Plenum & Baffle Sealing

[jmorrical]

I am about to seal the plenum and baffles. I would like to hear how to get a clean professional looking job. My RTV experience is always a mess. I'll use black RTV silicone gasket/seal maker.

The EX(1) Firewall Froward Manual says to mark all places where the plenum will contact the engine and all mating surfaces. That implies I would lay a bead down all around that line and those surfaces then seat the plenum.

• Suggestions to keep it neat as possible?
• How big of a bead do I put down?
• How do I clean up a mess?
• Is this better done with extra hands?

Screen Shot 2022-03-08 at 9.38.01 PM.png

[aeroaddict]

Only suggestion I have is to use a tube of RTV so you can use a calk gun.

Also, you can smooth/blend a bead with alcohol on your finger.

On the areas I could, I used blue painters tape to tape off the area to be sealed.

My EX-2 manual stated to seal the contact areas after installment of the plenum.

I think it would be impossible and a big mess to try to lay a bead down then install the plenum. I believe the goal here is to seal air gaps to make the plenum as efficient as possible.

[Andy]

I am about to seal the plenum and baffles. I would like to hear how to get a clean professional looking job. My RTV experience is always a mess. I'll use black RTV silicone gasket/seal maker.

The EX(1) Firewall Froward Manual says to mark all places where the plenum will contact the engine and all mating surfaces. That implies I would lay a bead down all around that line and those surfaces then seat the plenum.

• Suggestions to keep it neat as possible?
• How big of a bead do I put down?
• How do I clean up a mess?
• Is this better done with extra hands?

Baffling on an FX-3 is very different but the factory used red (I assume high temperature) RTV and appears to have applied it after the baffling was installed.

I don't claim any expertise in running beads of RTV but have found that it helps to make the nozzle the right size for the bead that's needed, to keep moving at constant speed, and a wet finger works well as a finishing tool if needed. It's hard to avoid discontinuities in the bead shape where a manual gun has to be reset. It may be worth using an air driven applicator (air caulk gun) for long beads.