Once again if you have not read Windows 101 go down the page and start there please.
At this point the sash and frame have been cleaned and polished up. Make sure the sash is very clean. Make sure no tiny bits of rubber, butyl , or broken glass are in the groove inside the sash. All of these will impede your forward progress.
The butyl tape is very sticky and very easily stretched out of place. You need to handle it carefully for consistant thickness is what you need. You also do not want to get any debris in it. I have found unrolling it paper side down to work best.
I cut one end square and unroll it down the groove. If you butt the end against the inner groove and slowly roll it out, you will easily be able to cut it to length. I mark it with my razor knife and then put a scrap piece of wood under and cut it cleanly.
You are going to mess this up at least once, so do not fret. This butyl grows on trees, well it actually does. The trees grew millions of years ago and were transformed to oil when they fell into the swamp along with some dinosaurs. That is a whole other lesson plan. Just try and learn when you mess up. As you saw in the photo above, the tape is off set on the paper. The narrower side goes toward the inside of the sash. The placement on the paper actually helps align it in the groove perfectly. Press it in real well and peal back the paper.
So here it is all lined out with the butyl.
Now this brings me to that caution about accurate sizing. Say you have some glass around and you cut it yourself. If it is too big and you try and muscle it into place it might crack. could happen, it is possible. Like I have been saying, learn from those mistakes. Do not repeat them.
Another simple mistake is not seating the glass all the way. See those air pockets?... you do not want that. Carefully seat it in by applying even pressure. You will see solid black all the way along the glass.
Next the outer gasket goes on. I showed that to you in lesson 101. The technique I use is to seat it into the groove using a screen door tool. By applying pressure in the right location it will go right in as it is supposed to. A forty five degree cut in the corners is needed to wrap the whole window. Now a small amount of vulkem over the miter and the sash is done.
Time to prepare the frame for the new sash. the "O" shaped seal goes in the inner groove. The long edge tail goes toward the inside of the slot and then the outer is eased in with a tool of your choice. I found dragging a dental pick made it very easy. It just slides right in with very little difficulty. I suggest starting in the upper right hand corner and going clockwise around the frame.
At the corner, you just fold the bead and keep going. This way there are no gaps and the only seam is at the top where it is protected by the drip cap.
I did not include installing the sash back in. It is simply a matter of reversing the removal. Your windows are now ready to go. Some hints for those in the south or those want to make the windows look cooler... You can apply film to tint them or even use the mirror film. This will help in cutting down on hot sun light coming in and keep the trailer considerably cooler. To maintain the seals and gaskets I recommend a twice yearly application of glycerin. A product readily available in most drug stores. It will keep any rubberized material supple for a long time. This works very well on windshield wiper blades.
Good luck out there. Hope these three lessons helped you with your project. Please drop me a line and let me know how it went.