Historic HomeWorks Forum

[Skuce]

Ok.

I've been looking through lots of info on the interlocking bronze meeting rail seals. The items that Kilian Hardware sells

http://www.kilianhardware.com/sprinbronwea.html







And I have a couples of concern about the stuff.

1st: Since you have this up facing trough between the 2 meeting rails. Wouldn't it catch debris in there during the open-window seasons?
As soon as you get bugs/dirt in there the meeting rails start getting offset and by all rights will start stressing the seal and the sash lock.
It would be nice if you could have the seal self cleaning

2nd: The interlock seal has to be retrofitted into the sash by cutting a groove in both meeting rails. Not a huge fan of that because the original window probably just had the meeting flat bevels.



So what about using V-bronze strips that open towards the bottom.
Should be self cleaning (gravity) and also don't need extra grooves cut into the meeting rail.
By all rights if you have super tight meeting rails that the V won't clear. Buzzing off a kerf width or less off of one meeting rails should give enough clearance.
Also when you open the lower sash...you don't see the opposing interlock or a cut meeting rail bevel.






Or using Flat Spring Bronze?



Thoughts?

[sswiat]

If the meeting rails were not originally designed for their use you most likely will not be able to retrofit them in. Even when the meeting rails were designed for them, they can become troublsome in the future. Very common in my area. Usually the bottom hook catches debris and dirt. In the long term, this debris blocks the window from closing fully. The homeowner starts to force it closed , the meeting rails get bent and then the rest is history and not in a good way.

I use them when I build new window units or if I am replacing what was there but generally would not attempt to retrofit them.

[jade]

i use a silicone bulb--WS32 or WS33--at the meeting rail...i use the slot cutter from rct (see below) as the bearings are set up for perfect placement on the rails...

http://www.conservationtechnology.com/building_weatherseals.html

hope that helps....
.....jade

[sschoberg]

We use a kerf style silicone vinyl bulb. On the larger sashes (2 1/4" thick) there is enough room on the meeting rail to install two lines of silicone vinyl bulb. We install them on the meeting rail of the top sash, so you don't see them from outside when the sashes are open.
they still catch dirt, but not as much as metal interlocking does.
When setting up your router with a cutter you want to make sure you cutting the kerf just deep enough for the bulb to fit. Cutting to deep will weaken the meeting rail.

Installing these does less alteration/damage to the weakest part of double sashes.

Steve S

[johnleeke]

Bulb seals are usually designed for parts that meet in a compression fit, like where the bottom edge of the sash meets the sill. In the common angled check at the meeting rail it is a sliding fit where the sash parts meet, so here I use a weatherstrip designed for sliding fit, like V-profile. The risk in using a bulb in a sliding fit is that it is more subject to wear by abrasion and tearing.

I don't doubt that they can be made to work in a sliding fit, there is always more than one way to skin a cat.

[Skuce]

So the V or the Flat bronze works for meeting rails nicely?
No issues with the overall thickness? or the nail heads?

[johnleeke]

I usually fasten the flat or V-profile bronze with bronze or stainless steel staples and then tap them flush with a tack hammer, slick and quick with no nail heads to stick up.

Select a type that has the thickness that will work. The flat bronze does not take up much more than 1/16". V-bronze takes more depending on the specific product.

It's been a long time since I've fiddled with all those little tiny nails, although I might use them again if I could get my hands on one of those Accurate nailing punches.

[Skuce]

Are you talking about those magnetic nails sets? Drop a nail in and then use the heel of your hand to press it in to a point that you can easily hit it with a hammer?

[sswiat]

Those finishing nail punches will work. You will likely have to open up the tip with a small drill bit to hold the bronze nail as the head is larger than the hole. Accurate Metal sell a punch that works very well as it holds the nail and you can get a real good set. Often you need to pre-drill your nail holes to get a good start.

I used to use V-bronze but because on a 1 1/4" thick meeting rail you can only at best use a 1" wide V-bronze but often on the meeting rail design it can only use a 1/2" to 5/8" wide one. The problem that exists with narrower v-bronze is it becomes stiffer and I have found that I cannot get a could close of the meeting rails. Also, since it is less flexible, it does not evenly fill any gaps evenly but also can become an obstruction (often making the opening worse than if no weatherstrip was used). I have run into several instances where it has actually caught up and bent upwards in the corners. The most troublesome is that you do not know if it will be thin enough until you mount it and try it. I used it years ago but have abandoned using it altogether.

I agree with John on the wear problem with silicone. It often can be seen rubbing along the lower sash stiles when the sash is lowered/raised. The center area will only rub minimally just before compression.

I am experimenting with self-adhesive pile which was recommended
by Dave Bowers of Olde Window Restorers. The jury is still out on that. The concern is the long term durability of the adhesive.

The most troublesome thing I find with weatherstripping meeting rails is that often there is no or very little gap based on the design and then trying to put something into where no gap existed causes the sash to actually not close as well. Often whether it should be there or shouldn't is a case by case basis.

(Since you are in Southern Ontario, stop by the Old Home Expo in may as I will be doing window restoration presentations. I will be demonstrating the different weatherstrip types and their applications)

[sschoberg]

I agree with Steve, you probably won't like the V-bronze for the meeting rails. We've used about everything and for cost, ease of installation and the ease of replacement, the vinyl bulb has been the best for our application.
But you know the old saying, different tokes for different folks. You may decide on something completely different.

Although if clearence is an issue at the meeting rails, I have double troughed for vinyl bulbs. this is a two step installation. Using a router, I plow an area say 1/16"-1/8" deep and a little less than 1/4" wide. And then I route my kerf for the finn on the bulb. Once installed the bulb is recessed in the face of the meeting rail a bit so sticks out less so hinders the closing of the sash less but still keeps the breeze out more.

OOPS! That may have been a Schoberg Restoration trade secret. keep it to yourself ok.

Steve S

[jade]

i've been using silicone bulbs at the meeting rail for years and have never had an issue with them...as there is typically very little gap once the sash are closed, i use the smallest diameter bulb (WS32) which can fill a 3/16" gap down to about 1/64"...the meeting rails don't actually 'slide by' as the sash against the jamb does...the term i would use is 'compress'...

i install the bulb to the exterior of the bottom sash so it cannot be seen from the interior yet it is always on the interior and is not exposed to precipitation...the bulb doesn't collect dirt and the silicone holds up to uv better than vinyl...

hopefully this doesn't confuse the folks who are looking for one 'best' product...think of the song "i say banana, you say banahnah'...

...jade

[johnleeke]

Steve's "double trough" method reminds me that I sometimes use fin-pile-kerf type weatherstripping and set in a "double trough" so the fin sticks out past the meeting surface just 1/16"+ or what ever is needed.


Fin-Pile Kerf weatherstripping (not shown on a meeting rail)
More on fin-pile-kerf here:
http://historichomeworks.com/forum/viewtopic.php?p=5218#5218

[johnleeke]

Jade is right:

[EPS&C]

We attach spring bronze to the upper sash meeting rail. The logic is, if you attach to the lower sash, it must be inverted - open side up - and it would become a little trough for crud to collect in. Plus, it looks sharp because we use the copper stuff and the client gets to see it when the window is opened - a little visual reminder of what they paid for. We've never had a problem as far as the sashes being able to pass one another and it hasn't gotten caught or bent (this was my primary concern before we implemented it) that I'm aware of.

I would add that you need to make sure your lower meeting rail is nice and clean - no paint drips as are common with this area - otherwise you'll get a poor seal.

Sorry for the obnoxious flash flare in the photo, but I think you get the idea.

[johnleeke]