Repainting galvanized steel garage door

My south-facing galvanized steel garage door was last painted (red) about 18 years ago, but now it has faded to pink and is peeling in several places to expose the bare galvanised surface. In other words it's long overdue a repaint.
I'm thinking of repainting it with Hammerite, a nice dark green colour. I'll do the usual preparation (sanding/wire-brushing/washing), but does anyone know if Hammerite will be OK to paint over the old (non-Hammerite) red paint, or will I need to strip the whole door down to the galvanised surface (a daunting thought)?
--
Andy Clews
University of Sussex
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Strip it using a good paint stripper. Clean thoroughly and prime with a good galv friendly primer. Paint with whatever gloss paint you like. Cheaper than *trying* to find out with Hammerite (Which always looks shyte anyway)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Hammerite is IMHO unsuitable for painting such a large area owing to the great difficulty of maintaining a wet edge. It dries too quickly.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Thu, 25 Mar 2010 10:15:42 +0000 (UTC), snipped-for-privacy@DENTURESsussex.ac.uk gently dipped his quill in the best Quink that money could buy:

Use a heat gun, prime and finish with Dulux Metal Shield
Mike P the 1st
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
     snipped-for-privacy@DENTURESsussex.ac.uk writes:

Not done anything like this, but I would be careful not to go through the galvanizing with sanding or wire brush, or you might find rust staining starts coming through the new paint after a while.
--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Thus spake Andrew Gabriel ( snipped-for-privacy@cucumber.demon.co.uk) unto the assembled multitudes:

Many thanks to all for their replies. I take your point about damaging the galvanizing, so will probably go down the route of using paint stripper and then gentle sanding to provide a key.
--
Andy Clews
University of Sussex
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 27 Mar, 09:30, snipped-for-privacy@DENTURESsussex.ac.uk wrote:

I wouldn't even go that far - just strip. Weathered galvanising is a good painting surface all on its own.
Use a good quality zinc-rich primer (often aerosols) to repair damage.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Thus spake Andy Dingley ( snipped-for-privacy@codesmiths.com) unto the assembled multitudes:

Thanks for the tip.
--
Andy Clews
University of Sussex
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.