Weld-On

[n2faith2]

I'm about to start the window installation and recently heard there were problems with the IPS Weld-On that Van's sells. I was told there are cracks that appear after a short time. Has anyone experienced this? What other glue is recommended?

Bill
RV6A - sold
RV10 - FWF N545RV

[brules]

There are cracks on the winshields of the Vans demo RV-10 aircraft. Whenever a clamp is installed during the curing process, the crazing will likely occur to the plexi. As far as recommended glues or substitutes, bear in mind that the glass is most likely structural in keeping the cabin top from crushing the occupants during a crash rollover. Therefore, consideration must be made as to the choice of adhesive that is compatible with not only the plexi, but the fiberglass and structural qualities as well.

[PJSeipel]

My understanding was that the cracks occur in the paint that goes over the gap between the plexi and the fiberglass, and that they occur due to the difference in expansion rates between the materials. I'm interested to hear if it's something different.

PJ
RV-10 #40032

[brules]

yes this is something different. the plexi has severe crazing which in appearance looks like cracks in the glass. I cannot tell you once the crazing has happened if it will continue accross the windscreen.

[rv8ch]

Just as a point of comparison, here is one way the glastar guys glue on their windows:

http://www.rv8.ch/article.php?story=20050303230533751

[Scott Will]

I used Weld-On #10 on my -7A tip-up with good results. However, I do have some crazing in various areas. I think it was due to the solvents I used to clean it prior to bonding. I lightly scuffed the area with 320 then I wiped it with denatured alcohol. And the areas where it crazed is where it was clamped during the cure.

The Weld-On stuff acts pretty quickly... under 30 minutes if I recall.

All my crazing will be hid under the fiberglass fairing, thankfully.

[n2faith2]

Thanks for the input. Gave me some options.

[Rick S.]

This was given to me by David McNeill. He used it on his -10 and his Glasair. He claims no cracks and it makes a perfect joint at the window to cabin.

Original message:

Although the procedure takes only about an hour to accomplish per window, setup and planning is substantially more.. I recommend that you do one window to get the procs correct and plan to do the windshield on a day by itself.




(0) tape off the inside and outside flange area of the window using 3M Fineline (.5 width)

(1) then signstrip blue on the center areas to protect the inside and outside of the window . Be generous when painting it on as this makes it easy to pull off.

(2) sand the inside/outside edges of the window in the area of the flange to roughen the glass for adhesion.

(3) sand the flanges of the lid; CLEAN ALL SANDED EDGES WITH ACETONE

(4) prepare a set of aluminum "fingers" . Strips of .080 1" by 3" ; with a slight bend in the center. one end gets a #30 hole and the other is adequately taped. each is numbered. See the picture.

(5) Trim the window to fit the frame and temporarily hold in place with the NUMBERED "fingers". Clecoes should be place about .50" outside the window. Drill #30 only through the external layer; NOT THROUGH THE LID. RETAPE OFF THE EDGES 3M FINELINE TAPE .

(6) prepare a mixture of epoxy with chopped fibers and cabosil. Consistency should be peanut butter. Potlife should plan to be 30-40 minutes. We refrigerated it to further slow the cure.

(7) putty the lid flanges, wet the window flanges with a small amount of catalyzed epoxy and place window in frame; holding in place with "fingers" at the preplanned locations.

(8) inside person should be wiping excess putty away with a 50-50 mixture of mineral spirirts and acetone; outside person should be smoothing putty on outside flange. excess will be sanded off later. then PULL THE TAPES BEFORE IT CURES.

(9) allow to cure 24 hours.

(10) Inside lid , flange should be finished . If rough, tape glass and sand lightly.

(11) outside the lid, RETAPE the edge at the flange line, then cover the flange with two 1" layers of glass (E-7782?). (Note this was the Glastar procedure.) Remember to pull the tape before the layered glass sets up. The windscreen on the RV10 requires a different layering of glass on the aluminum.

(12) Retape the edge , then sand and fill external flange area for paint. The sanding can feather into the edge of the tape.

(13) when painted , paint should cover the flange.

(14) MUST BE DONE BEFORE THE MIXTURE CURES. If you accidentally get epoxy on the Plexiglas during the process, it can be safely removed using a clean cloth and the 50-50 mixture of mineral spirits and acetone. Have it handy.

(15) 50-50 mixture is also good for removing any signstrip that does not come off when finally removing the protective covering before flight.