Painting a front wing

[Kram]

Most of the chips out, the rust spot on each was about twice the size than the chip in the paint.

Now to mannually key all the edges for primer.

2k filler primer (or epoxy) 2-3 coats

To get a even thickness I was thinking to spot prime all of the metal areas before a full coat or two. Is that wise?
I almost want to put a 120 disc on and take all the visible areas back to metal.

 

[qwakers]

nope. pointless.

 

[richie00boy]

I would just go over the whole panel in one go. If it shows through it's likely the feathering out wasn't quite gradual enough and you would have the same issue even if it had been spot primed.

 

[Kram]

I've made many cockups today.
I made up 400ml of HB 989 epoxy primer. The first 100ml I added a few drops of red so I could identify the last layer. The mistake was instead of base coat red, I picked up the direct gloss 2k red! I realised when it didnt mix well, but it did eventually mix. I dont think I put enough to cause any problems.

Started with gun on full, only I'd undone the fluid screw too far, it started dripping and took a few moments to realise why. I then put my hand in it.

Wiped that all off with thinners and started again. I should have tried some practise on the scrap panel first!

I cant easly move the panel and I've remembered that its not easy to spray upwards as the gun runs out of fluid. So enof the edges will be a pain. Going back for a other coat...

 

[Kram]

 

[Kram]

There is a visible line /shrunken area where it was back to metal. Its also the same area where I had to wipe off my hand print with thinners.
Has thinners reacted/ swollen the previous layers?

Should I try to sand it out tomorrow, or filler/2k primer first?

I can see I will need to do a lot of sanding!


A tip I picked up from YT is to microwave warm the paint, and I have a spare old microwave. 5 seconds at a time, until its 30-40c. Supposed to help it flow better, and its extra heat. Anyone else do this?

Anyway heres a pic of the lines, had to hold light at an angle for it to show up.

On the 3rd coat, last of the paint, I found the gun spluttering and clogging up, I guess it was starting to set from the heat. I had been filtering it.

 

[Dcal]

Block the whole panel back, it will remove every imperfection and if it doesn't, prime the whole wing and block sand again. Even better apply a guide coat before sanding.
If everything is covered in the same material you have a fighting chance of getting a straight panel with no issues.

Consider your original wing.
It had bits that were lacquer, bits with base coat, bits with primer, bits with bare steel, and bits with rust pits.
The chances of base and clear covering that without issue are slim.
If everything is covered with something that sands the same you have a good chance of getting good results.

The beauty with epoxy and two pack primers in general is they cure quickly. With single pack primers, they can cure over weeks / months and a perfect paint job can show shrinkage months later (usually after the weather improves and the car sits in full sun)

 

[richie00boy]

Did you wipe the whole panel with thinners and literally start again or just wiped the mistake areas?
Just give it all a flatting back and with a couple more coats it should be ok.
Putting basecoat or 2k in as a tinter is not a good idea as the chemical technology is different and incompatible.
There is no need to heat epoxy primer up like that unless you are painting in the middle of winter (which brings other issues anyway). It doesn't need to flow better as it's getting sanded, it's not like it flows poorly anyway, the HB Body stuff is proper automative paint.

 

[Kram]

We are not in summer yet, spring is often as cold as winter, yesterday was barely above 15-20c and the TDS says not to use it below 15c. That is why I heated the paint, heated the tent and heat the panel.
It was also a test to see how well microwaving paint works.

I havent looked yet this morning to see if the runs are fully cured, I turned the heater off at midnight so its been ~9c since then.

The whole front got wiped.

Basecoat is perfectly ok as a tint, it is literally just pigment suspended in thinners. As I said, 2k colour was a mistake..