metal prep window channel [Archive]

MARTINSR

May 26th, 02, 11:58 AM

I am right there with you ambitious, I am not a big "magic wand" product kind of guy. Though, I also have no experiance with Por in particular, it may be a wonderful product. I just feel the same REMOVE AS MUCH RUST AS POSSIBLE. But I don't like the metal preps like 224. It isn't a bad choice on exterior panels where you can nutralize it COMPLETELY. On an area like those channels the acid can get trapped in the nooks and crannies and NOT get nutralized! This acid WILL let you know it is there LATER. I use an etching primer called "vinyl wash" it is very thin and offers a vinyl coating. Any "wash" style primer will do similar (likd PPG's DX1791). It has the acid in the reducer and does the same job as the metal prep, only the acid flashes off and you don't have to worry about it. Then after the vinyl wash, a few coats of epoxy primer. This is the authorized way you do it on late model cars where the glass is an integral part of the unibody structure. I also don't believe in using ANY filler in the channel of ANY kind. There is no reason too, it will never be seen, right? The bottom surface where the butyl tape actually lays needs to be as smooth as possible, that is right. But I avoid using any filler at all costs, even there. I take a little angle grinder with a 3" 50 grit disc on it to cut some of the high spots off the area and leave it more even. NO, don't grind the metal thin, just run the grinder over the area holding it nice and flat a few times. You will not overly thin the metal. What you want to do is let the urethane sealer do the job of sealing the butyl tape IF there is a pit or something that could cause leakage. But I can tell you, that butyl tape WILL fill most low spots. One trick is to be sure it is good and warm. Do this AFTER it has been laid on the window or channel (what ever you choose). If you have that stuff warm before you roll it out, WOW it gets sticky and can be ruined very fast. By the way, when applying the butyl tape, roll it out leaving the paper on it, then after it is layed down and pressed a little to make a good contact, pull the paper up behind you as you roll it out. That way when you get to a corner, you can pull the paper up ahead of you and make the tape go around the corner. With the paper, you can't get it around the corner because the paper doesn't flex.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> I have done many of them with good success. Let me say that there are a few different ideas on things, these have worked very well for me. This instruction is starting after any rust repair, primer/paint. That would require MUCH more instructions. I'm assuming from your post you are past that.

First off get some 3M (or there are other brands) "pinch weld primer." It comes in a little 1/4 pint or so sized can and has a brush attached to the underside of the lid.

Before you install the clips be sure they are correct!!! You should start with either new ones or VERY nice old ones. When they are installed the top of the clip should be just a hair below the top of the pinchweld or body surface. I also recommend that you trial fit a piece of the molding to see if it fits correctly. This is time very well spent. If you find later that the clips are wrong, you will REALLY wish you did this trial fit.
You could even set the window in on some rubber blocks and install the mouldings to be sure it will all work well.

After you install the clips brush the pinchweld primer on the bottom of the pinchweld where the butyl tape is going to lay. Brush up around the clips good. The paint gets scratched when you slip the clips on to the studs and this primer will help protect it.

Next you want to set the window in the hole and find what rubber setting blocks you want to use. There are a few that come with the butyl tape kit and you set them different ways to make them higher or lower. Be sure that the window fits evenly all the way around. Run a piece of masking tape from on the glass out onto the body on the sides and the center of the top and bottom. Really only one should be needed but it helps to have more so you helper can see one well too. These tapes are then cut on the edge of the glass so you can remove the window again. Just leave the tape on the window and the body for alignment purposes.

Be sure the window is clean and free of residue of any kind. With it lying on its back, put the butyl tape on the edge of the glass without hanging off. Roll it out and as you go you can pull the paper off it so that way when you come to a corner you can get around it. If the paper is on, you can't get around the corner. But you want the paper on as you are going down the tops and sides to help you get it straight and so you don't touch it. At the point where they meet, run one next to the other and at the point they pass, cut it with a NEW razor blade. Then DON'T touch the tape, using the razor push it, blending it together. Most guys will tell you to make this joint at a certain spot like on the side or at the bottom. I really don’t think it matters as far as leaking, if it is done incorrectly it WILL leak, what does it matter where it leaks? The point is, do it properly and it won’t leak. I like to look at where it will be the least seen. On the sides it is usually seen and looks like hell. I usually make this splice at the bottom, it seems to be the most hidden spot. You can get the butyl tape in ¼”, 5/16” and 3/8” in diameter. I have found that the 5/16” is the most common with ¼” being used in late model cars on the quarter windows. The 3/8” is rarely used and can really get you in trouble. If you set the glass with the 3/8” you may find that it is impossible to install the mouldings because the glass is too high! The ¼” squashes down to about 5/32 or 3/16” the 5/16 goes down to about ¼ or 7/32” and the 3/8 ends up at about 5/16”.

NOTE! I have been told that some of the new windshields are thinner glass and the 3/8" buytl tape is needed to set the glass. It raises the glass up to make up for this. So, check with a good trial fit first!

Then with your helper set the glass in using the masking tape as a guide. DON'T LET IT TOUCH till you have it where you want it. YOU WON'T HAVE A SECOND CHANCE the butyl tape sticks RIGHT NOW and will not let go. If you have the glass a little over or up or down too much you can move it a LITTLE after the glass is lying in. Before you push on the top of the glass, using a plastic setting tool or even a piece of wood you can wedge it into the pinch weld channel and pry the window over, VERY carefully. At this time it is best to get it warm. If you can get it in the sun and warm up the glass and butyl tape and push on the top of the glass to get a good seal all the way around.

Now comes the real important part, sealing. First let me say that I have done many windows and used NO sealer what so ever. The Butyl tape alone should be sealing enough. But as an added "safety net" I do the following.

I take a plastic "bondo" spreader and cut it to about a half inch in width. I also round the corners with the razor nice and clean. Using a high quality urethane sealant I put a little strip right on the side of the glass edge or on the butyl tape it's self. Using the spreader I spread it down the side of the glass over the butyl tape to the bottom of the pinch weld, forming a seal from the top to the bottom vertically. DO NOT PUT THE SEALER ALL OVER THE CLIPS OR FILL THE CHANNEL this is a DEATH sentence to you job.

If you do this and you and see the seal has been made from the top edge of the glass down to the bottom, you know it will never leak. When water gets in there, it will be able to evaporate. If you fill the channel with sealant, the water gets in and can't get out!

You now can put the mouldings on and off at your leisure. If your moulding is giving you trouble and not clicking into place on the clip. You can take a rubber squeegee and place it on top of the moulding and then a small block of wood and tap; JUST tap lightly on top and you can get even the most stubborn moulding on. But if you trial fit them and didn't put sealant all over them this shouldn't be needed.

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1965 Buick Gran Sport Convertible
1965 Buick Skylark H/T
"Fan of most anything that moves human beings"