I have read two different ways to install the rear window on a 76'. One says to put the butyl tape on the body first and then put the glass next. The other says to place the tape on the glass first and then stick the glass to the body. I was wondering if anyone else has installed theirs and witch way they did theirs? I'm getting ready to install mine.
Thanks for the help.
Larry

 

I reto fit a removable window in my 76 but I would put the tape on the body.

 

Thanks Greg for the help, I guess that will be the way I will do it. Thanks again.
Larry

 

For what it is worth,

I apply the butyl tape to the body VERY CAREFULLY...making sure you DO NOT touch the contact surfaces where it goes on the body and where the glass touches. If you have to move it ..you have to do it from the sides ....carefully.

I can say...you might want to be in the CORRECT frame of mind when applying the butyl tape...because if you want it to look clean and even from the outside when completed...it can be a bit 'test of wills'.

AND....hopefully you are using the correct butyl primer so the butyl tape will stick to the body. And..I prefer to use the 5/16 butyl tape.

DUB

 

Thanks Dub Yes I'm little worried about installing the tape. I have ordered 3m general purpose adhesive cleaner, and window weld primer from what I have read it is the product to use,or a least I sure hope so. I hope I have a good steady hand, from what I have read is that you have one shot at it. I see you on here all the time and value your opinion.
Thanks again.
Larry

 

Larry,

VERIFY with 3M that teh primer you have is the correct primer to apply on the body for the butyl tape. I had to get the primer from another company due to when I looked a long time ago...3M discontinued it. That may have changed since then.

DUB

 

Yes Dub when I typed in window weld primer it came up on the bottle as one step primer. The tape i got from Dr. Rebuild there is no paper work with it as what to use. I may need to call dr. rebuild and check with them.
Thanks again Dub
Larry

 

I doubt Dr.Rebuild will know...they may...but I would call 3M to make sure the primer you have is for butyl tape. I hate to keep 'harping' on this...but it is important. If the primer you have TRULY is for butyl tape...then please excuse my tenacity.

DUB

 

Will do
Thanks Dub
Larry

 

I would think carefully putting the adhesive strip on the body just where you want it would be better than on the window first because it will be in the right place for sure that way. Window first might end up with the adhesive uneven around the body and not look as good.

 

minitech: That is the only thing I could think of the reason would be by putting the tape on the body first. But one stated put the tape on the glass first and that was my concern was the tape might not meet the body lines wright. But sometimes the obvious way is not the wright way. But in this case it is.
Thanks
Larry

 

I did not mean to communicate that NOT using a primer is what I do. I DO USE the correct butyl primer on the body flange AFTER i clean it. This is a WISE step to make sure the butyl will stick to the primer.

I know many who apply the butyl tape directly to the body with NO primer and I also see them dealing with the it coming loose.

AND I have done tests....cleaning the body flange and taking section of the butyl tape and lightly applying it...and also do the same thing on a section where the correct primer has been applied. AND I can tell you the instant that the butyl tape touches the primer... it sticks aggressively. The cleaned body flange with NO primer....well...lets say...it is NOT the same. I can peel the butly off rather easily.

DO as you wish.

DUB

 

I placed the butyl tape on the window first and then installed. I did this only after mocking up the window in the opening and then running masking tape on the window, showing where it meets the body. I did it this way because it is a LOT easier to get the butyl straight and well positioned on a bench than scrunched in the back of the car. DUB is right, that the neatness of this line is important when outside the car.

The instructions I used:

I did my 73 about 3 months ago with kit purchased from Zip.

Step 1 removed rear glass by cutting the old sealant with a razor knife. I used one of the knives with about a 3/8" blade that could be extended as much as 6" purchased at lowes cheap. Pick up extra blades. Also had helper inside car to catch glass when it released

Step 2 clean clean clean & clean again glass & frame with 3M weatherstrip release agent or an alternate paint friendly cleaner

Step 3 mask off the glass leaving a 3/8" to 1/2" edge exposed all the way around the edge. Then mask off the body window frame to prevent getting the butyl primer where you don't want it. The primer is not paint friendly so do a good masking job.

Step 4 apply butyl primer to window & window frame. Once complete remove masking tape

Step 5 apply butyl seal to glass. You want the ends of the butyl seal to meet at the top of the glass in the center.

Step 6 make sure the rubber spacers are in place. I used contact cement to hold them in place. I used a grease pen to mark the center of the glass & the center of the frame for a reference point.

Step 7 helps to have a helper at this point but I did mine by myself. Lay the glass into the frame aligning your center marks. I sat the bottom of the glass on the rubber spacers & then tilted it up into the frame. Press along the edges of the glass compressing the butyl sealant to approximately half it's original thickness to ensure a good seal.


The primer I used is CRL 1106 Pinchweld Primer for butyl tape

 

Thanks Dub and Tom I guess I will use the primer. I was not sure what to do from the information I got. I could not see where not using the primer was a good thing. But the information I got from the corvette shop had me messed up on which to go. When the primer gets here I will read the instructions on the bottle to see if it is to be used on butyl tape. The problem I have google primer to use on butyl tape and have not found the answer and the primer I ordered did not say anything whether it was for butyl or not. This has become a pain in the you know what.
Thanks again guys
Larry

 

C.R. Laurence is the company that produces much of the butyl productshttps://www.crlaurence.com/ Many internet sites distribute their products. The product # of their primer is 1106

 

The only reason I apply the butyl tape on the body is because I do not see that being that hard to do. Start a the top in the middle and go around the frame....and when the curves in the frame cause the liner on the butyl tape to not allow it to bend....I peel off the liner CAREFULLY and apply the butyl tape around the curves MAKING SURE that the liner is slowly pulled off AFTER I KNOW I have it where I want it. And by doing it this way...I can set the butyl tape where I want it for the 'visual' effect I am looking for.

NOW...I DO AGREE...it can be put on the glass...but for me....it takes too much time trying to get it 'just right'.

Two different way of doing it...that can be successful.

DUB

 

It can be put on poorly.

On one car I took off the window bezel to dye it a different color and with a few days in hot weather the window fell out!

Also whenever this type of window is out, going to be out, or needs to be changed the thought should be to move to a removable window option. Very easy to do, easier than putting a new window in. All of these cars have the same fiberglass cutouts for the removable window if you remove the window bezel.

 

I hate to disagree with you on this. There is NO WAY that putting in all what is needed for a removable rear window is EASIER than bonding in the factory stationary back glass. Not even close. AND the rear window areas are NOT all the same for the Corvettes with the vertical rear back glass.

AND..I have done enough removable factory rear windows that they can be a bit of a PAIN to keep from leaking a drop.

DUB

 

I suppose not easier for the new removable versus the new rubber seal of the glass. I just like the removable window and don't think it is that much of a job. As a DIY person it can be fun to do something like that and look forward to what you will have after the afternoons work when it is done and maybe that part made me think it was easier. For a real pro car rebuilder the comparison would be hour versus hours and it would take longer for the new removable window.