exhaust riser heat wrap material & tips?

vas

vas

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evening all,

finished with my custom elbow for the yanmar 2GMF (modified to rise an extra 160mm above exhaust port which enabled me to scrap the waterlock out of the exhaust route)
So now I have this 45mm ID SS which is approx 400mm long that I want to lagg/insulate/call it what you wish. Don't want to burn myself, or cables that are around it.

I can get locally 1 and 2 in (approx) wide glassfibre tape and wrap it.
Any serious reason not to or choose another material?

Mind I also have two slightly larger in dia (iirc 76mm) main engine risers that I could do as well.

Sliding something like a pipe insulation over is a no go as there are EGT gauge outlets (and some stuck thermistors there) plus the mixer pipe. Main engines sliding over is even more difficult as the 80mm dia pipe increases to 128mm for the mixer.

so looks like it has to be something wrapped or alternatively make a form, create some sort of material that I can zip/tie around, seen that on some mobos but looked v.bespoke (and no doubt v.expensive)

cheers

V

.2GM_elbow.jpg
 
I used an exhaust wrap on my old exhaust and it did the job but brush skin against it and omg you itched afterwards.
On my new exhaust I bought some titanium wrap, a little more pricey but no where near as itchy. Both the wraps provided enough heat insulation that if you were to grab it momentarily you would not get burnt.
I bought the cheaper one from ebay for less than £10.
 
thanks, so wrap it is then!
is there something I could cover them with, or just get a dark coloured wrap as inevitably I'm going to grab them (when cold hopefully) with oily hands and they'll look awful for the rest of their lives.

Slightly concerned with itchiness of materials.
Rappey, what does the titanium wrap actually mean? looks like it's normal glassfibre wrap painted in a charcoal/titanium grey? Maybe I should get that as it kills two birds with one stone so to speak.
5M Titanium Exhaust Heat Wrap Roll For Motorcycle Fiberglass Heat Shield Tape | eBay

cheers

V.
 
Quick tip (if you haven’t come across it before...) - soak the material before wrapping. Goes on much tighter/neater as a result.

Beta wrapped my new elbow for me and must say it was rather baggier than I usually get it after leaving the roll in a bucket of water for 5 mins (not complaining, mind!).

Nice job on the fab btw.
 
thanks for the tip and comment, will check what (and what price) I can get locally and then decide
Curious about ways to make the finished surface less vulnerable to dirt and disintegration.
 
I always use the black stuff, more of a dark grey/graphite colour which fairs well under cars etc. It’s cheap and easily replaced when needed if access is okay.
 
OK, makes sense, final (I think!) Q, do you put a clip to secure the wrap after the first full turn, or just at the end of the wrap?
Thinking of a 2in width and almost 1in overlap on each turn...
 
Yup, that’s what I do - clip at the starting end quite soon. But here’s where the wet wrap comes in - helps get the first turn(s) on extra tight. Tuck the starting end maybe a cm or two under the first wrap and you’ll find, when wet, it grips itself really tight(!). Then roughly a 50% overlap, as you suggest, should create a nice even effect.

The other advantage of wrapping it wet is that it seems to tighten up further when it dries, so little creases etc. that are hard to avoid around bends even out. It’s possible to get a pretty clean ‘professional’ look even with the cheap eBay stuff.
 
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vas said:
Rappey, what does the titanium wrap actually mean?
Click to expand...
Good question and ive no idea. It sounds and looks superior to others so maybe thats it?
I needed one meter of stainless dry flexible exhaust and found polylock was not up to the job as it leaked. corrugated was what i needed, just like diesel hot air heater exhausts, but at 48mm.
Wasnt the easiest to find but i did eventually and whilst chatting to them on the phone the subject of wrapping came up. they told me they sell a premium titanium wrap (i would assume not all titanium wraps are the same quality) and said theirs feels very soft to the touch and is no where as itchy as the cheaper stuff on ebay .. they were true to their word !
The company is a specialist in exhausts and tubing . Cheapest? no idea but helpfullness was superb.
Myriad Automotive - Exhaust Manufacturer, Tube Supplier Firm
for your short section i would think any ebay wrap would be suitable as they all stop heat .
some wraps are not meant for wetting before fitting.
 
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I only just managed to wrap my 1m length dry exhaust with 3 meters so would say a 3m length would suffice for yours.
I left a cable tie on mine whilst wrapping it and it still has not melted after many hrs engine running. !
 
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HI

You are right after a while the tape wrap will start to look mucky. We used some 2 inch wide self adhesive ally tape (looks a bit like Baco foil), it worked very well and only took a few mins to apply.
Good luck
 
back from the boat and this thread is probably the best to report on the only failure I had this season (so far at least :rolleyes: )
Due to the various mods done to the yanmar/generator combo, the original MASE soundbox is scrapped. So thing is noisy and I end up starting the generator and watermaker and going for a swim...
After two weeks doing so, coming back half an hour later I noticed the generator exhaust tone had changed, thought it was odd, but was about to leave the anchorage, so fired up the engines only to see the e/r autobilge pump dreaded orange light on!
went down there and to my horror bilge had probably 200-300lt of seawater. Turned thing off and realised what the problem was:

yanmarexhaustelbowfailure.jpg

tig weld failed horribly, so all exhaust gasses ended up in the e/r (luckily only has 60h after a full rebuilt so conditions were okay down there) and all water injected in the elbow was coming down the broken ss tubing in the bilge...

Got the big 1.5in manual electric bilge pump to empty the place and on next port got a machinist to redo the weld.
Thinking about it, it's obvious that increasing the elbow like that welds are stressed due to the vibrations and weight of the pipework clamped at the end of it.
When current heatwave is over, I'll remove it once more and tig weld two brackets one on each side from the flange area to just above the exhaust hose clamp area at the far end. This way stresses are going to be taken by the brackets and not the welds alone. Obvs fabricator missed something as it's clear that the TIG arc penetration wasn't enough, he's done excellent work on various other projects of mine, so I'll just let him know.

so yes, good to have a long/high reach exhaust elbow, but best if you support it somewhat to avoid such failures. OK, mine was a generator, if it were my main engine, things would have been v.different in the wrong weather conditions.

cheers

V.

PS. bought wrap, time to do it after the bracket welding :)
 
I agree you need to support it.

One thing to think about is the support needs to go back to the engine mount if its mounted on vibration mounts so it all moves as one. I have seen exhausts break away this on some supposedly well engineered boats because the exhaust elbow bracket was secured to the hull not the engine!
 
for sure! it is on vibration mounts, was planning to just get the bracket to the exhaust flange bolted on the cylinder head, but maybe I can find a decent spot (well threaded hole!) lower on the block so the angle of attack is going to support the weight better.
thanks for the idea

V
 
To prevent it breaking brace the whole length with a stainless bar bent to touch and be welded at as many places as possible. You have to stop it wagging by securing the other end to the engine somewhere.

Old fire blanket is great heatproof wrapping, white nylon zip ties will not melt too quickly but I wind galvanised wire all around my wrappings after fitting as tight as possible.
 
yep, thought of that as well, maybe a 2mm thin by 15mm wide plate bend and tig welded on the top following the S shape AND a 15mm ss tube, flattened at both ends tig welded on the top of the S and somewhere on the block.
Belt and braces approach
 
Securing the lagging I use stainless seizing wire rather than the stainless cable ties, it's a bit neater
 
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