any - Anti-seize for hot stainless steel - edlithgow

Replacing corroded exhaust-manifold-to-downpipe bolts with some stainless steel studding. Didn't particularly want SS, which I know has its own problems, but just happened to have some that fits.

Seem to have lost my Pertex aluminium anti-seize (bought in Japan). Have some copper-base stuff from the UK, but don't think thats compatible with SS.

So ho-hum-home-made again.

Got three greases which I could grind some aluminium into.

(a) Some cheapo local chassis grease.

(b) Some Japanese-bought ("Daytona Brand "Tools for the Sunday Mechanic" a pretty small target market in Taiwan) "brakku-grizu" (that's what the yoof in the motorcycle shop said) silicon grease.

(c) Some 3M lithium bearing grease that nobodies ever heard of and might be fake.(3M responded to an enquiry after a couple of months but in Chinese. I'd already used it by then so havn't bothered having the response translated)

I'm thinking cheapo local chassis grease, since I've read somewhere cheap greases have clay in them, which might be not bad on its own.

Any experience with stainless steel exhaust fastners? I have no idea what grade of stainless this stuff is.

Other suggestions? Toothpaste, maybe?

I've read somewhere of some (formerly?) common household chemical being used as a high temperature anti-seize on B52 engines, but irritatingly I can't remember what it was.

Maybe borax? - Wickipedia doesn't think so.

Maybe Milk of Magnesia? (Magnesium hydroxide suspension). Got to see the doctor Monday.

www.practicalmachinist.com/vb/general/high-tempera.../

Edited by edlithgow on 24/02/2019 at 03:05

any - Anti-seize for hot stainless steel - bathtub tom
I've read somewhere cheap greases have clay in them,

I was told that grease is oil in clay!

any - Anti-seize for hot stainless steel - edlithgow
I've read somewhere cheap greases have clay in them,

I was told that grease is oil in clay!

Think you were told wrong, (as a general statement).

The silicon grease is clear and colourless, the alleged 3M lithium stuff is cloudy pink. I'm pretty sure neither of them have much clay in them.

The cheapo local chassis stuff is very dark brown so could well have clay in it. Some greases specs mention bentonite, which IIRC is a refined/defined form of clay.

I'd think these solids might prevent metal-metal contact and so act as an antiseize, and they shouldn't cause any electrochemical corrosion, unlike, say, copper, which has that potential. (NPI).

Maybe that's all you need.

any - Anti-seize for hot stainless steel - bolt

Replacing corroded exhaust-manifold-to-downpipe bolts with some stainless steel studding. Didn't particularly want SS, which I know has its own problems, but just happened to have some that fits.

Seem to have lost my Pertex aluminium anti-seize (bought in Japan). Have some copper-base stuff from the UK, but don't think thats compatible with SS.

So ho-hum-home-made again.

Got three greases which I could grind some aluminium into.

(a) Some cheapo local chassis grease.

(b) Some Japanese-bought ("Daytona Brand "Tools for the Sunday Mechanic" a pretty small target market in Taiwan) "brakku-grizu" (that's what the yoof in the motorcycle shop said) silicon grease.

(c) Some 3M lithium bearing grease that nobodies ever heard of and might be fake.(3M responded to an enquiry after a couple of months but in Chinese. I'd already used it by then so havn't bothered having the response translated)

I'm thinking cheapo local chassis grease, since I've read somewhere cheap greases have clay in them, which might be not bad on its own.

Any experience with stainless steel exhaust fastners? I have no idea what grade of stainless this stuff is.

Other suggestions? Toothpaste, maybe?

I've read somewhere of some (formerly?) common household chemical being used as a high temperature anti-seize on B52 engines, but irritatingly I can't remember what it was.

Maybe borax? - Wickipedia doesn't think so.

Maybe Milk of Magnesia? (Magnesium hydroxide suspension). Got to see the doctor Monday.

www.practicalmachinist.com/vb/general/high-tempera.../

Why not leave it bare metal, SS is usually good if its a good grade and should be easy enough to undo in years to come assuming you need to undo it, I know some have problems with undoing nuts from bolts but sometimes people use anti seize and sometimes it makes for a harder than it needs to be removal

I have never used anti seize compounds on exhausts as it can make life more difficult to undo the bolts, but some people insist its a good idea, imo it isn't

any - Anti-seize for hot stainless steel - skidpan

Using stainless bolts/studs into allow castings is not a good idea. They can be pretty much impossible to extract even when tightened correctly due to galling.

Buy some plated steel bolts/studs.

any - Anti-seize for hot stainless steel - edlithgow

Using stainless bolts/studs into allow castings is not a good idea. They can be pretty much impossible to extract even when tightened correctly due to galling.

Buy some plated steel bolts/studs.

Manifold looks like cast iron. Exhaust is presumably mild steel. These are of course alloys, but not aluminium alloy, which I guess is what you meant.

But as I said, not set on SS, just had some. If I had some mild steel bolts that fitted I'd use them. Buying replacements that fit is likely to be tricky, but I may attempt it.

Didn't go well today,

One of the original bolts sheared off. Looked like gasket had failed to the bolt hole, torching it and maybe destroying temper. Probably have to drill that out from underneath, a quasi-impossible job, or take the exhaust manifold off, a whole other bucketful.

One of the two installed replacement studs doesn't have much of a grip on whats left of the threads in the manifold, and there isn't clearance to put a nut on it, unless MAYBE I file one side down, in which case I can't use a stainless steel nut.

I suppose Rawlbolts wouldn't take the heat?

any - Anti-seize for hot stainless steel - skidpan

Buying replacements that fit is likely to be tricky, but I may attempt it.

Why. Cars use standard bolts which on most cars are now and have been since the early 80's metric (except on cars from that 3rd world country the good old US of A).

They do come in different strengths which on metric normally start at 8.8 and this is well up to the job of a manifold to downpipe fixing.

Some are threaded all the way to the head (technically a screw) or have a plain shank before the thread (which is technically a bolt).

99% used on cars are the standard pitch for the diameter.

So just measure the diameter, length and decide if its a bolt or screw (a screw suffice in a location like this) and simply buy some, they are available everywhere since they are used everywhere.

any - Anti-seize for hot stainless steel - edlithgow

Encouraging, but this is Taiwan, so there are various additional language, cultural and ignorance (mine and theirs) obstacles to overcome (Eg, buying RTV silicone recently, with a probably-correct translation written down and a picture, I had two places try and sell me wood glue, insisting it was the same thing.). I don't offhand know where to buy bolts and I'm pretty sure I don't know anyone who does.

Plus I have some technically-screws that I think are the right diameter and they bind, so I'm not sure the universal thread-pitch thing applies in this case.

(Admittedly I think "universal" is often a myth. This bias has been strongly reinforced by the introduction of "Universal" Serial Bus connectors, of which I have collected a big non-interchangable bag )

But mostly its because I think the tapped holes on the manifold flange are eroded so maybe even the correct fastener wont grip them adequately. I thought I could get around this with a nut on the end, but there isn't clearance at at least one of the flange holes.

But needs must. Yesterday morning I took a 1000 NT bet (Off a philosophy lecturer. Lamb-to-the-slaughter I thought) that I'd have it drivable by the end of the month. I'd expected to have it done that afternoon. Not QUITE so confident this morning.

any - Anti-seize for hot stainless steel - edlithgow

I have never used anti seize compounds on exhausts as it can make life more difficult to undo the bolts, but some people insist its a good idea, imo it isn't

I suppose it might depend on what you mean by anti-seize. Most people probably mean copperslip-type-stuff. I've never liked that idea and never used it in the UK, where it is available, unlike here. My brother gave me a tube when I was back last summer and I used it on the rear exhaust joint, which won't get so hot. Rather wish I hadn't, but we'll see.

The copper will tend to promote galvanic corrosion of steel, though evidently you often get away with it in practice. Aluminium should be OK, so I'd use that in preference. Nickel seems to be the picky recommendation, but I've never seen any.

The oil-based grease will tend to bake to hard carbon, also a potential galvanic corrosion problem.

I'm not sure what silicone grease bakes into, but its thickened with fumed silica so I'd guess mostly that. Shouldn't be too bad.

I did one bolt with aluminium-in-silicone grease, the other with aluminium-in-cheapo-chassis grease. Probably not enough aluminium, since hand grinding it is tedious.

If I was doing this again (and I probably will be) I'd go for just a solid, perhaps dispersed in water, as in milk of magnesia. I have access to unlimited supplies of blackboard chalk, which might be OK, though I'm not sure about the sulphur. Similarly, pencils could provide graphite-in-clay, though there is a potential galvanic issue there.

I had some thin aluminium Tunnocks Tea Cake wrapper, personally imported from Scotland, reserved for this but it blew away in a gust of wind at the critical moment.

Sad.

Edited by edlithgow on 26/02/2019 at 22:27

any - Anti-seize for hot stainless steel - galileo

Ed, have you actually had galvanic corrosion from Copperslip on exhaust manifold fasteners?I would have thought these were usually hot enough to prevent any moisture being present to act as an electrolyte?

any - Anti-seize for hot stainless steel - galileo

Ed, have you actually had galvanic corrosion from Copperslip on exhaust manifold fasteners?I would have thought these were usually hot enough to prevent any moisture being present to act as an electrolyte?

Had a think and recalled that for foundry hot shell-moulding machines the lubricant was a Rocol product, based on MoS2.

Rocol do now make an antiseize for hot stainless, but don't suppose you can get this where you are, unless anyone does aircraft servicing and can be persuaded to part with a bit.

any - Anti-seize for hot stainless steel - edlithgow

Ed, have you actually had galvanic corrosion from Copperslip on exhaust manifold fasteners?I would have thought these were usually hot enough to prevent any moisture being present to act as an electrolyte?

Dunno. I've never used it until a couple of weeks ago, but previous owners of my cars may have.

Its largely a theoretical objection. Clearly you can get away with it, though I have seen some US Navy technical bulletins that deprecate its use, along with graphite, on ships,

Ships do get wet, but then so do exhausts, and mine spend a fairly small proportion of their service lives at operating temperature.

any - Anti-seize for hot stainless steel - edlithgow

I cheated. I put a couple of G-clamps (1 and 3 inch) alongside the sheared bolt. Bit of a struggle getting them tight with the limited clearance but hopefully they'll hold for a while.

The bet was that the car be "drivable" by month end. There wasn't anything specified about it not being on fire.

any - Anti-seize for hot stainless steel - Andrew-T

<< Other suggestions? Toothpaste, maybe? I've read somewhere of some (formerly?) common household chemical being used as a high temperature anti-seize on B52 engines, but irritatingly I can't remember what it was. Maybe borax? >>

Talcum ? Mica ? Rouge ?

any - Anti-seize for hot stainless steel - bathtub tom

I've used coppaslip on sleeved exhaust joins with great success. I had one car that rotted its back box every couple of years, coppaslip allowed it to be replaced with ease.

any - Anti-seize for hot stainless steel - edlithgow

I've used coppaslip on sleeved exhaust joins with great success. I had one car that rotted its back box every couple of years, coppaslip allowed it to be replaced with ease.

Re regular back-box rotting, slightly OT, but I try and limit internal corrosion by shoving some crumpled beer can in the downpipe when the opportunity arises. My theory is this will sort-of flame spray the inside of the pipe with aluminium. I also usually add a teaspoon or so of Portland cement, for anti-acid buffering, but this time didn't have ready access to any.

Of course if the can rolled itself up and caused a blockage I'd look pretty silly, but so far, so-so.

Probably not applicable to a catalyst-equipped system

Since I had the front pipe section off I gave the outside my aluminium-and-sunflower oil treatment and its looking pretty shiny, but I'd guess most of that will burn off.

If there's a next time I might try wrapping it in aluminium.

any - Anti-seize for hot stainless steel - edlithgow

<< Other suggestions? Toothpaste, maybe? I've read somewhere of some (formerly?) common household chemical being used as a high temperature anti-seize on B52 engines, but irritatingly I can't remember what it was. Maybe borax? >>

Talcum ? Mica ? Rouge ?

Think it was Milk of Magnesia, but talcum/mica makes sense, if you can get the straight stuff (IIRC think the baby powder is cut with cornflour, which would char.)

I suppose jewellers rouge might work (its mostly a fine abrasive though) but it isn't really a common household chemical

Edited by edlithgow on 01/03/2019 at 14:07

any - Anti-seize for hot stainless steel - skidpan

I've used coppaslip on sleeved exhaust joins with great success. I had one car that rotted its back box every couple of years, coppaslip allowed it to be replaced with ease.

Coppaslip is indeed an antisieze compound but its not intended to lubricate and seal sleeved joints on exhausts. There are proper pastes for that job.

 

Ask Honest John

Value my car