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Sealing Firewall Rivets

RV12Roger

Active Member
I have searched the threads but my question covers a finner point.

Pg 29-05, Step 4 says "Cover the heads of each rivet on the firewall with a thin layer of fuel tank sealant". The operative word is cover the "HEADS".

LP4-3''s - Does this mean just to cover the top of the head thereby filling the center of the pop rivet head? - or do I need to seal the periphery around the head also? Technically you would be correct to just "cover the top of the head".

Using a bright tungsten light I do not see any light coming through these rivets.

Keep in mind we are talking about vapor and liquid traces at low pressure where as the tank rivets are looking at up to 120 pounds of fuel pressure trying to seep around the rivets.

Any thoughts on making this a "neater" job. Saw one site where builder punched holes in pieces of masking tape to mask the rivet heads.
 
Mask and Paint

I have a gasket hole punch set I used from Mac Tool. Punch the tape on a piece of wood and set over the rivet, seal and remove tape. I then painted the firewall. Looks nice and clean.
You can also sharpen a short piece of tubing for punching masking tape and do the same thing.
 
I have a gasket hole punch set I used from Mac Tool. Punch the tape on a piece of wood and set over the rivet, seal and remove tape.

Clever craftsmanship!

Roger, I'd seal around the perimeter of the rivet also, just to eliminate oil seepage.
 
I used the punched-out mask technique for some of the isolated rivets. For the long straight runs of rivets like on the firewall seams, I used long strips of plastic tape on both sides of the rivets /seams with shorter cross pieces of tape. When the tape is removed, the result is a nice neat series of square sealant pads over each rivet - in some cases blended neatly into the seam sealant. Masking tape is a great way to cut down on ProSeal mess.
 
I have a gasket hole punch set I used from Mac Tool. Punch the tape on a piece of wood and set over the rivet, seal and remove tape. I then painted the firewall. Looks nice and clean.
You can also sharpen a short piece of tubing for punching masking tape and do the same thing.

What type of paint did you use on the firewall, Dan?
 
Paint

I have used the PPG single stage Concept over PPG DP50 Epoxy primer. Same for the cockpit.
By the way, it is easier to prime the panels before sealing. I actually preped and primed before installing all fuselage panels.
 
I have a gasket hole punch set I used from Mac Tool.

Dan... I was able to use a crafting hole punch made by EK tools in 3/8 inch sold by that very large Internet company online. They sell hole punches in many different sizes.

Jeff
 
Office Depot / Staples / Etc.

I used the donut shaped thing-a-ma-jiggys that you use on notebook paper. Can't think of their name right now. The reinforcement donut-shaped, self-adhesive deals that you'd put over the three holes in a piece of notebook paper, before putting the sheets into a 3-ring binder.

After the ProSeal set's up, just peel them off. Works great!

* I started by using some that were paper-based. When trying to remove them, they tear and it is MUCH harder to remove them. Then I found some that were a plastic-based reinforcement. They peel off in one piece.
 
I used the donut shaped thing-a-ma-jiggys that you use on notebook paper. Can't think of their name right now. The reinforcement donut-shaped, self-adhesive deals that you'd put over the three holes in a piece of notebook paper, before putting the sheets into a 3-ring binder.

After the ProSeal set's up, just peel them off. Works great!

* I started by using some that were paper-based. When trying to remove them, they tear and it is MUCH harder to remove them. Then I found some that were a plastic-based reinforcement. They peel off in one piece.

Love it! What a great idea...

I think IN the USAF we called them paper A**holes...

Bob
 
I started by using some that were paper-based. When trying to remove them, they tear and it is MUCH harder to remove them

txaviator... I am setting up even now to seal the rivet heads. My current plan is to use blue masking tape with holes punched out, and it sounds like I should perhaps add plastic hole reinforcements to my paper tape, correct?

Also, what did you do with the flush rivet heads. Perhaps just fill in the holes?

Jeff
 
Masking rivet heads??

You guys are shaming me with all this prettiness. Heck, I just swabbed each one with a Q-tip and pro-seal. A little ugly, but functional...just like my tank!:)
 
txaviator... I am setting up even now to seal the rivet heads. My current plan is to use blue masking tape with holes punched out, and it sounds like I should perhaps add plastic hole reinforcements to my paper tape, correct?

Also, what did you do with the flush rivet heads. Perhaps just fill in the holes?

Jeff

Sorry for the delayed response. I'm so busy at work these days that I really don't have a chance to check-in here very often.

The blue tape with holes should work just fine, without the reinforcements! The plastic hole reinforcements are a bit difficult to find, with the paper versions being the norm. But the plastic ones work great IF you can easily find them!

It worked great on my RV-12 build, and yes, on the flush rivets, I filled the holes but also the area surrounding the rivet. It makes everything look uniform.

* DISCLAIMER: my process worked great with the circular reinforcements....but I stole the idea from DancesWithBassets :rolleyes:
 
The blue tape with holes should work just fine, without the reinforcements!

Hi Gary... Yup. I removed the blue tape as I worked and it worked fine.

sealingRivetHeads.jpg

3-8EKHolePunch.jpg


Thanks,
Jeff
 
sealing rivet heads

My current plan is to use blue masking tape with holes punched out

I got inspired by that idea.
hope it'll work out well without messing much with proseal beyond the masks.
I use a generic electrical insulation tape

126cxlj.jpg


35mkuib.jpg
 
Anything disadvantage to just sealing from the cockpit side? Sure would make it easier to clean the engine side of the firewall. Would look better too.
 
Anything disadvantage to just sealing from the cockpit side? Sure would make it easier to clean the engine side of the firewall. Would look better too.

Yeah. If the firewall ever has to deal with a fire, the sealant on the inside will probably ignite. Think how much you will enjoy polysulfide sealant smoke.
 
Fuel tank sealant is flammable. I set a sample on fire with a propane torch. When the torch was removed, the sealant kept on burning and kept on giving off obnoxious smoke.
 
Sealant

Instead of tank sealant, or Pro-Seal, a better sealant is BioTherm 100. It's not flammable and hardens with a paintable finish and will withstand 2000ºF, about 125º more than burning Avgas.

Another brand line is RectorSeal, but it's made by the same manufacturer as BioTherm and has the same functionality, just branded differently for different industries.

Both are available online, although I got a tube with my heater bypass valve from www.planeinnovations.com.

Also, the Avery poly-vinyl hole reinforcements are about $1.50 for 200 on Amazon.com...work great.
 
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Stainless steel.....

Epoxy cowl and Perspex screen.

It is a bit like Alien v Predator, I know which one would win.

Building 2 12's, not sealing anything. There is a solid mandrel in all the pop rivets. Not much chance of anything getting through, especially with a well sorted Rotax.
 
Avgas; it's not just for breakfast anymore

Sealing the rivets is not really about protecting you from a fire, but CO getting through while idling on the ramp or in flight. Case in point, the rivets are aluminum and the cable linkage and wire holes use a rubber grommet (hey, how about a little sealant around that little assembly at the firewall?). That stuff will all melt ASAP if torched with AVGAS, somehow seemingly glossed over - but don't forget your heat shield on your stainless braided teflon fuel hoses! :eek:

Even with a well sorted engine, CO and other wonderful scents can get through, mostly after that nice new tight exhaust system starts to get some wear - most evident while idling on the ramp. I blew the $5 worth of sealant and sealed the firewall, between seams when I assembled the skins and firewall together as well as the non-solid rivet heads.

Those mandrels are fairly tight when new, but there's still a little hole in the head that can be a great collector for oil and muck, which is part of the idea behind sealing the little suckers up.

May you never have a fluid leak on your FWF, but if you do, a few extra minutes sealing rivet heads will prevent giving guuck a hiding place.
 
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Another way to do it

I took a 3/8" wooden dowel and cut two pieces from the stick - one piece about 6" long and the other about 12" long. Smooth one end of each stick that you will use.

Place dowel into a vice, etc. facing 'up' - take your hand-held drill motor and chuck up a drill bit about 3/32" or so - drill out the end of dowel to about 1/8" deep. Center the hole. Gradually enlarge the hole into the face of the dowel until you have a concave face on the end of the dowel. This hole should be about 3/16 deep. I finished up grinding out the hole on the end of the dowel by using a round Dremel sanding bit. You are aiming for a inverted moon shape on the end of the dowel.

Fill the end of the dowel with a small amount of whichever rivet covering material that you choose. Place end of 'loaded' dowel over the rivet and twist as you remove the dowel. Easy and pretty fast way to get a good cover and seal of the rivet. Looks pretty good too.
 
Sealing the rivets is not really about protecting you from a fire, but CO getting through while idling on the ramp or in flight.

Nope
That has nothing to do with why the plans specify sealing the rivets.


Those mandrels are fairly tight when new, but there's still a little hole in the head that can be a great collector for oil and muck, which is part of the idea behind sealing the little suckers up.

May you never have a fluid leak on your FWF, but if you do, a few extra minutes sealing rivet heads will prevent giving guuck a hiding place.

This is the only reason......
 
Mmmmmm,

Our plans are 29A and don't show that sealing process. It does mention the tooling holes and the gaps where the firewall flanges are.

Our plans are dated 2014 at that point.
 
On the earlier plans it was section 29-05, step 4.
"Cover the head of each rivet on the firewall with a thin layer of fuel tank sealant".
Cheers, DaveH
 
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