Angle grinder discs
 

Hi, What would be the best type of abrasive disk for my angle grinder to remove all the charred paint etc?

I use a coarse wire brush attachment on my angle grinder to remove rust and old paint.

It might feel to the hand as a really aggressive method - and if it does end up running up your arm it will most certainly effing hurt! - but for the car it is much less abrasive than a stripping disc.

(Just in case stripping disc = disc with bits of sand paper on it)

With a stripping disc you can remove metal as fast as you can with a grinding disc (especially with a new disc - they do dull)

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For your situation you need to make sure you have gotten rid of all of the burnt paint and make sure the surface is spotlessly clean.

The way I would tackle the job would be

1) Angle grinder wire brush - remove the worst

2) Something like engine cleaner that will degrease and clean in one

3) Rinse with water - don't soak so you get water trapped in corners etc

4) Sand with an orbital sander to blend in the edges of the paint that seems to have survived

5) Don't forget that heat will have spread further than the burnt area - if you have a layer of filler under the paint you need to strip back a lot further as it is likely to have come loose.

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Usual PPE requirements - HD gloves - breathing mask - safety glasses

When one of those wires comes loose from the angle grinder attachment they go some way - they can easily find their way through thick overalls - so no shorts - no T shirts etc!

I like the 3M Clean 'n Strip discs. Should give you good control and just remove the paint without marring the metal surface. That's important for the bonnet but less so for the bulkhead etc. You can get small versions of these to use in an electric drill and these could prove useful for the fiddly bits. Flap discs are cheaper but need a careful hand. Good luck. I guess you aren't getting the insurance company involved?

Abrasive personality
 

Use something like the 3M 'clean and strip' discs. They remove paint and rust but not steel.

Once everything is cleaned up what would be best for finishing, preparing for paint?

Unless you're really good/experienced, the paint shop will invariably find fault with your work and do it over again. They will rub down the entire bonnet with maybe a thin skim of filler here and there, and/or some primer filler. You could do some extra work on the bulkhead and the underside of the bonnet but they will also prime and flat those areas too before the coat of blue so again I would leave it to them. If in doubt have a chat with them, but in theory at least they are the experts. Keep them happy. If they are the same shop as did your paint before they should at least be able to do a good match on the colour. Good luck.

I read this before I saw your other post saying you were going to DIY it. You should be able to get a reasonable finish in the engine bay and the underside of the bonnet if you use quality paint and aerosols. Maybe you have automotive paint supplier within reasonable distance that can supply and also make up some cans of the correct colour. Think I would like to get the outside of the bonnet done professionally for best results. It can all be back on the road with a big primer patch on the bonnet so you can drive it in for the final touches.

Not read the other post, but judging from the reply above it sounds like you want to paint a bonnet. This cannot be achieved with an aerosol and it'll look absolutely rubbish if you try. You can apply primer with an aerosol though.

For taking off paint, a flap-wheel works wonders. They're much more forgiving than a disc sat on a rigid backing pad.
https://upload.wikimedia.org/wikiped...-Flap_disk.jpg
I usually use a P80 grit, because it's faster and any scoring will be taken up by the primer. But if you're using an aerosol to prime it, then you're probably better off with P120 which will be more gentle to the metal and leave smaller scores, for the simple reason that you're probably putting on less primer than a bodyshop normally would.

As said above, you can probably get away with painting some out-of-sight areas using an aerosol, but the finish can never be showroom perfect - you simply cannot get enough paint out of an aerosol fast enough to achieve the flow-out necessary for a professional finish, along with several other mechanical disadvantages.

Second to that said above; I absolutely hate working on other people's preparation. They never get it flat enough, and although they say they're "not fussed if it isn't perfect", what they end up with doesn't match their expectation and their disappointment is obvious. No matter which way you try to hide it, bad prep shows and it's especially obvious on a bonnet. Everyone looks at the bonnet first.

Painting bonnets is actually quite hard to do right. Being horizontal, they're prone to collect dust, and ask any refinisher about bonnet stripes and they'll shudder and pull faces. Silicon spots love bonnets for some reason, which is absolutely heartbreaking. Sinkage is always a worry, which is why I suggest you use a P120 not a P80. And do yourself a favour - leave the primer to cure for DAYS before you try flatting it, or six months down the line, you'll start to see sinkage.

Yes, there's really no way to paint a bonnet with an aerosol. Sorry if this is bad news.

P.S.: If you need any advice, feel free to PM me. By the way, I'm "oldschool" when it comes to prep, which may or may not suit you. Good luck anyway.

Just to be clear. The bonnet has been taken to the paint shop, the same one that painted the car. It's only the engine bay I am painting as I can't get the car to the shop easily. The recovery people want €400 to transport it! The bay was painted by me originally. I intend to spend as much time as possible flatting the bay.The worst part is on the top corner which will need a lot of work. You can see the side panel where I did a trial, not too bad but I will go over it again. Going to paint supply shop today to see if I can get some high build primer in a rattle can.