powder coating and durability

[eteled]

Hello

I am looking for suggestions on what is going wrong with the powder coating I am have done. My products are made and
sold in Ontario Canada where we get quite a range of climate from + 30 deg to - 30. I use hot rolled steel and have same results whether I have them sand blasted or not but they start to rust through generally before there outside for a year. I've change suppliers a few times with the same results. Are they all using inferior powder, should they be primed first and powder coat, clear coated after powder coated I just hate it when the customer comes back and say's there metal art is starting to rust. any suggestions that I could pass along to the powder coater would be helpful Thx

[wickedinhere]

Have you checked the specs on the powder your using some are for interior use and may require a clear coat for exterior use.

[tnbndr]

How are they prepping the material prior to powder?
The place I use sand blasts all rust and mill scale off prior to powder, then powder primes and powder coat. I have bumpers going on three years with no issues. I am currenlty having a patio fire pit table done by them so we will see how that holds up.

[conradestrada]

its all in the preparation plaster sand and river sand are not what you want to use use garnet, starblast, or aluminum oxide sand will impregnate silica in your lungs and your substrate when it gets to 400 it pops and leaves fish eye looking dots which will start to rust quite rapidly. also ensure you are using the correct powder as mentioned earlier the only thing that will do is chalk over like an electrical enclosure because it is an epoxy and not uv stable but the integrity of the powder should still hold up. finally if you are doing it in a house over your just wasting your money you are not gonna get a quality cure it is not going to vent the exhaust and impurities just rattle can it if that is what you are using.