skin seam sealant
 

I thought I would find something in the archives on this one, but no joy in my searches(4).

Did anyone seal the fuselage skin seams - other than the firewall? I'm not looking for a proseal nightmare, but that would work . . .

???

Rick 90432

Maybe off the subject but I am wondering why you would want to do this.

Reason
 

Neatness. Maybe avoid the risk of paint-suck into the seam.

If nobody has done it or sees the need . . . I'm not looking for another titchy task, lol.

Rick 90432

I know an old 4 that had all its joints prosealed. Seemed stiffer than most.

Top idea
 

Hi Rick,

It's a good idea to seal your skin lap joints, helps keen the joints clean and tight especially later in the airframe life when rivets start to work and smoke and fine dust gets into the lap joint.

Any faying surface sealant would work fine in this application (PR 870 is perfect http://www.bergdahl.com/SealantTable.htm[/url]) as long as it's not a low adhesion sealant. Choose a working life for the job your doing.

My RV-6 has the belly skins sealed, 10yrs later there is no working rivets and still looks as good as the day she was built.

Good luck..

Take a look at these two links.

http://www.aviationproductsinc.com/f...ter/cs2415.pdf
http://www.skygeek.com/flamemaster-c...r-sealant.html

An A&P buddy of mine ordered some for his RV-10 and apparently he decided to order a tube for me too. I just got off the phone with him a few minutes ago and he said I should be seeing a package soon. I wasn't really looking for it, but since it's here I might try it out on a scrap piece and decide if it's something I want to put on my airplane.

I also want to send a sample up to Grady and see how well it takes primer and paint. The documentation says it should take paint without any issue at all, but I'd like to know for sure.

It's the real stuff though. MIL-S-38228

Phil

Polysulfide on fuselage joints...
 

...is commonly used to seal pressurized aircraft. The BEDE 5 kit aircraft are assembled with polysulfide and pop rivets. I did not do my -4 this way, but will consider for my next plane.... When I built a new rudder for my -4 (using 0.020" skin), I used polysulfide on the faying surfaces of the stiffeners, spar, ribs, fairings, etc. It worked great and seems to have taken paint well (~3 years so far..)

Good luck

Dean Pichon
Bolton, MA

Sealing Skins
 

For better or worse, I prosealed a thin bead on all fuselage top skin joints down to the longerons. Thought it might stiffen-up the fuselage, reduce resonance, and make it more waterproof.

Jim Diehl
RV-7A
99% complete

Sealing the seams with CS 2415
 

Hi guys (Sealing the Seams)

I haven’t made many posts in the last three years but I guess I’m the A&P friend Phil was talking about.
I have a substantial amount of information on the subject of sealing fretting surfaces and seams on my web site if you’re interested. In my opinion you should seal at least the bottom of the aircraft seams if not all of them.
Note: I'm suggesting CS 2415 for external seam sealing and I'm planning on using...
ES 6228 Aeropoxy, (thin viscosity epoxy adhesive) for Faying surfaces. (lap joints)

http://www.txrv10.com/pages/CS2415.html

Dave Murphy
RV10

If you do apply sealant you should roll it on, very thin layer (there is a spec but I don't recall the thickness off hand)

Fay surface sealing is standard practice in the jet production world, but keep in mind these are all pressurized aircraft and they generally fly more in a year than an RV will fly in 10 lifetimes. Airframe hours of 60, 000+ are not unusual in the airline world :eek:

So do "need" to fay surface seal, well it definately won't hurt anything but not sure it's really necessary.

I worked for a while building Sikorsky black hawk helicopter airframes (the workhorse of the military), no sealant is used even in the Navy model.