caulk caulking gun vs putty knife and glazing compound

Does anybody use a caulking gun and "premium" caulk when
repairing window glass instead of the traditional glazing compound
and putty knife?

Pros and cons ??

When I do a repair like that I use a silicone caulk and a caulking gun and it seems to work very well and the glass will never fall out. I could tell you a story about that caulk and a porch that would not fall even with its leg cut off and all that held it up was the silicone caulk

I've done it both ways. Useing a caulking gun is a lot faster SHOULD you know how to run a nice bead. I'm not talking the average size bead of caulking. I'm talking a bead big enough to cover push pins used in glazing windows. I use a good rubber base caulk, like OSI, or OSI QUAD. The OSI is also paintable. Silicone is not paintable. Did I mention how I HATE silicone caulking.

Silicone caulking is one of the most mis used products ever invented. It does have it's place, but it is not a cure all for all sealing projects.

the important thing is that you prime the surface before applying the caulk.

They do make glazing compound in a caulk tube. I've used it but prefer the standard method from a cost standpoint. It did seem to adhere better over the long run but you use up tubes fast.

Caulk is not as permanent as glazing compound especially if you put caulk on thick enough to simulate glazing compound. Glazing is a pain but I think it is worth the trouble. The important thing to do is take the glazing compound out of the can and kneed it in the palm of your hand for a few minutes before using it.

1. Glazing compound is paintable, and in fact, is meant to be painted over slightly so that the paint touches the glass at the glass to glazing compound joint. This helps prevent water from reaching the wood structure of the window.

2. Silicon caulk can damage a window under some conditions. Years ago, my brother-in-law used silicon caulk to caulk the joint between raw insulated glass units and the wood framing before applying the stops. These were large units, probably 40" X 60". Later in the year when the weather changed, the expansion and/or contraction of the framing caused several of the insulated glass panels to break. That may not be an issue in the application you're asking about, but it's something to be aware of.

Stan

Any sealant you use, needs to be able to bond with each substrate, there is a pull test to determine if the particular sealant has bonded and achieves the desired or designed strength.

Not all sealants require priming, some types do, nasty stuff too, you have to select one that will bond to both the glass, unfinished or finished wood (painted, stained etc.) If not it will delaminate, and likely fail. Some sealants require good cleaning and priming, some just cleaning before it is applied.

Silicone is prevalent in metal and glass windows, but even in those a glazing gasket is likely to be used, glazing blocks for the glass to bear on, then glazing stops to hold the glass, and sealed in a variety of ways.

Wood windows, typically used the glazing compound, like the old single pane, single strength, double strength, commonly found in old double hung and many other wood windows, you take the little triangle push pins, mount the glass with those to hold it and glaze over them, tool off any excess, then let it cure, then paint, thats it.

If you were to use silicone, you just need it to achieve a bond or seal around the glazing meaning both the glass and the wood must be prepared to receive a compatible sealant. It must be paintable or can receive a finish, or you had best tool it neatly, even, slightly concave. The difference in material is that the sealant like silicone and or non silicone is that it is elastomeric, vs glazing compound being rigid, stiff and or brittle. You do want to be able to remove it in case you want to reglaze the opening. Silicone is strong, you could pull wood off with it if it bonds, in that case you would need a special knife, like what a supplier like CR Laurence provides for auto glazing, to cut the seal, not pull.

The DLO or day light opening, is the rough opening that the glass sits in, the glass is sized appropriately to allow for a gasket, expansion, and so on, you don't really want to bed the glass in a sealant that is structural like a Dow 795 silicone. You want the glass to fit, with a little space around it, yet be retained with stops, (like the little metal triangles, wood stops or what have you) I have used glazing compound in conjunction with wood stops, not triangle pins, to seal that inside joint from the wood stop to the glass, than you can seal the outside joint of the wood stop with glazing compound if there is any slight gap, then paint, will keep water out for along time, you don't want trapped water.

I remember a stack of freshly glazed new wood window sash in the shop where I worked, one got pinned too tight, glass was a tad bigger than it should, that wood must have shrunk, heard the "tink" bet a coworker there is a broken one, heard it from outside the shop too, "you're on!" flipped a few sash back, there it was, broke, glass does funny things, not so predictable sometimes.

I learned about wood window glazing, repairs etc. from an old timer who worked for Marvin Windows locally, for many years, after he got out of the Signal Corps of the U.S. Army, Korean veteran before he worked at the lumber yard, a great guy, he passed years back, his wife just passed recently. When there were no deliveries, I would either work in the mill, or the glazing shop helping John, fond memories of working with him. The other would hide in the yard, get their hours, smoke weed, drink beer with the 2 drunk forklift operators, I mean drunk, into a six pack before 9AM.

With the right tools, say something to strike the glazing compound with, I don't think its any extra work, 12 years ago I rebuilt, and reglazed a bow window here, glass had fogged, the base of the window rotted, and the bottom operating sash rails were rotted, it was like new when I was finished, local contractor said it can't be done, or just too labor intense which it was, but not more than any other similar work, all that glazing is tight, and just now I need to scrape and repaint, it faces southwest and gets all the weather, sealants may not last as long.