| Tips -- Why Blast? |
| Premier POWDER Coating For All Your Powder Coating Needs: |
| 221 W. 17th St. Ottawa, KS 66067 Ph# 785-242-3955 Fax# 785-242-3758 |
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Although clean mill scale looks like a good surface to paint on,
as most fabricators know it is very hard and brittle. When
attempts are made to remove it by grinding or abrading, it is
often left polished and shiny, this makes an unsuitable surface
to paint on. Should the component suffer an impact, the paint is
likely to chip off the mill scale.
As a general rule, all hot roll steel must be blasted to remove
mill scale
as most fabricators know it is very hard and brittle. When
attempts are made to remove it by grinding or abrading, it is
often left polished and shiny, this makes an unsuitable surface
to paint on. Should the component suffer an impact, the paint is
likely to chip off the mill scale.
As a general rule, all hot roll steel must be blasted to remove
mill scale
This is part of a chair powdercoated by another trade coater.
We were asked to strip and re-powdercoat it, because of
chipping when it fell over. They had applied a thick coat of
powder over mill scale, and as can be seen the mill scale has
chipped taking the paint off with it.
When powdercoating is applied properly to a good key, it can
sustain a hammer blow. The paint will smudge but not chip.
Caution should be used when dealing with a Powder Coating
company that does not include grit blasting, as part of their
specification when painting over mild steel for architectural
use.
We were asked to strip and re-powdercoat it, because of
chipping when it fell over. They had applied a thick coat of
powder over mill scale, and as can be seen the mill scale has
chipped taking the paint off with it.
When powdercoating is applied properly to a good key, it can
sustain a hammer blow. The paint will smudge but not chip.
Caution should be used when dealing with a Powder Coating
company that does not include grit blasting, as part of their
specification when painting over mild steel for architectural
use.
| Mill scale chips off metal. |
| Paint chips off clean mill scale. |
| All thick gauge steel is grit blasted. |
As a matter of policy RML inc. grit blasts all thick gauge steel to
SA 2 1/2 (grey metal). This will produce an excellent key for the
paint to adhere to. The finish will also be improved because;
mill scale being so hard, chips leaving steps under the paint.
Blasting will remove mill scale, rust and most contaminants; it
will also reduce light scratches and blemishes.
SA 2 1/2 (grey metal). This will produce an excellent key for the
paint to adhere to. The finish will also be improved because;
mill scale being so hard, chips leaving steps under the paint.
Blasting will remove mill scale, rust and most contaminants; it
will also reduce light scratches and blemishes.
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