Plastic doghouse covers and fire oh my....

[bkahler]

Originally Posted by Air345Fly

Aluminum or steel probably doesn't make much difference. You will still have the rubber gasket which will fail long before any metal will melt.
You need to get the fire out fast or everything will go up.

That's not necessarily the case. The fire that occured on the 75 Argosy managed to keep the fire contained within the engine compartment even with the rubber sealing gasket for the doghouse cover.

There is no argument that the fire needs to be put out. The goal is to keep the doghouse cover from melting away and falling onto the engine thereby exposing the cockpit to open fire. It took them something like 6 fire extinguishers and garden hose spray to get the fire out.

[PeterH-350LE]

my more fire resistant cover is completed. After soaking the old insulation shell with 1 1 /2 gallons of sodium silicate, some 1/8 thick metal insulation in the center and the Techflex to cover it all up, the cover now weighs 34 pounds.

[martin300662]

Two thumbs up!

[bkahler]

Excellent!

34 pounds doesn't sound too bad. Have you tried lifting it onto the doghouse to see how manageable the 34 pounds is?

Also, did this mod affect the fit of the cover to the doghouse frame?

[PeterH-350LE]

Originally Posted by bkahler

Excellent!

34 pounds doesn't sound too bad. Have you tried lifting it onto the doghouse to see how manageable the 34 pounds is?

Also, did this mod affect the fit of the cover to the doghouse frame?

Its manageable, wouldn't want it to be 10 pounds more.
The fit is excellent, since I did a lot of clean up, build up and sanding of the mating surfaces. I know its quieter, too and I sure it will help keeping the heat on the other side.

Wrapping the techflex (awesome product btw) around the edges helps keep everything in place.

[PeterH-350LE]

Originally Posted by PeterH-350LE

Its manageable, wouldn't want it to be 10 pounds more.
The fit is excellent, since I did a lot of clean up, build up and sanding of the mating surfaces. I know its quieter, too and I sure it will help keeping the heat on the other side.

Wrapping the techflex (awesome product btw) around the edges helps keep everything in place.

Update after going for an extended ride. The noise level has stunningly improved. Quietest Classic I have owned to date. I can barely hear the fan clutch engaging, which means a lot.

I am big fan of the sodium silicate and what it did to the falling apart, very flammable insulation. Besides being more fire resistant, it changed the density enormously. Thanks for all the input on available products. I do not think, I ever would have thought of and used the sodium silicate if it wasn't for Brad's very keen product searches:

Originally Posted by bkahler

Just found this product, Colloidal Silica Rigidizer - Coating for Refractory Ceramic Fiber Products - 1 Quart. I wonder how well it would work on the inside of an engine compartment?

I now think that a ceramic fiber mat would work just fine, If you only have the cover without the insulation shell.
I would double or triple it up and then soak it with sodium silicate followed by wrapping everything with the techflex 3'x6' sheet.
The space on the top of my air cleaner to the doghouse is less than an inch. It just barely left an impression on the Techflex, when I pulled it off to check it.

[bkahler]

Peter, that's great news! Do you consider the weight increase to be worth it now that you've made this change and have taken a test drive?

[PeterH-350LE]

Originally Posted by bkahler

Peter, that's great news! Do you consider the weight increase to be worth it now that you've made this change and have taken a test drive?

yes, well worth it and like I mentioned, I would use the hardened ceramic fiber mat now that I know how to encapsulate everything

[marcvl]

Peter: Did you look at/compare the various versions of Techflex material? The one you linked (from Summit) is rated for max ambient temperature of 1,200 F. There are others, like this Thermo-Tec 14620, that can withstand 2,000 F.

[PeterH-350LE]

Originally Posted by marcvl

Peter: Did you look at/compare the various versions of Techflex material? The one you linked (from Summit) is rated for max ambient temperature of 1,200 F. There are others, like this Thermo-Tec 14620, that can withstand 2,000 F.

Great info and same size,always can add another layer

[kidjedi]

Somehow I missed out on this thread, but here's some information I posted over on the Diskotrek build thread...

So I've looking at different options for fireproofing the doghouse cover.

I think a ceramic fiber mat on the underside is the way to go. It's incredibly toxic stuff (if you breath it in, you'll get cancer), so it will need to be encapsulated, but it's what we used in glass blowing to line the furnaces. It can withstand 2400F and doesn't start to melt until 3200F. I think a 1 inch layer of that covered in a thin layer of aluminum sheet (to encapsulate it) will be good. Then on the exterior (inside the cab) a layer of 80 mil foil backed butyl mat and another layer of 150 or 315 mil closed cell foam to help further with heat radiation and sound.

Ceramic Fiber Blanket
https://smile.amazon.com/Lynn-Manufa.../dp/B07ZQPC43B

Foil Backed Closed Cell Foam Mat
https://smile.amazon.com/gp/product/B01I4F0J76

Foil Backed Butyl Mat
https://smile.amazon.com/gp/product/B0751CBXBT

High Temp Fiberglass Tape (says it'll do 1022F direct contact)
https://smile.amazon.com/gp/product/B08JKQK3TX

40% Sodium Silicate Waterglass (as a high temp adhesive for the fiber blanket)
https://smile.amazon.com/gp/product/B008FMD4QM

You can get a gallon of Waterglass for $45, but I'm just using it for a small amount of adhesive, so I don't need that much, thus I'm paying through the nose for 4 oz. of it. You can use it to "firm up" the ceramic blanket to help it keep it's form. If you're doing that, definitely purchase the larger quantity, because you'll need a decent amount.


I saw that someone mentioned some worry about the rubber seal around the doghouse being a point of weakness for flame intrusion. While the carpet around the edge of the doghouse did get singed (didn't actually go up in flame though), I was quite surprised by how well that thick rubber seal held. I don't think it was anything special, just thick adhesive backed foam rubber typically used for weather seal.

[kidjedi]

Originally Posted by marcvl

Peter: Did you look at/compare the various versions of Techflex material? The one you linked (from Summit) is rated for max ambient temperature of 1,200 F. There are others, like this Thermo-Tec 14620, that can withstand 2,000 F.

Man... that Thermo-tec looks way better than the Butyl Mat I linked. The Kilmat is rated to 300 degrees, so the 2,000 claimed by the Thermo-Tec is obviously a much better way to go. I will probably keep the Kilmat to use for sound deadening in various places, but I will go with the Thermo-tec over the doghouse.

[kidjedi]

So... I just ordered the Thermo-Tec mat. Currently Summit is running a promo... if you order the 60x36 sheet (part# THE-14620), they throw in a 24x36 sheet for free (part# THE-14610). I actually ordered two of the 60x36 mats (free shipping when you spend...) and they included two of the smaller mats for free. Seems like a pretty great deal.

[kidjedi]

Having read through the rest of this thread now, first of all, sorry I didn't see the thread until now, or I could have given some good information regarding using the waterglass (40% Sodium Silicate) for adding rigidity to either insulation or ceramic mat. When we build furnaces, "parking garages," etc. for blowing glass, it's a tried and true product. You can also purchase rigid ceramic panels (basically the blanket with sodium silicate already incorporated), but for this application using a flexible material and then adding the rigidity after the shape is formed is obviously best.

Regarding actually building a dog house (vs. using the plastic one that so many people already have), it seems like using an existing doghouse (plastic or steel) for a form to cast a fiberglass cover would work. Better yet, spend a little more money (it's not that expensive) for a sheet of carbon fiber (lighter and more durable) and use the appropriate resins to form it just like fiberglass. And even better yet, there are high temp resins you can use that would make the shell even more fireproof.

So... using the original doghouse cover as a mold, create a new shell out of carbon fiber using high temp resin, then use the 1" ceramic fiber blanket and Thermo-Tec to encapsulate, and add another layer of the thermo-tec on the top side of the new Carbon Fiber shell and you've got a relatively light cover that should withstand temps close to 2400F.

It would probably be best to use some metal reinforcement on the Carbon Fiber shell before adding the ceramic blanket. I think this would be strong enough to hold the weight of someone standing on it.

[kidjedi]

Finally, I know this isn't a fire suppression system thread, but here's this anyway (because the topic is terrifying and it's nice to have an actual link)...

https://rvcoolingunit.com/Halon-Fire...s-C243521.aspx

I thought Halon had been outlawed completely, but evidently places are still selling it. Horrible for the Ozone Layer, but hopefully it never needs to be released into the air. If it does need to be released... this stuff is the best option for putting the fire out without ruining all your engine and electrical components in the process.

[bkahler]

Here's the approach I'm currently taking to make a fireproof doghouse cover. A while back I stopped by the local fab shop and talked to the guy I've been doing business with for the last 13 years or so. I gave him the ABS cover to ponder over for a while and and then we discussed options for making something similar out of steel.

This is what we came up with, a weld it yourself kit




Here's a picture of the pieces sort of laid out in the places where they will be used.




I had him fabricate enough pieces to make two covers so I plan on building them side by side. I have no idea how well this method will work out but I figured there was only one way to find out and that was to do it.

The two top curved corner pieces have not been fabricated as yet. We felt it would be easier to figure out how to close the corners once the pieces had been welded together.

I'll post more pictures when I start the assembly/welding work.

[kidjedi]

Looking good, Brad!

FWIW, I started on my GMC's "doghouse" cover yesterday (there really isn't a doghouse, just a flat cover for the engine access).

I was worried about GMC's using "just a piece of plywood" for the engine access cover, but I'm happy with how it will be "fireproofed" once I'm done.

First, the plywood is 1" thick. It's a serious hunk of wood. I will be covering the bottom (engine side) with the 1100 degree rated heat/sound mat. I am then adding a layer of ceramic fiber blanket over the top and another layer of aluminum clad 1/2" ply. The metal clad ply will be attached with stand-offs to allow the fiber blanket to remain uncompressed. Finally, the topside gets another layer of the heat/sound mat before being treated like the rest of the cockpit (floor liner, carpet, etc.).

I also got my FireFight ss-100 installed in the engine bay.

[Beltran]

I installed the firefight system as well. Engine, Gen and fridge components. Will now consider the dog house improvements if only to ensure safety as well as better sound insulation.

[bkahler]

Just a couple of quick pictures to show the main section of the metal doghouse cover sitting in place. I think the rear down leg is a little to long. I believe the top flat surface of the cover should be parallel with the floor surface so I'll be taking some measurements and making adjustments as necessary.

Right now there is well over 1" of clearance between the cover and the air horn.

[PeterH-350LE]

Originally Posted by bkahler

Just a couple of quick pictures to show the main section of the metal doghouse cover sitting in place. I think the rear down leg is a little to long. I believe the top flat surface of the cover should be parallel with the floor surface so I'll be taking some measurements and making adjustments as necessary.

Right now there is well over 1" of clearance between the cover and the air horn.


Attachment 403878

Attachment 403880

Keep the clearance, with the cover being metal you want lots of fireproof insulation and sound proofing