RVbySDI
Well Known Member
Dan,
That question was directed at L. Adamson but if he or someone else could supply a sample of it for you to test I would be very interested in seeing the results.
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FWF-Insulation glue !
- Thread starter Pilottonny
- Start date
That question was directed at L. Adamson but if he or someone else could supply a sample of it for you to test I would be very interested in seeing the results.
L.Adamson
Well Known Member
I haven't found it in sheets. It doesn't seem to be what Dan tested either...........but I can't be sure. This material is not foil back, or sold at stores like Home Depot.
L.Adamson
westexflyboy
Active Member
ORCOTEK
ORCON (ORCOTEK) strip blanket - company specifies all products meet FAA flammability requirements as used by Boeing, Douglas, and Airbus. Available from Aircraft Spruce. I don't particularly like the look of it; maybe could be covered with lightweight carpet?
ORCON (ORCOTEK) strip blanket - company specifies all products meet FAA flammability requirements as used by Boeing, Douglas, and Airbus. Available from Aircraft Spruce. I don't particularly like the look of it; maybe could be covered with lightweight carpet?
RVbySDI
Well Known Member
Are you saying this is the material L. Adamson was talking about that is used to wrap Air Conditioner and refrigerator lines?
westexflyboy
Active Member
No. Only looking for correct solution to firewall insulation question.
RVbySDI
Well Known Member
Ok, gotcha. I will look into that material.
Finley Atherton
Well Known Member
The Fiberfrax blankets and boards look interesting. Fiberfrax has been used as an apparently acceptable alternative to a SS firewall. Rutan recommended 1/8" fiberfrax covered with a sheet of aluminum (to protect the fiberfrax from fluids/wear and tear) as a light weight firewall substitute for SS for the Vari-Eze, Long EZ etc.
At the time I built my Vari-Eze in Australia, the aircraft was required to be certified to similar standards as certified aircraft and our regulatory department approved the use of fiberfrax as an alternative to SS for the firewall.
Fin
9A
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<<company specifies all products meet FAA flammability requirements as used by Boeing, Douglas, and Airbus. >>
You'll often see "meets FAA standards" in relation to upholstery, sound insulation, and other materials for aircraft. It is very important to ask "Which FAA standard?" Most of the time you'll find it is FAR 25.853. FAR 25 is for transport category aircraft. There is no cabin firewall standard in 25.853.
Materials meeting the above standard are great for the walls and floors of your airplane, but a firewall? Maybe, maybe not. Two tested samples so far would have resulted in a fatality. I've checked another which does fine, and I have two more on the way for which I expect good results. Best that you check it before you assume anything for the firewall application, and consider this from FAR 23.853:
(f) Airplane materials located on the cabin side of the firewall must be self-extinguishing or be located at such a distance from the firewall, or otherwise protected, so that ignition will not occur if the firewall is subjected to a flame temperature of not less than 2,000 degrees F for 15 minutes.
You'll often see "meets FAA standards" in relation to upholstery, sound insulation, and other materials for aircraft. It is very important to ask "Which FAA standard?" Most of the time you'll find it is FAR 25.853. FAR 25 is for transport category aircraft. There is no cabin firewall standard in 25.853.
Materials meeting the above standard are great for the walls and floors of your airplane, but a firewall? Maybe, maybe not. Two tested samples so far would have resulted in a fatality. I've checked another which does fine, and I have two more on the way for which I expect good results. Best that you check it before you assume anything for the firewall application, and consider this from FAR 23.853:
(f) Airplane materials located on the cabin side of the firewall must be self-extinguishing or be located at such a distance from the firewall, or otherwise protected, so that ignition will not occur if the firewall is subjected to a flame temperature of not less than 2,000 degrees F for 15 minutes.
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Beancounter
Well Known Member
Insulation
It appears as though the ceramic fiber blanket sold by ACS etc under the name Fiberfrax is the same product as the pottery industry uses in some types of kilns. It also appears as though it isnt subject to the aviation price premium. Sources I looked at were about half of the aviation supply prices. I havent tested it but the claims are continuous service life of 2300deg. Sounds promising. Dan, have you torture tested this product yet?
It appears as though the ceramic fiber blanket sold by ACS etc under the name Fiberfrax is the same product as the pottery industry uses in some types of kilns. It also appears as though it isnt subject to the aviation price premium. Sources I looked at were about half of the aviation supply prices. I havent tested it but the claims are continuous service life of 2300deg. Sounds promising. Dan, have you torture tested this product yet?
westexflyboy
Active Member
Would you mind sharing which insulation passed your test?
Chase, there are quite a few readily-available high temp insulators. I've already offered to check fiberfrax and other generics, and then report the results here. I've also offered to check samples for individual builders and vendors. If you have something you want checked, send it.
Glasair uses fibrefax on its firewalls. I have heard of fires in Glasairs and the firewall held up. Their demo video shows the firewall maintaining integrity for extended period with direct flame.
westexflyboy
Active Member
Thank you, Dan, I really appreciate your efforts and this discussion. Hopefully a list of verified firewall insulation alternatives will emerge. Amazing how many manufacturers seem to avoid the truth. I saw one ad that claimed compliance with 23.853(b), yet that section is blank! Another claimed compliance with appendix F "first part", but the first part is only about conditioning the sample prior to testing. Please send me an IM with address and I'll send you a piece of the ORCOTEK for testing. I'll predict failure, but I've only seen the pictures so far.
I promised to post results for readily available, common insulation materials suitable for FAR 23 firewall temperatures. Here's an example of how easy it is to pick a good material, courtesy of RV-7 builder Don Pansier. More coming soon.
This one is called Cerablanket. You'll find it in the McMaster-Carr catalog; Search "ceramic insulation":
http://www.mcmaster.com
You should find it on page 3462, "Ultra-High Temperature Sheeting", Temperature Range: 0° to 2000° F, about halfway down the page. Don picked the 1/2" thick blanket, part #93315K52.
This photo is about one minute into a burner run. Look close and you'll see the stainless steel glowing red just above the blanket. My hand is not the least bit uncomfortable.
Backside surface temperature was about 400F. It took 1:40 for the black radiant heat target to reach 200F.
The addition of a lightweight reflector (in this case a sheet of 0.010" soft aluminum flashing) improves radiant performance a lot. Ordinary HD aluminum foil would work just as well, and you need something to protect and encapulsate the fiber material anyway.
With the aluminum backing sheet, the radiant heat target stabilized at about 140F, and stayed there for the entire duration of a 3 minute burn. No smoke, no flame, no problem. You could fly in your bare feet.
If somebody wants to spring for a roll of the 1/4" 6lb density (part #93315K51) it would be interesting to compare performance at half the weight. A 24 foot roll would cost a whole $27.33 plus shipping.
I also ran some expensive Part 25 airliner cabin wall insulation this afternoon:
Nope, don't want to use that on a firewall.
I'll get to Fiberfrax next.
This one is called Cerablanket. You'll find it in the McMaster-Carr catalog; Search "ceramic insulation":
http://www.mcmaster.com
You should find it on page 3462, "Ultra-High Temperature Sheeting", Temperature Range: 0° to 2000° F, about halfway down the page. Don picked the 1/2" thick blanket, part #93315K52.
This photo is about one minute into a burner run. Look close and you'll see the stainless steel glowing red just above the blanket. My hand is not the least bit uncomfortable.
Backside surface temperature was about 400F. It took 1:40 for the black radiant heat target to reach 200F.
The addition of a lightweight reflector (in this case a sheet of 0.010" soft aluminum flashing) improves radiant performance a lot. Ordinary HD aluminum foil would work just as well, and you need something to protect and encapulsate the fiber material anyway.
With the aluminum backing sheet, the radiant heat target stabilized at about 140F, and stayed there for the entire duration of a 3 minute burn. No smoke, no flame, no problem. You could fly in your bare feet.
If somebody wants to spring for a roll of the 1/4" 6lb density (part #93315K51) it would be interesting to compare performance at half the weight. A 24 foot roll would cost a whole $27.33 plus shipping.
I also ran some expensive Part 25 airliner cabin wall insulation this afternoon:
Nope, don't want to use that on a firewall.
I'll get to Fiberfrax next.
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RVbySDI
Well Known Member
Dan,
Do you know if this is the "6 lbs./cu. ft" or the "8 lbs./cu. ft" material?
az_gila
Well Known Member
Yes, let's give Dan a round of applause for his help on this. Might save your bacon or mine.
I just came across CONTEGO Fire Protection from Aircraft Extras (http://www.aircraftextras.com/Contego.htm). It's a latex based product that you spray on the firewall on the engine side & when exposed to heat or flame it supposedly forms a char layer that keeps the substrate from burning. They claim that with 1,800 deg applied to a firewall, the opposite side only reached 400. Still too hot, but it wouldn't take much insulation to protect the cockpit side against 400, I would think.
So, Dan, what do you think?
I just came across CONTEGO Fire Protection from Aircraft Extras (http://www.aircraftextras.com/Contego.htm). It's a latex based product that you spray on the firewall on the engine side & when exposed to heat or flame it supposedly forms a char layer that keeps the substrate from burning. They claim that with 1,800 deg applied to a firewall, the opposite side only reached 400. Still too hot, but it wouldn't take much insulation to protect the cockpit side against 400, I would think.
So, Dan, what do you think?
<<thanks for your help in locating what looks to be appropriate material for inside the firewall.>>
Bob, there are dozens of good choices; true 2000F insulation is an industrial commodity. The good ones are all ceramics. I'm not here to recommend a particular material. I just want builders to understand how bad some of the other choices can be. Take a look at the smoke boiling off a bad choice (last picture, previous post) and imagine being trapped in an enclosed cockpit with it.
<<thats pretty good compared to some of the rubberized options.>>
The one expensive rubber "firewall insulation" I've looked at so far will, IMO, kill you dead as lunchmeat. The seller says it meets FAR 25 standards....but there is no cabin firewall standard in FAR 25:
Bob, there are dozens of good choices; true 2000F insulation is an industrial commodity. The good ones are all ceramics. I'm not here to recommend a particular material. I just want builders to understand how bad some of the other choices can be. Take a look at the smoke boiling off a bad choice (last picture, previous post) and imagine being trapped in an enclosed cockpit with it.
<<thats pretty good compared to some of the rubberized options.>>
The one expensive rubber "firewall insulation" I've looked at so far will, IMO, kill you dead as lunchmeat. The seller says it meets FAR 25 standards....but there is no cabin firewall standard in FAR 25:
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<<CONTEGO Fire Protection from Aircraft Extras...spray on the firewall on the engine side..>>
A material placed on the engine side obviously eliminates the smoke/flames in the cockpit problem. The only way to be sure about performance is to test, the old "trust but verify" mantra homebuilders are well advised to follow. I'd want to be sure it doesn't peel off and fall away.
A material placed on the engine side obviously eliminates the smoke/flames in the cockpit problem. The only way to be sure about performance is to test, the old "trust but verify" mantra homebuilders are well advised to follow. I'd want to be sure it doesn't peel off and fall away.
Mike S
Senior Curmudgeon
Here's a thought starter, a simple perimeter channel:
You could drill a few holes in the flange, and lace with safety wire to make sure the insulation stays in place.
That setup will allow you to attach a close out panel inside the cabin too.
westexflyboy
Active Member
Read the Warning Label
Dan, it looks like you received a sample but not the the box it came in. OOPS! I just received my ceramic fiber blanket from McMaster-Carr. Ugly warning labels.
In case the photo print is too hard to read:
1. Possible cancer hazard by inhalation
2. Known carcinogen
3. May cause temporary irritation to eyes, skin, and respiratory tract
Precautionary Measures:
1. Minimize airborne fibers with engineering controls
2. Wear a respirator
3. Wear long sleeve loose fitting clothes, eye protection and gloves
4. Wash clothing separately
Can anybody think of an engineering control appropriate to the confined cabin of a vibrating airplane?
Dan, it looks like you received a sample but not the the box it came in. OOPS! I just received my ceramic fiber blanket from McMaster-Carr. Ugly warning labels.
In case the photo print is too hard to read:
1. Possible cancer hazard by inhalation
2. Known carcinogen
3. May cause temporary irritation to eyes, skin, and respiratory tract
Precautionary Measures:
1. Minimize airborne fibers with engineering controls
2. Wear a respirator
3. Wear long sleeve loose fitting clothes, eye protection and gloves
4. Wash clothing separately
Can anybody think of an engineering control appropriate to the confined cabin of a vibrating airplane?
Not surprising; this is the stuff that replaced asbestos in the refractory industry. Hard to say if there is a real handling risk or just CYA due to the plaintiff's bar. The MSDS is an interesting read:
http://www.thermalceramics.com/pdfs-uploaded/msds/americas/201.pdf
Note the level of exposure for the rats and mice in section 11, toxicology....200 fibers per cubic centimeter, 6 hours a day. It was probably hard to see the rats in an atmosphere that dense <g>
The builder who submitted the last sample intends to enclose the material in an aluminum foil "envelope" (roll foil with neatly folded edges). A few panels under the front carpet get stainless foil, as there are several reported incidents of RV's burning through single-panel belly skin right behind the firewall.
Fresh news: Another RV builder and I ran two-minute burns on three samples last weekend, all enclosed in an Reynolds Wrap aluminum foil envelope. One was 1/2" Cerablanket. The other two were samples of the latest and greatest exotic, which we will call Brand A (yes, that's a hint...legal restrictions on the samples).
1/2" Cerablanket/foil and slightly thinner 10mm Brand A/foil exhibited similar practical performance, about 400F backside temp at 2 minutes and less than 140F for the radiant heat target at 6" distance. A different Brand A product in 5mm thickness didn't perform quite as well, but was still a very safe choice compared to the rubber, fiberglass batt/aluminized plastic, and polyester fiber/aluminum foil examples previously tested. Oddly enough, the 10mm Brand A sample did exhibit minor outgassing through a seam in the alumimum foil, and the outgass did ignite, burning with a weak flame much like a Bic lighter. Not significant enough for a condemnation, although not a plus. Given the insignificant performance difference, I don't see much point in fooling with the far more expensive product anyway.
Please remember my personal interest here. I simply don't want to see anybody burn to death due to a bad choice. Some materials have been very bad indeed. I've avoided recommending a specific product, instead focusing on bad choice, good choice material types. If a possible cancer risk makes you nervous, find another material and I'll be happy to test it.
http://www.thermalceramics.com/pdfs-uploaded/msds/americas/201.pdf
Note the level of exposure for the rats and mice in section 11, toxicology....200 fibers per cubic centimeter, 6 hours a day. It was probably hard to see the rats in an atmosphere that dense <g>
The builder who submitted the last sample intends to enclose the material in an aluminum foil "envelope" (roll foil with neatly folded edges). A few panels under the front carpet get stainless foil, as there are several reported incidents of RV's burning through single-panel belly skin right behind the firewall.
Fresh news: Another RV builder and I ran two-minute burns on three samples last weekend, all enclosed in an Reynolds Wrap aluminum foil envelope. One was 1/2" Cerablanket. The other two were samples of the latest and greatest exotic, which we will call Brand A (yes, that's a hint...legal restrictions on the samples).
1/2" Cerablanket/foil and slightly thinner 10mm Brand A/foil exhibited similar practical performance, about 400F backside temp at 2 minutes and less than 140F for the radiant heat target at 6" distance. A different Brand A product in 5mm thickness didn't perform quite as well, but was still a very safe choice compared to the rubber, fiberglass batt/aluminized plastic, and polyester fiber/aluminum foil examples previously tested. Oddly enough, the 10mm Brand A sample did exhibit minor outgassing through a seam in the alumimum foil, and the outgass did ignite, burning with a weak flame much like a Bic lighter. Not significant enough for a condemnation, although not a plus. Given the insignificant performance difference, I don't see much point in fooling with the far more expensive product anyway.
Please remember my personal interest here. I simply don't want to see anybody burn to death due to a bad choice. Some materials have been very bad indeed. I've avoided recommending a specific product, instead focusing on bad choice, good choice material types. If a possible cancer risk makes you nervous, find another material and I'll be happy to test it.
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vfrazier
Well Known Member
There are a vast number of products to insulate your firewall. One that I have used and had good luck with is Heat Shield mat, a foil faced, ceramic material that is self adhesive for easy installation. Under normal conditions it reflects normal engine heat away from my feet which is my immediate concern. If the engine were on fire, I'm certain that it would also buy precious time.
Since I'm one of the guys who still remembers Von Alexander, I don't take this subject lightly (I wear a chute in his memory and for my wife). OTOH, firewall insulation needs to be:
1) reasonably priced and lightweight
2) easy to install
3) keep my feet cool
4) buy time in a real emergency
Some have said that firewall insulation might come loose during a real fire. That's true, but you may also have fire burn through the aluminum belly of the plane, so common sense applies here. By the time you have all of the goodies mounted on your firewall, your firewall insulation will have quite a bit of stuff supporting it... at least reducing the chance of it simply falling off!
For those who are interested, there is more info about this product on my store at
http://www.flyboyaccessories.com/store/index.php?main_page=product_info&cPath=1&products_id=204
http://www.flyboyaccessories.com/store/images/Insulationkit_1.JPG direct link to an installation photo.
BTW, if you're concerned about the firewall, be sure to get a good fireproof heat box from http://www.planeinnovations.com
Since I'm one of the guys who still remembers Von Alexander, I don't take this subject lightly (I wear a chute in his memory and for my wife). OTOH, firewall insulation needs to be:
1) reasonably priced and lightweight
2) easy to install
3) keep my feet cool
4) buy time in a real emergency
Some have said that firewall insulation might come loose during a real fire. That's true, but you may also have fire burn through the aluminum belly of the plane, so common sense applies here. By the time you have all of the goodies mounted on your firewall, your firewall insulation will have quite a bit of stuff supporting it... at least reducing the chance of it simply falling off!
For those who are interested, there is more info about this product on my store at
http://www.flyboyaccessories.com/store/index.php?main_page=product_info&cPath=1&products_id=204
http://www.flyboyaccessories.com/store/images/Insulationkit_1.JPG direct link to an installation photo.
BTW, if you're concerned about the firewall, be sure to get a good fireproof heat box from http://www.planeinnovations.com
Noah
Well Known Member
I have some of Aspen Aerogel's Pyrogel XT (http://www.aerogel.com/products/overview.html) that I obtained with the thought of using it on my firewall. I will send some to Dan for eval (Dan, please let me know your min sample size and mailing address).
I was involved in the design and build of Stardust (http://stardust.jpl.nasa.gov/tech/aerogel.html) , a cometary sample return mission which used an aerogel catcher's mitt to decelerate tiny interstellar & cometary dust particles traveling at 7 km/sec without vaporizing the particles.
For more info on Aerogel: http://en.wikipedia.org/wiki/Aerogel
Aspen Aerogel's products combine aerogel particles in a fiberglass non-woven batting. Only rated at 1200F, but we'll see how it does. Dan, I'd be interested to see the results as well as hear your comments, having seen other products' performance.
rzbill
Well Known Member
Overdue reply
Hi Dan,
Sorry for the late reply. I lost touch with this thread until it popped back up recenty. I did not get pictures of the RV-4, however the damage was exactly how it would be expected. The root cause was a fuel leak at the fuel pressure sensor tap into the mechanical fuel pump. I was told by a common aquaintance that the pilot delayed turning off fuel, so the fire burned longer than it had to. My understanding is the fire was discovered while the aircraft was decending for a VFR pattern entry and the damage occured in the time it took to get on the ground. I want to be clear that I am not placing blame. I was not in the cockpit, he was, so I cannot say that I would do any different in regards to fuel valve. The SS firewall remained intact. The "floorboards" by the left rudder pedal (the fuel fire was mostly on the left) were burned through. Please don't hold me to this, but my weak memory says that there was about a 2" by 6" open gap in the aluminum floor and the pilot had reported his left shoe was scorched.
I like the McMaster Carr ceramic that has been found and tested on this thread. Unless there is some revelation when and if Fiberfrax is tested, I will use the McMaster stuff for a minimum 12" band from the firewall.
Hi Dan,
Sorry for the late reply. I lost touch with this thread until it popped back up recenty. I did not get pictures of the RV-4, however the damage was exactly how it would be expected. The root cause was a fuel leak at the fuel pressure sensor tap into the mechanical fuel pump. I was told by a common aquaintance that the pilot delayed turning off fuel, so the fire burned longer than it had to. My understanding is the fire was discovered while the aircraft was decending for a VFR pattern entry and the damage occured in the time it took to get on the ground. I want to be clear that I am not placing blame. I was not in the cockpit, he was, so I cannot say that I would do any different in regards to fuel valve. The SS firewall remained intact. The "floorboards" by the left rudder pedal (the fuel fire was mostly on the left) were burned through. Please don't hold me to this, but my weak memory says that there was about a 2" by 6" open gap in the aluminum floor and the pilot had reported his left shoe was scorched.
I like the McMaster Carr ceramic that has been found and tested on this thread. Unless there is some revelation when and if Fiberfrax is tested, I will use the McMaster stuff for a minimum 12" band from the firewall.
Noah, I got your PM. Last evening's post was a quick response; I had just returned from a pilots-'n-wives social event involving a nice bottle of Glenlivet <g>
Industrial samples often include boilerplate restrictions, in this case "...you agree that you will not disclose the material, or information relating to the material for any purpose to any third party..." It may be boilerplate, but it is still an agreement under which I accepted certain materials. So, I'll put it this way: If you encase Pyrogel XTF or Pyrogel 6671 in aluminum foil and place it against the backside of a red hot firewall, I don't think it will kill you, unlike some other choices. That is the focus of this thread. Careful readers of the manufacturer's published data sheet will note the products are rated for 1200F, not 2000F; the above is an off-sheet application well beyond the manufacturer's representations. They will also realize the commercial Pyrogel insulation line is not the amazing translucent blue stuff shown in the Aerogel marketing materials and used for the Stardust catcher.
Gentlemen, testing firewall insulation is a friggin' minefield; this world is full of lawyers. I originally had no intention of discussing private experiments. However, I'm also a long-time TC and my Mom sent me to school with the nuns so they could beat a conscience into her little boy. I couldn't remain silent about glue on a firewall given knowledge I already had....so here we are. Ya'll are giving me reason to think about the situation Henceforth, here's the deal.
(1) If a fellow amateur builder sends me something to test, I don't think I have any restriction about publishing my amateur results and personal opinion.
(2) If I've already tested it under another agreement, I maintain that agreement.
(3) Testing costs time and money, and I'm a volunteer. If I feel pushed, it's over.
Industrial samples often include boilerplate restrictions, in this case "...you agree that you will not disclose the material, or information relating to the material for any purpose to any third party..." It may be boilerplate, but it is still an agreement under which I accepted certain materials. So, I'll put it this way: If you encase Pyrogel XTF or Pyrogel 6671 in aluminum foil and place it against the backside of a red hot firewall, I don't think it will kill you, unlike some other choices. That is the focus of this thread. Careful readers of the manufacturer's published data sheet will note the products are rated for 1200F, not 2000F; the above is an off-sheet application well beyond the manufacturer's representations. They will also realize the commercial Pyrogel insulation line is not the amazing translucent blue stuff shown in the Aerogel marketing materials and used for the Stardust catcher.
Gentlemen, testing firewall insulation is a friggin' minefield; this world is full of lawyers. I originally had no intention of discussing private experiments. However, I'm also a long-time TC and my Mom sent me to school with the nuns so they could beat a conscience into her little boy. I couldn't remain silent about glue on a firewall given knowledge I already had....so here we are. Ya'll are giving me reason to think about the situation Henceforth, here's the deal.
(1) If a fellow amateur builder sends me something to test, I don't think I have any restriction about publishing my amateur results and personal opinion.
(2) If I've already tested it under another agreement, I maintain that agreement.
(3) Testing costs time and money, and I'm a volunteer. If I feel pushed, it's over.
Noah
Well Known Member
Nice!
OK, That makes sense. I would do the same.
Good to know.
Yes, this is the basis of my concern - aerogel is well characterized, but it has been unclear whether using small pieces of it in a fiberglass mat provides any real benefit, maybe it is just "sexy marketing". And yes, because of this thread and the realization that the published (FAA) requirement is 2000F, I became a little concerned about the 1200F mfgr's published limitation. This is certainly beyond the mfgr's published limitations. But to me, this is unimportant. It is test data that matters to me, and test data only. The fact that the data originates from a guy who is (A) a TC (B) an RV builder and (C) a professional test guy who seems to do this at his day job is all icing on the cake.
Me too (the nuns, that is)...
Dan, that's all quite reasonable. I hope I speak for everybody interested in this thread that we appreciate your stepping up and providing invaluable test data on something that's near and dear to all of us, namely, our hides. As several have alluded to here, manufacturer's salesmanship doesn't cut it. What I was hoping for was a defacto recommendation on which product is the best choice for a homebuilder given performance, weight, and cost - but I understand your concerns about making such a blanket statement or recommendation.
I received my Pyrogel XT from a friend of a friend who has an in at Aspen Aerogels manufacturing facility, so it didn't cost me anything. Anybody know what the stuff costs? Nothing is available on their website.
I think I know what I need to know regarding my personal use of Pyrogel XT in my homebuilt aircraft. My offer stands to send you a sample Dan if you want to be able to publish data on it using samples obtained without restrictions. If not, no problem:! )
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Another Sunday evening with the burner....and another surprise.
Fiberfrax has a problem.
This is about 1 minute into a session:
It only took a few minutes to determine what was happening. The flame you see here is due to the fiberfrax outgassing inside the aluminum foil envelope. Look down at the lower edge too; the soot streak is where another flame was burning merrily a few seconds before I took the picture. It has almost gone out.
This a fresh piece of plain fiberfrax exposed directly to the burner:
Note the smoke (poor photo, sun was going down and the camera flash didn't light it very well). That's binder material burning off the fiberfrax fiber mat. The binder (think of it as an adhesive) holds the fibers together. Many of you have handled fiberfrax; it has a nice firm felt-like texture with reasonable handling strength. After the burn, this sample had little handling strength in the heated area. The fibers were intact, but there was nothing to hold them together; the binder had burned away. You could poke a finger through it with ease.
Binders, adhesives, fabric sizing, and other additions to the base material are all problems when one of the goals is no smoke in the cockpit. In free air they burn away as smoke. When they outgas in an envelope they tend to ignite as they escape through a seam. Given that fiber materials really need to be encapsulated in order to be a practical cockpit-side firewall insulation (consider dirt, durability, and loose fiber), I'd have to recommend against fiberfrax inside the cabin.
Fiberfrax has a problem.
This is about 1 minute into a session:
It only took a few minutes to determine what was happening. The flame you see here is due to the fiberfrax outgassing inside the aluminum foil envelope. Look down at the lower edge too; the soot streak is where another flame was burning merrily a few seconds before I took the picture. It has almost gone out.
This a fresh piece of plain fiberfrax exposed directly to the burner:
Note the smoke (poor photo, sun was going down and the camera flash didn't light it very well). That's binder material burning off the fiberfrax fiber mat. The binder (think of it as an adhesive) holds the fibers together. Many of you have handled fiberfrax; it has a nice firm felt-like texture with reasonable handling strength. After the burn, this sample had little handling strength in the heated area. The fibers were intact, but there was nothing to hold them together; the binder had burned away. You could poke a finger through it with ease.
Binders, adhesives, fabric sizing, and other additions to the base material are all problems when one of the goals is no smoke in the cockpit. In free air they burn away as smoke. When they outgas in an envelope they tend to ignite as they escape through a seam. Given that fiber materials really need to be encapsulated in order to be a practical cockpit-side firewall insulation (consider dirt, durability, and loose fiber), I'd have to recommend against fiberfrax inside the cabin.
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f1rocket
Well Known Member
Just to clarify the use of Fiberfrax on the Rutan kits, it is used only as an insulator between a thin sheet of stainless and the composite firewall core. It is not exposed directly to flame.
Great work Dan. I am following your experiments closely. I thank you for taking the time to perform these and to report the results. It is a great service to all who visit here.
Great work Dan. I am following your experiments closely. I thank you for taking the time to perform these and to report the results. It is a great service to all who visit here.
TCONROY
Well Known Member
Anyone try this stuff??? It's cheap.
http://www.jcwhitney.com/complete-insulation-kits/p2010772.jcwx?filterid=c1431j1
http://www.jcwhitney.com/complete-insulation-kits/p2010772.jcwx?filterid=c1431j1
CharlieWaffles
Well Known Member
It looks like the result of this was fiberflax had a problem when encapsulted in something like foil and resulted in the gases burning when it vented. Earlier in the thread there was a test of Cerablanket from McMaster but the test was with only a stainless shield in front of it. I don't know if it was ever tested encapsulted. Does anyone know if it was?
It was. No binder, so no outgas and nothing to burn inside the cabin. The only objection to Cerablanket is a possible health risk; inhaled ceramic fiber, a good reason to encapsulate in foil.
Old thread......later work showed that insulating the engine side of the firewall offers the best performance. My own airplane has no insulation inside the cabin. If I found a need (a big if) for spot insulation on the cabin side of a firewall, cerablanket in a foil envelope with no adhesive of any kind would be on the very short list of possibilities.
§ 23.1191 Firewalls.
(f) Compliance with the criteria for fireproof materials or components must be shown as follows:
(1) The flame to which the materials or components are subjected must be 2,000 ±150 °F.
(2) Sheet materials approximately 10 inches square must be subjected to the flame from a suitable burner.
(3) The flame must be large enough to maintain the required test temperature over an area approximately five inches square.
(g) Firewall materials and fittings must resist flame penetration for at least 15 minutes.
§ 23.1182 Nacelle areas behind firewalls.
Components, lines, and fittings, except those subject to the provisions of §23.1351(e), located behind the engine-compartment firewall must be constructed of such materials and located at such distances from the firewall that they will not suffer damage sufficient to endanger the airplane if a portion of the engine side of the firewall is subjected to a flame temperature of not less than 2000 °F for 15 minutes.
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Old thread, three questions!
I am planning on using Cerablanket from Mcmaster-carr.
These are the my areas of uncertainty:
Most discussions mention Aluminum foil for encapsulating the Cerablanket. 1. For engine side of firewall installation, should one not use SS foil on the engine side rather than aluminum (which will melt rather quickly I would think)?
2. Should I use aluminum foil on the other (firewall) side as encapsulating material?
Then the last question:
As in case of the RV4 fire with melted floor, I am left with clear impression that insulating the firewall alone leaves one with the risk of burn through the aluminum floor directly below and behind the firewall, since flames follow airflow.
3. Any ideas how to "meltproof" that area? Applying SS directly to the forward floor skin might still melt the underlying aluminum if no poor heat conductive material is placed between the SS and Al (I think).
Thanks.
Johan
I am planning on using Cerablanket from Mcmaster-carr.
These are the my areas of uncertainty:
Most discussions mention Aluminum foil for encapsulating the Cerablanket. 1. For engine side of firewall installation, should one not use SS foil on the engine side rather than aluminum (which will melt rather quickly I would think)?
2. Should I use aluminum foil on the other (firewall) side as encapsulating material?
Then the last question:
As in case of the RV4 fire with melted floor, I am left with clear impression that insulating the firewall alone leaves one with the risk of burn through the aluminum floor directly below and behind the firewall, since flames follow airflow.
3. Any ideas how to "meltproof" that area? Applying SS directly to the forward floor skin might still melt the underlying aluminum if no poor heat conductive material is placed between the SS and Al (I think).
Thanks.
Johan
RVbySDI
Well Known Member
You might want to read this thread:
http://www.vansairforce.com/community/showthread.php?t=112905&highlight=firewall+insulation&page=2
click on the links in post #12 of this thread for stainless (engine side)/aluminum (firewall side) foil wrapped insulation materials.
There are many other threads on firewall insulation in addition to this thread. You might do a search on firewall insulation and start reading.
