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Stonwwalljac, The HB glues I was mentioning that we have here are somewhat thick and set up fast and stay elastic. The question would be, heat. Silicone is about twice as viscus as the HB 45 and about 10 time more viscus than the HD Direct. I am in no way saying that one of these products is better, I was just wondering. It sounds like the method you described does more than just using an adhesive, as it also aligns the glass to the channel, which as you pointed out, any kind of glue would not necessarily do.
I do like these food for thought discussions, and thanks for taking the time to share your thought and experience. At the end of the day, it's the experience that likely maters the most.
Another idea would be to machine a new channel from aluminum billet with a straight sided glue channel. instead of the original spring steel channel. But would make the whole thing pricy.
The problem you may run into with replacement glass is that it is made overseas and is a nominal 6MM thick .230-.240 more or less. The original Carlite glass is .185-.190 thick. Also, it is tempered so even a little hit on the edge, and it will explode into a thousand pieces. You need to measure the width of the channel and subtract the width of the glass. It needs to be a tight fit using glass setting tape. I clamp everything to a table and use two bar clamps to force the glass into the channel. You can use whatever you want to lube it Windex. WD-40, Kero etc. but it has to be a tight fit.
I will post pics and measurements as I can get them. Probably won't be back on this until the weekend. I have some setting tape en route that ought to be here by Saturday.
Good discussion and info being shared! I appreciate all of it.
The problem you may run into with replacement glass is that it is made overseas and is a nominal 6MM thick .230-.240 more or less. The original Carlite glass is .185-.190 thick. Also, it is tempered so even a little hit on the edge, and it will explode into a thousand pieces. You need to measure the width of the channel and subtract the width of the glass. It needs to be a tight fit using glass setting tape. I clamp everything to a table and use two bar clamps to force the glass into the channel. You can use whatever you want to lube it Windex. WD-40, Kero etc. but it has to be a tight fit.
Very true. the clamps work well if you have them. The glass is tough if handled properly, no sharp licks to the edge of it for sure. I always make sure I have ample padding to the edge. It is not a difficult task, it is just a matter of getting set up to do it. You have a good system there.
Another idea would be to machine a new channel from aluminum billet with a straight sided glue channel. instead of the original spring steel channel. But would make the whole thing pricy.
Again, I am learning something new.... I have been reading in this discussion, the term spring steel. When I think of spring steel, I first think of steel coil springs that are much harder to cut. After that, I envision some spring type of form, such as a leaf spring or spring tabs of some kind. So now, I have to ask, since I am purely in this discussion from the informative point of view, and have yet to actually put my hands on, or even put my eyes on the actual parts we are referring to, what makes the glass channel "spring steel", rather than just a stamped steel piece with a profile to hold the glass? Does this channel have some "springy" form that is intended to better maintain some tension on the glass edge thus better hold the glass in place?
I realise at this point this is likely no longer helpful to 67charger and I apologise if I have highjacked the thread, it's just that I have some vague memory of glass slipping out of the channel of my old BMW E3 thirty years ago. If memory serves, there were only two points of contact with a small rubber spacer that were intended to "grip" the glass into the channel and hold it in place. I can remember doing a repair, but also remember that it failed to stay in place after some time, what I do not remember is if double sided tape was involved, and if the failure was the tape, or not enough pressure from the channel itself. My only other experience was on a series one LR Discovery, where I had to get creative to fabricate a new plastic roller bearing for the arm that carried the glass and channel up and down...but I don't think that I even looked at how that glass was attached to the channel.
If memory serves, the windows in my '66 have some play in them as I roll them up and down (Lucy, my beloved '66 is 5k miles away from me right now and it still might be some time before I can be reunited with the old girl). I am not sure if that is due to movement in the channel or just 60 year old glass guides that are way beyond their intended lifespan. The glass guides I can see, and they need to be replaced, so that is on the agenda. But this discussion is relevant in my mind because, I am wondering if it might be good idea to do a visual on the glass channel to hopefully avoid any possible risk if the glass coming out of the channel and getting broken as a result.
Again, Thanks for input and thoughts, also, Crop Duster, thanks for the photo reference to the jig you built, from that, you can also envision how the ratchet straps would help as a technique previously mentioned.
OEM glass is 0.193
AMD glass is 0.230
OEM setting tape 0.083 (uncompressed, exposed, dried up)
OEM total in channel: 0.359 minus compression
0.359 minus 0.230 is 0.129, divided by 2 is 0.0645.
1/16 (0.0625) tape ought to be perfect, or at least close enough. The thicker glass may be tight in the tracks, though. We'll see.
I ended up using 5/64 tape to get a tight fit but 1/16 might work for you. If you have new door glass runs the thicker glass is a snug fit but works just fine as long as the glass is a tight fit in the lift channel.
Again, I am learning something new.... I have been reading in this discussion, the term spring steel. When I think of spring steel, I first think of steel coil springs that are much harder to cut. After that, I envision some spring type of form, such as a leaf spring or spring tabs of some kind. So now, I have to ask, since I am purely in this discussion from the informative point of view, and have yet to actually put my hands on, or even put my eyes on the actual parts we are referring to, what makes the glass channel "spring steel", rather than just a stamped steel piece with a profile to hold the glass? Does this channel have some "springy" form that is intended to better maintain some tension on the glass edge thus better hold the glass in place?
I realise at this point this is likely no longer helpful to 67charger and I apologise if I have highjacked the thread, it's just that I have some vague memory of glass slipping out of the channel of my old BMW E3 thirty years ago. If memory serves, there were only two points of contact with a small rubber spacer that were intended to "grip" the glass into the channel and hold it in place. I can remember doing a repair, but also remember that it failed to stay in place after some time, what I do not remember is if double sided tape was involved, and if the failure was the tape, or not enough pressure from the channel itself. My only other experience was on a series one LR Discovery, where I had to get creative to fabricate a new plastic roller bearing for the arm that carried the glass and channel up and down...but I don't think that I even looked at how that glass was attached to the channel. It is slight, but there.
If memory serves, the windows in my '66 have some play in them as I roll them up and down (Lucy, my beloved '66 is 5k miles away from me right now and it still might be some time before I can be reunited with the old girl). I am not sure if that is due to movement in the channel or just 60 year old glass guides that are way beyond their intended lifespan. The glass guides I can see, and they need to be replaced, so that is on the agenda. But this discussion is relevant in my mind because, I am wondering if it might be good idea to do a visual on the glass channel to hopefully avoid any possible risk if the glass coming out of the channel and getting broken as a result.
Again, Thanks for input and thoughts, also, Crop Duster, thanks for the photo reference to the jig you built, from that, you can also envision how the ratchet straps would help as a technique previously mentioned.
When looking at the glass / tape channel grove. it pinches in at the top slightly (spring steel) so that when you insert the glass with tape applied it force it open. when the glass is seated the tape and the sidewall of the channel will be straight at this point, making full contact with the glass and the tape channel. This little bit of extra pinch adds to the gripping power of the tape on the glass.
Last edited by stonewalljac; Sep 30, 2025 at 10:59 AM.
That's not spring steel just stamped mild steel. It's formed to grip the glass with setting tape and sometimes has a slight pinch or taper. It's not heat-treated or alloyed to meet spring steel specs. Spring steel is high-carbon or alloy steel that's been heat treated to retain elasticity and return to shape - used in coil springs, leaf springs and retaining clips as examples. It's much harder to machine or bend and you wouldn't want it in a lift channel because it would fight the glass fitment and be prone to cracking under stress.
That's not spring steel just stamped mild steel. It's formed to grip the glass with setting tape and sometimes has a slight pinch or taper. It's not heat-treated or alloyed to meet spring steel specs. Spring steel is high-carbon or alloy steel that's been heat treated to retain elasticity and return to shape - used in coil springs, leaf springs and retaining clips as examples. It's much harder to machine or bend and you wouldn't want it in a lift channel because it would fight the glass fitment and be prone to cracking under stress.
You're picking at hairs. Your definition is correct, but the fact is the channel does have a degree of elasticity / spring action on the sides of a good channel. worn tracks may not show this, but good ones will. They had to temper that edge slightly or it would be too soft to grip the tape. we are talking about tthin sheet metal. if made of standard sheet it would bend to easy and not hold its shape. So I disagree with you on this one. If you have proof that the metallurgy has not been tempered, (and they would have done this after forming the metal into shape) I will then agree, but having worked with metal for years I know what I am talking about.
Some channels have a slight pinch or flex at the top to help grip the glass - this can feel “springy” when inserting the glass with tape. That tactile feedback might lead someone to casually call it “spring steel,” but it’s not metallurgically accurate. Simply tempering metal does not make it spring steel. Just being accurate not picking hairs. I don't have enough left to pick! I wind springs for people and have sold several here to forum members - brake springs and latch springs to name two.
What you are seeing is formed tension not metallurgical elasticity.
While we're on the subject of door glass replacement....
I had to purchase a replacement channel because my original piece was corroded along the edge. The replacement piece does not come with the elongated protrusions at both ends. I assume these were omitted for ease of fabrication and cost cutting reasons. I'm guessing they help to keep the glass aligned within the window track. Is it worth the effort to tack weld them to the new channel or does the window function okay without them?
Additionally, the tape I ordered from LMC appears to have two sides to it: a black side and a colored thin skin plastic-like side, does it matter what orientation I use when applying it within the channel?
Thanks so much for all the information gleaned within this post.
Some channels have a slight pinch or flex at the top to help grip the glass - this can feel “springy” when inserting the glass with tape. That tactile feedback might lead someone to casually call it “spring steel,” but it’s not metallurgically accurate. Simply tempering metal does not make it spring steel. Just being accurate not picking hairs. I don't have enough left to pick! I wind springs for people and have sold several here to forum members - brake springs and latch springs to name two.
What you are seeing is formed tension not metallurgical elasticity.
Tempering is tempering. If you were to take a piece of standard sheet, and form it into the same shape as the window channel, and you pressed onto a glass with tape, it would slide in with little effort. it would also slide out with little effort. any side loading from the regulator lifting action would bend it open the channel and lose the glass. If you want to say it is not spring steel, I will bow to that, It is tempered to retain its form., which is slightly pinched in at the top. Without Rockwell testing the hardness of it, I would not know to what extent it was tempered or annealed. I would suspect that it was run through an oven and then cooled. before being cadmium plated. Hennery would have done it the cheapest way possible.
@stonewalljac was asked a question by @The Dassler if it was really spring steel. I suppose I should have addressed my response directly to @The Dassler to clarify that it is not.
