Steps to DIY sanding car back ready for respray....

[silviaz]

2 hours ago, GTSBoy said:

With stone chips, you really can't just try to fill them. You really have to sand that spot to lower the edges of the chip, so that the filler will end up covering a wider patch than just the chip. Otherwise, you're trying to have a sharp edged paint surface match up to some filler, and they just do not sand the same and you always end up with a noticable transition.

A bunch of adjacent chips should be well sanded back, to round off all those edges, and use a lot (in a relative sense) of filler to raise the whole area back.

Ok got you.

Edited June 1 by silviaz

[silviaz]

On 01/06/2025 at 12:25 PM, Murray_Calavera said:

Oh I probably didn't speak enough about the small sanding block for blocking large areas. 

In the video about 3 minutes in, he talks about creating valleys in the panel. This is the issue with using a small sanding block for a large area, it's way too easy to create the valleys he is talking about. With a large block its much easier to create a nice flat surface. 

Hard to explain but in practice you'll notice the difference straight away using the large block. 

You weren't kidding about the long block, what a difference it made!! I fixed every dent almost and all of them except for one and it feels 100% smooth on the others! I just need to fix one up and put some guide coat. Thanks a lot, that was game changing and time saving. 

Edited June 7 by silviaz

[silviaz]

So I ran into the same problem. I got stuck in the cycle of again of putting putty sanding it, putting putty sanding it, because of a low spot. And notice my block is not completely flat with the panel, even though it's a long block. My panel is slightly curved. Is this an issue? Do I need something that matches the door perfectly, or no? 

 

I do have the smaller flexible block that covers the width of the repair just not the length, I was experimenting with it again to but seems to be the same issue

[GTSBoy]

When sanding across a convex panel, you need to sand, as much as possible, at right angles to the curve. If the panel is compound convex curved (ie curved in both directions) then you are SOL and have to use "craftsmanship" to get it right.

[MBS206]

42 minutes ago, GTSBoy said:

When sanding across a convex panel, you need to sand, as much as possible, at right angles to the curve. If the panel is compound convex curved (ie curved in both directions) then you are SOL and have to use "craftsmanship" to get it right.

Complex conex, sand in X shape. And don't go hardcore.

I find putting on filler to be the art here to help.

[silviaz]

34 minutes ago, MBS206 said:

Complex conex, sand in X shape. And don't go hardcore.

I find putting on filler to be the art here to help.

Yeah been doing it in an x shape. Do you reckon it's worth putting guide coat early where the filler isn't sanded down completely smooth? Reason I ask is because as I'm sanding it one part might be level which I don't need to sand anymore but the other part might be high so I can just focus on that instead of sanding across the whole repair area.

I wonder if the putty is too thin, though the area is almost completely smooth before I do it as I've already put filler prior.

Edited June 8 by silviaz

[MBS206]

1 hour ago, silviaz said:

Yeah been doing it in an x shape. Do you reckon it's worth putting guide coat early where the filler isn't sanded down completely smooth? Reason I ask is because as I'm sanding it one part might be level which I don't need to sand anymore but the other part might be high so I can just focus on that instead of sanding across the whole repair area.

I wonder if the putty is too thin, though the area is almost completely smooth before I do it as I've already put filler prior.

Murray will have better input, but I'd be going with less filler, and aimed at the low spots mainly, and hence won't need as much sanding, which then means get the guide coat on earlier.

That's how I'd do it, BUT, I'm not a pro, I'm a DIY hack who will then get the shits halfway through, and have one spot awesomely repaired, and the other spots look like a 3 year old was left unsupervised with workshop tools...

[silviaz]

16 minutes ago, MBS206 said:

Murray will have better input, but I'd be going with less filler, and aimed at the low spots mainly, and hence won't need as much sanding, which then means get the guide coat on earlier.

That's how I'd do it, BUT, I'm not a pro, I'm a DIY hack who will then get the shits halfway through, and have one spot awesomely repaired, and the other spots look like a 3 year old was left unsupervised with workshop tools...

I am probably calling this too early but I think I found what part of my problem is. I have a couple of dents that are fairly close to each other and I tried to fix them individually. Recently I put one larger coat across all the dents and sanded it and for the first time ever it's all even except for the edge where the bare metal is, I just need to put some putty there.

I'm ordering some better longer blocks that are more flexible.

Other good news is that the other repairs on my panel are flat even with the guidecoat. It's these 2 dents which are an absolute c*nt l lol.

Edited June 8 by silviaz

[silviaz]

Just putting this here for reference for other beginners. Similar to what I said above. 

I learnt if you have a few dents that are fairly close to each other (within a couple of inches maybe 2-4 inches?) Use filler across them all and sand it all at once with the long block as opposed to fixing them seperately. 

Will make life MUCH easier because you won't get stuck in the cycle that I did. I think doing it seperately there is some overlap (mean your whole repair zone might cover near the area of the other dent) and you start sanding near the other dent making a low spot.

[Murray_Calavera]

You beat me to it, I was going to say this - 

On 08/06/2025 at 7:49 PM, silviaz said:

I'm ordering some better longer blocks that are more flexible.

And this - 

3 hours ago, silviaz said:

Use filler across them all and sand it all at once with the long block as opposed to fixing them seperately. 

Sounds like things are coming along pretty well and your learning heaps along the way. 

[silviaz]

1 hour ago, Murray_Calavera said:

You beat me to it, I was going to say this - 

And this - 

Sounds like things are coming along pretty well and your learning heaps along the way. 

Yep its been awesome. Thanks as always for the help 

[silviaz]

On 10/06/2025 at 11:43 AM, Murray_Calavera said:

You beat me to it, I was going to say this - 

And this - 

Sounds like things are coming along pretty well and your learning heaps along the way. 

I had small pin holes in my glazing putty but didn't want to put more putty to not make a mess again and I put 2 coats of epoxy primer to prevent it from rust. Though you can only see the pin holes if your eyes are almost against the panel. Do you think when the 3x coats of high fill 2k primer and 2 base coats go on that it will be visible? 

[Murray_Calavera]

8 hours ago, silviaz said:

I had small pin holes

It happens, that's what your single stage filler is used for. 

8 hours ago, silviaz said:

Do you think when the 3x coats of high fill 2k primer and 2 base coats go on that it will be visible?

If it is still visible after the 3 coats of 2k primer, it will be visible after the paint is laid down. 

Its hard to give 100% perfect advice without being there in person, I'm very tempted to say stop where you are, fill your pin holes with a single stage putty first then keep going. 

[silviaz]

12 hours ago, Murray_Calavera said:

It happens, that's what your single stage filler is used for. 

If it is still visible after the 3 coats of 2k primer, it will be visible after the paint is laid down. 

Its hard to give 100% perfect advice without being there in person, I'm very tempted to say stop where you are, fill your pin holes with a single stage putty first then keep going. 

Will do thanks.

[silviaz]

On 14/06/2025 at 10:27 PM, Murray_Calavera said:

It happens, that's what your single stage filler is used for. 

If it is still visible after the 3 coats of 2k primer, it will be visible after the paint is laid down. 

Its hard to give 100% perfect advice without being there in person, I'm very tempted to say stop where you are, fill your pin holes with a single stage putty first then keep going. 

I made a mistake today. I had a spot I fixed, and used guide coat and I kept sanding until it went away and it did (sort of),  the guide coat was still there if I used wax and grease remover but was gone if I just blew the dust off.

I ended up removing all of the filler and can feel a dip lol. The weird thing was I could still feel something after removing the guidecoat when the filler was there. 

Is the proper way to check that all guide coat has been removed is to use the wax and grease remover or is just dusting it off fine?

[Murray_Calavera]

4 hours ago, silviaz said:

I made a mistake today. I had a spot I fixed, and used guide coat and I kept sanding until it went away and it did (sort of),  the guide coat was still there if I used wax and grease remover but was gone if I just blew the dust off.

I ended up removing all of the filler and can feel a dip lol. The weird thing was I could still feel something after removing the guidecoat when the filler was there. 

Is the proper way to check that all guide coat has been removed is to use the wax and grease remover or is just dusting it off fine?

I'm a bit confused by this post, so I'll address the bit I understand lol. 

Use an air compressor and blow away the guide coat sanding residue. All the better if you have a moisture trap for your compressor.

You'd want to do this a few times as you sand the area, you wouldn't for example sand the entire area till you think its perfect and then 'confirm' that is it by blowing away the guide coat residue. 

Sand the area, blow away the guide coat residue, inspect the panel, back to sanding... rinse and repeat. 

[silviaz]

9 hours ago, Murray_Calavera said:

I'm a bit confused by this post, so I'll address the bit I understand lol. 

Use an air compressor and blow away the guide coat sanding residue. All the better if you have a moisture trap for your compressor.

You'd want to do this a few times as you sand the area, you wouldn't for example sand the entire area till you think its perfect and then 'confirm' that is it by blowing away the guide coat residue. 

Sand the area, blow away the guide coat residue, inspect the panel, back to sanding... rinse and repeat. 

So to clarify, I can blow away the guide coat with a compressor or a blower but what I mean is if I wipe down the area with wax and grease remover I can still see the guide coat even though I thought it was gone after blowing it away.

[Murray_Calavera]

11 minutes ago, silviaz said:

So to clarify, I can blow away the guide coat with a compressor or a blower but what I mean is if I wipe down the area with wax and grease remover I can still see the guide coat even though I thought it was gone after blowing it away.

I'm confused, so your saying after blowing the area off, the guide coat is gone. But then when you wipe it down, the guide coat residue becomes visible again?

This isn't a trick question like there is guide coat residue on the rag that your wiping the area down with? 

I cant see how once something is removed, it comes back when cleaning with wax and grease removed?

[GTSBoy]

1 hour ago, Murray_Calavera said:

I cant see how once something is removed, it comes back when cleaning with wax and grease removed?

It's just that it looks like it's all gone dry, but when you wet it the different materials darken differently and you can see the traces of the remaining guide coat, which are otherwise too thin to see when dry.

[Murray_Calavera]

@silviaz 

Maybe have a play with dry guide coat and using the compressor liberally and report back if its working better for you.