Did anyone prime their manifold heatshield before painting them?
I've used 2 cans of Hammerite paint which is resistant to 625C but it flakes in the same place each time.
did you not use that acid ectch primer stuff?
No. Who makes it? The Hammerite can states that they recommend that no primer is used before using their paint. Probably so that mugs like me get though cans of the stuff s:roll: :roll: s:roll:
You can get it from halfrauds... but dont take my word for it... its just what i heard someone saying... if it all goes to pot blame Coley or something! s:wink: :wink: s:wink: s:lol: :lol: s:lol:
Cool I may give it a go if I can be @rsed to rub it all down again! Thanks for the advice. If it fails I'm sure it won't look as cr@p as it does at the minute.
wsire brush will strip it off in no time.
You can get Acid-Etch Primer from Halford, it isnt a Brand as i remember.
10 coats of Halfords extreme manifold spray is what i've used!
when painting the heatshield, surely its not a good idea to paint it black as this will absorb heat and keep the engine bay hotter? i would have thought a bright colour (chrome/silver) would be better as they reflect heat
Hi,
Is this Halfords acid-etch primer ultra-high temperature too ??
If not then wont it will flake off and take whatever is ontop of it ??!
Crankshaft
Quote from: "Tomr2"when painting the heatshield, surely its not a good idea to paint it black as this will absorb heat and keep the engine bay hotter? i would have thought a bright colour (chrome/silver) would be better as they reflect heat
We're painting the outside black. The heat is generated from the inside so it won't make sufficent difference I wouldn't have thought.
Black surfaces absorb and give out heat quicker than silver ones don't they?
Quote from: "Bongo"Black surfaces absorb and give out heat quicker than silver ones don't they?
Yes, but since you're not converting the metal itself to black, you're adding a coat of black paint on top of it. So you have to also consider how the heat transfers from the metal to the paint first.
Then black paint will absorb heat quicker and give it out quicker than, say, silver paint?
absorbing heat quicker and transfering it quicker doesnt really make sense to me? s:? :? s:?
It's basic priciples of heat transfer - the heat is being radiated from the manifold and being absorbed by the heat sheild - if it's black it will absorb and emit the radiation more readily. Think about black leather seats in the sun and white or light coloured leather in the sun - black ones burn your arse more s:wink: :wink: s:wink:
understand that perfectly clear rusty, think you misunderstood me. i meant how can the black paint give off heat quicker than light coloured paint.
i know black will always be the more absorbent to heat
For the same reason that it can absorb more heat i guess.
I suppose you could compare it to a pipe - a bigger pipe will take in water quicker and spew it out quicker s:crazyeyes: :crazyeyes: s:crazyeyes:
here's an idea s:idea: :idea: s:idea:
how about spraying the air intake tube and air box a light colour? would this not benefit when sitting in traffic and with the baking hot ait sitting in your air box? as i imagine it gets quite hot on those sunny days...
Covering it in some form of silver insulation ala DP might be even better s:? :? s:?
Also, about the black/white thing in the sun, you're mixing two things. Yes, black gets hotter in the sun, because it absorbs all visible light frequencies, while white reflects all of them. But heat is NOT visible light and thus doesn't care about visible colors either. If you heat black and white pieces with IR, they both heat up the same.
The heat transfer is affected by colors too, but the color itself doesn't cause it, the stuff in the color makes the difference. A white surface generally lets about 95% heat through and black 96%, so no real difference. Best heat transfer coat is asetylene ash (I wonder if straight translation from finnish is right) with 97%, for comparison bare aluminum only lets some 85% through.
So painting a metal with any color transfers heat better than bare metal. So if you want to keep the heat in, don't paint it. Obviously there are special stuff to do the reverse, but this goes for normal paints.
Whether that 10% difference makes a real difference or not, I doubt it...