Understand Your Bake Oven Belt

May 6th, 2021

by Staffan Karlsson of BANDAID AB

In a previous article I tried to describe, some of the key criteria important to be aware of when dealing with solid or perforated steel belts in bake ovens. A number of intelligent and challenging questions were also asked as a result. So, let’s try and bring some more understanding into this game.

Terminology

“Band or Belt? What is the correct wording? Is there a difference?” Actually, there are different opinions here. One definition, and the one I like best, says: “A Steel Belt is an engineered steel band”. In other words; When the raw material arrives to the belt manufacturing plant, it arrives like a band. Before it’s called a belt it has to undergo a number of complicated processes necessary for its future baking mission. Just like us, a steel belt needs to be shaped and educated with love and care.

Bake Oven Inside

Photo source: © Berndorf Band Group

Unpacking, cleaning and protecting

When the new bake oven belt arrives to its new home, it’s well packed and because of the carbon steel properties it is also well covered with rust protective oil. Before the belt goes on the oven as much as possible of this oil should be removed from bottom and top surfaces. If you don’t have anything better some boards and rugs soaked in some cleaning agent, such as alcohol, can serve as a “cleaning jig.” I know that some folks use to just “burn off” the oil at high temperature in the oven. But seriously, I’m trying to be as environmentally friendly as possible in my advice here.

When the product side (baking side) of belt is clean, it should be protected in two steps. Firstly, with bees’ wax that is carefully polished onto the warmed-up belt surface. After that it is ready for your release agent of preference.

Graphite

Backside of belt should soonest be covered with graphite. Easiest is to use graphite skid bars or a graphite bar station and let the backside of the belt have a continuous graphite smearing . Traditionally graphite powder is used and sometimes mixed with water. It takes some carefulness to do this and the outcome should be closely monitored. Graphite in this form is not dangerous but can easily create a mess for you to clean. Leave 50 mm on each edge unsmeared.

So why bother with this graphiting? Well, the carbon steel surface needs a low friction cover and to protect it from corrosion. Also, the terminal drums, the support rollers and not least the cast iron skids need this substance to feel good during production. Graphite will normally not cause tracking issues either as oil can do when a slippery environment has been created. If your baking belt vibrates during operation, it is most likely because of dryness on the back side. Add some graphite and your problem is probably gone. And you become the hero of the day. Feels good to be a hero.The amount of graphite, the layer, should be fairly modest. Just like made with a pencil.

Carbo Cookies

Photo source: © Berndorf Band Group

Steel Belt Benefits

“A steel belt cannot always be the best option for baking of biscuits!” This relevant comment came to me after the last article. And of course, there are segments where solid or perforated steel belts not are being used. One reason is cultural, another is cost and the reason could be product driven or a branding issue such as burnt markings from wire on snacks. Short term, steel belts seem expensive but they are for sure difficult to wear out without heavily abuse. We have seen steel baking belts still in operation after 70 years of service. If you are into energy saving a steel belt is the best choice. If you don’t like downtime costs for cleaning, a steel belt is easy to deal with. Less water usage, less chemicals used and no permanent elongation of the belt either. But as said, if none of this is important there are substitutes.

Energy saving

Back to energy savings. How come a solid steel belt is more energy efficient than other belts? Well simply because that a steel belt weighs half of the similar mesh belt (CB5) for the same baking purposes. Of course, there might be products that are different, but no matter what, in most cases it cost more to heat up 2 kg of steel than 1 kg of steel. On top of this you can lose an additional 25% of belt weight when using a perforated steel belt compared to a solid one.

A dirty belt with burnt in debris from the baked goods, dust, fat and carbon will require more and more energy over time in order to reach and keep the right temperature. As a solid or perforated steel belt is easier to clean this will also add to your energy saving.

And, a clean belt will not catch fire as easy as dirty one. Both bakery owners and insurance companies see a great advantage here.

debris floor

Good house keeping is essential/BandAid

My belt is dirty. Can it be cleaned?

Honestly, in most cases yes it can. But try not allowing it to become dirty in the first place. It’s a lot about chemistry here. Make sure you are using oils, fats, sugars etc that work together without creating messy residues after sometime within the oven. When changing an ingredient, be extra careful monitoring the belt surface for a while.

Check out your cleaning scrapers and or brushes. I’ve learned that carbon steel ones are the best. A rotating cleaning brush should run in the same direction as the belt is. The drive should be connected to the belt drive. (If the belt stops, the brush stops) On a perforated belt the brush should not be driven.

The hardness of carbon steel scrapers and brushes should match the steel belt properties. And as said before its of outermost importance to carefully monitor the impact any cleaning unit might have on the belt surface.

I get questions about softer rotating brushes, made from plastic, nylon, etc; But no, my recommendation is steel.

Manual cleaning of the belt surface can every once and a while of course be necessary for a number of reasons. Most of the time it’s good to have a warm belt during cleaning. Oil, rugs and a lot of hands usually works. Light “Scotch-Brite” can gently be used as well if required. Dry Ice blasting and salt blasting are other more sophisticated methods used.

extra layer

Oil reacted with sugar and an "extra surface" was built up/BandAid

Map to success

Finally remember, the steel belt surface is your map. Learn how to read this map and you can learn how to safely navigate your biscuits to the top shelf of the best supermarkets.