I had a crack at painting my front and rear discs on the weekend. Before painting, I used paint stripper to get rid of the tatty paint that still remained and rinsed them thoroughly with water. I used a wire brush to take off the residue and then rubbed them down with 600 grit wet and dry and masked them up.

After the prep, I sprayed one coat of primer. I let that dry for approximately 30 minutes and then sprayed the gold. I sprayed the rear disc first and it came up beautifully. However, when I sprayed the front discs, the paint didn't seem to want to stick to the primer and it would drip away in some spots and run very easily in others as you can see below:





My questions are these:

1. First, why on earth would the paint not stick on the primer? Should I do anything differently next time?

2. Second, in order to fix up the areas above, do I need to strip the entire disc or can I just sand back the problem spots and spray another coat (I've only done one coat of gold so far)?

Id strip it back and use a etch primer on the bare metal. Before any paint or primer goes on the surface needs to be surgically clean, use thinners or panel wipe on the bare metal and just panel wipe on the he primer if need be.

I'm hoping to avoid that if at all possible, given it's a serious pain the arse. The primer looked to be fine, so unless I'm missing something, I don't think it was a problem with the application of the primer to the bare metal.

Ok you can mess about with it if you want but any bare metal should be primed with etch primer and left for atleast 24hr to work, use normal primer and if you dont get a repeat of what happened in your firat attempt the paint will lift in no time. Sorry but theres no short cuts with painting .
If you just wanna slap paint on use a hammerrite type paint if you can get the right colour and just apply that direct to metal.

I found gold engine enamel, that worked nicely no primer and heat resistant

Sorry DM, I may have misunderstood your first post.

Are you saying there's a distinction between 'primer' and 'etch primer'? How can I tell which is which?

This is the primer I bought:

http://www.whiteknightpaints.com.au/mob ... ose-primer

Yes theres a difference between etch primer and normal primer and it will state on the data sheet or can which it is.

I not familiar with that product so cant comment if it will do the job or not but the details on that website suggests it will.

If i had to use a can id use this stuff http://www.ebay.co.uk/itm/U-pol-Acid-8- ... 4897.l4275

Thanks mate. I'm in Australia so I'll look for a local equivalent.

Here's hoping it's second time lucky!

Super cheap have etch primers...

Cheers, I'll check them out.