1949 Cadillac Roadster Build

[daveb]

Originally Posted by Jack 1957

I used a 40 grit diamond bit. 1/4" shank 1/8" cutting diameter. See post #920 on page 75.

Thanks Jack!

[Jack 1957]

The new bit came today so I jumped back on the windshield. I finished cutting the left side then sanded the edge smooth. No cracks or problems. That's a load off my mind.















This is Armour Etch. It's a very strong acid used to etch glass. It actually erodes the glass surface and leaves a flat, slightly coarse surface that allows paint to stick tight. No flaking or pealing.





The tan colored tape is plastic like packing tape and really keeps a tight seal. The acid won't effect it and won't allow the acid to seep under it. It leaves a super clean edge.
The blue tape is just masking tape along the outer edge to prevent the acid from seeping into the plastic laminate between the two layers of glass.





Lots of protective gear for this part. This acid is dangerous. Actually, I'm surprised they sell it retail. Keep a bucket of water handy, rubber gloves, eye protection, ventilation, etc.. You just brush it on, let it set for a few minutes and squeegy it off with a bondo spreader, and wipe the surface with water and a rag. I was doing this in sections about 12 to 18 inches. After it's etched you can feel the slightly rough surface. It has a whitish look to it but once the black paint is on it, that goes away.
After the etched surface is thoroughly cleaned and dried, I just used a Rustoleum black spray bomb to paint it. Enamels are best for unprimed surfaces. It dries slow, it's relatively durable, and it doesn't go brittle over time.






Done.


I'll probably install it tomorrow.

[Gojeep]

That came up well Jack. Glad you did so well cutting the glass again. I can't remember what you used to sand the edges with afterwards?

[Larry4406]

What is the purpose of the perimeter glass black out? Glare reduction?

[billfunk29]

Excellent work Jack. Thanks for posting this seldom shown process. You are wise to fear the glass etching. We do it at work. Typically hydoflouric acid is used. At 20% dilution, a couple drops can cost you a finger. Get it on 10% of your body, it can kill you.

[Jack 1957]

Originally Posted by Larry4406

What is the purpose of the perimeter glass black out? Glare reduction?

The windshield will be glued in with urethane adhesive. The black around the perimeter is there so the adhesive can't be seen from outside the car. Same as all the late model vehicles.

[Jack 1957]

Originally Posted by Gojeep

That came up well Jack. Glad you did so well cutting the glass again. I can't remember what you used to sand the edges with afterwards?

See page 75 of this thread.

[crystallographic]

Originally Posted by Jack 1957

The new bit came today so I jumped back on the windshield. I finished cutting the left side then sanded the edge smooth. No cracks or problems. That's a load off my mind.


Attachment 58669




Attachment 58670




Attachment 58671


This is Armour Etch. It's a very strong acid used to etch glass. It actually erodes the glass surface and leaves a flat, slightly coarse surface that allows paint to stick tight. No flaking or pealing.


Attachment 58672


The tan colored tape is plastic like packing tape and really keeps a tight seal. The acid won't effect it and won't allow the acid to seep under it. It leaves a super clean edge.
The blue tape is just masking tape along the outer edge to prevent the acid from seeping into the plastic laminate between the two layers of glass.


Attachment 58673


Lots of protective gear for this part. This acid is dangerous. Actually, I'm surprised they sell it retail. Keep a bucket of water handy, rubber gloves, eye protection, ventilation, etc.. You just brush it on, let it set for a few minutes and squeegy it off with a bondo spreader, and wipe the surface with water and a rag. I was doing this in sections about 12 to 18 inches. After it's etched you can feel the slightly rough surface. It has a whitish look to it but once the black paint is on it, that goes away.
After the etched surface is thoroughly cleaned and dried, I just used a Rustoleum black spray bomb to paint it. Enamels are best for unprimed surfaces. It dries slow, it's relatively durable, and it doesn't go brittle over time.



Attachment 58675


Done.


I'll probably install it tomorrow.



Attachment 58676

So nice to see the glass finished, Jack.
Complex and detailed, with risks ever present.


(ps, "hydrofluoric" used to be the acid we'd etch glass art work with. Good to see this product now.)

[Jack 1957]

Kent, the warning doesn't go into detail but says "Amonium/Sodium Bifluorides". Common sense mandates that if you can't spell it, or even pronounce it, DON'T TOUCH IT.

[Steve Hamilton]

hi Jack

there are only 56 pages in this thread.

I cant find the post for sanding the glass.

steve