Thanks Wallace and Rob. I hope I haven't hijacked the post with shiny machinery however as it was my second and biggest overhaul, I did find out the hard way on several issues that hopefully others can avoid.
I would scrape off the hammerite if it was a bare casting or sheet metal, and sand blast if you can, this avoids any issues with the new topcoat reacting with the old paint and gives a good key for paint.
If you do sandblast, paint if after quickly, and not just primer as that is usually porous, the shed condensation season is coming soon, plus it will be too cold to paint in an unheated workshop in a couple of months so get a move on. If you use epoxy primer, that is not porous so you can leave it without a topcoat, however it is not UV stable so cover it up if you have lots of sunlight in your workshop until you get time to put the top coat on.
If it has been filled I would be tempted to put the scraper down sand it smooth and fill any imperfections, I used upol fantastic for big holes and upol dolphin glaze for smaller imperfections. I didn't use wet and dry but used abranet with a vacuum. You can get different bases for curves etc.
Before painting I used upol slow panel wipe and clean cotton rags, old shirts will do. You can get slow and fast, the slow gives you time to give it a good rub and remove most of the residue before it dries.
When it comes to new primer/top coat, it is worth testing it on a smaller component or area first. There is nothing more disheartening than spending days sanding and filling only to see the top coat wrinkle up.
This only happened on the feed selector control box, I think it was because this had been leaking oil for years and was soaked into the casting and filler. I scraped this off, thoroughly degreased it
I did get the big cast aluminium belt covers sandblasted, big mistake, they were full of filler and it took quite a while to get it smooth as the castings were as rough as a badger's. I used an etch primer before a coat of primer and top coat, this is necessary on aluminium otherwise the paint will not adhere and peel off it time. However epoxy primer sticks like the proverbial and can replace etch primer in most instances, it is also a good barrier for paints that don't like each other, but difficult to sand if you get a sag and you leave it to fully cure before attacking it.
On the milling machine I used synthetic enamel and undercoat, probably Paragon or Craftmaster both very similar, may even be the same, both do a Tom Senior Green and many other machines plus RAL colours etc. If I was doing it now I would use epoxy primer then whatever top coat, I would probably use Lechler epoxy, it comes un-tinted so you usually have to specify what colour you want. The reason is that it's as tough as old boots, is impervious to moisture if the film is thick enough and unbroken and effectively nullifies the top coat from reacting with the original paint. There is the risk that the epoxy may react with the original paint, always try a bit first before spraying it all over.
I sprayed the miller but I know people that roller epoxy primer and get a superb finish, even a whole car. As far as topcoat is concerned, I prefer to spray but if you must brush then you can add wet edge extenders like Owatrol oil to the paint, this helps brush marks to sink as well as giving you more time to push the paint around. I have some on the shelf but not used it in anger yet, but I know people that have used it successfully on large panels like tractor wings etc. and swear by it.
I tend to use synthetic paint as a top coat as it is a lot more durable than cellulose and I don't have the proper PPE for 2 pack. The epoxy I use is safe with the right face mask, and I always spray it in the downstairs barn which has lots of ventilation. I would not touch 2 pack unless you know what you are doing and you have the right PPE including air fed mask (from a remote air source) and completely cover all skin etc.
The problem with synthetic is you can't cut if back like cellulose or 2 pack, so the finish you spray/brush/roller is what you end up with. To avoid issues I don't paint below about 10c, preferably higher, plus preparation and cleanliness is everything.
Here's my fourth renovation, a 50" Colchester lathe, before
and after
Paint is
Paragon, Colchester Dove grey above, and I think it was Colchester Raven below.
Cheers
Andy
I only picked it up yesterday and on closer inspection it's mainly dirt and lack of maintenance.
