It’s Christmas Eve. Kjell Olav, service manager at Nordic Bulk, has three hours left of the working year when his phone buzzes in his pocket. IVAR Recycling’s sorting plant has a large longitudinal crack in a conveyor belt.
IVAR has many conveyor belts for waste management, and soon overflowing bins with gift wrap, half-eaten ribs, cardboard boxes and Christmas trees from thousands of homes will be disposed of. The conveyor belt needs repair. Now.
Examine the underside of the conveyor belt
The underside is the side that lies against the drive drum and is not in direct contact with the material it carries. If possible, always glue repair tape (rope tape) and patches to the underside of the conveyor belt. This is to avoid problems with scratching.
If you glue rope tape on the top side (on the same side as the material), you must remove the scraper to prevent it from tearing the patch. Without a scraper, you get spills and a conveyor belt that can slip from side to side on the rollers.
The effect of missing a scraper can be significant, see how much here:
How scraping on transportation saves you tons of work
Ensure good access for work
To ensure good access to the underside, in this case we used 2 angle irons and laid over the conveyor belt close to the area to be repaired and jacked it down.
In many works, it is enough to run the conveyor belt in the appropriate position. If necessary, you can also slacken it slightly.
Cut rope ties to the right length
After measuring the tear, cut the patch case to the correct length. On a longitudinal crack, the patch should be approximately 10 centimeters longer than the crack. The patch should overhang each side of the crack by 5 centimeters. You can double-check by taking the patch and placing it on top of the crack before the next step.
Wash the patch properly
Wash and rub thoroughly with rags and a cleaner specifically for rubber. Preferably a strong one like removes all grease, dust and dirt. This is important, otherwise the patch will fall off again after a short time, and the whole patch job may be in vain.
Cleaning fluid we use: Nordic Cleaner
Sand the patch cases for good adhesion
To ensure that the adhesive sticks well, it is important to sand the patch on the side to be laid against the conveyor belt. It should have a rough surface. Sand all the way to all edges. We use special belt sanders for this. We recommend sandpaper with roughness p24.
The machine we use: Makita belt sander
Wash and release conveyor belt
Repeat the previous two steps, but this time on the conveyor belt itself. You can use the same sanding machine and sandpaper as in the previous step. Make sure you wash and sand both sides of the conveyor belt around the injury, as well as inside the tear.
Mix glue and hardener well together
With our adhesive kit, the mixing ratio is already made for you. You pour one box of hardener into one box of contact adhesive. Put the lid back on, make sure it is tight, and shake the can well for 1 minute. Then use a stirring stick and stir for 1 minute. Ensure that hardener is mixed evenly with contact adhesive.
We use Nordic adhesives and hardeners
Apply glue
Use a regular paintbrush to apply glue all over the patch. It can be a cheap brush, as the glue sticks and should be thrown away afterwards. When you have finished applying glue to the patch, apply glue to the conveyor belt. Glue on both sides around the crack, and inside the crack along the entire length.
Wait 30 minutes
Clean the workplace, grab a coffee, or do as Kjell Olav does; tell some tall tales to the operators. For example, how you once stopped an airplane with your bare hand.
Apply another layer of glue.
The first coat of glue was like a primer. Other coats may be somewhat fuller.
Stick rope ties to the conveyor belt
Rep tape is applied when the glue is so dry that it does not stick to the finger knuckles. Massage, rub and squeeze the patch firmly with your fingertips, especially along the edges.
Fix loose tabs and bubbles
If there are any loose flaps or bubbles along the sides or at the end, apply more glue in this area and wait another ten minutes. Squeeze, rub and mash the patch down to the tape again.
Roll over with a double ruler
Screw the double ratchet tightly so that it really squeezes the patch into the crack, causing the rubber from the tape and patch to fuse together. Roll over along the entire length of the patch. Make sure you roll over every square centimeter of the entire patch.
Mix bag with Eli Flex rubber paste
The bag contains two substances separated by a yellow plastic rod. To activate a chemical reaction in the fabrics, remove the rod and use it to scrape all the yellow fabric against the black fabric so that it mixes. Be careful not to puncture the bag. Knead the fabrics together for 3 minutes. Then you will feel that it gets warm inside the bag.
NB: Knead and knead the bag well for 3 minutes, until hot.
Lubricate Eli Flex rubber paste
Cut off a corner of the bag, leaving a hole. Squeeze the black rubber paste into the tear on the opposite side of the patch. Spread it evenly with a small plastic scraper included in some packages, or cut a small piece of rubber yourself. Lubricate well, until the entire tear is full. It should be as good as even with the conveyor belt.
Use as many bags as necessary. In this case, we used five bags of Eli Flex rubber paste on the rift in this case.
We use this type of Eli Flex
Say goodbye and Merry Christmas
Clean up, pack up, say Merry Christmas and take a well-deserved holiday????????
Curing time
Wait for it to harden properly before starting the conveyor belt. For a crack between 40-50 cm in length and 2-4 cm in width, you can normally wait 3-4 hours. If you have a larger crack, you should wait at least 5-6 hours.
Equipment for repairing conveyor belts
Click on the image or title to read more about the different products.
Cleaning fluid for rubber and metal
filler
If you’re quick, you can secure these used wash rags on finn.no. The seller describes them like this: Good thick wash rags are given away. Can be picked up at the address in Egersund or sent home for postage (75,-)
Contact adhesive and hardener
Patchwork
Eli-flex rubber paste
Belt sander
Preferably use a cordless belt sander, as it makes it easier to get into tight spaces. Then there are no cables and extension cords hanging up and causing dangerous situations. You avoid both high currents and tripping hazards with a battery-powered machine, and it’s a hell of a lot more fun to work with. Buy one with a battery.
Paintbrush
Since you spent so much money on a cordless belt sander, you can save a few pennies by using a cheap brush. The glue sticks incredibly well and the broom has to be thrown away afterwards anyway. The brush in the picture costs 20 kroner.
Double rinds
The double groove is a special tool that you need to rub the patch into the conveyor belt properly. Contact Kjell Olav and he’ll get it from our supplier.
Think safety
- Work gloves
- Verne glasses
- Mask (in case of poor ventilation)
Change gloves if there are holes. Put on a new mask if the solvent bothers you when breathing in. The adhesive is a strong substance designed to melt rubber and is not good for skin or inhalation. In case of contact with eyes, seek medical attention immediately.
Thanks to the IVAR recycling plant????
Thanks to IVAR (renovation and recycling in Sandnes) for allowing us to document the work Kjell Olav did for them, and thus create this recipe for repairing conveyor belts.
We hope you find it useful.