Exhaust coating vht or ceramic coating?

[Timo]

I have just removed my heat exchangers and exhaust in preparation for the new st/st heat exchangers and replacement exhaust to be fitted. I have a very good original liestritz exhaust to go back on, at the moment it is in bare steel so I need to decide on a suitable coating for it.

I have read up quite a bit on both vht options and ceramic coating but thought I’d ask the good people of ddk what their opinions/experiences are as I’m a little confused on which way to go.

I have a local powder coater who offers ceramic coating but at £400 for the silencer and tail pipe it’s not a cheap option. Alternatively I can go for one of the many vht options out there such as this vht flame proof paint from frosts

https://www.frost.co.uk/vht-flameproof- ... aint-312g/

In a perfect world I’d like to go ceramic but the cost is making me hesitate a little, does anyone have experience good or bad with either?

Is the vht flame proof paint as good as they say? Seems to have a few good reviews on line but every time I’ve used vht paint in the past it has been next to useless. Although I have not tried the flame proof stuff before.

[neilbardsley]

Do you have the metal plate that sits between the muffler and fuel pump? I think that would help more than ceramic paint and I got one for not much from PRS

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[Timo]

Which metal plate do you mean Neil, do you mean the screw on tinware piece? If so yes all tinware is present and correct.

I’m not thinking of using ceramic coat as a cooling aid particularly, my engine has always run quite cool even on really hot days when driven hard it only reaches half way on the temp gauge. I’m thinking more along the lines of a robust coating to prevent corrosion, the fact that it makes your engine bay a little cooler is a bonus but not the main driver.

[911hillclimber]

All I know is preparation/cleanliness is the secret to the coating staying in place over time/use.

The silencer corners get a lot of tyre/road grit etc and that will have a good go at thinning the coating.
£400 is a lot, about the same as a SS Dansk?

[Timo]

Hopefully the extra I spend should offset the sheer frustration of trying to get a dansk part to fit properly?

[mycar]

Stainless is most probably the way to go. How about Turbo Thomas ? His kit will fit.

Other than that, my only advice is to not use BBQ paint... heat resistance to 650'c sounds impressive, (surely even the sun isn't much hotter than 650'c ) but it's sh1te, as is any other 'heat resistant' paint that the DIY auto industry offers.

That's my experience anyway.

Which is not inconsiderable.

When it comes to sh1t exhaust paints.

[Timo]

Well stainless is a good option and I must admit I did originally think of going that route but I feel the sound is slightly different with stainless and I really like the sound it has currently so when I had the chance to buy an oem mild steel exhaust I took it. I think the turbo Thomas silencers (and other st/st offerings) were about £600 when I looked into it a while back so not really a cheaper option either.

It’s interesting that you mention bbq paint Mike, I notice this is a favourite of the motor bike world.

Out of interest which products have you tried during your research?

[BILLY BEAN]

What is described as " ceramic coating" is often actually ceramic paint. It is likely that someone offering powder coating and "ceramic coating" is actually using ceramic paint. This is applied to a part and then baked in an oven. It is often stated that the part cannot be used for a few days thereafter.

Proper ceramic coating is a hot application with ceramic powder applied at pressure through a flame. This process requires specialist equipment.

I used B&B coatings in Huddersfield 01484 866386. Turn around was a couple of weeks. They will prepare by cleaning your exhaust, apply a "primer" coat and then the final colour. Colour choice is limited. The price was very reasonable.

[stretch]

I have my headers in a ceramic paint coating. I used Cerakote in Sussex. I have installed a new Dansk muffler to my system that i have stripped to bare metal and applied VHT primer and top coat. Colour of the VHT looks spot on although i can't comment on performance of either until i'm allowed to go out to play...!

[mycar]

I've tried most of the heatproof paints offered by Frost, most of which claim heat resistance to 650'f which is only around 340'c.

I've had hotter curries.

As has been mentioned, whatever coating is used, it needs to be applied at a hotter temp than the exhaust will see and not just painted on at room temperature.

I see Frost's now do an Eastwood high temp coating, resistant to 1400' !! (doesn't say if it's F or C) and there was a time when I'd have paid the £60 but these days I'm fairly sure it will be just as hopeless as all the other offerings.

I ended up getting a stainless exhaust for the 911 which came, ironically, painted black... which blistered. I stripped the black off and all was well.

I remember reading discussion about how SS exhausts didn't sound too good but with a bit of use and a bit of carbon build up they don't sound much different from the mild steel version.

[stretch]

The one i used has a higher rating.
https://www.frost.co.uk/vht-flameproof- ... aint-312g/

[Timo]

Stretch, that vht flame proof is the same stuff I linked to in my original post, it has some good reviews from users, some stating it has continued to stay put several decades later.

The chap I have spoken to locally about c coating apparently used to use the flame application type but has now reverted it would seem to the spray on powder type which cures at atmospheric temp over a period of 80 hours. He reckons it’s more robust than the flame application type, I honestly don’t know which is best.

[stretch]

I am hopeful the VHT will hold up. Big price difference between both methods, i think it's all in the prep. I had my fuel cap Cerakoted and that has started to rust already.

[Timo]

Oh dear, that doesn’t sound great. Has it rusted through the ceracoat or lifted from underneath?

[911hillclimber]

I think these coatings work on a metal that simply gets hot and cold repeatedly.

It is not good at resisting the corrosive attack of normal road use or the abrasive attack of said roads.

Common exhaust systems are stainless for a reason.