High temp head gasket sealer comparison

I ran some head gasket sealer tests months ago and showed a comparison. But it was missing the copper coat sealer and some people have asked me about it. So I bought the permatex high temp "copper spray a gasket" and some K&W brush on copper gasket sealer. Both copper sealers use copper powder as an ingredient. I made a temp test and found that the carrier (liquid) still breaks down at around 400 deg (Nort heads can get hotter than that when pushed). Between the two copper sealers I tested - I prefer the brush on K&W because it smoked less and seemed to adhere a tad better than the permatex spray up to 400F. Here's the whole list I've tested. I'm still rating pliobond at the top for its high temp adhesion and oil resistance qualities.

Pliobond darkens & hardens at 450 to 500F and loses integrity at 500 but still stays in place and when its cooled it remains adhered to the metal. Stays adhered at 400 deg.

Permatex copper spray a gasket high temp – starts smoking and loses adhesion at 400F but stays in place and is still adhered when cooled.

K&W Copper coat brush on gasket sealer – loses adhesion at 400F but stays in place and is still adhered when cooled.

Silicone sealer resists heat up to 500F, starts to fail by 550 and loses its adhesion. Did not harden but has mediocre oil resistance. Silicone leaked oil as a head gasket sealer.

Permatex “Ultra” silicone based oil resistant gasket maker lost adhesion at approx 500F and failed. Minimal hardening. Silicone leaked oil as a head gasket sealer.

“The right stuff” by permatex should have worked but leaked oil in a Norton as a head gasket sealer.

Gasgacinch Weldwood and Barge contact cements burned black & hardened before pliobond and lost their adhesion at lower temps around 400F.

Permatex motoseal 1 grey (same as popular Yamabond 4) bubbled at 400F and hardened but did not lose its adhesion. Became very brittle but was still adhered when cool.

Yamabond 5 (clear contact cement) bubbled at 400F burned black, became brittle and lost adhesion.

Permatex high tac turns to liquid, smokes and loses adhesion at about 350 F.

Silver paint gets soft and loses adhesion around 350F

Permatex formagasket started smoking & bubbling at 250 – 300F and failed.

Jim,
Have you tried Hylomar AF? Specs show it should be good to 600+ degrees..
Pete

Thanks Jim, for the experiments. It saves the rest of us a lot of trouble. Still looking for the best though.
Jaydee

Deets55 said:

Jim,
Have you tried Hylomar AF? Specs show it should be good to 600+ degrees..
Pete

Click to expand...

Halomar AF is rated up to 480F
If you have a near empty tube - send it and I'll test it.

But even if it holds up to the heat, it needs sufficient bond to prevent hot oil from worming between it and the metal. This is what happened with "the right stuff" because I didn't apply it to every surface. It was bonded to only one surface and the tension alone on the mating surface didn't do the job. Same applies to the other sealers. It should be applied to each surface for a head or the oil can seep through. So far the pliobond and the brush on copper coat are looking the best. Its not the copper powder that seals - its the gooey carrier or glue that squishes and flattens out when you tighten things up.

jseng1 said:

Deets55 said:

Jim,
Have you tried Hylomar AF? Specs show it should be good to 600+ degrees..
Pete

Click to expand...

Halomar AF is rated up to 480F
If you have a near empty tube - send it and I'll test it.

But even if it holds up to the heat, it needs sufficient bond to prevent hot oil from worming between it and the metal. This is what happened with "the right stuff" because I didn't apply it to every surface. It was bonded to only one surface and the tension alone on the mating surface didn't do the job. Same applies to the other sealers. It should be applied to each surface for a head or the oil can seep through. So far the pliobond and the brush on copper coat are looking the best. Its not the copper powder that seals - its the gooey carrier or glue that squishes and flattens out when you tighten things up.

Click to expand...

Jim,
I have never used the AF series myself, and never tried any Hylomar on a copper head gasket. I typically use Universal Blue which I believe is rated @ 480F when I need a sealer. It was just out of couriosity I checked the spec sheets on Hylomar and that is where I saw the AF formula was good to 600+F. I may have some Racing Blue home I can send you, I'll have to check when I get back. I'm pretty sure Racing Blue is the same as Universial Blue but is a thicker consistency. I didn't like it so I'm not sure if I tossed it or its somewhere on my work bench.if I come up with something I'll get it to you. Permatex dropped the Hylomar line so it is harder to get, especially anything other than Universal.
Pete

Does the pliobond act as a glue and make the head difficult to take off? Will it work with a flame ring head gasket?

seattle##gs said:

Does the pliobond act as a glue and make the head difficult to take off? Will it work with a flame ring head gasket?

Click to expand...

Pliobond is not going to glue the head on - that just doesn't happen and it always comes loose with the valve spring pressure on the pushrods. I think pliobond would be pointless on a flame ring but it might help it last longer. The flame ring can eventually fail. They are not hard and flat and so your head can warp a little with a flame ring.

It might be that the copper powder in the copper coat products acts like the rocks and sand in concrete.

That is the cement by itself is not very strong but when bolstered by the aggregate it gains great strength, especially in compression. I can imagine tiny pieces of copper getting a bite in the decks of the head and barrel on similarly taking a bite in the gasket.

That bite would help the carrier - the glue - deal with the pressure of combustion gasses and volatile fluids that are trying to push the gasket and its sealant out of the way.

If Hylomar really does have much higher temperature strength, then maybe a copper powder infused Hylomar?

Just as a follow up on Hylomar AF

I just went to the Hylomar web site. In the general info section below, it's listed as good to 250 C [482F]

http://hylomar.com/hylomar-product-rang ... compounds/

So I went to the documents section & found the technical data sheet. It also says 250C

http://hylomar.com/warrick/wp-content/u ... sion-6.pdf

Since it appears that the temperature range is the same as Universal Blue, perhaps he could test with the more commonly found Universal Blue?

Just wondering what temperature a non-race commando head gets up to. I use the permatex copper spray on a flame ring gasket. So far so good.

chaztuna said:

I just went to the Hylomar web site. In the general info section below, it's listed as good to 250 C [482F]

http://hylomar.com/hylomar-product-rang ... compounds/

So I went to the documents section & found the technical data sheet. It also says 250C

http://hylomar.com/warrick/wp-content/u ... sion-6.pdf

Since it appears that the temperature range is the same as Universal Blue, perhaps he could test with the more commonly found Universal Blue?

Click to expand...

I just dropped a couple of almost empty tubes of Universal Blue in the mail for Jim to test.

Pete

baldy said:

Just wondering what temperature a non-race commando head gets up to. I use the permatex copper spray on a flame ring gasket. So far so good.

Click to expand...

Normally around 300 to 400F in mild conditions. A 10 minute idle will get you over 400F in warm weather but it can get over 500F at the back of the head and cylinders when climbing a long hill.

Deets55 said:

Jim,
Have you tried Hylomar AF? Specs show it should be good to 600+ degrees..
Pete

Click to expand...

I have a friend who swears by Hylomar and uses it on copper gaskets on his racing K4 350 Hondas.

I have used Pliobond in my recent build, we will see, but it came highly recommended by Ken Kanaga, who has I think been a long term user.

SteveA said:

Deets55 said:

Jim,
Have you tried Hylomar AF? Specs show it should be good to 600+ degrees..
Pete

Click to expand...

I have a friend who swears by Hylomar and uses it on copper gaskets on his racing K4 350 Hondas.

I have used Pliobond in my recent build, we will see, but it came highly recommended by Ken Kanaga, who has I think been a long term user.

Click to expand...

The pliobond should bond to each surface to work (both sides of the copper gasket, the head and the cylinder.

jseng1 said:

SteveA said:

Deets55 said:

Jim,
Have you tried Hylomar AF? Specs show it should be good to 600+ degrees..
Pete

Click to expand...

I have a friend who swears by Hylomar and uses it on copper gaskets on his racing K4 350 Hondas.

I have used Pliobond in my recent build, we will see, but it came highly recommended by Ken Kanaga, who has I think been a long term user.

Click to expand...

The pliobond should bond to each surface to work (both sides of the copper gasket, the head and the cylinder.

Click to expand...

Yep, I used the 4 layers.

Deets55 and Steve A

I got the Halomar AF (thanks Pete & Steve), applied it to some aluminum beside some pliobond and let it set overnight. The Halomar went on gooey and has not dried or adhered to the aluminum. It was unchanged. Then I tried clamping it overnight. It's still as it came out of the tube - a thick viscous sticky liquid. How well does this perform as a sealer in extreme conditions? There are other similar sealers such as "tite seal" and liquid teflon pipe joint compounds. But with no adhesion to the metal I don't see how it keeps the hot oil from worming through. There must be some benefit with a high viscosity non drying paste or these sealers would be off the market but I don’t think they can equal a semi hard compound with excellent adhesion. The mating surface width between the pushrod tunnels and the front studs is only about 1/8" wide, its not much more between the tunnels and the bore (especially large bores) - this is the reason for using the .005" thick copper wire around the tunnels. I'm sure there is value to the non-drying paste and it may work for some but I think there are better options with higher 'blow out" resistance.

jseng1 said:

Deets55 and Steve A

There must be some benefit with a high viscosity non drying paste or these sealers would be off the market but I don’t think they can equal a semi hard compound with excellent adhesion. The mating surface width between the pushrod tunnels and the front studs is only about 1/8" wide, its not much more between the tunnels and the bore (especially large bores) - this is the reason for using the .005" thick copper wire around the tunnels. I'm sure there is value to the non-drying paste and it may work for some but I think there are better options with higher 'blow out" resistance.

Click to expand...

I agree. I am suspect of non-drying sealers in a high pressure application. Hylomar is great otherwise.

Slick

jseng1 said:

Deets55 and Steve A

I got the Halomar AF (thanks Pete), applied it to some aluminum beside some pliobond and let it set overnight. The Halomar went on gooey and has not dried or adhered to the aluminum. It was unchanged. Then I tried clamping it overnight. It's still as it came out of the tube - a thick viscous sticky liquid. How well does this perform as a sealer in extreme conditions? There are other similar sealers such as "tite seal" and liquid teflon pipe joint compounds. But with no adhesion to the metal I don't see how it keeps the hot oil from worming through. There must be some benefit with a high viscosity non drying paste or these sealers would be off the market but I don’t think they can equal a semi hard compound with excellent adhesion. The mating surface width between the pushrod tunnels and the front studs is only about 1/8" wide, its not much more between the tunnels and the bore (especially large bores) - this is the reason for using the .005" thick copper wire around the tunnels. I'm sure there is value to the non-drying paste and it may work for some but I think there are better options with higher 'blow out" resistance.

Click to expand...

Jim,
Have you tried Wellseal jointing compound yet? http://www.wellseal.co.uk/
I have used it with success on the crankcase halves and flame ring gasket as per Hemmings video. Using his instructions to leave it overnight to go tacky.
Good to hear all the comments.
Cheers,
Thomas

Thanks to Hobot who sent some Aerograde Hylomar to test. This stuff is semi drying and has adhesion where the Hylomar AF does not. I think the Aerograde would work better than the AF. The AF doesn't dry much at all but is unchanged to 500 deg F.

Aerograde Hylomar is semi hardening. It has some adhesion (not much) after drying and is good to about 450 deg F but looses adhesion around 500 deg and has poor adhesion compared to pliobond at all temps (loses all adhesion permanently at 500 deg).