After removing excess rust off a Victa full crank engine cowl and and briefly wiping with wax and grease remover, the combination undercoat and rust converter lifted off in spots the next day as I went to blow dust off with an air gun.
Was it because I was too light with the prepsol or the fact it was quite late in the day (4:30pm) and chilly outside? The can states to apply between 10�c -30�c and it felt like it was no less than 15�c.
One thing I did notice is where the metal was exposed, the product did convert the remaining rust quite well.

Hi Mowerfreak,
Why not use a molasses bath, easy and it gets you back to bare metal. I just made a frame and use a plastic sheet. Only you just have to wait..............
Or leave it in the sun to complete the chemical reaction.
speedy

Odd that this would happen. Seems like there was something on the metal that the paint didn't like. I did have this happen once when I spray painted a blade disc and left it out in the sun on a hot day. Next day the paint had pealed and flaked badly and I ended up sanding it off and starting again. The next time I left the disc inside the shed in the shade so that it dried slowly over a few days. No problems that time.

I took to it with an old toothbrush to remove any paint flakes that had lifted and leave as flush a surface as possible before I re-prepsoled the exposed spots and hit them with regular grey undercoat.
I then painted it with satin black topcoat and hope for the best. This one is going on a beater so no biggie. It looks good so far. The next one I do will be with a lot more care and earlier in the day!!

Pictured are the products I used and the finished work I have drying in the house out of the cold!

If you are after a gloss black finish that sticks like the proverbial s... to a blanket, and in a one step process try this stuff.

I get it from my local metal dealer for $9.50 for a 400gram can. It is also available in silver that has a near chrome like finish when sprayed over smooth metal. It is my go to stuff for treating welds and making old metal look like I spent a lot of time prepping it.

I will endeavour to get some. This looks to be the (almost) perfect product for doing this job with minimal fuss. I would prefer semi gloss , but I can always refinish it afterwards.
This will allow the molasses method speedie
recommends (no rust to covert - avoid grey primer that may show through in the future).

It's not a super high gloss, probably somewhere between a semi gloss and a high gloss. The company is Silver Zinc Supplies in Qld. Phone them on 07 - 32874567. They can probably let you know if they have a distributor in your area.

When I repainted the top cover on a customer's Victa 160, I used a heavy duty wire cup brush on 5" angle grinder to remove the old paint and rust and then used it to polish the steel. Then I wiped over the cowling with Prepwash and used Wattyl Killrust Gloss Black paint. I didn't use any primer nor filler to smooth the rust pitting as it wasn't a full restoration and would see regular use.

(Norm, you probably remember this mower! The last I heard was it was starting easily and they love the throttle control that your carby modification provides)

I have that as well. I tried out on the cowl that goes on my Victa Twin ( as it is mostly obscured by the plastic dress cowl) and wow, you could have a shave from the mirror like gloss.
That is what prompted me to go for a more subdued finish as I think extreme gloss contrasts too much with the plastic dress cowl as it sticks out the side.
In the case of that side pull above without a dress cowl, it looks very smart and enhances the whole machine despite the shabby paint on the base.
The Killrust paint is not fast drying at all, but the Wattyl semi gloss still feels a tiny bit tacky after 20 hours, so I think I'll give it a few days before installing it back on the mower.
I wish I still had some of my Wurth Sabesto lacquer semi gloss left as it was super fast drying and could be handle in less than ten minutes!
Might order some more. A bit exy but very useful.

Yes the Killrust takes ages to dry. When I worked at a Case IH tractor dealership, the trick was to use a hot air gun to speed up the drying time. However, you have to be very careful not to overheat the paint as it will bubble. I've also used the Killrust Matt black, which dries quickly. However, it is probably too dull a finish for what you want.

This is Killrust Matt black on a door top from my ex Army Land Rover.

Hi LRT looks good and it should last them for years to come, only wish I had come up with the float needle fix back then and it would have been without any potential problems. I could never understand why you would not have throttle control on a slasher. Back in the old days with the Toecutters you tied a rope around the handle, swung it above your head into the blackberry pile and when it chewed its way down to the ground you could drag it back out with the rope

Yes not many people need a mower for blackberries nowadays. They just use Roundup and then either burn it or use a whipper snipper. Even the 20+ hp ride on mowers can't do more than trim a lawn & tow a baby trailer to pick up twigs & leaves.

You could also try using an etch primer to provide a key for the new paint. I think we used a Wurth paint at the dealer that was fast drying. Unfortunately it seems to be quite hard to find locally.

I got my last can of Wurth paint direct from the distributor in Melbourne. Trouble is postage costs almost as much as the can to Sydney. Might be cheaper within Vic.
There are random outlets I have discovered that stock Wurth paints but they may not carry the specific paint you want. The last place I saw them in didn't have the satin black.
I called them yesterday and they have me the number if a sales rep closest to my location.
I will try and contact him tomorrow to get some more.
Regarding your use of the heat gun, mine has a high and low speed setting. How far do you have it from the work and for how long? I would err on the side of caution myself.

Yes it takes a bit of trial and error! Depending on how powerful your heat gun is, I'd use high speed and keep it a couple of feet away and keep it touch warm. Careful not to burn yourself though!

We usually used the hot air gun straight after painting the part to speed it up to the 'touch dry' stage. The main reason was to get it dry enough to bolt it up to the tractor rather having to wait a day for it to dry as the shop rate was $110 per hour and management based efficiency on the turn over of machinery per day.

The rotten thing is the mechanic who just ticks off the pre-delivery sheet on a new tractor without actually checking it gets promoted and the other mechanics who do the pre-delivery properly get hit with penalties and even threats of the sack if they don't get more vehicles through.

When the customer gets charged for a 'service' don't expect the filters or valve clearances to be adjusted!

Maybe you could try some paint on a similar metal and experiment? Once the paint bubbles it has to be redone.

The other thing we did to prevent the 'orange peal' effect when painting in cold weather, was to put the can in a bucket of hot water.