# Exhaust tips - Melting?



## straight6hatch (Jul 17, 2020)

Hi folks!

Very inexperienced when it comes to painting and how paint works in all honestly. I get the basics as you kind of have to for detailing :lol:

So, heres my problem. I own a BMW M140i which has 2 gloss black exhaust tips. They're well known for 'pitting' or 'melting' the paint over time and its been done to death on the forums.

About 9 months ago, I removed both tips, used my air dremel to remove most of the paint, prepped and rattle can'd them with VHT (Very High Temp) Paint which says its rated to 350 celcius or something pretty high. They cured and I fitted them. They were pitted and looked rubbish after about a month.

I lived with it for a bit but they just let the back of the car down and annoy me. I took them off again, took them to the inlaws where they got shot blasted and powder coated. Then into the oven and looked amazing! They lasted less than 6 months before they melted again :lol:

Another very basic strip and another coat of VHT (father in law didnt trust me to do it properly ) and they've lasted about 5 weeks.

So, help me! What on earth is going on to make them pit/bubble/peel/melt? It cant be heat, surely? Im not running tonnes of power and the exhaust tips cant be getting _that_ hot? Ive seen the brand VHT do a flameproof option which is rated to 1000 celcius so thats the next step.

Any advice appreciated


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## Andyblue (Jun 20, 2017)

Pictures may help mate …

Is it the metal and some sort of reaction ?? 

Rather than being heat (which it could be) are they getting hammered by everything that’s getting picked up by rear wheels ??


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## straight6hatch (Jul 17, 2020)

Youre right Andy, pics would have been helpful :lol:

Ill stop being so lazy!










This is kind of a poor picture. Yes, the tips are dirty. The bubbling is kind of the beginning of it. If you look at the top of the tip you can see the kind of 'scarring' in the paint. This is exactly how they go after a couple of weeks which then leads to the paint peeling off. Its almost like a chemical reaction that ive seen with paint where it blisters. But it cant be chemical as we always panel wipe the hell out of the metal before applying the paint....


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## Rappy (Oct 2, 2020)

My suggestion is to use gloss black BBQ paint :thumb:

You can thank me later :lol:


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## straight6hatch (Jul 17, 2020)

Rappy said:


> My suggestion is to use gloss black BBQ paint :thumb:
> 
> You can thank me later :lol:


Hold on, are you telling me there isnt a Polish Angel product for this?! :lol:

Im beginning to think this is the only route. Or just fully send it and go for 1000 degree flame proof stuff. Its only £12 for a can weirdly


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## GeeWhizRS (Nov 1, 2019)

Think I'd try a high temperature primer before applying your finish coat.


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## Rappy (Oct 2, 2020)

straight6hatch said:


> Hold on, are you telling me there isnt a Polish Angel product for this?! :lol:
> 
> Im beginning to think this is the only route. Or just fully send it and go for 1000 degree flame proof stuff. Its only £12 for a can weirdly


Not yet, cheeky :lol:

The higher temperture the better.. safe for BBQs, Stoves, Firepits.


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## straight6hatch (Jul 17, 2020)

So, general consensus is that its a temperature related thing? Crazy how hot the exhaust tips get then huh! 

Ill attack them properly with high temp primer and then flame proof VHT and see how we go. Wish me luck guys


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## Andyblue (Jun 20, 2017)

straight6hatch said:


> So, general consensus is that its a temperature related thing? Crazy how hot the exhaust tips get then huh!
> 
> Ill attack them properly with high temp primer and then flame proof VHT and see how we go. Wish me luck guys


From your post with picture and description, it sounds like it's actually the exhaust gases that are the issue, rather than the actual tips getting hot (if that makes sense) so are heating the inside edges / a small specific point etc and causing the problem…

Hopefully works this time…


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## straight6hatch (Jul 17, 2020)

Andyblue said:


> From your post with picture and description, it sounds like it's actually the exhaust gases that are the issue, rather than the actual tips getting hot (if that makes sense) so are heating the inside edges / a small specific point etc and causing the problem…
> 
> Hopefully works this time…


Oh hello again Andy :wave:

Yeah, I think that could also be the logical explanation. Exhaust tips not getting that hot but exhaust gasses are obviously pretty hot. Must be my heavy right foot 

Ill update the thread once ive got round to sorting it


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## vsideboy (Sep 1, 2006)

Are they rolled in, could be the gasses can't escape enough so sort of funnelling at certain parts of the outlet and increasing the heat if you know what I mean?

Clearly a rubbish design if it's happening to everyone. See if you can find someone with aftermarket exhaust, what do their tips end up like, if aftermarket tips are fine then clearly bad design with not much you can do other than replace the exhaust or go for some super high temp paint.


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## straight6hatch (Jul 17, 2020)

vsideboy said:


> Are they rolled in, could be the gasses can't escape enough so sort of funnelling at certain parts of the outlet and increasing the heat if you know what I mean?
> 
> Clearly a rubbish design if it's happening to everyone. See if you can find someone with aftermarket exhaust, what do their tips end up like, if aftermarket tips are fine then clearly bad design with not much you can do other than replace the exhaust or go for some super high temp paint.


They are rolled in slightly but its a bit strange as the actual exhaust slides into the middle of it. Difficult to explain with words!

Ive looked at loads of aftermarket options and most of them work exactly the same way which is baffling me! Some are 'billet' and unpainted which makes me think people are realising how rubbish the originals are. Also, the aftermarket options are horrendously expensive IMO for what they are. Even a mid range set are £200+ just for the tips!


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## vsideboy (Sep 1, 2006)

yeah loads of cars just have a tip over the top of the exhaust, I wondered if it was the actual exhaust rolled in but then you'd not get the tips off so ignore me.

Strange one then pal.


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