Stainless Steel Firewall Thickness

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Stainless Steel Firewall Thickness

Postby Tralika » Sun Jun 02, 2019 12:47 pm

I was looking at a friends Super STOL recently and I noticed his stainless firewall seemed to be made of thinner material than what came with my kit. His kit was produced a few years ago, my Highlander kit is a bit older, produced in 2009. I wasn't able to measure the thickness of his firewall because it was mounted, with the engine, on his airframe. If anyone has a kit produced in the last few years that hasn't mounted the the stock stainless firewall yet, could you measure the thickness for me. I'm curious if they have gone to a thinner material. Mine is .032". I ended up using titanium and saved about four pounds over the stainless.
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Re: Stainless Steel Firewall Thickness

Postby BucF16 » Sun Jun 02, 2019 5:44 pm

What titanium thickness was yours?
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Re: Stainless Steel Firewall Thickness

Postby danerazz » Sun Jun 02, 2019 6:38 pm

Can’t find it immediately, but mine is .018” ss, I had found a spec showing that met adequate fire protection
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Re: Stainless Steel Firewall Thickness

Postby Tralika » Sun Jun 02, 2019 6:57 pm

BucF16 wrote:What titanium thickness was yours?


My titanium firewall is .020. It's available from McCaster-Carr for about $165
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Re: Stainless Steel Firewall Thickness

Postby danerazz » Sun Jun 02, 2019 7:34 pm

Dane

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Re: Stainless Steel Firewall Thickness

Postby Tralika » Sun Jun 02, 2019 8:01 pm

.018 seems about right. Like I said, the firewall that came with my kit is .032 and I could tell the one I was looking at on the Super STOL was quite a bit thinner. Someone might want to check my math but I have in my notes that the .032 stainless weighs 1.1 lb/sf. The .018 stainless should weigh 60% of that or .66 lb/sf . The firewall blank is 24" X 31.4" or about 5.25 sf. So the new stainless firewall blank should weigh 3.46 lbs compared to the titanium blank which should weigh 1.97 lb (.375 lb/sf), a savings of about 1.49 lb or 23.8 ounces. The titanium costs about $165 from McMaster-Carr so that comes out to about $6.92 per ounce saved. It would be a little less if you did not order the stainless firewall blank with your kit. Also, the finished firewall is slightly smaller because you trim off the top of the blank to fit the bottom of the rounded boot cowl. Whether saving weight is worth over $7 and ounce (don't forget the shipping) is a personal decision. If my math is off let me know, I'll try again later this evening after I've had a couple of beers. That should make it easier.
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Re: Stainless Steel Firewall Thickness

Postby BDA » Sun Jun 02, 2019 8:32 pm

.032 stainless in my kit too

So Titanium for me.
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Re: Stainless Steel Firewall Thickness

Postby BucF16 » Sun Jun 02, 2019 9:45 pm

Thank you all! It is amazing how many items I’ve Upgraded from the original kit.

Cheers Bruce
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Re: Stainless Steel Firewall Thickness

Postby CanadianSheepHunter » Wed Oct 09, 2019 12:30 am

Hi guys I’m new here, I live in Dawson Creek, BC, Canada, just got my kit, i called today looking for Titanium and had no luck, so I’m glad I stumbled onto this. Is there anywhere else on the build it could be used? How hard is it to drill?...what drill bit is needed to drill Titanium? How is Titanium for cutting ? And what do you cut Titanium with?
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Re: Stainless Steel Firewall Thickness

Postby Tralika » Wed Oct 09, 2019 11:36 am

The titanium was not hard to work. I cut it with a pair of big tin snips. I was able to roll the bottom edge over a dowel to make a slight curve that fits around the the bottom piece of airframe tubing. I drilled it with standard hardened drill bits. Easier to work than the .032 stainless that came with the kit. My titanium blank is .020. You could go as thin as .016, that is the thinnest approved by the FAA for certified aircraft.
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Re: Stainless Steel Firewall Thickness

Postby BucF16 » Sun Oct 13, 2019 3:18 pm

I got my .020 Titanium firewall this week. My Harbor Freight shear made easy work sizing it to fit. Next question. What type drill bits did you all use? Your normal carbide jobber and titanium step drill bits? I have looked up that you should use high speed.

Also when you cut your firewall to fit the boot cowl, what tool is best?

Thanks
Bruce
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Re: Stainless Steel Firewall Thickness

Postby Tralika » Sun Oct 13, 2019 10:09 pm

I used plain old carbide drill bits, probably Craftsman. I don't remember if I used a step drill but I'm sure it would work fine. I used the specialized titanium cutters seen in the photo that I found about half way down the tin snip bin at the used tool store. Honest, the .020 titanium is easy to work. Just cut it like you would a piece of aluminum. Rough cut to within a quarter inch or so of your line. Then cut again for your finish cut. If you have already cut it to fit the firewall try some test drill and cuts on the scrap.
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Re: Stainless Steel Firewall Thickness

Postby BucF16 » Mon Oct 14, 2019 8:22 am

Thanks John! I'll practice with my large aircraft shears.

Cheers
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