Firewall Clad

[mike roe]

I have a 52 B mdl.Am I correct in assuming the firewall from the factory was aluminum(?) clad steel.If so anyone know if it is possible to have it redone.If so any leads on who does this type of thing.

[c170b53]

Removal and installation relatively easy but why do you need to replace it? (New stainless steel were available from Cessna at around $400)

[n2582d]

Look under the "Bird of Prey" website listed on the "links" tab of the home page for pictures of Guido Perla's refurbished firewall. Here's what he says about who did the work:

# Allied Technical Services Corp. Also Pacific Aircraft Welders. They are owned by Steve Hansen and John Shockley. A pair of nice guys. Very knowledgeable and with a lot of skills. They do many things. Precision machine work, steel/aluminum welding, powder coating, galvinizing etc. If you need to repair something they are the guys to do it. Best recommendation. They are in Seattle near Boeing Field. 6239 Airport Way So., Seattle, WA 98108, (206)763-3316. http://www.security-one.com/lesd/Allied/ You can e mail them at AlliedTech@worldnet.att.net

It might be cheaper to take it to some place listed in your phone book rather than ship it across the country though.

[mike roe]

Thanks I will contact them and research some more.I am trying to keep this plane factory original.The engine side of the firewall shows corrosion spots.I thought of going stainless,but it isnt original.It also opens a can of worms with which fasteners are used(ss,monel,etc)With the aluminum clad you dont have the dismilar metal problem.Harry in Porterville has the press to make one in ss.I am also contacting Cessna,they have the part # in stock to see the material used.
Thanks

[Metal Master]

When I ordered the fire wall by the part number listed in the 170A parts list for my aircraft, what I received was a stainless fire wall. Which had a usable on tag that came with it. The tag listed 170A's 170B's and early model 172's. Later Cessna aircraft with stainless fire walls stock used aluminum "AD" rivets to attach the firewall to aluminum structure. I have never see any degree of corrosion caused by dissimilar metal associated with any stainless fire wall I have removed. The fire wall had the heater cut out in it on the wrong side and for the rectangular type control. it also had the holes piloted for the cross fire wall heat distribution duct. I installed it. It looks great. I am happy.

However I can say that I have had many dealings with Allied Technical Services other wise known as Pacific Aircraft Welders and both John & Steve. They have helped me solve many problems over the years. Almost nothing I taken to them has been routine. I had some people contact me one time about trying to do a repair on the elevators on the Space Needle (Seattle’s Own Flying Saucer). It seems they had some how damaged the aluminum skin on the elevators and could not find any one that could repair it. I had them call John and in short order Allied Technical Services had them Elevating again. They do not always do things themselves but they do know who can get it done. They may not tell you who that is that does or did the work wanting to manage the job themselves as a middle man.

[c170b53]

Good info from M.M. on the wall. There's unserviceable,serviceable and perfect all subjective, depending on your time in or personal traits. If you want to keep it as original as possible then your probably leaning towards cleaning up the local areas of damage. I'd use scotch pads on an angle drive to remove the corrosion, try to avoid overheating the metal. Its hard to imagine areas of corrosion that would require significant material removal from the firewall unless we are talking damage from corrosive fluids from the battery. The reason I say this is even if the engine doesn't leak oil, the breather probably will providing a protective oil film aft of the baffles.

[hilltop170]

The aluminized coating is very thin and easy to rub through. I would do all cleaning/corrosion removal by hand, no power tools.

[c170b53]

A picture would help but if the removal is being contemplated it sounds a bit late for that.

[mike roe]

I have contacted and spoke to Allied Tech Services on cladding the firewall.They seem to remember doing one and were going to get back with me this week.Its not much,if any corrosion but more aluminum clad worn off thru the years.I will keep everyone posted.
Thanks

[n2582d]

Mike,
I can appreciate your desire to keep the plane original. In my unbiased opinion the '52 model is the best 170 Cessna ever made. I especially like the panel with the piano key switches --"truly classic". One thing Cessna improved with the later models though was the heating system. As you will be removing your firewall anyway your might consider updating the heating system. Only a 170 guru would realize the change is not original. I would also think your passengers would appreciate the upgrade when flying in the winter in Virginia.

Heater installation.jpg

My firewall looked like swiss cheese so I replaced it with a stainless one from Del-Air. I have yet to install it. At this point I'm leaning toward putting in the later style heating system. Any Californians with an opinion on whether this change is necessary out west? This upgrade means, among other things, mounting the battery on the other side and a muffler shroud change. I think this change can be done with just a logbook entry as a minor alteration. Other IA's out there care to agree/disagree?

I thought of going stainless,but it isnt original.It also opens a can of worms with which fasteners are used(ss,monel,etc)With the aluminum clad you dont have the dismilar metal problem.

Good point. It is interesting that on many later model C-172's that I have seen the monel firewall rivets are corroded. Dipping the rivets in zinc chromate primer before installing them might reduce this corrosion.

[c170b53]

O.K. sounds like Hilltop 170 had a better idea of what you were trying to address, why would you not just paint it silver?

[GAHorn]

... At this point I'm leaning toward putting in the later style heating system. Any Californians with an opinion on whether this change is necessary out west? This upgrade means, among other things, mounting the battery on the other side and a muffler shroud change. I think this change can be done with just a logbook entry as a minor alteration. Other IA's out there care to agree/disagree? ... Dipping the rivets in zinc chromate primer before installing them might reduce this corrosion.

Something to consider: Airplanes are not "regional" like autos. (Thinking of "California emissions" type autos versus the other lower-47 states.) An airplane is very likely to be sold to someone from another region, and a good cabin heater is a strong selling point beyond it's functionality to the present owner. If you're up to the task (and not committed as Mike is to originality) then the heater upgrade is a great one! It will measureably add value to the airplane to anyone knowlegeable about Cessna 170s. Since it's a Cessna design, and also since it's an interior item, it's a logbook entry.

As for dipping rivets.... most rivets are already alodined.

[c170b53]

I think there's a bit of work to be done if you want to upgrade. Replaced mine with a new Cessna firewall (original attached with AD rivets) and as M.M. mentioned it comes pre-drilled which made replacement easy (very important to break the edges of the holes and the stock firewall will arrive with that process completed by the factory). I read that the Aussies have a AD (170/84 10/2008)to check the engine mount fuselage structure and I believe George may have also previously mentioned this to members and advised them to check this area.

[n2582d]

Airplanes are not "regional" like autos. (Thinking of "California emissions" type autos versus the other lower-47 states.) An airplane is very likely to be sold to someone from another region ... .

My plane has been through over 20 owners in the last 56 years. Surprisingly, over all those years it has not been sold out of a 60 nm radius here in California. On the other hand, I bought my Honda in Texas and Volvo in N. Carolina! Nevertheless, I agree with your point George. My plane (and autos) just happen to be exceptions to the rule.

[GAHorn]

Well, YEAH! Your airplane stays in California, of course! It 's got no heater!

(This is just a joke, folks. No need to send missles.)