Silicon Beading not sticking on Head Gasket

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abuhafss

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Jan 8, 2012
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I need to create silicone beading on the surface of engine head gasket made of Asbestos or Non-Asbestos material. I have been trying to use liquified silicone rtv (adding xylene to silicone caulk) make the beading. After drying, the beading formed is perfect but its adhesion to the gasket surface is very poor. It can easily be removed with gentle rubbing of finger.

Can anybody guide me how to increase the adhesion of the liquified rtv silicone.

Thanks in advance.
 
I'm no chemist, but I can't figure out why you chose this product for your gasket repair.

One of the major attributes of RTV Silicone (not silicon) is it's ability to be easily separated from a mold.

I would think that if you installed the coated gasket soon after applying the silicone that it would cure in place and work just fine.  Let the compression of the mounting help to form the bond.
 
Why do you need to add silicon to your head gaskets? Felpro gaskets and others come ready to use. There is also a spray that is used for extra sealing, made by Felpro.
J
 
As an ex-auto mechanic, I am wondering why you would want to use ANY additional sealant onto a head gasket?  Head gaskets are subject to high pressure/temperature around combustion chambers, hot coolant under pressure, and oil passages.  They are designed to be used without any added sealant. 

Is there more to the story?
 
I'm curious too why you'd want to put silicone onto a sandwich gasket. Old style, metal only gaskets were often sealed with a shellac type sealer which was painted onto both sides. Occasionally with specific engines one might use a little permatex around certain water jacket holes. When the new sandwich (paper like material on each side with perforated metal middle) gaskets came out they were very vocal about not needing any additional sealants, because many old timers insisted that head gaskets needed sealer.

Now the thing that does come to mind is that perhaps you have a warped head that isn't sealing for some reason. The solution is to have it surfaced flat again at a machine shop. Another possibility is that you might be talking about an intake manifold or much more likely an exhaust manifold to head gasket. Warped exhaust manifolds are pretty common and silicone won't work there either. Again the solution is to surface the manifold and go again.

Please come back and tell us the problem, we might have a solution.

Ken
 
First of all, thanks all of you for responding.

I think, I could not put in my problem clearly. I am a small-scaled gasket manufacturer and  I need to increase my production range.

Some models have silicone beading (the red line as shown). I screen printed the thinned RTV silicone on the gasket. After drying the appearance and texture is fine but the adhesion with the gasket surface is very poor, a gentle rubbing with thumb would remove it.

Some models have thin silicone layer on gasket surface. I added more xylene and sprayed on gasket. After drying everything is fine but the same issue, it could be removed by rubbing thumb.

Any suggestions please......?
 

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A gasket is used to seal two surfaces,, why do think its necessary to add to that,, we've been with out silicon for a hundred years!!>>>Dan
 
utahclaimjumper said:
A gasket is used to seal two surfaces,, why do think its necessary to add to that,, we've been with out silicon for a hundred years!!>>>Dan

Just to follow the OEM style !!!
 
OK, now it makes much more sense. You aren't talking about head gaskets--cast iron, V-8 type stuff, you're talking about head gaskets--air and water cooled snowmachine, motorcycle, single cylinder lightweight stuff.

I suspect there is a secret to preparing the surface of the gasket material you are using. I have no expertise in this area. You've probably already tried to lightly scuff the surface or wipe with an alcohol or other solvent to allow the silicone to adhere? Those would be my thoughts.

It's possible that Sandi at Olsons Gaskets in Pt. Orchard WA might be willing to assist. I don't have a Hemmings with me, but he advertises there under Olson's Gaskets. He's been making and selling unique and obsolete gaskets for at least the last 38 years that I've known.

Good luck.

Ken
 
My range is not limited to small engines, I am also making V8 and 6 cyl. gaskets.

There is no special treatment to the surface of the gasket, I have seen Chinese manufacturers. I guess there is something additional with the RTV silicone and Xylene.
 
I echo Bucks2 last post.  I see your delema now. 

You mentioned no special treatment to gaskets before you get them.  How about whatever is used in the manufacturing of the gasket that is preventing a bonding surface for your process? 

Other than that, I can't help you either.  I just buy them, install them, and put a couple bucks in my pocket (or a case of adult beverage).  Good luck.
 
denmarc said:
I just buy them, install them, and put a couple bucks in my pocket (or a case of adult beverage).
Two things here...what adult beverage are you buying a case of for a couple of bucks and why would you want to put it in your pocket? ;D  Just askin'.
 
  Silicon adhesives can be" fast cured " using live STEAM,, I have a background with engineers whom produced the process for fast curing of silicon.>>>Dan
 
Molaker said:
Two things here...what adult beverage are you buying a case of for a couple of bucks and why would you want to put it in your pocket? ;D  Just askin'.

"couple of bucks" used loosely.  I don't give my time away.  But I remember my debts.

I did say a couple of bucks OR some adult beverage.  Truth is I have great neighbors at the homested and we help each other out with all kind of projects.  I just happen to be the auto mechanic of the bunch.  It's all good.

It sure is a great feeling knowing you have good neighbors around you.
 

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