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sovereign76 · 10-25-2012, 10:15 AM

We have just noticed that there are tiny bubbles that look like balls of pine pitch just at the edge of the black gasket, between the double paned window in the kitchen, bathroom and one of the bedroom windows...If it was on the outside, I'd think pine pitch, but in between the panes? Help please if you know what this is and what's causing it. Thank you

**azflycaster** · 10-25-2012, 10:28 AM

The tiny balls that you see are most likely an agent used to remove humidity from between the layers of glass. They were installed when the windows were assembled. I'm not sure what they are exactly, but are similar to silica gel.
Silica gel - Wikipedia, the free encyclopedia

HairCream · 10-25-2012, 11:20 AM

Desiccant - Wikipedia, the free encyclopedia

Belegedhel · 10-25-2012, 11:58 AM

I've got similar "balls," but they look more crystalline on my trailer. They are showing up between the panes of glass on my front wing windows, the rest of the windows are single paned. These amber crystals seem to be growing right out of the rubber sealish stuff. I don't think they are a dessicant, as much as some kind of by-product of 40 year old rubber.

HairCream · 10-25-2012, 12:09 PM

I'm curious as to what sort of rubber by-product you suppose these crystal balls are?

sovereign76 · 10-26-2012, 06:41 AM

No they aren't a drying agent...the little white balls (silica?) are the drying agent. This substance seems to be oozing out of the rubber gasket. I thought it might be whatever glue they used to adhere the gasket. It first started on the curbside windows that were facing the sun, but is now happening in the roadside windows that are away from the sun....I may try to upload a pic.........Thanks Janet

sovereign76 · 10-26-2012, 06:44 AM

Belegedhel: Exactly, seem to be coming out of the gasket. All windows involved are side windows, none of the front windows are doing this. All are double paned as well...

**azflycaster** · 10-26-2012, 07:16 AM

Could someone post a picture of these?

Protagonist · 10-26-2012, 07:20 AM

This web page may help:
Windows, Vents & Doors - Vintage Airstream

sovereign76 · 10-26-2012, 11:27 AM

Okay I think I got this..........

Protagonist · 10-26-2012, 11:41 AM

A close look at the photos leads me to believe that the space between the two panes might no longer be sealed, allowing who knows what contaminants to enter the space between the panes, along with air. The stuff looking like little bits of amber might have nothing to do with the gasket/seal material.

HairCream · 10-26-2012, 11:56 AM

I think that is the dessicant.

vswingfield · 10-26-2012, 01:02 PM

Quote:

Originally Posted by HairCream

I think that is the dessicant.

Perhaps I could be wrong, but that's what I've always though it was too.

reinergirl · 10-26-2012, 03:43 PM

It reminds me of what happens sometimes when you urethane a wood floor in low humidity (ie winter). The finish will flow into the cracks between the boards. This produces a thicker column of urethane between the boards.

Urethanes need air to dry, so the solvent evaporates at the surface and dries, but traps the remaining solvent in the column along with the uncured urethane. When the humidity increases and the openings between the boards begin to close due to expansion, the undried finish is forced to the surface and forms wet or tacky beads between the edges of the boards.

When I moved into my current house literally every wood floor had these crystalline beads on every board edge. They scraped off pretty easily and never reappeared.

I'm not saying your windows were urethaned!! But maybe the same sort of thing is occurring?

Belegedhel · 10-26-2012, 03:57 PM

OK, I have attached two nice closeups below. I'm sticking to my earlier assertion that the amber crystals are some chemical that is precipitating/outgasing/growing out of the aging rubber, for the following reasons:

1) They are found all along the rubber seal material, even on the upside down and vertical parts. I have a hard time believing that dessicant sprinkeled into the airgap between the windows 40 years ago would not have shaken down to the bottom.

2) One of my wing windows is original and is sealed with the black stuff (that has crystals growing out of it). The other has been repaired at some point and was done with some kind of grey glazing putty. They both have some moisture (fog) between the panes, but no crystals in the grey glazing putty.

3) If I look really closely, I can see tiny crystals that are just emerging from the rubber.

Some time in the near future, I will pull the window frames apart and rebuild/reseal the windows. I'd be glad to save a sample of the crystals if someone has access to a mass spectrometer and would like to do a detailed analysis. Any grad students out there looking for a thesis?

Since there seems to be some fans of Wikipedia on this thread, I went ahead and did a little search for "crystalized rubber," and low and behold, got a wiki hit:

Strain crystallization - Wikipedia, the free encyclopedia

Not a very enlightening article, but the gyst is right here:

Strain crystallization is a phenomenon in which an initially amorphous solid material undergoes a phase transformation due to the application of strain. Strain crystallization occurs in natural rubber, and some other elastomers. The phenomenon has important effects on strength and fatigue properties. There are various techniques for measuring crystallization in rubber, including: x-ray diffraction, specific heat changes, and density changes.

Because I tend to over-think these things, I did some more looking, and I have bad news for my budding grad student that might have gotten excited at the above. The study has already been done, you can find the dissertation (bed-time reading) at the link below (there are some sections in German, but don't them them slow you down). It gets really interesting around page 92 "Deformation-induced crystallization in polyethylene-polybutene copolymers depends on temperature and strain rate in a similar way as does polyisoprene rubber, although the molecular rearrangements taking place are dfferent. In the early stages of drawing an unoriented crystalline polymer, spherulites become..."

http://tuprints.ulb.tu-darmstadt.de/...ssertation.pdf

Ah...so if I take rubber and squeeze it between two sheets of glass for 40 years, it might undergo a phase transformation, producing crystals. QED. Guess I still have to take the window apart or live with them.

sovereign76 · 10-27-2012, 06:55 AM

Belegedhel: That's pretty much the conclusion we were drawing and makes the most sense. "Dan" had been parked in the shade for the last several years and since the end of June, has been parked directly in the sun, although the roadside has not been directly in the sun (the crystals are predominently on the curbside with only a few on the roadside). So there has been a change in the way the airstream has been exposed to sun and heat....Wow you have a lot more crystals than we do and I can see that if not taken care of, it can get a lot worse. Looks like we know what you and we will be doing in the not so distant future....Thanks for the research...........Janet

DanielB · 10-27-2012, 04:05 PM

Make some Airstream jewelry out of them.

Belegedhel · 10-27-2012, 05:04 PM

Whether it is rubber or diamonds, it's just a bunch of carbon, hydrogen, and oxygen, right?

DanielB · 10-27-2012, 05:27 PM

Indeed.. Vintage carbon, hydrogen, and oxygen :-)

onelisab · 02-02-2016, 02:26 PM

It's been a while since the posting about the strange Crystals growing between the windows in our 40+ year old Airstreams. I too have this amazing growth of not only golden, but also purple crystal growing in my windows of our 1976 Overlander. I call it my
Amber and Amethyst collection and I show it to everyone. Should I ever replace my windows, I promise to post picture of the jewelry that comes from these lovely stones.