The BrickWood Stainless Steel Needles Guide
Stainless Steel Needles: Crack Control for Castable Refractory Pizza Ovens
What stainless steel needles do, why castable ovens need them and how to mix them in. Written in plain English for first-time builders.
BrickWood Stainless Steel Needles are 1 inch serrated stainless steel fibers that you mix into castable refractory to control cracking. They withstand temperatures up to 2,400°F. They're the same needles we put in every Cortile Barile and Mattone Cupola castable pizza oven, and they work in any castable refractory project, from forge liners to fire pit rings.
Stainless Steel Needles: Quick Answers
- What they are: 1 inch serrated stainless steel fibers for castable refractory.
- What they do: hold castable together so small cracks stay small.
- Rating: withstands up to 2,400°F.
- What's in the box: 12 bags, 1 lb each, about 5,600 needles per bag.
- How much to use: 1 bag (1 lb) of needles per 50–55 lb bag of castable.
- Shipping: FREE to the contiguous United States. Non-refundable once shipped.
Inside this guide
Why Castable Ovens Need Stainless Steel Needles
Every refractory expands as it heats and shrinks as it cools. Over hundreds of fires, that movement creates tiny hairline cracks in a castable dome. That's normal. The problem is when those cracks keep growing until pieces spall off.
Stainless steel needles work like rebar on a tiny scale. Thousands of serrated needles spread through the castable and grip it from the inside, so hairline cracks stay hairline cracks. Regular steel would rust and weaken. Stainless steel holds up to the heat and moisture of an outdoor oven.
Stainless Steel Needles Specifications
| Material | Stainless steel |
| Shape | Continuously deformed (serrated) needles |
| Length | 1 inch |
| Maximum temperature | 2,400°F |
| Count | About 5,600 needles per 1 lb bag |
| Package | Box of 12 bags, 1 lb each (12 lb total) |
| Use with | Castable refractory, including BrickWood Castable Refractory |
| Made for | Cortile Barile and Mattone Cupola castable pizza ovens |
How to Mix Stainless Steel Needles into Castable Refractory
This is how we mix every castable BrickWood oven. The rule is simple: 1 bag of needles for every 1 bag of castable refractory, and the needles go in while the castable is still dry.
Step 1Pour 1 bag of castable refractory into the mixer
Open one 50–55 lb bag of castable refractory and pour it into your cement mixer. Don't add any water yet. The needles go into the dry mix.
Step 2Add 1 bag of needles per bag of castable
Pour in one 1 lb bag of stainless steel needles for every 50–55 lb bag of castable. Shake them in a little at a time so they spread out instead of clumping.
Step 3Dry mix until blended, then add water
Let the mixer run until the needles are blended evenly through the dry castable. Then add clean water slowly, about 2.5 to 3.5 quarts per bag. Start at the low end. Too much water makes the castable weak.
Step 4Check the consistency
It should look like this: damp and chunky, with needles all through it, and stiff enough to hold its shape in your hand. If it's soupy, it's too wet.
Step 5Place it in your form right away
Your castable with needles is ready to use. Dump it into your oven form and pack it down tight to push out air pockets.
Safety and Handling
- Wear work gloves and safety glasses. The needles are sharp and can puncture skin.
- Keep loose needles off the ground where people or pets walk barefoot.
- Store sealed bags in a dry place, out of reach of children.
Mistakes to avoid
- Adding needles to wet castable. Blend them into the dry mix first, then add water.
- Dumping them in all at once. They'll clump. Shake them in a little at a time.
- Using carbon steel fibers. They rust inside an outdoor oven.
- Skipping gloves. The needles are sharp.
Stainless Steel Needles: Frequently Asked Questions
What do stainless steel needles do?
They mix into castable refractory and hold it together as it heats and cools, so small cracks stay small instead of growing and spalling.
How hot can they get?
They withstand temperatures up to 2,400°F.
Do I need them for a castable pizza oven?
We strongly recommend them. We use them in every Cortile Barile and Mattone Cupola oven we build.
How many needles are in a box?
Each box has 12 bags, 1 lb each, with about 5,600 needles per bag.
How much do I add?
Use 1 bag (1 lb) of needles for every 50–55 lb bag of castable refractory. Blend them into the dry castable first, then add water.
Can I use them in mortar?
No. They're made for castable refractory, not for the thin joints between fire bricks.
Can I return them?
Refractory products are non-refundable once your order has shipped.
How fast do they ship?
They ship within 1 to 2 days, with FREE shipping to the contiguous United States.
Please Order Carefully: Refractory Materials Are Non-Refundable Once Shipped
Refractory materials are heavy, costly to ship and can't be resold once they leave our warehouse. For that reason, refractory products can't be cancelled, returned or refunded once your order has shipped.
We're happy to help you get it right the first time. If you're not sure which product or how much you need, contact us before you order and we'll walk you through it.
Shipping
FREE shipping on every refractory product to all locations in the contiguous United States (the lower 48 states). Orders ship by ground carrier or commercial freight, depending on size, and freight carriers will call to schedule delivery. Please leave a phone number we can reach you at in the order notes.
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