Topic: Strip caulk (butyl) vs Rope caulk

[CharlesTurner]

It seems that there are 2 different strip caulk types that are made

The current 3M 8578 is most definitely a butyl-based material as it will stick/bond if strips are touched together.  It never dries out and is very "tacky"/"sticky" to work with.

The material that AMK sells in gray color is not butyl based, which after reading up on, is commonly referred to as "rope caulk".  It does not stick together with other strips, but can be kneaded together if desired.

What I have seen originally on at least 1st generation cars appears to have the consistency of rope sealer, not butyl. 

Throwing this out there for discussion.

Attaching a pic of some old-school 3M strip-calk[sic] - (3M name brand).  It appears this stuff is more like rope caulk.  It has hardened a bit over time, but becomes pliable with a heat gun.  I usually use a deep socket and roll it out flat to use.

[KevinK]

I have used both.  The rope caulk by 3m seems to resemble what was used at the factory for the front fenders and gas tank. I'm not sure about the color, black verses gray.

The butyl sealer is typically used on window installations such as the quarter windows on a Fox body. If it was used in place of the rope caulk in the first gen. Cars, it would be very difficult to remove those parts for service.  Basically, you need to cut the material to remove the part. Only comes in black I believe.

[CharlesTurner]

I have used both.  The rope caulk by 3m seems to resemble what was used at the factory for the front fenders and gas tank. I'm not sure about the color, black verses gray.

You're saying the 3M 8578 is rope caulk?  The current version, probably been in use for 10 or more years is butyl-based for sure.

[J_Speegle]

I have used both.  The rope caulk by 3m seems to resemble what was used at the factory for the front fenders and gas tank. I'm not sure about the color, black verses gray.

Ford service the stuff with a light gray in the 70-80's and since NOS was all the rage in early restoring of our cars many just accepted the color and assumed if it was NOS then it was correct and used it.  And things IMHO that lead some astray is that once exposed to the elements and sun the original product will turn a much lighter color as it chalks, dries out and becomes brittle.

[preaction]

Was the assembly line product used black in color ? I have seen this type (black) on restored cars.

[CharlesTurner]

Was the assembly line product used black in color ? I have seen this type (black) on restored cars.

Yes, but seems to turn dark gray with age.

[J_Speegle]

Was the assembly line product used black in color ? I have seen this type (black) on restored cars.

Yes IMHO

You will find it used at the rear quarter panel extension holes near the back edge of the quarter panel on 65-6, around quarter extension mounting nuts, fender to inner fenders, gas tank mounting and plenty of other places

[svo2scj]

http://i38.photobucket.com/albums/e136/svo2scj/100_3619.jpg

I figured if it turned white faster than the 35 years the first stuff took I would be ok !

Mark

[J_Speegle]

http://i38.photobucket.com/albums/e136/svo2scj/100_3619.jpg

I figured if it turned white faster than the 35 years the first stuff took I would be ok !

Mark

Yep that was the service replacement/NOS stuff they use to sell. Had a couple of rolls/boxes of the stuff. Just threw it away since I could not bring myself to selling it to some other restorer.

[CharlesTurner]

I bought a couple different styles recently.  The eastwood stuff seems to be too deep black in color.

As far as the 3M stuff.  I have been using it since the late 80's.  I know for a fact that it wasn't always the sticky messy type that it is now.  Maybe it was changed to that style in 2004 as indicated in the reply from 3M.  Regardless, I don't believe the current 3M style is correct at all in replicating what was on the cars originally.  It works and makes maybe 95% of folks happy, but if we're going for authenticity, it simply does not hit the mark.

As far as defining the term 'rope caulk', I don't know if it's just a generic term, but most definitions I have found say it is putty based.  https://en.wikipedia.org/wiki/Rope_caulk

The 3M stuff is most definitely butyl-based now, more like butyl cord or butyl tape.


Ford assembly manuals note ESB-M4G32-A, black sealer, .19" diameter

     Synthetic resin plastic sealer
          This sealer is specified for hand application and is applied in daubs or extruded beads or ribbons as required


SAE standards page for 'Synthetic resin plastic sealer':
http://standards.sae.org/j250_195905/

[markb0729]

Since there is mention of applications for the use of strip or rope caulk, would rope caulk be used at the factory for sealing between the 2 halfs of the heater box for the early 65 through 66 Mustangs?  I've read through several threads and the consensus seems that be that most use the 3M 8578 but I'm not 100% sure rope caulk was even used while putting together the heater box at the factory, makes sense though.  I'll be putting together my heater box soon.

[CharlesTurner]

Since there is mention of applications for the use of strip or rope caulk, would rope caulk be used at the factory for sealing between the 2 halfs of the heater box for the early 65 through 66 Mustangs?  I've read through several threads and the consensus seems that be that most use the 3M 8578 but I'm not 100% sure rope caulk was even used while putting together the heater box at the factory, makes sense though.  I'll be putting together my heater box soon.

I haven't found any type of caulking between the heater box halves on 65-68 cars.  Would be good to discuss in another thread.

[markb0729]

I haven't found any type of caulking between the heater box halves on 65-68 cars.  Would be good to discuss in another thread.

Good idea.  I'll start another thread later on.

[PerkinsRestoration]

Charles,

The Original Caulking Cord Ford used at the Dearborn Assembly Plant 68-73 was Ford Part # AB-19560-A dark gray. Like all NOS Ford parts the production date means everything. Note the AUTOLITE box in the picture. This tells us the item was made prior to 1972. The box SVO2SCJ  and Jeff reference is a totally different part # made years later. NOS parts produced within 5-10 years of vehicle production are identical to assembly line parts in nearly every application. NOS parts often get a bad rap by uneducated individuals who must believe all service parts were made in the 80's & 90's? Remember DAP assembly line parts and service parts all came thru the Wood Haven ( largest facility of its kind in the world) parts distribution center as the cars were built. All Dearborn Assy sheetmetal was primed at Wood Haven. Same fenders were shipped to DAP as service fenders wrapped in Ford paper to be shipped to dealers.  No difference from Ford service parts and assembly line parts when they left Wood Haven. Real date code correct nos Mustang parts are a rare find today ,however it does not mean real assembly line service parts are not still available. If and when Ford parts division made the call to make a new supply of say fenders rather than obsolete them often new tooling or upgrades to tooling resulted in parts that would work but not exactly to original assembly line specs. I laugh when I see experts say Ford never serviced a correct 69 or 1970 Parking parking lamp or back up lamp. They sold thousands in Autolite box's, but not in 2005.

[CharlesTurner]

Thanks Bob.  That stuff looks more like the consistency of rope caulk... in other words, not the sticky butyl stuff.

Do you agree with me that the butyl style strip caulk was not used for 1st generation cars?  I haven't found any original that was gooey and sticky.