Author Topic: Gasket cement?  (Read 12703 times)

Offline Rusty nuts

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Re: Gasket cement?
« Reply #15 on: 16.07. 2010 18:00 »
Quote
back in the day grease was recommended by BSA service sheets.

I find it hard to imagine that grease on a head gasket would would act as a sealant.
John
To clarify, I was not implying that.
Just that service sheets mention it's use.
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Offline a101960

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Re: Gasket cement?
« Reply #16 on: 16.07. 2010 18:49 »
Rust Nuts,

I apologies if you construed my comment as a criticism of you. I fully understand that the service sheets disseminated what was the perceived wisdom of the day. For example, BSA advocated using twine to prevent oil leaks from the bottom of the fork seal holders for example. Time has moved on, and technology has advanced. We now know that PTFE tape for example is the method of choice to achieve this object, and that PTFE tape reliably does the job. I accept that what you quoted was in good faith, and what is more I always apply grease to the head gasket because I believe that it is useful in the context of aiding spread during tightening down and holding it in place.

John

Offline trickytree

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Re: Gasket cement?
« Reply #17 on: 16.07. 2010 18:54 »
Wellseal, excellant stuff....TMS in Nottingham sell it (amongst other places)
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Offline Rusty nuts

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Re: Gasket cement?
« Reply #18 on: 16.07. 2010 18:57 »

John,

Not at all, just wanted to clarify.
Twine: I still use it, works fine.
PTFE: hate the stuff unless I'm plumbing.
Grease, as you said.
It's the word!

Rusty
1949 A7 Plunger
1947 A7 Rigid Star Twin
1969 Triumph T120R
1972 Triumph T120V

Offline zitman

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Re: Gasket cement?
« Reply #19 on: 16.07. 2010 18:58 »
I am a firm believer in silicone.  I do not use it on head gaskets but it was the only thing that stopped my primary case from leaking.  A friend of mine who is a mechanic rebuilding car gearboxes uses it and swears by it.  I have used it the primary both with and without gaskets and it worked either way.  I would not use it anywhere near oil ways etc but everywhere else has been ok.  And yes it is just the ordinary bath room sealant stuff.

Just use it with care and don't put huge great gobs of it on and its fine.

Z

Offline alanp

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Re: Gasket cement?
« Reply #20 on: 16.07. 2010 19:05 »
Rusty, your comment about using nail polish remover to get rid of Silicone had me rushing to get one of my pairs of trousers and the wife's remover. I had accidentally (absent mindedly) wiped some silicone on my trousers, virtually ruining them. I'm now a happy bunny since it worked!
Thanks mate.
Alan
Member of the 'Last of the Summer Wine Club - Jennycliff'.

Offline Rusty nuts

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Re: Gasket cement?
« Reply #21 on: 16.07. 2010 19:53 »
 *beer*
1949 A7 Plunger
1947 A7 Rigid Star Twin
1969 Triumph T120R
1972 Triumph T120V

Online groily

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Re: Gasket cement?
« Reply #22 on: 16.07. 2010 20:39 »
Ah, Alan, ruined trousers ('pants') . . .  Every time She goes to a place (like the USA or the UK) which sells big sizes she buys me new ones in the vain hope I might look half decent for a bit. And within days, sadly, they are 'ruined' but more comfortable. There's no hope for a man with a shed, no fashion sense and who's past trying to pull the opposite sex with antiseptic displays of domestication.
It's good to know there are products out there though!
Bill

Offline JohnH

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Re: Gasket cement?
« Reply #23 on: 16.07. 2010 20:52 »
Phew! - You guys really are helpful - Many thanks.
Some responses from me:
I personally wouldn't use gasket cement of any kind on a solid copper head gasket. I would however, use grease, just to facilitate a bit of movement between the four mating surfaces (as mentioned by several posters). I really wanted to confirm that my technology was still valid. I'm less sure about a composite (copper/asbestos .... do they really still contain asbestos?). The gaskets can rarely be re-used so I might use a good quality sealant such as Blue Hylomar. That view seems to be supported by Rusty Nuts and others
     John from Solihull - I live in Cranleigh in Surrey - near to Guildford. My son and his family live in Moseley so I spend a fair bit of time there too!
     Very intersting to hear all the thoughts about silicone sealant - and it's removal - strewth - that will be useful. I'll keep the use of silicone in mind for my primary chaincase although I shall try to get by with a seal with grease alone as John (A101960) suggests is possible - although my experience with a 16MS AJS were pretty miserable!
     I'm very interested in those rocker box gaskets (again John A101960). I can remember using gaskets that were pink on one side and green on the other - slightly furry at the edges as I recall - possibly because they were a bit thicker?
     Finally, I would be very interested to know where in the UK the sheet gasket material can be obtained - as mentioned by Groily.
Thanks for all the very willingly delivered help - I like the humour too!

John
Triumph Bonneville - long gone (sadly)
AJS 16MS - keeps coming back (thank goodness)
BSA B31 - also long gone
Greeves 250 twin (good fun)
Francis Barnett 197 (first bike)

Offline a101960

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Re: Gasket cement?
« Reply #24 on: 16.07. 2010 21:22 »
I just thought that it might be worth mentioning that silicone sealant has corrosive properties on aluminium due to the acetic acid content. I am a retired avionics technician and silicone sealants were a big no no on aircraft applications. Amongst the many and varied items that I worked on in particular the pressure relief units incorporated two rubber diaphragm housings that could prove to be troublesome to seal. we used grease to effect a good seal on these. Silicone sealer would have been an easier option but it was not permitted because of potential corrosion problems. This was on military aircraft.

John

Offline brackenfel

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Re: Gasket cement?
« Reply #25 on: 17.07. 2010 10:08 »
John mentioned Dowty washers a while back...
These are really good - a friend gave me 3 for the rocker feed oil pipes on my Velo about 10 years ago & they haven't leaked since.. I want to get some for the A10..
Are the sizes measured across the metal part or the rubber insert?  Anyone know what size I'd need for the 2 rocker feeds and the oil pipe feed/return outlets on the crankcases please?

Thanks,
Adrian
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Offline Lannis

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Re: Gasket cement?
« Reply #26 on: 19.07. 2010 17:34 »
I went back to read the thread and was surprised to see that a couple of techniques that have worked very well for me are not mentioned:

1) Anaerobic gasket maker such as Loctite 515 or 518.  This has a big advantage in that, unless it is squished tight into the joint, it does not set up or harden and form stringers or bits that can get into oilways.   For the cylinder base gasket on my A10, for example, I used a thin layer of 515 with NO gasket, and the joint is as tight as Dick's hatband, no oil leaks at all.   My primary case with a paper gasket (Permatex on one side and grease on the other) was leaking after a short time - I replaced it with a thin skim of 515 and now no leaks.   Same on the A65 - the paper cylinder base gasket stayed soggy with oil all the time, and would weep a little - with a layer of 515 on clean metal surfaces, no leaky.

2) Copper head gaskets for A10 or A65 - I always use an annealed copper gasket with a thin spray coat of "Copper-Cote" sealer on each side.   Never any leaks, problems, or blown gaskets.   WORST thing I've ever done is used one of those sandwich-layered "composite" head gaskets - I've tried it on two different bikes - modern technology is bound to be better, right?   Both times I had to continually tighten the head bolts down and ended up blowing the gasket.

So that's my data point ....

Lannis
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Online bsa-bill

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Re: Gasket cement?
« Reply #27 on: 19.07. 2010 18:24 »
Quote
Anaerobic
Thanks Lannis that is the word I was looking for, good stuff goes on thin and brings piece of mind as you know it is not going to set anywhere it's not supposed to be
All the best - Bill
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Re: Gasket cement?
« Reply #28 on: 19.07. 2010 21:26 »
John,
My last stock of Flexoid gasket paper in rolls came from Netley Marsh via a mate (so source unknown), but in this case e-bay is as good as anywhere if you just google 'gasket paper'.
Or go to www.auto-connect.co.uk/Autoconnect_Gasket_Paper_3100.html
There are several thicknesses out there in 1 metre sheets, plus loads of A4 sheets, and there are also sets of tubular cutters for making holes of various sizes. Also some good Klinger-stuff for tricky joints, but usually 'non-asbestos' these days. I still use some gaskets I made years ago in Klingerite for one engine's rocker boxes - they seem indestructible.
Re the 16MS . . . I've never managed to seal AMC pressed-steel chaincases for very long myself . . . It is supposed to be possible with neoprene seals etc etc, and I've managed for a while from time to time, but I gave up on permanent leak-free status long ago and just tolerate small drips, which the real experts wouldn't. (The alloy chaincases do seal well though, just as well as on a BSA, so no excuses there for any of us.)
Bill

Offline JohnH

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Re: Gasket cement?
« Reply #29 on: 25.07. 2010 18:33 »
Yet more incredibly useful information. Many thanks to all who have responded - especially the more recent posts from Groily and Lannis and the comments from A101960 about the aggressive nature of silicone sealant. I had wondered about the acetic acid content in silicone sealant - that settles it, I'll use the anaerobic sealant when I can and blue Hylomar when i need to use paper. Thanks Groily re gasket paper - do you use a particular thickness most often?

Thanks again,
John
Triumph Bonneville - long gone (sadly)
AJS 16MS - keeps coming back (thank goodness)
BSA B31 - also long gone
Greeves 250 twin (good fun)
Francis Barnett 197 (first bike)