new proseal over old proseal ?

tonyjohnson · #1 10-29-2006, 06:02 PM

I am doing the fuel pickup modification. I plan to just proseal, without the gasket, when I reinstall the round plates with the fuel pickups attached. There is a lot of old proseal around the area. I am wondering if it is necessary to remove the old proseal, or if it is ok to just apply the new proseal over that existing now.

Any experiences or thoughts?

Thanks in advance,

Tony

jarhead · #2 10-30-2006, 06:39 AM

Invest the time in removing all the old material. The plate won't seal well without an even surface under the new proseal to bear down on.

Use a non-metallic scraper for this - a piece of plexiglass with a "chisel" filed or sanded into one end works great. I use pieces of old aircraft windscreens for scrapers...

tonyjohnson · #3 10-30-2006, 11:16 AM

Ken,

Thanks for the info. I had just about decided to go ahead and remove all the proseal. You mentioned a non metallic scraper. I was going to use a razor blade. My wings have not yet been attached and there has never been gasoline in them. Is there a reason not to use a razor blade or other metallic scraper?

Thanks
and Semper Fi

Rick6a · #4 10-30-2006, 12:28 PM

Quote:

Originally Posted by tonyjohnson

...............I had just about decided to go ahead and remove all the proseal. You mentioned a non metallic ..scraper..........

A little known alternative..........

More details....http://www.browntool.com/productsele...?ProductID=695

az_gila · #5 10-30-2006, 01:05 PM

Quote:

Originally Posted by Rick6a

A little known alternative..........
.....
More details....http://www.browntool.com/productsele...?ProductID=695

Rick, Neat... another tool most of us don't have....

Looks really useful... thanks for the link....

gil in Tucson ... can't have too many tools...,

ron voss · #6 10-30-2006, 05:53 PM

I used a scotchbrite pad in my angle die grinder to remove proseal. Worked great, but does make a bit of a mess.
Ron Voss
RV-6 N642R (reserved)
almost ready for paint

brianwallis · #7 10-30-2006, 07:33 PM

The reason you use a non-metalic scraper is that you dont scrape the metal and break the protective barrier formed by primer or etc... and have corrosion form. If you do scratch anything to bare metal... get some Alodine.... and the cleaner.... clean it with the cleaner... then dab alodine on it for about 1-2 min and then wash it off with the cleaner....it should have a faint yellow tint to it... NOT dark yellow.... I hate to say it burns the metal... but it is a chemical reaction and it forms a barrier to protect it. Use some plexiglass or something similar sharpened with a file etc.... Good Luck
Brian Wallis

tonyjohnson · #8 10-30-2006, 07:51 PM

Brian,

Thanks for the explaination, it makes sense.

jarhead · #9 10-31-2006, 08:49 AM

Brian said pretty much exactly what I was gonna say.

One other factor against using razor blades, putty knives, or anything else harder than aluminum to scrape sealant or paint ,is the fact that you can scratch or score the Al and cause a stress riser (which we all know is Step 1 in crack formation).

Rick, those sealant cutters are nice. I wish I could get my QA department to buy-off on them... guess I'll have to push harder once I'm there for a while longer.