painted firewall

Hi All,

years ago i was so smart to prime/paint the entire cockpit side of my 7's firewall. i guess that i just didn't switch on my brain before that building step. lately i was looking at it and concerns raised within myself that the paint, in case of an fire, could (or better will) create unwanted fumes. Making the whole event even worse. that kinda violates the idea of an firewall, i think.

So that paint has to go. Anybody with an idea what kind of solvent or procedure to use here? I will have to live with the paint between the SS and the aluminum angles, but at least the main part of the paint could be removed. Problem is that the aircraft is basically finished with all systems etc. installed.

Glad to hear ideas from you.

Best Regards from Germany
Kay

Depending on how well it is adhered, a razor blade scraper might remove much of it. Round the corners of the blade so you don't scratch the firewall badly.

How did you prep the surface before you painted?

What about just using lacquer thinner sparingly on a small piece of rag? Little bit at a time and go slowly.

Either one of these will work exceptionally well:

http://www.kleanstrip.com/product/aircraft-paint-remover

https://www.homedepot.com/p/Rust-Ol...ional-Grade-Aircraft-Remover-255447/205816466

Be careful, you could remove the entire aircraft! . They are available at local auto parts stores, hardware stores, Walmart, HD, and Lowe?s.

KayS said:

Hi All,

So that paint has to go. Anybody with an idea what kind of solvent or procedure to use here? I will have to live with the paint between the SS and the aluminum angles, but at least the main part of the paint could be removed. Problem is that the aircraft is basically finished with all systems etc. installed.

Glad to hear ideas from you.

Best Regards from Germany
Kay

Click to expand...

No, it doesn't have to go. If you take extra precautions on the firewall side its not likely to ever be a problem. I'd be more concerned with smoke entering the cockpit from everything in front of the firewall burning, not behind.

rocketbob said:

No, it doesn't have to go. If you take extra precautions on the firewall side its not likely to ever be a problem. I'd be more concerned with smoke entering the cockpit from everything in front of the firewall burning, not behind.

Click to expand...

I can personally assure you that at least some paints are flammable long after they've cured. Several years, ago, I welded hooks (wirefeed arc welding) on the bucket of a tractor I'd owned for a couple of years and, sure enough, the paint caught fire and continued to burn even after I was finished welding. I was quite surprised.

I don't at all doubt cured paint will burn but how will it burn if there is a flame barrier on the engine side that would protect the painted surface?

Is your floor painted? Everyone paints the floor and its far more susceptible to burning through than would be an adequately protected firewall.

@rocketbob: I do believe that a direct flame is not necessary to let the paint burn (or evaporate fumes). It's just heat, or...? The firewall is very thin and thermally conductive. But I'm no expert on the topic.

As I recall i just scuffed the firewall a bit before priming. The paint sticks very well fo the FW.

I will give that paint remover a try.

rocketbob said:

No, it doesn't have to go. If you take extra precautions on the firewall side its not likely to ever be a problem. I'd be more concerned with smoke entering the cockpit from everything in front of the firewall burning, not behind.

Click to expand...

I agree with rocketbob. If you have adaquate sealing on the firewall and vents to clear cabin smoke, which I hope you have as that is a must, you will have adaquate cabin vent to deal with fumes.

(1) Stainless firewall, paint on cabin side, nothing on engine side: given an engine compartment fire per FAA standard, the cabin-side paint will become a fire transfer mechanism. I would expect significant open flame in the cabin, plus toxic smoke.

(2) Stainless firewall, paint on cabin side, and a good reflector-over-insulator on the engine side: performance entirely dependent on the effectiveness of the insulator package. There will be hot spots at points of hardware penetration, regardless of the insulator package. Those hot spots may reach temperatures in excess of paint ignition. At a minimum, I would expect smoke generation at the hot spots.

Returning to the OP's question...

Kay, ordinary MEK will generally soften and wrinkle paints so it can be removed easily. Although it has some toxic potential in use (might want to use good gloves and a respirator), it would not pose a long term corrosion risk to the airframe.

So, try this; soak a rag to just short of drip saturation, place it against the painted surface, and cover it with ordinary aluminum foil to prevent evaporation. Come back in 30 minutes.

I've used this approach to remove paint from small areas needing crack inspection, like with the horizontal stabilizer spar bulletin.

now i'm totally confused. but i will remove the paint. In that area it doesn't serve a purpose anyway.