Powder Coating leaf springs

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I can't speak to the question about the oven, but I would think the powder coating would crack and flake off with the flexing of the springs.

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Powder coating should be fairly flexible. At least the product I'm familiar with is. However, if the ovens raised the spring temp above 400 degrees f, then temper of the springs could become an issue as many spring steels temper anywhere around 400. 350 and lower,it shouldn't be a problem. Any metallurgists, powdercoaters care to confirm or deny?

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Coat them with RPM? Im sorry, what is this?

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The real reason you don't chrome plate suspension parts is because of HYDROGEN EMBRITTLEMENT. It works like this: when the part is being plated, hydrogen atoms migrate into the steel. There is enough space for a hydrogen atom to fit in the matrix. But the hydrogen atom isn't "happy" with being all alone and "wants" to join up with another hydrogen atom to make an H2 molecule. There isn't enough room in the matrix for that. Thus, the steel is internally stressed and can break with a brittle-appearing fracture at much lower stresses than the original steel part. To safely use chromed suspension parts the part has to be baked for several hours after plating to drive out the hydrogen atoms, even then you can't be sure.

R.

PS: To all those who know the correct ways to refer to the atoms, ions and molecules, I apologize as I can't remember after 35 years away from the classroom.

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Good reply, however that applies to most plating and should make many scratch their heads regarding using yellow zinc plated grade 8 bolts, etc. My plater says they after bake my grade 8, stressed stuff, but how does one really know?

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As previously mentioned there is no similarity at all between chrome plating and powder coating.

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So which one is the one that you can see stress cracks beginning underneath?

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It's been my experience that any brittle coating will show cracks when the substrate deforms. I use it to discover where deformation has occurred. Chrome either cracks or flakes. Powder coat cracks unless it is very elastic. Paint cracks. Even mill scale, the blackish stuff on the surface of hot rolled steel, will crack if the part deforms.

Of course, I was using something I had already learned. An older way of determining strains in parts (before finite element analysis) was to make a part and coat it with special paint called "brittle coat". Then load the part. Remove the load and inspect the part. Cracks in the brittle coat would be perpendicular to the strain. One could tell from the cracks what strains were occurring.

R.

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I agree to a large degree, however I think the issue with chrome is it can delaminate, hiding a beginning crack, and as others seem to think, powder coating is elastic, which would delay? a coating crack. the brittle paint idea is cool. Regardless this is splitting hairs, unless this is an F1 site.

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I would do it if the springs are pit free after blasting (most are not) and BTW, after you blast and powdercoat , get a re-build kit with the interleafs and straps you may have over $500 into a set of old worn out springs.

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