Topic: Hondabond 4 or Hondabond HT

[eigenvector]

What the heck is the difference between the two?  The application for either is generic enough that it doesn't seem like there's any real difference.

So the question - what are their intended uses?  Let's completely take what I'm trying to do out of the equation - I'd like to know what they're supposed to be used for.

[RAFster122s]

The HondaBond HT is a +75 to +600 degree F non-hardening gasket material with similar properties to Hondabond 4.  Main difference for HT version is the temp rating and it is a silicone that will not attack your aluminum like the acetic acid typically in a silicone gasket material.  Should not use HT version on copper either.  Both are good for ensuring gaskets seal if there are any scars on sealing surface and they handle contact with water, coolant, gas and oil and most chemicals. Both also hold up to vibration and pressure very well and unlike typical silicone gasket material it will not have a piece break off clogging an oil passage and then engine failure.  Not sure about brake fluid but it is likely to be capable of handling it as well.
Either can be used for your cases since the SOHC4s do not use a gasket at that location and they are also good for other areas where a gasket is not needed and fluids need to be retained.  It works very well on the valve cover oring seal and is not a major project cleaning the groove like typical gasket material good be.  As you know for the non-gasket seal areas such as a case it only takes a extremely thin coating of the material to seal.
By contrast the Hondabond 4 is better suited to lower temps seen away from the head surfaces near the cylinders or exhaust, it will not stand up to exhaust temps of course, or not for very long. Hondabond 4 is good for surfaces seeing +40F to +300F. 

I typically follow HondaMan's and other's recommendations  (such as Branden's guide for a leak free head) to not use this on an entire head gasket as it would interfer with proper sealing by the head gasket.  It is/would be suitable for around pucks and orings for dowels and oil o-rings as long as it is used sparingly and you will not clog an orifice tube or oil passage into the head.

[eigenvector]

Thank you.

Since this will be to join the crankcase halves - I'm still on the fence as to whether 4 or HT would be preferred, but given the proximity to the oil pan I think HT would be more appropriate as the temps would likely be close to the limits of what Hondabond 4 could withstand.

[eigenvector]

Last question (for now...)

Would it be a good idea to degrease the mating surfaces prior to application?

I don't mean 'wipe down with blue shop towel' I mean - brake cleaner/MEK kind of clean.

[CycleRanger]

Last question (for now...)

Would it be a good idea to degrease the mating surfaces prior to application?

I don't mean 'wipe down with blue shop towel' I mean - brake cleaner/MEK kind of clean.

I usually use acetone, most brake cleaner is mostly acetone anyway.
I try to avoid MEK, it's pretty nasty stuff and kind of overkill for simple degreasing.

[eigenvector]

Degrease it I will.