How about aluminium tape? I've used that to cover a crack in a header pipe 2 inches from the exhaust port on one of my bikes, it passed several MoT tests that way.

This is for use as an antiseize, on the bolt threads, since I'll probably have to do it again so being able to take it apart easily is nice.

Antiseize is unobtainable here in Taiwan, and I'd think aluminium repair tape might be too. I also seriously doubt it would hold up to the pressure once the gasket fails.

For the repair I intend to put a steel tube insert between the manifold and downpipe, which should reduce the pressure on the gasket, though it will restrict the exhaust a bit more.

A lot more if it collapses

Edited by edlithgow on 08/06/2020 at 09:44

I understand PTFE is basically teflon. Back in the '60s it was used as an outer covering for wires to allow them to be pulled into place more easily. A couple of cases resulting in fatalities occurred when some was inserted into cigarettes as a prank.

I wouldn't use it anywhere on an exhaust.

PTFE and teflon are the same thing by scientific and trade names. It can pyrolyse in the quoted temp range, but IMHO the quantity and temps involved are most unlikely to harm anything on an exposed exhaust, unless anyone is in the habit of lying under a vehicle with the exhaust hot ?

Polythene will melt and then burn above about 100°C, rather like candle wax. Thin Melinex film (PET) should stand up to 200° plus.

Surely copper loaded grease such as Copaslip is obtainable in Taiwan. Standard auto workshop stuff. The classic high temperature anti seize.

I've seen a kg tub of it, once, which I've been told may be the only one in Taiwan, and would last me until the heat death of the universe.

Its not a huge problem since I can improvise. Aluminium would probably work OK here, but if PTFE will stand the temperature it'd be a useful backup.

If itt might cook off fluoric acid I won't bother.

I doubt there would be much of a health hazard if it completely breaks down because it''ll boil off, but I might have to handle it when only partly broken down, and its nasty stuff, plus it might corrode the threads.

Edited by edlithgow on 08/06/2020 at 14:37

Molybdenum disulphide grease, ceratec brake grease, even Lithium based grease would probably do.

Why not use stainless bolts and nuts? Or don't they have those in Taiwan either?

Ceratec brake grease in TAIWAN??

HA!

There isn't ANY brake grease in Taiwan.

In fact I can't find ANY recognisable grease of any kind in Taiwan. The best I could do, for standard Lithium grease, was some 3M branded pink stuff which no one has ever heard of but which I now think probably isn't fake.

3M eventually after about 3 months, responded to an email about it, but in Chinese, which I have never got around to having translated.

Here's a fairly typical product. “Liki Hara” grease, which sounds local, though it does say “Made Product American” on it.

Perhaps they mean they’d made the product seem American by writing bad English on the packaging, appealing to a more redneck truck driving customer base?

They seem to be pretty globalized, though, since a web search turns up The British Swiss Corporation (Taoyuan) as a source, ( for another of their products) which of course traditionally implies massive integrity and uber-anal attention to detail

https://www.jyc555.com.tw/ShowItem.php?id=4845&sid=9f90674b4eb05d3fcf711f7572646b46

This was one of the few I found which gave any clue as to what was in it, though a rather enigmatic one

"Moly none (3%). "

I’d guess their made-American corporate lawyers have a lot of fun cooking up product descriptions like that.

It MAY be excellent stuff, and if I needed to source a grease locally which probably had molybdenum in it this might be the best I could do .

Would you use it?

Anyway the ""Mysterious Grease of The East"" jive is a bit of a sore point I could rant about for a few pages.

Stainless is of course widely available since steel rusts fast in the monsoon, and I've replaced the two front bolts I could get out with some stainless studding. I understand stainless isn't always a panacea, but it seems OK in this application so far. .

Edited by edlithgow on 09/06/2020 at 01:33

What about dispensing with the gasket and using some thin asbestos cord anointed with gungum?

Yeh.

Or Kryptonite.

But only if I'm Superman, eh?

As it happens I sometimes do something like that with RTV silicone (which IS available, unlike GunGum) and cotton or nylon cord (ditto, and less fatal than asbestos) for lower temperature gaskets.

If I was doing a higher temperature version I'd maybe try copper wire and potters clay, The gaskets I've been making for this are a dimpled aluminium sheet sandwich with either potters clay or RTV silicone in the dimples. The aluminium sheet was a bit of scrap pipe insulation.

These seem to last ok until the joint loosens up and then they torch out (though it could be the other way around)

Either way,. I'm hoping a pipe insert will buy them a bit more time.

If I had remembered doing that I'd have worn gloves for the removal, though I dunno if skin contact with PTFE pyrolysis products is a real hazard. The literature seems to be mostly about inhalation risks.

I think the pyrolysis product causing worry is HF, which boils at about ambient temp so isn't going to hang around. If it was in solution perhaps more of a worry, but as the quantity of PTFE present is probably measurable in milligrams I reckon you can forget about it, especially as you say the tape seems to have survived.

Smallest rawl bolt I found was too big, so I put it in a drill chuck and ground down the conical expansion head on a concrete block. Replaced the steel tube thingy with my very last bit of old TV arial tube (wish I'd got more when I could) cut down the side with a hacksaw. Have some hopes that will grip the thread remains better.

Snag with alignemt though. The old bolt stump is one fixed point, and the new insert pipe is another. This doesn't leave much wiggle, and when the light went and mosquito happy hour stopped me it was looking as if I woulldn't be able to get the other two bolt holes lined up.

Insert may therefore not be workable, The old bolt isn't doing anything useful but would be very difficult to drill out or cut offf where it is, and this might not solve the problem anyway..

Removing the manifold MIGHT be helpfull, but it might also be a 55 gallon drum of worms that I don't want to open.

Edited by edlithgow on 11/06/2020 at 14:41

Either way,. I'm hoping a pipe insert will buy them a bit more time.

I'm surprised GunGum or equivalent is unavailable in such a large country as Taiwan. I suppose your pipe insert will consist of a bean can with ends removed, cut longitudinally to form a variable sized cylinder, then gummed/spot welded/wired/bandaged into position, thus causing minimal resistance to gas flow. Might be worth drilling a small hole for a self tapper screw to further hold it in position.

Wouldn't think that would last long. This is the manifold-downpipe joint and gets pretty hot.

(You can't get baked beans in Taiwan anyway :)

Manifold is slightly bigger (about 40mm IIRC) than downpipe (about 37mm). The upper and lower frame tubes of a scrap bicycle had about the right dimensions and are a snug fit inside each other and repectively into the manifold and downpipe.

I went for a fairly short insertion into the manifold, perhaps about 1.5 cms. Further would be more secure but would be more disruptive of gas flow and would probably get hotter. The bike tubing is quite thin-walled and there is probably a risk of it collapsing and blocking the pipe.

I'm surprised GunGum or equivalent is unavailable in such a large country as Taiwan.

I don't know for sure it isn't, just that it would be effectively impossible for me to find.

I do know this is the case for antiseize, because a British mechanic who runs a garage business here told me that according to his supplier, he was the only user in Taiwan. He was very surprised I found The Taiwan Tin, but it/d clearly been on that shelf for a very long time.

This is for a few reasons, notably sloppiness, ignorance, and a complete lack of DIY.

Sloppiness and Ignorance: The difference between, say, lithium bearing grease and molybdenum grease for CV joints is going to be of no interest to Taiwanese mechanics or their customers. The fact that the retail market is almost exclusively dominated by dodgy looking knockoffs suggests a pervasive customer indifference/ignorance.

Complete lack of DIY: I've seen it argued by an American mechanic that antiseize is for amateurs, and this makes some sense. It takes time to apply, and its function is to save time/damage in the future. For a pro, that's likely to be someone elses problem.

GunGum is probably mostly a DIY bodge for older cars with iffy exhaust systems. Here, they'd sell you a new exhaust, or another car.

Incidentally, I would say Taiwan was a fairly small country, and the population, though dense, is still less than that of Greater London.

You may be mixing it up with China, (a common mistake), which could be described as a large country.

I'd bet you can't get GunGum there either..

Edited by edlithgow on 11/06/2020 at 01:37

Yes, that is of course possible, and thanks for the offer.

Many online suppliers won;t ship directly to Taiwan, but I can get stuff delivered to UK addresses and then sent on. Some chenicals aren't approved for shipping though.

I'm expecting a couple of points sets from Latvia and tthe UK that look as if they'll fit, though the online compatability checker says they won't.

Indirect shipping adds quite a lot of cost and delay though.

It appears you may in fact be able to get exhaust repair paste online in Taiwan, though I'm told the text here says its sold out.

https://www.pcstore.com.tw/autocare/M07901249.htm

Interesting. I suppose you can't use nylok nuts on an exhaust because the nylon would melt or burn, and that's why they use those.

It does say they work by deforming the thread though, which might raise a slight doubt about re-use

I THINK the polythene sheet (from poly bags) that I use on, for example, wheel nuts, probably has a nylok-stylee action, but I mostly use it for its anti-sieze / anti-galling effect.

Skooshed WD40 on the manifold bolts this morning pending a decision on trying to take that off, but I think I'll probably end up putting it all back the way it was with a half-baked home made replacement gasket that won't last long.

Bit of a waste of time.

I had a feeling this would be the outcome when the improvised insert tubes were a perfect fit.

There's always a catch when something like that happens.

Glad to hear you can at least get WD40 in Taiwan, Ed .... :-)

I think WD40 is probably the dominant penetrant in the UK too

WD40 is not a penetrant, its a WATER DISPURSER (the clue is in the initials and I guess the first 39 attempts must have been rubbish.

I still have a can of Plus Gas I bought back in the 70's and when I last used it on a car (probably when I did the exhaust gasket on the Mk 1 Focus over 10 years ago) it still worked a treat. Or did it? never tried the nuts before applying and leaving overnight and doing the job.

Pending hopefully locating the extractor set, I've seen it claimed that electrolysis can loosen rusted fastners.

I don't think I believe this, but I believe it can remove rust, and have been meaning to try it, so I did.

I mentioned possibly using extinguisher dry powder for this when someone posted about disposing of old extinguishers a while ago, so A NOTE OF CAUTION.

I had some powder stored in a plastic bottle and when I cracked the cap it exploded in my face. Yellow dust everywhere. Evidently this stuff gases off.

Maybe an egg-cup full of powder in a plasic washing up bowl, flattened scratched-up aluminium beer can as positive electrode, manifiold as negative with the bolt end projecting closest to the beer can.

Once it was gassing I hooked up a smart charger to the battery.

Only left it for about an hour and a half. Might have been better overnight, but then I didn't really think it would have any effect inside the bolt hole. The stump got pretty clean but remained firmly stuck and I chewed it up a lot trying to move it..

The submerged part of the .manifold blackened, with a pretty clear "tide line". Whether this would have happened with the solution alone, without any applied voltage, remains to be seen.

https://tw.forumosa.com/t/exhausting-all-options/193821

Summary with pictures.

Holding so far but I had to use rather skinny bolts so may not be very durable.

Probably of little interest to Forumosa (expats dont do car repair much) but they host the pictures