How do you seal joints?

[Bob Wild]

I have just finished the water pump for my Merryweather Fire King. This the first working engine I have made, so I have no experience in sealing the joints. There are flat surfaces, screwed parts and some glands.
What’s the best way to do this? What should you pack the glands with? I have some fibre paper, Hylomar Blue and ptfe tape.
Bob

 

[dnalot]

When I saw the header I thought that's easy, you just twist the ends. But then I read the full question and I could see I had jumped to a wrong conclusion. For flat surfaces paper gasket material that is rated for water. The packing for glands I use waxed heavy sewing thread.

Mark T

 

[ShopShoe]

dnalot,

Your post above raises a question: "..waxed heavy sewing thread" Would dental floss work?

--ShopShoe

 

[Charles Lamont]

Thick brown paper is good enough for steam gaskets so it ought to be OK for water. If the flat surfaces are flat enough you don't need a gasket. I have tried Hylomar but have recently learned about Wellseal, which I find a lot better for metal to metal joints. As you are in the UK, most model engineering suppliers have graphited yarn gland packing for steam, and ptfe packing which would probably be better for the pump gland. For screwed joints Wellseal, or one of the white jointing compounds such as Hawk or Boss. I would put the ptfe tape back in the domestic plumbing drawer.

 

[dnalot]

For sealing close fitting parts I use Honda Bond. For waxing a string use bee wax in paste form.

Mark T

 

[rleete]

Indian Head Gasket Shellac is the best thing for sealing two flat metal surfaces. I've been using it for decades on all sorts of cars and trucks, and it has never failed me.

 

[dnalot]

Your post above raises a question: "..waxed heavy sewing thread" Would dental floss work?

I would think so, but I would check to see if it might have an abrasive in the wax

Mark T

 

[johwen]

Yes, Head gasket shellac is the best for sealing flat machined surfaces and if you have to dismantle at anytime meth spirits will clean the surfaces easily. For glands I use cotton threads and graphite grease seals well and lasts well.

 

[johnmcc69]

"When I saw the header I thought that's easy, you just twist the ends."
I had to go back & read the header to see what you meant!
Hilarious!

 

[petertha]

Indian Head Gasket Shellac is the best thing for sealing two flat metal surfaces. I've been using it for decades on all sorts of cars and trucks, and it has never failed me.

The issue I'm having with most all the type squeeze tube gasket maker RTV/silicone 'pastes' is they stick too good on small parts typical of model scale. They seal fine & easily bridge any surface irregularities, but when I try to remove them it requires force or edge prying leverage, I'm afraid of distorting or chowdering up the part I spent a long time making. Is this shellac any different in this regard, like a weaker bond?

 

[mcostello]

Indian Head is good stuff, Permatex #2 is also good and a little easier to find. Both need alcohol for clean up.

 

[ICEpeter]

The issue I'm having with most all the type squeeze tube gasket maker RTV/silicone 'pastes' is they stick too good on small parts typical of model scale. They seal fine & easily bridge any surface irregularities, but when I try to remove them it requires force or edge prying leverage, I'm afraid of distorting or chowdering up the part I spent a long time making. Is this shellac any different in this regard, like a weaker bond?

Petertha,
I have used Teflon film of 0.005 thickness in two variations of the available films, purchased from Mc Master Carr. The plain 0.005 inch Teflon film I had laser cut for use in high temperature (Up to 500 degree F) application for head gasket and manifold uses.
The other film of 0.005 inch thickness was adhesive coated on one side and good for applications up to 250 degree F - I guess the temperature limitation here was / is the adhesive, not the Teflon film itself. I used it for sealing the oil pan / timing gear cover, etc. that will see lower temperatures.
The reason why I used the adhesive backed Teflon film in certain locations was the elimination for laser cutting since I could cut around the outside / inside contours cleanly with a sharp pointed knife.
I chose this approach because A) it sealed well and B) comes apart without he need of force to pry it apart and C) the joint doesn't ooze inside / and outside the joints and D) it is a very thin gasket / sealer equivalent to the gap thickness stated on the data sheet for Hylomar and similar compounds.

 

[Bob Wild]

Fascinating replies. I think I know what to do now. We shall see

Bob

 

[Sprocket]

Indian Head is good stuff, Permatex #2 is also good and a little easier to find. Both need alcohol for clean up.

I had used Permatex #2 before and really liked it. I needed more, and the only one in the display was #1. Didn't realize there was more than one kind.
#1 is AWFUL ! The #2 is silicone and works quite well, although this new tube doesn't seem quite like the old stuff, but the old one is too dried out to compare .
Doug

 

[petertha]

Petertha, I have used Teflon film of 0.005 thickness in two variations of the available films...

Thanks ICEpeter. I've heard nothing but good results with Teflon, so I think that's the way I'll go too. I have the CAD-ability, its just a matter of finding a cutting service. And as you say, so excess ooze where it doesn't belong.

 

[GrahamJTaylor49]

Thick brown paper is good enough for steam gaskets so it ought to be OK for water. If the flat surfaces are flat enough you don't need a gasket. I have tried Hylomar but have recently learned about Wellseal, which I find a lot better for metal to metal joints. As you are in the UK, most model engineering suppliers have graphited yarn gland packing for steam, and ptfe packing which would probably be better for the pump gland. For screwed joints Wellseal, or one of the white jointing compounds such as Hawk or Boss. I would put the ptfe tape back in the domestic plumbing drawer.

I have been installing compressed air systems in workshops and factories for the last 50 years. I purchase PTFE tape by the thousand rolls at a time. Try the thicker tape that is supplied by BSS and is recommended for gas systems. Boss white and hemp went out with the ark and is an absolute liability when it has to be taken apart. For gasket material I have used thicker brown paper and if the job calls for metal to metal joints I have always used Hylomar. It used to be supplied by Rolls Royce for use on their gas turbines and as a non setting compound it has no peers.
I have used PTFE tape on pipework up to 3" and have never had a problem, having said that I am over 70 and the idea of lifting 6.5 mtr lengths of 2" galvenized pie fills me with horror so I have gone over to using aluminium pipe and in over 12 factory installations I have had NO leaks and the system is so easy to modify. The pipe system that I now use is Prevost and it works superbly. Not as cheap as galvanized steel but the time needed to install is less than 30% compared to steel.

 

[goldstar31]

Digressing somewhat. I swear by PTFE clothing.☺ Helped to save me life-- but that is another story.

Again, I like silicone sealants. I had an old associate who used who sealed things like rusted silencers on his old car. I/we had a place at 1600 meters in the Haute Savoie in France and the fridge was 'mended' with the stuff. No , I did not do it but it was the French before my purchase. Again, I ha Spanish property( my wife and I used to 'collect' properties and I used it for lots of jobs especially when Spain had this infamous one pipe system of disposing of our sewage. Fresh water through the pipes by day and our sewage by night( or so it seemed) My wife- sadly not with us any more) cured the problem and planted a date palm in our septic tank. It grew like a Triffid
Then the local farmer- the Spanish equivalent of the Gully Gully man used to pump out the tnks and spread the stuff on his fields of tomatoes.
And yes, his old suction pipes were mended with silicone sealant.
Our Gore-tex clothing? Another day perhaps!

Norman

 

[Andy Munns]

Was advised many years ago as last resort for warped block was to use the sludge at the bottom of an old tin of Silverfrost that had Sat on shelf for a long time. Must not mix in the thinner liquid on top. Also let surfaces together without sliding.

 

[petertha]

Just wondering if anyone has used teflon (PTFE) sheet like this for high temp gasket material? The thickness is 0.1mm (0.004") which meets my requirements. Its something I could obtain & hand over to a local decal cutting shop. They told me their machine uses a laser so I image should be able to cut them.

https://www.amazon.ca/Transfers-Resistant-Protects-Thickness-×1000mm/dp/B078N3WN32

 

[10K Pete]

I had used Permatex #2 before and really liked it. I needed more, and the only one in the display was #1. Didn't realize there was more than one kind.
#1 is AWFUL ! The #2 is silicone and works quite well, although this new tube doesn't seem quite like the old stuff, but the old one is too dried out to compare .
Doug

Permatex #1 and #2 and Aviation-Form-A-Gasket are shellac based and contain no silicone. None. They've been around since air was new and way before silicon.

Pete