Tech Question - Powder Coating & Chroming Springs

Q -Greg from Monroe, MI called and asked which was the better way to finish his leaf springs, powder coating, painting or chroming.

A - A darn good question Greg.

All of our custom made springs are shipped bare metal. A film of metal dust is left on the surfaces of each leaf from the shot peening process. This film covering protects the spring's surfaces from rust. (don't leave them in the rain or a hose running on them)

The springs we make in volume and all coil springs in order to keep them from rusting before we ship them have been dipped in black paint. Not the nicest stuff, but it keeps the EPA happy.

The 1st thing to do is to dry fit the springs just to be sure the fit and finish is what you expected. Now remember, if the vehicle is not completely finished, engine, trans, sheet metal, glass, interior are all not installed then weight is missing and springs support weight. Therefore your ride will sit high.

Once they have been dry fitted and you like the fit, clean off the metal dust film so the coating will bond. Do not be stupid - DO NOT USE GASOLINE!

Simply put, powder coating is a process where dry paint particles are sprayed onto the surfaces on the spring. Then the springs are heated which melts and bonds the paint particles to the metal.

In order to get the paint particles hot enough to bond they must be heated very close to the annealing temperature of the spring steel. Annealing means the heat treatment of the springs is being removed. Annealed springs will no longer support any weight. Figure $225.00 to $250.00 per spring to fix this goof up.

To have the powder coat work without softening the springs the heat MUST be held to less than 350 degrees.

Painting should not have to be explained. I use high quality, hi temp engine enamel.

Hang the spring by an eye and spray 3 to 4 coats of paint. Be sure to let the paint completely dry in between coats.

Whether powder coating or painting, do not cover the top of the leaves nor the bottom part which is covered by the leaf below it. Either type of coating builds up a few thousands of an Inch per leaf. With several leaves in a spring pack the added thickness will be several thousands of an Inch.

The weakest part of a spring is where the center bolt goes through the leaves. This section of a spring must be held with such a force that there is very little movement in the center bolt area.

As a spring flexes up and down there is wear taking place between the leaves. If the inner surfaces have been coated this coating will wear through allowing additional movement in the center bolt area. The additional movement will allow the u-bolts to loosen and soon you will experience either a sheared center bolt or a broken spring. There is no warranty on any spring broken between the u-bolts.

If the vehicle is driven, after three to four years rust will began seeping between the leaves of a powder coated spring.

For a painted spring on a vehicle that is driven, after three to four years rust will began seeping between the leaves.

Expect to spend over $100.00 to have the springs powder coated.

Expect to spend around $20.00 to spray paint a pair of springs.

While a chromed spring looks neat, it can be a hidden time bomb. An improperly chromed spring may suffer from hydrogen embrittlement. This causes a spring to shatter. Not break, but shatter into several small pieces.

A multi-leaf spring that simply breaks normally will still provide enough support to safely get the vehicle off the road. However a spring that shatters may not provide any support leading to catastrophic results.

Chroming a spring is a very, very skilled procedure and should only be done by an chrome shop experienced with chroming springs.

I hope this helps you make up your mind. - Mike