Firebrick is a very fragile material and subject to breakage, spalling, and thermal shock.
The good news is that it is very easy to repair and maintain with the proper materials and techniques. Enclosed in this brick repair kit are all the materials you will need to do a first class job.
Use protective glasses and gloves when working with the Cement, Patch, Facing, or Primer.
This brick repair kit is intended for L&L kilns. If you use it on anything else you do so at your own risk. It will not work on other types of refractories such as are used in wood stoves, etc.
BRICK REPAIR KIT
Included with Brick Repair Kit
½ Pint of Brick Patch
½ Pint of Brick Cement
½ Pint of Brick Primer
½ Pint of Brick Facing
½ Pint of Brick Dust
1 New Firebrick
1 Brush
1 Sponge
1 Plastic Spatula
1 Tongue Depressor
Rubber Gloves
Instructions
BRICK PATCH
Brick patch is a versatile material that can be used to repair a variety of chips, holes, and gouges in kiln brick.
Brick Patch will work best on small to medium sized defects on a flat face of firebrick.
For more severe damage, consider using Brick Cement.
Repairing small holes and chips:
Remove dust and debris with a brush or vacuum.
Brush primer onto the area.
Squeeze the Patch into the voids with a plastic spatula.
Use a twisting motion of the wrist and push it in from
several directions to ensure the patch sticks to all sides of the hole.
Coat the repair with Brick Primer or Brick Facing to strengthen it. (Optional)
Allow to dry for 24 hours before firing. (We recommend a fast glaze fire to cone 05)
Brick Patch Formula:
If you require more than the included Brick Patch you can mix more from the other included materials:
Start by mixing 3 parts Brick Dust and 2 parts Brick Primer.
Mix with a tongue depressor or plastic spatula.
It should be on the edge between a liquid and a solid and have the consistency of wet clay or silly putty.
If need be, add a little primer to moisten it or a little brick dust to dry it until the correct consistency is achieved.
BRICK CEMENT
Brick cement can be used to repair severe damage to your kiln brick, such as large holes, chipped edges, and cracks.
Repairs with brick cement are more involved. For less severe damage, consider using Brick Patch.
Repairing very large holes and chips
If damage is too severe to use brick patch, you can use brick cement to adhere a new piece of firebrick into place.
Use a saw, router, or chisel to remove the damaged area, leaving behind an even and square void.
Cut a piece of the new firebrick to fit in the void. The piece should be slightly smaller (about 1/16” to 1/8”.)
Thoroughly clean all surfaces of dust and debris.
Wet down the area before applying cement.
Apply an even coat of cement onto all surfaces using a plastic spatula.
Press the new brick piece into place and wipe away excess cement.
Allow to dry for 24 hours before sanding flush.
Coat with Brick Facing and allow to completely dry before firing.
Repairing hairline cracks:
It is normal for your kiln to develop hairline cracks. Most are not a cause for concern and don’t require repair. However, if these cracks start to get more severe they can be repaired with this method.
Use a drill with a 1/8” drill bit to rout a channel along the crack. (The bit should protrude 1” into the brick.)
Remove all dust from the channel with a vacuum.
Wet down the channel. (A spray bottle works best.)
Thin out the cement with water or primer to ensure it seeps in.
Use a plastic spatula to fill the channel with cement. Push it deep into the channel and blend it smooth.
Allow to dry for 24 hours before sanding smooth.
BRICK PRIMER
Brick Primer is a binding agent that prepares the brick surface for patching by strengthening the brick and binding dust. It is also used as one of the ingredients in mixing brick patch.
Application:
Using a brush, paint or dab any spot on the brick you will be patching.
Be sure to put extra on large holes or edges requiring a larger patch.
In some cases, using just Brick Primer is enough to strengthen the brick and prevent further damage. Sometimes, less is more in repairing brick.
BRICK FACING
Brick Facing can be used to strengthen the surface of the brick and protect from future damage.
Application:
Mix the facing thoroughly.
Use a sponge to lightly smooth the facing onto the brick surface.
Only small amounts should be needed.
BRICK DUST
Brick Dust is the primary ingredient of brick Brick Patch. It is what ensures the repair will have the same look and thermal properties as the original firebrick.
BRICK PROBLEMS
Excessive Brick Wear:
Excessive brick wear can be the result of various conditions. Most common is improper curing of the brick when first fired. Follow the instructions in the installation section for the first firing and curing cycle!
All insulating firebrick expands and contracts when heated and cooled. Over time this leads to cracking and spalling. Spalling is the continued cracking of the brick, which eventually results in large pieces of the brick falling out. This is a normal condition as long as the emphasis is on eventually. Factors such as how often the kiln is fired at or near maximum temperature, how often and how fast the kiln is cycled up to heat and then cooled, and how heavy the loads are, all figure into the brick wear equation. There is no set rule as to how long a brick lining will last. There are some L&L kilns, which are 25 to 30 years old with the original lining still in place. Note that the type of brick we use is the same that we have always used and is the same brick generally used in the hobby kiln industry.
Frequent door openings when the kiln is at high temperatures can cause thermal shock, leading to excessive cracking and spalling. Do not open kiln when hot (>500°F). Thermal shock can destroy the brick and your ceramic pieces.
For light to moderate spalling, coat the brick with the Brick Facing
Removing glaze spots:
Be sure to remove any spots of glaze that get onto the firebrick sides or on the element holders. When the kiln is fired the glaze will remelt and potentially damage the elements.
Once removed, use Brick Patch to repair the hole left behind.
Loose bricks:
Firebrick will shrink slightly over time. This is more
pronounced when using the kiln at higher temperatures like cone 10. If you only use the kiln for low fire bisque you may never notice this condition. If the bricks shrink too much they can become loose.
Occasionally tighten the case by turning the screws of the case clamps. Do this 1/4 of a turn at a time on each of the clamps. Keep a balanced tightening (i.e. don’t tighten one clamp too much at one time). Slow is good.
You can do this on the bands around the top and bottom also. This will help maintain the integrity of those slabs even if there is a crack.
General lid and bottom maintenance:
Mechanical shock can crack the fragile lid if you close it too quickly.
Lids and bottoms developing hairline cracks is normal and not a cause for concern. These shouldn’t require repair.
If repairing cracks becomes necessary, see the section on Brick Cement.
Be careful not to overload the bottom.
As long as the bottom is fully supported by the stand the cracks in the bottom will not adversely affect the operation of the kiln.
If the bottom deteriorates over time, try putting a full ceramic shelf directly on top of it.
In many L&L Kilns the bottom can be reversed once the initial inside surface deteriorates.
It is okay to double up. You can buy a new bottom and place it under your cracked or spalling one.
Cover the bottom with kiln wash to prevent dripping glaze from sticking.
If glaze does get onto the bottom be sure to scrape it off. Apply kiln wash over area that you have scraped clean.
See https://www.youtube.com/video/dnsBoUAuK0E?ecver=2
How to replace a damaged side brick in an Easy-Fire or other sectional L&L kiln. This video shows replacing both a brick where the element connections are and where the peephole is (the two most difficult bricks).
This video shows you how to replace a lid on an Easy-Fire, School-Master, Jupiter, eQuad-Pro, JH Series kiln with a spring-assisted lid. For 23" and 28" models only.
See https://www.youtube.com/video/X3PhjpWxedQ?ecver=2
How to repair cracked brick in a front-loading kiln. First remove the damaged brick using a drill and chisel to route out and remove brick. Then shape a cut firebrick piece to fit in the space and cement in place. Then sand. Let the cement dry overnight and then do a slow bisque firing to cone 5. This same technique can be used on kiln bottoms and in other situations like on the side or back. Hi-Temp kiln cement can be used instead of phosphate bonded cement (which is no longer available).
See https://www.youtube.com/video/hXiVZNd57SU?ecver=2
This video shows how to repair minor cracks in the bricks on a front-loading Easy-Load kiln. Can also be used in other situations where you do not want to remove firebrick. Hi-Temp kiln cement can be used instead of phosphate bonded cement (which is no longer available).
