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DIY firewalls (plastic)

basslord1124

Well-known member
#1
Just wanted to share this with the community.

So, I tend to be pretty hard on the FT wood firewalls. I started looking for some alternatives. One thing that caught my attention was @nerdnic plastic trash can approach. I was at a Dollar General and unfortunately they didn't have any cheap small plastic trash cans. They had a larger trash can that cost more AND honestly the plastic felt flimsy. So I hunted around the store for something else I could use. Ended up finding a a plastic dishpan for $3. Something like this:

https://www.amazon.com/dp/B0039V2G5E/?tag=lstir-20

The plastic felt much stronger than that larger more expensive trashcan. So I gave it a try.

Using some large snips to help sort of break up the dishpan into workable sections. I used the Flitetest standard firewall template from the plans to get the basic size. Just with the bottom of the dishpan I managed to cut out 14 undrilled standard size firewalls. I haven't even started to tackle the sides of the dish pan yet but I'm sure I could rack up a bunch there too. Oh...and once marked, I could easily cut them out with a pair of scissors. And believe it or not, they definitely seem just as strong as the wood firewalls.

Not too bad for $3 and a little bit of work.

While I'm sure @nerdnic trash can approach works great as well, it just didn't work out for me when I went looking. So if you wish to pursue this, I would say just look around to see what you can find that has some strong durable plastic. That's the key. It could be a trash can, a dishpan, a storage container, etc.
 

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mayan

Well-known member
#2
I would like to know how this thing holds in flight and on a crash, so please share that information when you have a flight with it :).

I have a huge plastic board right outside of work been there for god knows how long and it’s about 3-5 mm thick. I’m sure it will work great but to be honest sort of afraid to try. If I am not mistaken it’s not plastic but something called fiber glass.
 

mayan

Well-known member
#3
BTW if you still want wooden firewalls you can pickup something like this for really cheap too.
7AEBC24C-DAE3-4E27-99B4-2B2FDA1BAA7A.jpeg

PS - I seem to have a picture of the thing I mentioned on the earlier post. Think that might work too? It’s that green thing hiding the water pipe ;).
FE2C3A6B-B812-48B5-8C49-9C2D66532BE4.jpeg
 

basslord1124

Well-known member
#4
Ooooo, clock idea is a good one. Anytime I've tried looking for any type of wood similar to what FT uses, it's either too thick or something.

Yeah I want to see how these hold up too. Right now, 2 planes will get them...my Simple Cub and my Storch. My other planes already have wooden firewalls that just luckily haven't been broken yet. Although give them time and I will break them lol.

I would say you could use about any material you want as long as keep some basic things in mind...
-avoid stuff that can crack real easily
-avoid stuff that's too flimsy
-make sure you could mount your motor on it...not too thick, etc
-lightweight
-make sure it will secure to your power pod ok
-not be too difficult to cut more if needed.

I don't how well this plastic will adhere to the foamboard power pod. I'll rough up the edges with a razorblade like we do with servos and hot glue it. BUT, I most always reinforce the firewall with packing tape or strapping tape so it should hold pretty good.
 

Merv

Well-known member
#5
Great idea, let us know how they work out.

In my thinking, when you crash, something is going to break. If you make the firewall stronger, you have just moved the weakest point somewhere else. I would prefer to replace a firewall instead of a motor shaft. The idea is to make the weakest point something that is cheap and easy to replace. Making lots of plastic firewalls may just be the answer.

My ideal solution, something that was strong enough to hold in flight but would pop off on a crash. The repair, just snap it back in place.