| Tips -- Preventing Rust |
| 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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| Water traps |
The railing shown was not welded on the top of the upright.
Although we have applied over 200 microns of paint in this area
in order to fill the gap, we have not been totally successful.
Water will flood and remain in the dark areas shown, and
because there is no paint will rust within a year. On design and
manufacture, all water traps should be avoided. This job could
have been galvanized; the zinc would have filled the cavity. If like
this job, it's a bit late, try filling the cavities with a sealant.
Although we have applied over 200 microns of paint in this area
in order to fill the gap, we have not been totally successful.
Water will flood and remain in the dark areas shown, and
because there is no paint will rust within a year. On design and
manufacture, all water traps should be avoided. This job could
have been galvanized; the zinc would have filled the cavity. If like
this job, it's a bit late, try filling the cavities with a sealant.
| Sharp edges |
This was a job we were asked to look at within view of the sea.
It had been on site for nearly two years and rust was beginning
to show. Two problems, generated by the desire to have a
smooth finish; the material was not galvanized which is
advisable when requiring white, as a pinhead of rust will leave
large brown stains on a contrasting background. The second
problem was the use of bright steel, which has sharp edges. It
can be seen that only these edges are failing, not the flat areas.
Powder wraps very well round curves but it does not cover well
over spikes and sharp edges.
Try to ensure sharp edges are rounded off.
It had been on site for nearly two years and rust was beginning
to show. Two problems, generated by the desire to have a
smooth finish; the material was not galvanized which is
advisable when requiring white, as a pinhead of rust will leave
large brown stains on a contrasting background. The second
problem was the use of bright steel, which has sharp edges. It
can be seen that only these edges are failing, not the flat areas.
Powder wraps very well round curves but it does not cover well
over spikes and sharp edges.
Try to ensure sharp edges are rounded off.
| Securing mesh |
The mesh has been trapped between the inside flat of an angle
iron and a strap. This has presented us with two problems. We
cannot get paint between the two flats and around the mesh,
and a water trap has been generated. Water will collect in these
areas and without any paint will definitely rust, in a matter of
weeks. We would expect brown rust marks to run over the fresh
paint. Shortly after the paint will begin to lift as the rust will creep
underneath. If like this job, it's a bit late, try filling the cavities
with a sealant.
iron and a strap. This has presented us with two problems. We
cannot get paint between the two flats and around the mesh,
and a water trap has been generated. Water will collect in these
areas and without any paint will definitely rust, in a matter of
weeks. We would expect brown rust marks to run over the fresh
paint. Shortly after the paint will begin to lift as the rust will creep
underneath. If like this job, it's a bit late, try filling the cavities
with a sealant.
| Perforated sheet |
This is a popular design for fixing perforated sheet. However it
is a very bad design for avoiding corrosion.
The visible area of perforated sheet will be well protected,
however the inner face of the folded edging will start to go rusty
in a matter of weeks.
On close observation it can be seen that it is not painted. This is
because there is no practical way of getting the paint in there,
leaving it with no protection. To compound the problem, water
will fill the bottom edging. Within a year, this may need
replacing. If this is an obligatory design, stainless steel should
be used with drain holes. Once painted introduce oil, or wax oil,
this will help protect the un-painted areas.
is a very bad design for avoiding corrosion.
The visible area of perforated sheet will be well protected,
however the inner face of the folded edging will start to go rusty
in a matter of weeks.
On close observation it can be seen that it is not painted. This is
because there is no practical way of getting the paint in there,
leaving it with no protection. To compound the problem, water
will fill the bottom edging. Within a year, this may need
replacing. If this is an obligatory design, stainless steel should
be used with drain holes. Once painted introduce oil, or wax oil,
this will help protect the un-painted areas.
| Distortion when galvanizing mesh |
If galvanizing is to be used, then for best protection the
component should be manufactured and galvanized prior to
powder coating.
Distortion of thin material should be considered. Pre-galvanized
mesh can be an alternative, but be aware of over lapping areas
that are not galvanised and are made in such way that it is
impossible to paint between. Powder coating cannot be relied
upon to fill gaps, or act as a sealer.
component should be manufactured and galvanized prior to
powder coating.
Distortion of thin material should be considered. Pre-galvanized
mesh can be an alternative, but be aware of over lapping areas
that are not galvanised and are made in such way that it is
impossible to paint between. Powder coating cannot be relied
upon to fill gaps, or act as a sealer.
| No paint, no protection. |
It is important to consider corrosion protection during the
design stage. Where there is no paint there will be no
protection. This area of over lap could have easily been
remedied by using the same size channel or removing the
bottom web and fully welding.
design stage. Where there is no paint there will be no
protection. This area of over lap could have easily been
remedied by using the same size channel or removing the
bottom web and fully welding.
| Within weeks this will rust due to poor design. |
| Heat from galvanising causing distortion |
| Inaccessible area for spraying. |
| Sharp edges should be rounded. |
All painting systems whether it be wet paint or powder coating
are more vulnerable on sharp edges because at these points it
is usually a thinner coat. On the picture the fabricator has
removed the sharp edges on the end of this balcony. A large
radius is not required as long as the paint film is uniform
thickness, which is not possible on a knife-edge.
are more vulnerable on sharp edges because at these points it
is usually a thinner coat. On the picture the fabricator has
removed the sharp edges on the end of this balcony. A large
radius is not required as long as the paint film is uniform
thickness, which is not possible on a knife-edge.
| Edges should be rounded. |
| Bottom edge stays wet longer. |
| Area for corrosion. |
| This design creates a water trap. |
| Sharp edges should be rounded. |
| Welds should be fully-sealed to prevent water traps. |
| The bottom edge is more likely to go rusty. |
The viscosity of water allowing it to form drips, along with it
flowing to the lowest point, and invariably because it is not in the
sun means the bottom edge of the steelwork is wet longer. If it
is wet, it is more vulnerable to corrosion.
Stair treads are often cut with a guillotine leaving a sharp edge
on the most vulnerable area of the tread.
flowing to the lowest point, and invariably because it is not in the
sun means the bottom edge of the steelwork is wet longer. If it
is wet, it is more vulnerable to corrosion.
Stair treads are often cut with a guillotine leaving a sharp edge
on the most vulnerable area of the tread.
| Water trap. |
As with the picture above, if it is wet, it is more vulnerable to
corrosion. This balcony platform has been manufactured with a
water trap. It will stay wet for most of its life. To make matters
worse it will have a square foot plate from a post bolted on to it.
This will mean the water will be sandwiched between two
plates. A bad situation for a structural fixing.
Place a layer of sealant between the two surfaces. Thick
grease will last many years repelling the water.
corrosion. This balcony platform has been manufactured with a
water trap. It will stay wet for most of its life. To make matters
worse it will have a square foot plate from a post bolted on to it.
This will mean the water will be sandwiched between two
plates. A bad situation for a structural fixing.
Place a layer of sealant between the two surfaces. Thick
grease will last many years repelling the water.
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