COE) or 950 (96 COE) and hold that temperature for 20 - 30 minutes - don't worry you can't anneal too long. For additional tips and firing schedules you can go to www.DelphiGlass.com/glassfusing

How do I anneal a small jewelry piece that I have tack fused? When I tack fuse my jewelry components they are so fragile that I can not even wire wrap them without breakage.

@ Lynne S. Are you fusing your two trees together before you slump them? Are you getting a hazy line around the edges of your glass? It may be that your grinder is leaving residue around the edges of your piece. Either wash you piece very thoroughly using a scrub brush or rubbing alcohol. If you must grind we offer a new line of bits that doesn't leave residue. They're called Durabits and that might help.

Thank you Jennifer. We figured out some of our problems. However the edges of the glass after slumping are still a little rough. I held at 1250 for 10 mins. Do you think we are grinding the edges too much or does it need to sit longer. We ramped up slowly and cooled slowly. We are using the christmas tree mold and system 96 glass.

@Lynne I'm not entirely clear about a couple of your questions but I will do what I can. I am not understanding the jagged edges - is the mold jagged or the kiln wash? Kiln was on the back of your mold will not hurt anything - it will burn off during firing. I think the dial and the digital box you are referencing are a Pyrometer which is how you set the temperature if you don't have a programmable kiln. You'll want to heat slowly to your target temperature. I'm not sure if flash venting is necessary or not. You can get some additional information at www.DelphiGlass.com/glassfusing. Our customer care center also offers technical support and they would be more than happy to assist you.

We are using the Christmas tree and heart slumping molds. Following the instructions for times etc. Have put molds in kiln to set kiln wash. First problem is edges are jagged and some of the kiln wash always sticks to the back of the mold. We are using system 96 glass. Also some say when it is time to flash cool, then just turn kiln off. Other instructions have you flash cool then have the kiln reduce the temperatures as indicated on the instructions for slumping. We have a refurbished Paragon kiln. Sorry one more question, there is a dial on the box that is attached to the kiln. Goes from low to high and there is a digital box then attached to that. Not sure what and how to use that dial?? Thanks, Lynne S.

@Lori J. I can't see any problem with that schedule off the top of my head but, because every kiln is unique, adjustments must sometimes be made. It may be that the glass is cooling too quickly - you could reduce the ramp temperature for slow down or increase the annealing time - it's a pretty thick casting and it can never hurt. The other thing that can cause cracking is incompatible glass. You can use a Stress Tester (item 103399) to determine if stress is the cause.

I have the butter dish mold. Yesterday I did the Base and it cracked. I put in 18 oz. of coe96 glass then fired it using the schedule that was on the web site. I've done this a few times and ended up cracking the one mold. I've looked at it at full fuse and looks good, and I've looked at it once it cooled down and has shut down and good then but crack once its completely cool. Fired again and didn't look until completely cooled down still cracked. I don't know what else to do here. Have a few people wanting one.

@Janelle K. Great Question! If you are using MR-97 you simply need to spray on 4 thin coats the first time you use a mold then another thin coat each time there after. Allowing the mold to simply sit for a few minutes until it's dry is sufficient, there is no need to heat it in an oven or a kiln. If you are spraying a texture mold or a holey mold be sure to turn your mold a quarter turn between sprays (on the original and subsequent coats) in order to get a bit of spray on all sizes of the post / texture. If you are using a brush on primer - like Primo Primer or other kiln wash - after applying a few coats to your mold you can 1) patiently let your mold dry over night until all of the release is dry OR pop it in an oven to speed up the process so that you can get going - either way is totally fine, just make sure your primer is totally dry or it can cause sticking.

I have purchased several molds and am finally getting around to prepping them for use. One of the direction sheets included suggested pre-firing @ 90F/hr up to 1470F, with no holding time and to let it cool on it's own. Other molds do not have any directions at all, but I was told by a sales person to just pray on the mold release and heat in oven to 400F after it had dried for 20 minutes. Do I need to pre-fire my molds? They are all pretty small. None of them are more than 30cm in size. I'm excited about all the possibilities with the molds but, frankly, am a bit intimidated and don't want to ruin them (or the glass) right off the bat. Janelle

I had to drill a small hole in the poinsettia mold too. Now it works great. Sorry I didn't get back to you sooner

@aglassact303 NEVER MIND all, drilled the holes, 5, 1.5" from each corner and one in the middle. SUCCESS. Please pass the word.

@comments2 I need help. I have purchased three of the Creative Paradise molds and used the schedules provided. The Art Nouveau rectangle is producing perfect pieces. But the larger round floral and the Tree of Life are creating large bubbles. Complete failures. The large bubbles are bursting or just deflated. Do you think drilling holes in the mold will help. The instructions do not indicate this is necessary. I have tried their fusing schedule as well as going slower. What about not going as high in final temp, 1470. Maybe 1400 or 1350? Please help

@StaceysLawnDecor I bought three of these beautiful textured mold. My first was the Art Neveau rectangle. Two layers of 96coe and used the tutorial fusing schedule. Perfect, two beautiful pieces and zero issues. But now with the Tree of Life and the Round Floral molds I have had complete failure. Ruining glass like crazy. Did you have any success? I am considering drilling some air holes.

@sydsgrammy you will need to use a mold primer prior to slumping the glass in your mold. There are a variety of primers available to choose from. Primo Primer is an excellent choice (item

I am new to fusing. I bought a kiln and a wavy slump plate mold. Do I have to put anything on the mold beside glass before firing. I am anxious to get started. No classes in the area. thank u for your help How do I know what temperature to set the kiln at. I started with a microwave kiln and had a lot of fun and success with it but limited to what I can do so I bought the larger kiln.

@StaceysLawnDecor The directions for the peacock mold are a good place to start. Bubbles happen when air gets trapped between pieces of glass or the glass and the mold. There are a few possible solutions. First - don't use frit between layers of glass; if frit is desired place it in the ridges on the mold. You can try venting your layers of glass by cutting one or both in half or quarters to give the air a place to escape. Alternatively use one double thick piece instead of two layered pieces. One of our experts also suggested drilling 5 tiny holes - one in the center and four around the mold to allow air to escape. Raising the mold up on kiln posts to allow the heat to circulate can also help.

@glassaudio3210 There are a couple of things that can cause breakage when draping over a cup mold. First, heating too quickly can cause cracking, ramp no higher than 300 degrees per hour, and be sure to let the glass anneal and then fully cool before opening your kiln. Use a piece of shelf paper between the glass and the cup - especially if you're using a ceramic mold - to add a little space - otherwise your glass can grip the cup too hard and break and/or become stuck to your mold. Of course incompatible COE will often cause breakage so you might double check your glass compatibility using a stress tester.

I'm having trouble with my cup slumping mold. Everything that I am trying to slump is cracking. No idea what I'm doing wrong It's a 6 " cup mold and I'm using a flat piece of glass about 5" square. COE 90.

I am having trouble with the new poinsettia texture mold. I keep getting a huge bubble in the middle. I tried two layers of glass and I tried putting frit in the middle. Nothing is working. It is very frustrating when these products do not come with instructions. The one that I downloaded and followed was for the peacock texture. Any help would be greatly appreciated. It is a beautiful mold, but is getting expensive creating failures.

I have an unfinished stained glass project I'd like to try fusing instead; I have no idea what the glass COE; any idea with regard as if there's any change of success to fuse this into one solid panel?

I have a B300 drop through mold and am having difficulty getting the.vessel in the middle of the base. Any suggestions? Am I letting it slump too long?

@Jameas H. As dichroic glass is fired in the kiln the way that the glass can fire can sometimes allow for that distinct line between where the dichro layer starts to become more pronounced/noticeable; this is indicative of the way the glass will want to stay a thick while firing so depending on how the number of layers you re using, etc. the way the glass shrinks up under itself can denote a line around the circumference of the fused piece. This is ultimately because the dichroic layer is a metal coating and doesn t move/shift with the glass.

Hi I need help can some one answer my question please when I fire my glass and dichroic caps with a clear cap I end up with a hair line around the out side of the cabs what can this be from.

@BigSkyDichroic You could always attempt to fire polish. But please be careful, given the temperatures for fire polishing and how long you may be holding you can seriously risk miss-shaping a slumped bowl or plate for example. There is also a product you could try, Clear Coat Overglaze (item# 7404ALT), but bear in mind that you would need to fire it to 1350F or higher which still risks miss-shaping a slumped piece.

@marlea Unknown, even if there was a way to indicate the COE of a certain manufacturer bottle chances are every other one you would look to use would be different. This is why we only recommend slumping bottles or utilizing a bottle cutter to create other forms of bottle art.

@jennalee Frequently, what you have described here is an indicator that you are in fact firing too hot. Also, you mention a post, are you working with a casting mold with a post? If so, you must be meticulous about detailing that primo primer into every nook and cranny of the mold and around the post. If you plan on doing more work with molds like this I may suggest you go with a boron nitride spray like MR-97 (item#93701).

@mary p. It sounds like the piece was stressed from the first firing and that is why it exploded. Did you use shelf paper in the kiln? Without it the glass would stick to the kiln. Shelf paper is a must. To repair the kiln you can use Kiln Repair Cement item #42902.

HELP! I am new to fusing. I was refusing a piece in my microwave kiln and it sort of exploded. When it cooled and I removed it-a bit of the kiln came with it, exposing whatever is under the white coating. can it be fixed? PS The piece came out pretty good!

Help! I've just started using my Studio 8 Kiln and I am having problems with the ceramic molds that came with my kit. I've broken 3 of them already!! I used the Primo Primer and put on 5 generous coats with ample drying time between. I think I am heating and cooling the glass slowly enough and I've tried to remove the glass from the molds at different temperatures. When I managed to pry one out it brought a lot of the bottom of the mold and the post with it.... Any ideas? Am I heating the glass too much or for too long that it is burning onto the mold? Thanks for any help!!

what is the COE of the glass used in wine and beer bottles

@ailismh Since it has been soaked in water you need to first make sure the molds are completely dry before the next firing b/c there is potential for explosion and you will have mold pieces all over the kiln. As far as cleaning it off it is a bit of a tedious process, the best material to use is a fine grit sandpaper and elbow grease; but you don t have to completely clean it before putting on the next coat of primer. After you have completed the cleaning process reapply 4-5 coats of primer, let it dry again and then it will be ready firing.

I bought your beautiful texture molds. I fired them a few times with good results. Now it is time to reapply kiln wash. When I fired last, the wash came off on my glass. How do I get what is left of the kiln wash off of my mold? I have been scraping for days. Due to the textured nature of the butterfly, holly and dragonfly molds I cant use my regular sander. Any suggestions? I have been using a thin "scalpel" like tool to scrape into the grooves. It is very tedious. I even soaked them in water for a few days, but that barely removed anything. Would appreciate any suggestions. Thanks

Hello Delphi Helper! When I remove my glass from a mold the surface has a matt finish. What is the best way to get that glossy look back? Thanks!

I slumped a beautiful 8" bowl, but the bottom came out rounded, I put it back in the kiln and slumped at a slower rate, it came out ok, not as rounded, but not like the mold. I tried it a second time with another 8" piece of glass, but set my kiln at a really slow mode, it came out the same way the first bowl came out, a rounded bottom. How can I slump a bowl and have it come out right the first time?? Thanks!! Lola

After I have TAC fused my weaved sushi plates, sometimes I have to grind the edges to make them even. This requires me to put them back in the kiln to "fire polish" the ground edges. After that is completed, I put them back in the kiln for slumping. Can I combine the sumping and fire polishing in one fireing?

I made a beautiful bowl using the 6-1/2" bowl mold. Now I want to flatten the bottom of it so that it doesn't wobble but I don't want to change the shape of the bowl at all. What is the best way to do this?

You will want to start with a boron nitride mold release we recommend MR-97 item number 93701. You can find a video on our website with application instructions. You will then fill your mold with frit (and the amount is based entirely on the expected thickness of the finished piece.) Just be careful not to overfill as that can create problems when you go to release your project from the mold. You can do some amazing work with these molds but it will likely take some trial and error before you get consistent results. Good luck and have fun!

i have a celtic cross mold. i'm not sure how to use it. help please. i'm assuming i use colour deverre but not sure how much frit to use.

@simplespark Here are my suggestions; since I'm not sure if you're working with COE 90 or 96, I ve given you item numbers for both. We don t sell dark blue in crinkle coating but we do sell some textures in this color and if you fire it without a clear cap you will still get that splinter effect (since the coating is metallic) and will not stretch with the glass as it melts. 153401, X153401, X4227

I need help fast! I am a budding glass artist and friend asked me to make earring for her wedding. The time is quick approaching and I haven't been able to get the right kind of dark blue crinkle. Any advice as to what glass to buy would be awesome. Thank you in advance! I am desperate!

@dlstressed, Of course you can re-slump! In a case like this it would be best to fuse again into a flat piece. Then you can use a bandsaw or a grinder to make sure your piece does not exceed the size of the mold. We recommend turning the mold upside down on top of the glass and tracing around it with a black sharpie. This will give you an accurate measurement and any sharpie remaining after grinding or sawing will burn off in the kiln. Any place the glass overhangs, you have the potential for this problem or as you pointed out it can sometimes slide during the slump if it doesn t heat evenly for some reason. Never refuse to re-fuse!

so i slumped my glass on the sushi tray-apparently it was slightly too wide(thought i cut it to right size) or else it slid crookedly when it slumped & now i have an uneven lip on 1 side-can i re-slump or what do you recommend?

@DelphiHelper (oops on 1st reply!) I actually went ahead & tried it (I'm so impatient when I get an idea) and it turned out beautifully. I used the rake I had purchased from Delphi, and followed various instructions I had found online. While none of them discussed using molds specifically, I followed the rule of ensuring several coats of kiln wash, and I made sure not to rake too deep. Also kept my intrusion quick then flash vented to 1200 before ramping down to anneal. Thanks!

@DelphiHelper

@mparent123, I wouldn't recommend this, not so much because the mold can t take the heat but because whatever glass barrier you are using will breakdown at high temperatures causing your glass to stick to the mold. If it does survive once you start combing you will drag the kiln wash through the glass which will create streaks.

Does anyone know how hot you can fire a casting mold? I'm thinking about trying combing in a mold, but I'm concerned about how hot I have to go for the combing... I don't want to damage the mold.

I just received my order for 2 piece drop mold. ring #806143 and foot #80719. Has anyone used these? Need to know firing schedules for these molds and any helpful suggestions.

I recently fired some glass in my Jen Ken kiln and for the first time I am getting 1/2" bubbles in various areas of the pieces. I used 2 layers of glass, some with clear on top and some with clear on the bottom. I've adjusted the firing schedule to 300 to 1000F - hold .30 - 300 to 1450F - hold .10 - full to 960F - hold 1.30. Still getting bubbles. Never had this before - any suggestions to avoid these? Also, is there a way to save these pieces? I have pierced the bubbles - can I cover the glass with a layer of clear frit (medium) and refire?

Has anyone here had any experience with the large lamp shade drape mold? I'm getting ready to use it to create a fused glass lamp shade. (item #806164) I've downloaded the PDF User Manual and noticed that it says to use "suitable glass separator". I was planning to use Primo Primer. Will I also need to use Thinfire paper? Any feedback will be greatly appreciated! Jackie

@DelphiHelper Thanks so much! :)

@Akrunner For 90 COE fusing schedules and questions, we usually refer artists to the Bullseye website. They have a lot of good information on methods and tips for working with 90 COE glass. Good luck! http://www.bullseyeglass.com/all-methods.html

I'm very new when it comes to fusing glass (only a few months of experience) and everything I have experimented with has been with system96. This site has been very helpful in all of my system96 needs and inspiration but since I've joined Delphi I've noticed a lot of people are also using 90 COE glass for fusing. I've done some browsing but I haven't come across anything in regard to there being a different firing schedule from system96 glass. I've been hesitant to experiment but is it safe to assume that the firing schedules that have worked for my system 96 projects will work also for 90 COE glass types? Is there some temperature differences I should be taking note of? Any help for this new fuser is greatly appreciated. :)

The anealing door will not have an effect on the firing of the kiln. It is a convienence for bead makers. Batch anealing beads in a kiln is just fine. And lastly, the ditigal control kilns are very reliable. They can also be programed with your firing schedules so, if you have schedules that you like you can use them!

I am finally going to upgrade from my ancient kiln to a modern computer controlled kiln. But when I looked at different option some have doors for bead annealing. I do mor fusing the torch work, but I have done it. My question is, does the bead annealing doors have effect on firing process, and I have always annealed my beads in my fusion kiln, I have never had a issue....yet. Am I ok or just lucky? And lastly, my old kiln was manual, so I have very specific firing charts. I know I am probably going to need new charts for new kiln, are the computer pre programs reliable?

I fused a 96 COE dichroic 3 x 3 square onto System 96 black 5 x 5 using the System 96 firing schedule (which I swear by) - but this time, I got big and small bubbles. Haven't had this problem since I started using this schedule and the glass is too expensive to have this keep happening - twice now. I noticed that Roy Kapp has a photo of one he did with a double plate mold (Item# 7448) and wonder if he would share his fusing schedule with me. I have ordered this plate mold and would like to try again. Thanks! Sally

Try soaking the mold in warm water for a few hours. Then use a brush with nylon bristles to clean the wash off. We recommend using Primo Primer on casting molds. Apply with a 1/2" soft bristle brush to help maintain the details of the mold. Four thin coats is standard. Coat with at least one coat before each new firing.

I am having a problem removing old kiln wash from a mold with small ovals on it. I used my regular kiln wash (Bullseye shelf primer) - should I have used something diferrent for a small details mold? Or, should I put a fresh coat of kiln wash on after each firing, (hopefully, never having to remove it). Can anyone suggest how to do this without wrecking the mold? (It would also be difficult to clean my pot molds - how does everyone else do theirs?) Thanks for your help. K

Hi This is not a comment it is a question or rather a plea for help.I make fused glass pictures.Recently I have two 12" squares which have cracked across one corner one after more than a year of moving from gallery to gallery. Before fusing I soak at 555c for 1 hour then soak again at 671c for 30 mins then fuse at 780 around 10 mins then flash cool.Finally I soak at 516c for 3 hours or four and then turn off the kiln and cool.My kiln is a top loader pearl 18 clamshell firebrick. larger pieces are drilled at the edges and screwed to board. Do I need to slow down my cooling process? These works are usually no more than 8 mill thick in any place though there are different depths in them and sometimes bullseye and wasser together. Any ideas and help would be most appreciated Yours Deborah A very confused by all the annealing info I have read recently uk glass maker

I just purchased the double candle mold. Yesterday I fused a sheet streaky glass with a piece of clear. When this cooled, I tried to slump it onto the candle mold; the glass broke! I thought that maybe the glass was too heavy because I fused a piece of clear on top before slumping. I tried to slump using just one 3mm piece of glass over the candle mold, it broke!! What am I doing wrong???

Try chipping the glass off with a chisel or paint scraper being careful not to chip the shelf. Wear safety glasses. Then use a 120 grit sandpaper followed with 600 grit to smooth the surface out. Avoid sanding too far. You don't want to create a divot which will trap air bubbles when firing. Re-apply kiln wash.

I fired a project and the kiln wash did not work, I broke up the glass (guess I'll have some pretty frit....) but now how to I get the rest of the glass pieces off the shelf and get it cleaned up so that it can be used again? Any suggestions?? Thanks in advance :)

Tiny pin pricks in the surface of the glass sound like small bubbles that have come to the surface. Adjusting your firing schedule may help. Remember that your kiln may run a little hot. This is normal and will take some use before you will know how your kiln is performing. Here is one suggestion. Try lowering the ramp temperature to 300 degrees per hour and then lowering the ending temperature to 1450 degrees. This may help to keep the bubbles from reaching the surface. Each color glass also responds diferently to heat. Ex. Black heats faster than white.

I recently purchased the Studio in a Box (Easy Pro 15-6 kiln) and I love it. I've made a few coasters to start getting familiar with the process. Both have turned out great except they appear to have a few very tiny "pin pricks" on the surface. I'm using the directions/firing schedule from Contemporary Fused Glass Chapter 8 with the glass provided with my kiln package. Any suggestions? Jackie

@TheDelphian I have twp platters stuck inside their stainless steel molds, will flipping the work & heating in kiln process work to release the glass?? Patrice Higgins

I am new to fusing and I'm using glass bottles but want to keep the center open is there a tool that I can put in the center of my glass to so that is will for a "o" but safe to put in the kiln while not fusing to the glass? Thx. Tracie

Are you using Primo Primer for the mold preparation? Because of the ridges and the depth of the mold sometimes the glass can get caught and stick to the mold which will cause cracking.

I am trying to slump into a soap dish. I have tried it 4 times and my piece is cracked every time it is done. The crack is a straight edge....which makes me believe that it cracks AFTER it initially slumps. I do not know how/where to adjust my firing schedule to help it. Any ideas? Thanks, Ta

You will want to take the 25 degrees off each step. This way you will have the temperature at each stage to get the results you want. Your hold time can stay the same however.

I did not understand segment 4. Is this your schedule going down? Could you just vent to 900?

Is there any way to get a glossy finish on the side of the glass slumped into a mold? Seems like I ought to be able to re-fire, but not sure how.

I'm trying to flatten a bottle in the kiln. Any tips or suggestions for best results, like how to keep it in one place?

Is there a product that would help prevent bubbles. Or is there a technique that would help? Thanks carol

try putting it in the freezer for about 10-20 minutes then lightly tap in to get it off

I am new to glass fusing and I just love it so much! The question I have is this: I read that glass can be refired to repair cracks. Can someone explain how this is done i.e. what temp and for how long? Thanks. Alyse

Sometimes what I think should be the simple projects stump me the most. Anyone use the 5" square coasters? I can't get the size right. I've fired with single sheets, double sheets and a variety of sizes and the edges keep shrinking in bad.

I have had this problem, too. My solution - put it in the freezer!! Check it about every 10-15 minutes. It should pop right off. i've done this to remove candle wax from candle holders, so I didn't think I had anything to lose. Voila! it worked!! Hope this helps.

I just got my Delphi 15 6 EZ Pro kiln and have had some trouble with the clear base glass, which I thought was also 90 COE as is the glass pieces placed on it. When I finished the programmed schedule for 90 COE FUSE, there were big bubble holes where there was no layer. What do you recommend in the 90 COE for the base clear glass? Is there something else I'm doing wrong?

problem: proper way to put oil in studio pro or any cutters. even the smallest amount seems to leak out thru sides. this is for student work. Is it even necessary to use oil? Thanx for any tips-the kids keep blowing thru cutters, heads, etc. while trying to learn. Lori

Thank-You Julie for your advise , I'm going to try it again  Deb

Hi Deb, I'm sorry to hear about your trouble. S lumping over ceramic is challenging!  Ceramic molds are nice because of  their cost factor over stainless steel.  However, the problem is the way that ceramic reacts to heat and cooling.  Generally you should slump "into" ceramic and slump or drape "over" stainless steel. The reason for this is that glass can shrink tightly around the clay. When using the ceramic molds for draping, it is important to use at least a 1/8" fiber paper and to use a schedule that will give you a loose drape.  Do this by watching the glass after it has reached the draping temp of 1150 degrees - 1250 degrees F. Keep a journal of all of your firing schedules so you know what works and what doesn't. All kilns heat differently, the only way to know what works in your kiln is to watch what is happening. Remember, don't open the kiln while it is moving into the annealing zone as this will result in cracking.

I need help ,I purchased the small ceramic vase slumper mold ,I've kilned washed it . First attempt was to make a small candle holder ,using 2 peices of glass offset ,fired to book beginners guide to kiln fired glass pg45.The result was glass stuck and cracked.Next time I used 2 peices of kiln paper ,slowed down the fire schedule same result.Third time I used 3 peices of kiln paper changed the fire schedule completely very slow with the same result. Can anyone help?  I've done some reading on the net and it was suggested that the mold will cool at a slower rate- therefore glass cracking.   Thanks Deb

I should have referred to a specific problem.  My reply, #11, has to do with your work not releasing from a ceramic slumping mold.  It works with a stainless steel mold, too. Please accept this as a reply for problem #1.    

When that happenes to me,  I immerse the entire thing, mold and glass, into water.  All the way in.  Cool it first, of course.  After a little while, the glass can be removed.  It has worked out this way every time.  Good luck.

Thanks for the help with the origami bowl.   I'll give it a try this weekend! Judy

  I have used the origami mold and have included the firing schedule.  It was done with 2 layers of glass. We feel that one layer of glass will pull in too much and you will not reach the bottom of the mold as this mold has a tendency to do that.  We used a slow firing schedule to allow the glass to drop into the mold while maintaining the upper edge.  Hope this helps.   Origami Bowl Slumping Schedule 4 Segments - GM1414 Skutt Kiln Seg. 1 300 Degrees per hour to 1000 Deg. Soak 10 min. Seg. 2 150 Deg. To 1200 Soak 20 min. Seg. 3 150 to 1225 Soak 30 min. Seg. 4 Full to 900 Soak 30 min.

I recently purchased the 7" origami bowl mold.  I have a piece of 96 glass I would like to use.  I was wondering if I had to fuse it to a piece of clear (96) or can I slump it with a single layer of the glass. Thanks!    

Delphi recommends doing a minimum of four washes with the kiln wash for any mold; (up & down/side to side/diagonal one way, then the next making an “X”) allowing each coat of wash to mostly dry before adding the next. For any casting mold we always suggest the Primo Primer (48325). This product is specifically designed to allow glass to release from the steeper sides and carved details of casting molds, as well as not breaking down at the higher temperatures needed for the glass in casting molds. Standard kiln wash occasionally works for these molds, but because it’s not dependable in this situation using it is risking your glass and your mold. If there is ever an issue or questions on a product or a project, Delphi is here to help.  Delphi has a 30 day money back guarantee.

The dish is made with Effetre sheets and millefiori in 104 Coe.  We have found that effetre sheets tend to devitrify when going up to those high fusing temperatures. I would start out fusing this using a 90 Coe fusing schedule and use Super Spray to prevent it from devitrifing.

I would like to know what fireing schedule you use for the Clear sheet moretti with the Millifiore's.  I have tried a couple but generally make a mess, it appears to not need as much heat.  What did you use for the dish shown by the Morettie Sheet glass page. Have lots of Milli's to use. Thanks Helen

Unfortunately the issue is most likely not with your fusing schedule. The main reason this product disappears during the fusing process is because the ink used to print the picture does not contain enough metal. You must have a black and white Laser Jet printer with an ink cartage that contains Iron Oxide . Most commercial printers will say their company can print these off for you, but we have found they do not work, so do not waste your time/money going to a professional print shop. Check the Material Safety Data Sheet (MSDS) for the printer cartage you are using in your laser jet printer. (You can ask an office supplies store associate for this sheet which gives you a list of the content of the ink.) The ink must contain iron oxide for the image to remain. The metal content of the ink is what is left behind on the glass to create the image while the other binders/components burn away.   

I have recently purchased the photograph paper and have tried firing it with a photo on it and cannot seem to get it to work.  I have used my regular Full Fuse, Tack Fuse and Slumping kiln settings and the photo is still disappearing... Has anyone had luck with this and if so, what firing schedule are you using?  Any help woud be greatly apprecited!   Frustrated in Iowa...    

Even if you did use kiln wash on the mold when slumping OVER ceramic molds you MUST MUST MUST use fiber paper as a release not just kiln wash. (2 pieces of thin fire, or 1 pc of thicker fiber paper.) Because of the expansion/contraction difference between ceramic and glass it is best to always slump INTO ceramic, not over…yet we have several molds that break this rule (nightlights, business card, floral slumpers). Using just kiln wash does not allow the extra wiggle room needed to remove glass off of ceramic, the glass has clamped down on to the ceramic during the cooling process.   You can break your glass, or break your mold (or both) to remove them from each other.   You might try putting the glass/mold back in kiln (flipped) with glass on bottom, (place on kiln washed surface or fiber paper) fire it to slump fuse again hoping that the glass will pull away from the mold if you wish to try to save them both. Good luck!  

I need help.  I've fused a piece of glass then slumped it over a night light mold.  It is STUCK!  I'm sure I used kiln wash on the mold before slumping, but it won't budge.  Any suggestions?