Frequently Asked Questions
If you are new to the roll forming business, CSC Machine would like to help you, not only with roll forming machines and trim making machines but with information on coil supply; based on our experience over the last 40 years.
Coil purchasing can be a confusing endeavor, the following information should make the process a little easier.
- Coil width
- For Tuff-Rib, Classic-Rib, Ag Panel, 36” coverage panel with ¾” ribs on 9” centers the coil width is usually 40 7/8” – 41 ¼”.
- For R-Panel, PBR panel, 36” coverage panel with 1 ¼” ribs on 12” centers the coil width is usually 42 ¾” – 43 ¼”.
- Either panel may be formed without a bearing leg with coil 1” – 1 ½” narrower.
- Coil gauge
- For Tuff-Rib, Classic-Rib, Ag Panel, the gauge is normally 29 gauge. The thickness of 29 gauge, according to the AISI Tolerance Ranges for Galvanized Steel Sheets is .0142”-.0202”, average .0172”. The thickness of 30 gauge according to the AISI Tolerance Ranges for Galvanized Steel Sheets is .0127”-.0187”, average .0157”.
- For R-Panel, PBR panel, the gauge is normally 26 gauge. The thickness of 26 gauge, according to the AISI Tolerance Ranges for Galvanized Steel Sheets is .0187”-.0247”, average .0217”. The thickness of 24 gauge according to the AISI Tolerance Ranges for Galvanized Steel Sheets is .0236”-.0316”, average .0276”.
- As you can see the actual thickness can vary under a gauge designation. The closer the thickness is to the minimum in the gauge range the lower your cost per lineal foot, or you get more square feet per pound than you do if the material is at the top of the thickness range for the designated gauge. Therefore, it is important to ask the supplier what thickness range they are supplying for a particular gauge designation.
- Coil Size
- Pre-Painted coil is usually sold in coils of 8000-10000 pounds. The center hole in the coil is normally 20”. The coils may be shipped to you vertically on pallets (eye to the sky) or horizontal. Usually the supplier will ship according to your request. Some suppliers will make smaller coils on request.
- If you plan to have a large number of coils in stock, the vertical arrangement takes less floor space than horizonal. But you will need to tip the coils before you can use them. This can be done using some old tires arranged so the coil cannot roll, then tipping the coil over with a forklift, so it lands on the tires. Or you can purchase a coil tipper to make the job easier and safer.
- You can have the coils shipped horizonal then you do not have to deal with tipping them, they just take up a little more space in your storage area.
- Silicon Modified Polyester (SMP) is the most common paint system used for pre-painted coil in the US. This system usually has a 20-45 year warranty on certain aspects of the paint performance. In some cases, extra paper work must be completed if your customer would like a written warranty.
- There are lower cost paint systems available from some suppliers. They may be marketed is liner panel coil, ag panel coil, or something similar.
- Convert pounds to lineal feet
- One of the issues in buying coil is that it is purchased by the pound and sold by the lineal foot. How is the conversion made from cost per pound of coil to cost per lineal foot of finished panel?
- There are a number of simple steps in this process, that may be calculated or entered into a spreadsheet.
- Steel weighs 40.8 pounds for 1 square foot, 1” thick.
- How much does a coil weigh per square foot?
- To determine how much your material weighs per square foot, multiply the thickness in decimal inches times 40.8. Example .015 X 40.8= .612, so your material weighs .612 pounds per square foot.
- How much does a coil cost per square foot?
- If your cost per pound is $.75, then your cost per square foot would be $.75 X .612 = $.459 per square foot.
- How much does a coil cost per lineal foot?
- If the width of the coil is 40 7/8”, the square feet per lineal foot would be 41.875 / 12 = 3.489 square feet
- Cost per lineal foot would be 3.489 X $ .459 = $1.60 material cost per lineal foot.