How Does titanium foil Work?

Check now

Originally Posted by Odd Man Out

Reflecting on a discussion from half a decade ago, it's incredible how fast time passes.

My brief stint with titanium (Ti) foil revealed some challenges. The foil I acquired was incredibly thin and lacked the robustness needed to replace the durable aluminum (Al) flashing I had been using. Although I experimented with it for a while, it never saw actual field use. At that time, during my alcohol stove prototyping, I relied on a cylinder of Al flashing that functioned as both a pot stand and a windscreen. Given this setup, Ti foil simply wasn't up to the task of supporting the pot.

While theoretically, a thicker grade of Ti foil might be more suitable, I didn't explore this option further because the weight savings would be minimal. Especially since my stand/screen only measures a few inches in both height and diameter. Moreover, since the heat is directed through the heat exchanger of my Olicamp XTS pot, it doesn't get excessively hot, preventing heat fatigue. These conditions might differ with designs like the Caldera Cone, where the pot support/wind screen channels heat along the pot's sides. Although I contemplated such a system, I never created one. While this might allow for a lighter pot, it would come at the cost of a bulkier and more intricate support/screen system. My primary design goal was ease of use – a system that fits inside the pot without the need for assembly or disassembly.

Titanium foil could serve well as a wind blocker if not used to support the pot. However, I've realized that many alcohol stove users underestimate the significance of the windscreen. More than just blocking the wind, it plays a crucial role in regulating oxygen intake and channeling heat output. These parameters are vital for maximizing the efficiency and power of your alcohol stove. While flimsy Ti windscreens are often used merely to block the wind, without proper placement around the pot, they don't effectively manage air and heat circulation, leading to inconsistent performance. But if detailed design isn't a priority, this might not be a concern.

Hi Bob

To start, why choose square holes over round ones? Square holes can be trickier to fabricate. Is there a particular advantage?

If square holes are essential, beware of sharp corners as they localize stress and can lead to cracks and tears. Opt for rounded corners – even using a 3 mm (1/8") drill bit in each corner can enhance durability tenfold, though I'd recommend 4 mm.

For those requiring a few square holes and seeking a professional finish, here’s my approach after years of working with Ti:

Use two pieces of Al sheet, roughly 1.6 mm (1/16") thick, and ensure one dimension surpasses the Ti foil size. Clamp them together. On the outer edges, drill two small registration holes outside the Ti foil boundary. These are crucial for realigning both sheets with the Ti foil in between.

Mark the square in the center and drill out the four corners with 3 or 4 mm bits. Remove the middle section by any means, possibly needing some filing. Do both sheets together for uniformity, creating a cutting template.

Next, position and clamp one Al sheet over the Ti foil, with a piece of hardwood beneath. Drill the four corners with matching bits. Replace the wood with the second Al sheet, clamp well, and cut out the square with a small box knife against the Al sheet. Repeat as necessary.

Note that attempting a square hole punch & die on a 5 thou sheet won't work; the clearance between punch and die is too large for foil, likely resulting in distortion and tears.

Cheers

Originally Posted by Odd Man Out

This was one of my threads from five years ago. How time flies.

My experimentation with Ti foil was short lived. The foil I got was very flimsy and not sturdy enough to substitute for the robust Al flashing that I had been using. I played with it for a while, but it never made it to field use. I don't recall where I was in my alcohol stove evolution at that time, but now I am using a cylinder of Al flashing that doubles as both the pot stand and wind screen. As such, the Ti foil would not be sturdy enough to support the pot. It is possible there is thicker grade Ti that might work, but I never pursued it as any weight savings would be negligible since my stand/screen is only a few inches tall and a few inches in diameter. Also since it directs heat through the heat exchanger of my Olicamp XTS pot, it doesn't get very hot and thus doesn't suffer from heat fatigue. The situation may be different with a design such as a Caldera Cone where the pot support/wind screen directs heat flow up the side of the pot. I considered that type of system but never made one. While it would allow me to use a lighter pot, it would be at the expense of a much larger and complicated support/screen. Having design that is easy to use (stores inside the pot, requires no assembly/disassembly) was an important goal of mine when developing my system.

Ti foil would work for blocking the wind when it is not supporting the pot, however I have come to the conclusion that the role of the wind screen is under-appreciated by many alcohol stove users, probably because it is called a "wind screen". I feel it serves a much more critical role of controlling oxygen intake and directing heat output, both of which are important design parameters if your goal is to optimize the efficiency and power of your alcohol stove system. I've seen lots of videos of people using flimsy Ti wind screens to block to the wind, but when placed rather haphazardly around the pot, I don't expect it is plays much role in controlling air and heat flow and giving optimal and predictable performance. But if that is not a design parameter that is of concern to you, then it doesn't really matter.

Hi Bob

First of all, why insist on square holes instead of round ones? They are definitely more challenging to produce: is there a genuine advantage?

Assuming that square holes are indeed necessary, be cautious of sharp (i.e., square) corners. They focus stress and can lead to cracks and rips. Aim for rounded corners; even a 3 mm (1/8") drill bit in each corner can significantly prolong the foil's life, although I would favor 4 mm.

If precision is key and you require a few square holes, consider this professional approach. With a few years of experience working with Ti, here's my process:

Take two pieces of Al sheet, about 1.6 mm (1/16") thick, each larger than the Ti foil by at least one dimension. Clamp these sheets together. At the edges, drill two small holes outside the Ti foil's boundaries. These serve as registration marks, ensuring alignment when the Ti foil is placed in between.

Outline your square in the center, and drill out the four corners with 3 or 4 mm drill bits. Remove the remaining center part any way that suits you – some filing may be necessary. Work on both sheets simultaneously to ensure uniformity, creating a cutting template.

Next, clamp one of the Al sheets over the Ti foil, placing a piece of hardwood underneath. Drill the four corners using the same drill bits. Replace the wood with the second Al sheet. Clamp everything tightly and cut out the square using a small box knife, running it against the Al sheet. Repeat as needed for all holes.

Note that a punch and die set for square holes may not work effectively with a 5 thou sheet: the punch and die clearance is too significant for foil, likely causing distortion and tearing.

Cheers