Spray Coppercoat Gasket Sealer?

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worntorn said:
The anaerobic sealer I mentioned is Loctite 518.
When in contact with air it remains like grease. Take the air away and it sets up to form a gasket ( crankcase joint)
It has good gap filling properties, iirc 25 thou.
The material that invariably squeezes in is dissolved into the oil.
I like it, but only for the crankcase joint . All others get Cometic nitrile rubber over Al. reusable gaskets whenever possible. Once you fit a Cometic gasket, you lose all interest in paper gaskets.
Copper spray on the head gasket has worked well.

Glen
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Does cosmetic sell MLS gaskets for commando engines. I’ve looked and found nothing.
 
Is there any of the treatments mentioned above that is useful if you use the eye-letted head gasket?
 
fiatfan said:
Is there any of the treatments mentioned above that is useful if you use the eye-letted head gasket?
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There’s no one answer to that!

My understanding is that the eyeleted head gaskets are already coated, and the coating is designed to bind to the surfaces and seal. As such, they’re designed to be assembled clean and dry. So using a gasket goo is undoing this feature.

I only ever assembled mine scrupulously clean (ie wipe head and barrel faces with brake cleaner repeatedly until nothing shows on a clean cloth) and totally dry. I never had one fail.

Mich Hemmings however, generously coated the gasket on both sides with Wellseal.

Ask 10 Norton folk and you’ll get 11 different answers…
 
fiatfan said:
Is there any of the treatments mentioned above that is useful if you use the eye-letted head gasket?
Click to expand...
I use copper coat spray on all types of head gaskets. It acts as a lubricant promoting a good seal and conducts heat. I first started using it on coated composite Harley Davidson Big Twin (hog) head gaskets. I would not use any outer gasket compound on a head gasket. Back on my father's day aluminum paint was used for similar reasons.
 
Just been to the workshop to locate the two tubes of Threebond I have, I use 1184. It doesn't mention Silicone once on the box. It does say 'synthetic rubbers' and 'rubber like elastic substance'. From the 1184 spec sheet for those who did not follow the link:

Product Outline
TB1184 is a visco-elastic semi-drying sealer which is resistant to oil, water, gasoline and chemicals. Application areas
include sealing transmission case covers, motorcycle cases, timing chain cases, side covers, 2-piece cylinders, clutch
housing bolts and oil filter mounting surfaces. Since it excels in padding properties, it is highly effective in sealing
surfaces with poor flatness or large gaps. TB1184 is a development of the popular liquid gaskets TB1104 and
TB1194, and can be used as a direct replacement in all applications.
Features
• High padding property, excellent sealing effect.
• Excellent resistance to vibration and impact.
• Forms a semi-drying rubber-like elastic body.
• Maintains stable properties from -40°C to +150°C.
• Excellent resistance to water, oil and gasoline.
• Applicable for threaded joints as well as flanges.

I have stripped a motor built by someone with a silicone gasket fetish and agree that stuff gets everywhere and bungs up holes, It is horrendous.

Today I do not use products marked silicone on my bikes, except maybe polishes, not that I am a great user of polishes!!

I recall in the '70s using 'silicone gasket' on the cylinder base and seeing clear marks of the cylinders moving around! I haven't seen that with 1184.

I have never had a worrying experience with '1184' and like I said before I have only found it where I put it, no bunged up holes.

Race engines are stripped more than road bikes, and I haven't found the 'silicone gasket' problem.

It appears wrong to assume that any 'synthetic rubber' is silicone.

1184 specifically says resistant to oil, water, gasoline and chemicals, but further references for silicone suggest it should not be an ingredient in a product designed for use on engine cases, to quote 'silicone UK' regarding the ingredient 'silicone':
  • Poor Oil/Petroleum Resistance
    • Silicone is prone to swelling if in contact with oil for a period of time.
Which probably means it will squeeze out even more over time, which is maybe why we find such a mess stripping a motor where it has been used.
 
Last edited:
ozcruiser said:
Does cosmetic sell MLS gaskets for commando engines. I’ve looked and found nothing.
Click to expand...
They will make any gasket you want.
I ordered a complete paper gasket set for the BSA A10 from eBay and had it sent to Cometic. Cometic cloned those gaskets in nitrile Al.
Now they have those shapes in their computer's program, future customers should be able to order any A10 gasket from them without providing patterns.
For the Commando , they definitely have some shapes as I purchased a MK3 primary gasket from them. I don't think they have all of the gasket shapes and for that reason I planned to send them an eBay paper set to copy. Then the Pandemic hit and cross border shipping became cost prohibitive. It still is, however the border will fully open on November 30.

Glen
 
Sometimes gasket thickness is critical with regards to internal tolerances etc. Are Cometic gaskets the same thickness as stock paper gaskets ?
 
SteveA said:
Just been to the workshop to locate the two tubes of Threebond I have, I seeuse 1184. It doesn't mention Silicone once on the box. It does say 'synthetic rubbers' and 'rubber like elastic substance'. From the 1184 spec sheet for those who did not follow the link:

Product Outline
TB1184 is a visco-elastic semi-drying sealer which is resistant to oil, water, gasoline and chemicals. Application areas
include sealing transmission case covers, motorcycle cases, timing chain cases, side covers, 2-piece cylinders, clutch
housing bolts and oil filter mounting surfaces. Since it excels in padding properties, it is highly effective in sealing
surfaces with poor flatness or large gaps. TB1184 is a development of the popular liquid gaskets TB1104 and
TB1194, and can be used as a direct replacement in all applications.
Features
• High padding property, excellent sealing effect.
• Excellent resistance to vibration and impact.
• Forms a semi-drying rubber-like elastic body.
• Maintains stable properties from -40°C to +150°C.
• Excellent resistance to water, oil and gasoline.
• Applicable for threaded joints as well as flanges.

I have stripped a motor built by someone with a silicone gasket fetish and agree that stuff gets everywhere and bungs up holes, It is horrendous.

Today I do not use products marked silicone on my bikes, except maybe polishes, not that I am a great user of polishes!!

I recall in the '70s using 'silicone gasket' on the cylinder base and seeing clear marks of the cylinders moving around! I haven't seen that with 1184.

I have never had a worrying experience with '1184' and like I said before I have only found it where I put it, no bunged up holes.

Race engines are stripped more than road bikes, and I haven't found the 'silicone gasket' problem.

It appears wrong to assume that any 'synthetic rubber' is silicone.

1184 specifically says resistant to oil, water, gasoline and chemicals, but further references for silicone suggest it should not be an ingredient in a product designed for use on engine cases, to quote 'silicone UK' regarding the ingredient 'silicone':
  • Poor Oil/Petroleum Resistance
    • Silicone is prone to swelling if in contact with oil for a period of time.
Which probably means it will squeeze out even more over time, which is maybe why we find such a mess stripping a motor where it has been used.
Click to expand...
I wonder why the sellers are advertising it as silicone. It certainly adds some confusion!
Added to that the Threebond 1211 and 1207, which are both listed as engine gasket makers, are labelled on the box as silicone.


Glen
 
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Fast Eddie said:
Sometimes gasket thickness is critical with regards to internal tolerances etc. Are Cometic gaskets the same thickness as stock paper gaskets ?
Click to expand...
Unlike paper sets, which come as they are, Cometic has a few options for thickness. We found one that works everywhere on the Vincent engine.
I forgot to mention, if you have ever ruined a paper gasket by accidentally tearing it, these gaskets do not tear.
The only downside I've found, aside from expense, is if the gasket needs trimming after installation it is a bit tedious. I use a very sharp wood chisel laid flat on the aluminum cases then pushed along.


Glen
 
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Schwany said:
"Ask 10 Norton folk and you’ll get 11 different answers…"

And if lucky the answers will still be about the same topic.
Click to expand...

Since the Chicago section of the Vincent club made the Cometic gaskets available to the worldwide club, there seems to be just the one answer now to the gasket question. At least from the crowd that has tried them!
I did try to let the old A10 boys know about the Cometic availability for their bikes, but the information was rejected soundly, as often happens on forums. " Our bikes don't leak a drop, why would we bother with this silly thing?"
Right, I'll move on.

Glen
 
worntorn said:
Since the Chicago section of the Vincent club made the Cometic gaskets available to the worldwide club, there seems to be just the one answer now to the gasket question. At least from the crowd that has tried them!
I did try to let the old A10 boys know about the Cometic availability for their bikes, but the information was rejected soundly, as often happens on forums. " Our bikes don't leak a drop, why would we bother with this silly thing?"
Right, I'll move on.

Glen
Click to expand...
I can't be a typical A10 owner!
Because I'm interested I have never been able to stop my rocker box base gasket leaking!!!
 
Give Cometic a call and be sure to tell them they should have all the A10 shapes saved on computer. The only gasket I did not get from them was the head gasket. With a pattern they will make those as well, but not in the Nitrile.


Glen
 
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Baz, I just talked with Cometic, will pm you the part number for the BSA rocker gasket.
Still working on the Norton items to sort out what shapes they already have and what is still needed.

Glen
 
worntorn said:
Since the Chicago section of the Vincent club made the Cometic gaskets available to the worldwide club, there seems to be just the one answer now to the gasket question. At least from the crowd that has tried them!
I did try to let the old A10 boys know about the Cometic availability for their bikes, but the information was rejected soundly, as often happens on forums. " Our bikes don't leak a drop, why would we bother with this silly thing?"
Right, I'll move on.

Glen
Click to expand...
My quote and observation had nothing to do with your information. It was about the way forums are in general. I thought what you mentioned was useful.
 
worntorn said:
Since the Chicago section of the Vincent club made the Cometic gaskets available to the worldwide club, there seems to be just the one answer now to the gasket question. At least from the crowd that has tried them!
I did try to let the old A10 boys know about the Cometic availability for their bikes, but the information was rejected soundly, as often happens on forums. " Our bikes don't leak a drop, why would we bother with this silly thing?"
Right, I'll move on.

Glen
Click to expand...
My comment was about the application, or not, of gasket goo to head gaskets…
 
worntorn said:
Unlike paper sets, which come as they are, Cometic has a few options for thickness. We found one that works everywhere on the Vincent engine.
I forgot to mention, if you have ever ruined a paper gasket by accidentally tearing it, these gaskets do not tear.
The only downside I've found, aside from expense, is if the gasket needs trimming after installation it is a bit tedious. I use a very sharp wood chisel laid flat on the aluminum cases then pushed along.


Glen
Click to expand...
I was thinking about Nortons, where the inner gearbox cover gasket is part of the required lay shaft end float equation. And the timing cover gasket governs intermediate gear end float and oil pump seal crush.
 
Yes, we have the same scenario with the Vincent timing cover. If the gasket is too thick then the oil doesn't flow where it should.
That's why the Cometics are offered in various thicknesses.

Glen
 
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