Preparing and painting hubs

Cast parts have an issues with being porous an collecting grease and grime over the years. Before i powder coat any cast items they go in the oven at around 475°f for an hour. This will bring to the surface any casting gas or debris left in the part during the cooling process. Once the part is cooled you can now media blast all the trash from the surface and not worry about any residual oil/grease destroying you nice paint job.If you want maintenance free polished aluminum have it clear powder coated after polishing it.
 
I can do that in my own oven I figure.
So I clean it down as much as possible as I have already done, oven for an hour and then blast it all. Sounds like an easy way to prep your aluminium.
Guess it's a good idea for engine parts as well. I have two questions

Will it smell?
Will all the grease not get blasted off anyway?
 
Selfteaching Dane said:
I can do that in my own oven I figure.
So I clean it down as much as possible as I have already done, oven for an hour and then blast it all. Sounds like an easy way to prep your aluminium.
Guess it's a good idea for engine parts as well. I have two questions

Will it smell?
Will all the grease not get blasted off anyway?
Click to expand...
Carbonaceous materials tend to burn off between 300° and 500°. It will produce fumes and if there isn't good enough circulation, it can make them worse then before you put them in. His ovens are for powder coating, most likely. So proper ventilation is present.
 
If I have oil on something, I'll give it a quick run over with a propane torch, burn everything off before I get ready for paint.
 
Ive done a propane torch before. I also second not using rattle can paint on your hubs. I have also tried it before and it chipped when lacing the 1st spoke. Use a HVLP setup with a catalyst or bake on your powder. Only thing I don't like about powder is that if a rock hits it hard enough, theres a possibility of it spider cracking.


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alexcb550 said:
Ive done a propane torch before. I also second not using rattle can paint on your hubs. I have also tried it before and it chipped when lacing the 1st spoke. Use a HVLP setup with a catalyst or bake on your powder. Only thing I don't like about powder is that if a rock hits it hard enough, theres a possibility of it spider cracking.


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Click to expand...
If the powder was properly applied and properly cured nothing will make it spider crack.
 
Selfteaching Dane said:
I can do that in my own oven I figure.
So I clean it down as much as possible as I have already done, oven for an hour and then blast it all. Sounds like an easy way to prep your aluminium.
Guess it's a good idea for engine parts as well. I have two questions

Will it smell?
Will all the grease not get blasted off anyway?
Click to expand...
Grease and oil will get sucked into the porous metal, no, blasting alone will not remove it, it only removes the surface debris. If the part is heated the pores open and the pent up oil comes out.
 
We're talking about aluminum, not skin. The "pores" don't open up. Porosity is not an accurate way to describe it, either. What's happening is there are small voids in the surface from the the molds gassing. Sand casting is particularly susceptible. The voids are only near the surface. The process which causes the oil to come to the surface as it's heated is called convection and it works because of a bouyant force on the less dense, hotter fluid. It's thermodynamics.
 
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Why is it so hard to find a spell checked Rickyism? ???
 
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