Thread: Exhaust Heat Wrap, how hot & how much

Originally Posted by Ancient Mariner

I don`t think so

AM

i know so... but feel free...

anything above about 440 deg c will cause grief...

Some good comments , exhaust wrapping is hard to beat on a cost basis , a 30 meters costs between 80 -100$ if you go to the industrial insulation shop. I posted the contact details of one shop in Brisbane yesterday on the thread about new exhaust pipe for my defender. ( 30 meters 60$ +GST). If it lasts 5 years no problems.

I think it would be easier to do a neat job if you took the pipe off. I'l be doing mine in a few weeks and can send a couple of pictures of how it comes out.

Stainless steel (304), exhaust pipes are easier to damage than you might think, it's more prone to cracking than mild steel, one of the problems with lagging it is the lagging can hold salt and contaminants close to the surface. SS 304 suffers from intergranular corrosion in this circumstance. For you that means a crack.

SS 304 is fine for decorative work and items that are low stress, kept clean, & away from salty atmospheres. I use SS 304 bolts & nuts everywhere on my motorbikes and cars for brackets, attachments etc because they're cheap don't rust and look good, and if they break it's not important. SS304 should not be used in stressed bolts positions, (suspension, brakes, steering, recovery points) if there's any chance they could become exposed to salty conditions or salt water etc. Their failure can be unpredictable, intergranular corrosion is not always obvious. SS 304 bolts and tube fitting are prohibited, by most offshore & marine operators, in case they are fitted by accident in place of SS-316. something to consider anyhow.

You can use the common industrial insulating fiberglass tape, (up to 500 degrees C) for landrover exhaust after the turbo. After the turbo is quite a lot cooler than before the turbo. cheers simmo.

Originally Posted by incisor

really, lasted 8 years on my shorty...

never heat wrap stainless steel.... you will anneal it and it will twist, crack, warp and generally go to crap in no time flat.

What Inc says.

People tell all sorts of dire stories about wrap with no practical experience what so ever.

Six years or so now with the wrap still looking as new and the (mild steel) exhaust still in one piece.

Who would've thunk it ?

321 stainless is the best for high temp exhausts, but it's damned near impossible to get in Oz.

Do they really use 304 stainless for exhausts? I thought 400 series was usual. It's easy to tell, 400 series is magnetic, 304 is only very weakly magnetic.

After nearly 30 years of installing diesel generators with exhausts from 2"x10' long to 14 "x13 stories high with the stainless lagged with 2" of either 650c rockwool Fiberfax or calcium silicate Stainless was either 316 ,316l or 321 with a 304 sometimes depending on the spec 321 was readly available in spiralweld but all bends had to be fabricated.You would think after all this time I would have noticed such catastropic failures Just looked at my Sanvik cat there are 15 different grades listed for elevated temps up to 1150c

AM

Since we're being slightly philosophical/ on a scientific tangent...

I've thought about exhaust wrapping in the past when ive been towing and its a 45deg day and we're all burning up even with the aircon on, BUT

i'm always mindful that wrapping/ heat-shielding wont strictly speaking "reduce heat" but just make it go somewhere else other than the cab.

Where it goes exactly, i'm not sure - some out the back, yes, but the rest into the mechanicals/ lubricants etc., and that bothers me ...

Originally Posted by Samblers

Since we're being slightly philosophical/ on a scientific tangent...

I've thought about exhaust wrapping in the past when ive been towing and its a 45deg day and we're all burning up even with the aircon on, BUT

i'm always mindful that wrapping/ heat-shielding wont strictly speaking "reduce heat" but just make it go somewhere else other than the cab.

Where it goes exactly, i'm not sure - some out the back, yes, but the rest into the mechanicals/ lubricants etc., and that bothers me ...

It all goes out the back. A wrapped exhaust has no temperature bearing on the engine upstream.