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Tips and tricks for baffles seals?

moespeeds

Well Known Member
Friend
The baffles on my RV8 had a few cracks and rips, though my engine temps were just fine. Because I'm OCD and a habitual tinkerer I've decided to replace them while the plane is down for it's condition inspection.

I pulled off the black cloth reinforced baffles, and bought a bunch of the red silicon stuff from Spruce. Looks fairly straightforward, but I'd love to hear any tips or see pictures to help me out. Never done this before.

Using aluminum baffle rivets, those little baffle screws/nuts, and a leather punch. Plan on lining everything up with the existing holes.

RV8 with IO360 parallel if that matters.

TIA
 
My-4

I used the black semi rigid baffle material and pop rivets/washers. I like minimal number of pieces, and at joints I "stitch" with safetywire or a pop rivet and washers, then coat with sealant. The inlet air pressure is high, and it will "flip' the baffles if the gaps are too big and they arent stitched or well overlapped.. My aluminum pieces are about 1/2 inch from the cowling, and everything curls toward the pressure side.
 

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Baffle seals

The seal material usually is shipped rolled up and retains a curved shape when you unroll it. Use that curve to your advantage and cut out the replacement pieces so that the curve is toward the airflow. I like to use retainer strips when possible vs individual pop rivets/washers.
 

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So here's what I got so far. Looks good but I'm not happy with the rear seal, it's all wrinkled. I'm thinking to re-make it and split it in the middle?
 

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They look very nice. I don't recall seeing Silicon used before, my concern being will they take shape and keep it like the standard black rubber does. Perhaps someone who has sued Silicon can chime in.
Regardless, the back corners can be stitched together to help form the baffle to the inside. You can split the back baffle part way down, here and there, push the tabs forward, and stitch the overlap together to reduce the puckering. The seal should show evidence over time of where it is sealing, or not, on the cowling.
I used Rib Stitching thread. It has held up nicely.
 
The silicone baffle material has worked well for me, however the material can tear if not carefully installed. If making a partial cut, I recommend using a punch of some sort to prevent the cut from progressing under stress. Punching a small hole is akin to "stop drilling" a
crack in aluminum or plexiglass.
 
I've realized that the material I used is not fiberglass reinforced. It's just regular silicon.

Should I tear it out and replace with the fiberglass stuff?
 
Leave it. If there's a problem, then you can do that. There probably won't be a problem, and on my C180 the fiberglass insert hasn't prevented tearing.

Dave
 
I've realized that the material I used is not fiberglass reinforced. It's just regular silicon.

Should I tear it out and replace with the fiberglass stuff?

I have the all silicon stuff in blue. I've had my cowl off a bunch since I replaced my seal about a year ago. This included rebuilding a baffle crack by the oil cooler recently. It has held up well and conforms really well to the cowling. In fact, my top cowl kinda falls into place now naturally and is easier to put on. I would keep it
 
I agree with Jake it is very easily torn if you are not careful. I now make sure that I use material with the fabric re enforcement and use a hole punch for the rivet holes. I used the non re enforced silicon once but found that it only lasted a short time where there were any sharper bends required as it would just split. The latest material I have found to work well is just from the local hardware company and is a fabric re enforced rubber strip 1.5 mm thick by 100mm wide it’s easy to cut and holds up well under the conditions around the engine. Plus it’s cheap.
 
I've realized that the material I used is not fiberglass reinforced. It's just regular silicon.

Should I tear it out and replace with the fiberglass stuff?

It should be fine.
The laser cut seals provided in the RV-14 FWF kit are made of silicone. As already mentioned, they are a bit less durable than the Garlock style seal material though and can tear. Just inspect as they age and replace / repair as needed.
 
wishing...

with all these little improvements, you have me wishing I built a 14, and wish I had the bank account to match.....
 
Plen-numb

My good friend Lance fabricated this excellent, simple aluminum plenum while he owned my RV6X. When I bought it back it was faster and cooler with no cowl mod, just baffle material in front.
Win win!
:)
V/R
Smokey





PS: And yes my airplane was in my garage!
 
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I like to use retainer strips when possible vs individual pop rivets/washers.
+1

Originally I had the black stuff from Vans and pop rivets. After drilling all those out when it came time to replace, I decided it was worth the effort to make strips and use those with screws & nuts, against the next time. And makes it easier to tweak and modify to get things to seal just right.
 
Nuts?

+1

Originally I had the black stuff from Vans and pop rivets. After drilling all those out when it came time to replace, I decided it was worth the effort to make strips and use those with screws & nuts, against the next time. And makes it easier to tweak and modify to get things to seal just right.

This is a good tip. I wonder it is worthwhile to put in nutplates?
 
overlap direction

The seal material usually is shipped rolled up and retains a curved shape when you unroll it. Use that curve to your advantage and cut out the replacement pieces so that the curve is toward the airflow. I like to use retainer strips when possible vs individual pop rivets/washers.

Looking at your 3rd picture the forward edge of the rear most side baffle pieces overlap the middle ones. Will this catch incoming air and be forced downward or does it not make a difference?
 
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