|
|
Like with Fred, it was a LONG time ago when I sealed my tanks, but must have been after his because I used the Jeffco sealer and it worked pretty well. I seem to recall I found two small leaks when I pressure tested tanks and was able to fix easily with vacuum on the tanks and some extra sealer on the outside to get sucked into the pinhole areas. The trick I found helped me was to do the sealing preferably after dark and use a strong lamp that I could direct the light in a fairly focused beam. I used an incandescent bulb in a parabolic reflector. In most areas I could use light on the outside of the tank (wing) and see the light transmit through the wing material. That often showed where the coverage was light and also highlighted pinholes. John Barrett From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Colyn Case
Sent: Friday, July 06, 2012 7:51 AM
To: lml@lancaironline.net
Subject: [LML] Re: Sealer, Tank and top ready for bond Highlighting the pinhole problem. The guy that sold me my project left his wings open for months after putting the gray sealer in the tanks. He said that every time someone came by to see the project he would ask them to look through the entire tanks and see if they could find any pinholes. He would fill them and then repeat. Until no one could find anything. So far no leaks in my airplane.... On Jul 6, 2012, at 12:36 AM, Frederick Moreno wrote:
I used the same stuff on my early Lancair IV. I think it was the recommended PRC product. Probably top of the line, but I know that to do both wings took four of us in gas masks several hours, and painting the stuff on with brushes was a real bitch. Patchwork w as required because after many minutes, sometimes a bubble would emerge, break, and leave a pin hole connecting with the honeycomb core, probably because the room got warmer as the day went on. So a second pass was required to fill pin holes. What a bitch. Still there was a leak in a hidden corner I had to track down. The stuff is a nightmare to work with, and really hard to daub into the three wall corners without leaving a tiny gap in the corner which is where the leak is most likely. If it did it again, I would not use a brush in the corners, but somehow pump it in and apply via a nozzle on the end of a flexible tube. Then I would start brushing out the excess pumped into the corner, and work from there. I was asked by another builder which epoxy is the best to use in tanks. I don't know, but getting some sound data and as clear recommendation would be valuable for the entire composite community. Forget PRC if there is a known reliable epoxy, readily available, with a proven track record. Sure would be great if West Epoxy, dyed to permit visual inspection, did the job. It is so widely used in boats that some research with the West folks might be worthwhile. Fred Moreno, still wincing at the thought of sealing another fuel tank. -------Original Message------- Date: 6/07/2012 3:45:27 AM Subject: [LML] Sealer, Tank and top ready for bond I have posted these previously but at least it is, again, what has worked for me. This sealer was very toxic, requiring a carbon breather mask when applying it. LNC2, 1994 to 2012, 1500 hr.+/-
Note: To protect against computer viruses, e-mail programs may prevent sending or receiving certain types of file attachments. Check your e-mail security settings to determine how attachments are handled.
| |
|
|