Hi temp gasket sealer

[OwnyTony]

This is not ducati related but is a tech question.  My brother just bought an aftermarket exhaust kit for his wrx.  The thing is, his manifold is connected in the middle similarly in the way our midpipe connect to the headers.  On our headers, it bulges out and is sealed by a ring metal gasket and slides into the midpipe.  My brother's pipes slide in but there is no bulge and no gasket. 

What I was wondering is how hot does exhaust gases get? Reason for me asking is that there are hi temp gasket seals that range from -50 to 600f. 

Do you think sealing the connecting pieces would be adequate?

Thanks in advance guys.

[CDawg]

I few folks have used this to good success on exhausts:
http://www.permatex.com/products/Automotive/automotive_gasketing/gasket_makers/auto_Permatex_Ultra_Copper_Maximum_Temperature_RTV_Silicone_Gasket_Maker.htm

[OverCaffeinated]

I know that some high performance diesels can hit egts of 1600F, and I'm pretty sure a turbo charged subaru can hit at least 1000F. As linked by CDawg the copper permatex does say it could be used on exhaust manifolds up to 700F. Will it work for you? Maybe. I think it depends on how big of a gap your trying to fill. It almost sounds like there might be some missing piece to the wrx kit.

[OwnyTony]

it fits pretty snug, just not snug enough for me.  Im thinking about some U-bolts to clamp them to get a nice seal.  The heat should cause the pipes to expand thus creating a tighter seal around the clamps.

[OverCaffeinated]

I was thinking major gaps. But if it's already snug and your using a gasket maker for extra measure, then I think you'll be okay, imo.

[OwnyTony]

Its "snug", just think about putting on the midpipe to the headers without a gasket.  It fits on there pretty snug, but there is gas leaking out.  I think I will seal it with the copper sealer and get a clamp