Morning Engineers! I have a 60 year old home and the joists are 2x8 on 16" centers across a span of about 15' (total flooring area 30x22, but there is a 6" girder down the center, effectively making the span 15' at the girder). The floors are safe, but not nearly as solid as I would like them to be, they just have a little too much bounce.
I'm about to begin major renovations, like expanding the kitchen, etc, and will be running a reinforcement support beam across the joists in the crawlspace with jack posts and 4" pads on the rough concrete floor.
I don't know what would be easier and less expensive, a steel 4" I-beam, a 4x6 'Lamabeam', or a 6" wood I-beam? The crawlspace is dry and termite free.
I will be installing this myself with a helper. I am more than qualified for the installation, I am just a little unsure of which material to use.
Any suggestions, input, or experience will be appreciated!

I would like to ask of you know where can I buy for my diy evaporatove cooler project a wicking paper like pad. I want to make it without a water puml therefore it would use a sort of a wicking material slightly dipped in a water tray.

In engineering projects, challenges often arise across various areas, such as project management, interdisciplinary collaboration, and stakeholder engagement. For example, project management hurdles might include resource allocation, schedule adherence, or adapting to evolving project scopes. Collaboration between disciplines can be hindered by differences in technical languages, conflicting priorities, or misaligned workflows. Engaging with clients and stakeholders often presents its own set of challenges, such as managing expectations, ensuring clear communication, and balancing competing interests.

How do you navigate these multifaceted challenges, and what specific examples from your experience highlight the most significant difficulties? Furthermore, what processes, tools, or cultural shifts do you think could improve these areas, particularly in fostering better coordination among disciplines and ensuring more effective communication with stakeholders?

I have two 3D objects, and I want to develop an algorithm to determine whether one 3D object can fit through another 3D object's geometry without obstructing any part of the structure. For instance, imagine I have a wooden bed that needs to be placed in a bedroom inside a house. While the bed fits within the bedroom itself, I want to verify if it can be transported from outside the house to the bedroom.

Practically, this often involves maneuvers like flipping the bed vertically to pass it through doors and then flipping it again to position it correctly in the bedroom.

I already have the 3D coordinates for both the house and the bed. Additionally, I know the target position where the bed should be placed. My goal is to check if it's feasible to move the bed from outside the house to this target position, ensuring it navigates through all pathways and doors without collision.

I believe this can be approached in two ways:

1. Start from the target position and work backward to the outside of the house.
2. Start from the outside of the house and progress towards the target position.

The desired output should be a trace of the path, including the necessary translations and rotations to successfully position the bed.

Is it possible to solve this? I apologize if this is not the appropriate subreddit for such questions. Any suggestions or guidance would be greatly appreciated.

Does anybody know a good source for 2", 5052 aluminum tubes 28 or 35 gauge? Welded or not, doesn't matter.

Only found TW Metal in LA but they charge stupid ridiculous shipping cost of $300 non expedited shipping even LA to OC within California for a single 12 ft tube.

Hi everyone,

I am in search of 0.1 mm hydrophilic coated aluminum for an HVAC-related project. The material needs to have excellent corrosion resistance and hydrophilic properties for efficient heat transfer. Specifically, I’m looking for: • Thickness: 0.1 mm • Coating: Hydrophilic • Application: Heat exchangers or air conditioning fins

If anyone knows manufacturers, suppliers, or distributors in India that deal with this type of aluminum, please let me know. Also, if you’ve worked with similar materials and have recommendations for brands or specific suppliers, I’d appreciate your insights!

Thanks in advance for your help!

I am going to preface this by saying that I am not an engineer, just have A LOT of leeway to think freely and use company funds to bring some ideas to life.

I recently built a small "filter" vessel, and I have had some decent results testing wise.

The filter is built by top layer being punch plate, the next layer is low micron ~50 mic SS mesh, followed by 3' of sand. The bottom is the reverse. The filter sits about 1' off the bottom of the vessel.

In past tests I have tried all sorts of sand mixtures from super fine beach sand to blasting media and the common problem that I run into is that I cannot get water to filter through fast enough. I'm looking for a media that will still maintain some integrity but let liquid flow a little bit faster. I would really like to avoid putting rocks/gravel in there so even if there is a non-naturally occurring or synthetic material I could put in there

Also, a couple of notable things to take into consideration. I cannot increase surface area. I cannot have less than 3" to keep integrity in the frame of the filter to bear the load on it. weight plays a major factor in this as it is a mobile vessel that has to adhere to limp dicked DOT weight restrictions. Lastly, there is vacuum pulling on the bottom side of the filter helping liquid com through the filter.

I apologize if this seems a bit jumbled, but I am not a great typer and because of that my brain is moving faster than my hands. Any and all help is appreciated

The idea is to make a non conductive electric high tensile wire fence post, with rebar or other metal rods.

That can withstand sun exposure , and durable enough to withstand being rough handled while being brought to the site, so that the coating doesn’t come off and present a potential grounding issue.

I see epoxy’s as promising but sourcing what type may work best for me has proven challenging. Concrete epoxy??

It’s a huge bonus if you can apply it to rusty material and it’s as easy as dipping the rods into a vat and then setting to dry.

Any help would be appreciated!

I bought a reflex punching bag called a grodex black mamba. The object has a base, a metal rod that bounces back and forth and a tennis ball on top that you punch. I was looking for clever ways to add something bigger than a tennis ball that would be somewhat easy to do. Any ideas are appreciated

Hi there!

I am looking to build a prototype for a CPR device as a personal, student project. However, I do not want the piston to be too strong so that the device remains safe around those who might tinker with it. It is not intended to be wholly representative of a traditional Stryker or Zoll model. As such, does anyone know where I might find a cheap air compressor that’s relatively quiet. I’m looking for:

• Low PSI max. 25 is more than enough.
• <60db
• No tank required
• Smaller the better
• <$70. <$50 preferred

I understand that the constraints seem weird and somewhat awry from the general air compressor market, but I’m not looking for a lot of power. I also am somewhat unfamiliar with air tools. I have put ~4 hours of research into this but I certainly am no expert.

I have asked around in r/Tools about potential options for this, and they are giving good advice, but a lot of it falls outside of my price range.

Please let me know if this can be done. Thanks!

As an aside, I have a little engineering experience. I am a third year student, and admittedly, I only know a drop, but I want to use this project as a learning opportunity and would love feedback. Said differently, please be gentle haha.

I'm not sure why I never thought of this before, but it takes an incredible amount of energy to melt or boil any material, even when compared to heating it up.

Hot water is dangerous. But steam is even more dangerous because of how much energy is inside of it.

Melting something or vaporizing it is the best way to store heat, instead of using a large thermal mass. When something turns from liquid into solid, it releases heat into the environment.

(I've totally overlooked this and wow I feel stupid)

Has anyone ever done anything interesting with melting things for thermal storage? I've heard interesting things with using concrete and water thermal and chemical storage but I've never thought of melting things for thermal storage until 10 minutes ago

So is what I'm considering an actually good idea? Are geodesic structures worth the effort of dealing with all the weird angles or are they the fantasies of people missing key elements of sound structural and practical engineering?

I'd like to build a geodesic structure (icosahedron)- a dome of frequency V2, V3 or maybe V4 using steel L-bar/angle iron. I'm looking for something I can do cost-effectively for a structure that supports glazing and some insulated wood paneling, but doesn't rot like wood does. First version is likely to be a 4 meter diameter V2 structure.

Here's a video describing my issue: https://youtu.be/usnHJEaubv0?si=d2sYVToAOmDff_Z4

Besides the initial general question posted above, I have two additional more specific questions:

The sections of the L-bars should be in line (parallel and and right angle) with the planes of the triangles that make up the geodesic structure. The plane of each panel is at a specific angle to its neighbor depending on the frequency and type of icosahedron chosen. This means that by design, there will be a gap between each of the panels. This gap will be facing the elements and some of these gaps will be horizontal, such that water has a high potential of pooling. I've thought about a few ways of making this work using beveled washers, cut tubing or some sort of other compressively strong solution to support the length of a bolt spanning the gap exposed to the elements and backfilling the rest with some sort of UV-resistant caulking and covering with some sort of tape-like membrane. What kind of fastener would you use here? How would you do this?

The second question I have is about the work done by the material within the structure itself. From my understanding, an icosahedron is a very strong structure from a static perspective, but what happens when compression builds up in the structure? Say I build the whole thing in the dead of winter, is there a chance the structure shears apart, bends or fractures at the height of summer due to the steel expanding in the hot sun? Would I need to account for this by using some sort of rubber between panels?

And yes, the elephant in the room is building with wood, but for this post I'd like to focus on steel.

(I've done some googling and haven't had much luck, AI was also not helpful.)

Basically, I'm trying to figure out if something is possible (even if incredibly inefficient) and if there is a name for it.

I'm picturing a kind of tube on the bottom of a ship that takes in cold water at the front, then dumps heat into it and the thermal expansion causes it to be pushed out of a nozzle at the back. I don't mean boiling the water or injecting steam, just a heat differential causing a flow of water. I imagine it would perform the same task a keel cooler does with the added benefit of thrust.

Some thoughts on uses:

- Using waste heat from marine diesel engines to provide additional propulsion

- Adding solar thermal to a ship for extra propulsion during the day

- Silent operations for submarines

- Inducing a current in a canal or canal pond

Has anyone ever heard of anything like this?

I know there are many different variables involved in how long a part lasts, but I'm wondering if there's a general guide for expected service life on various parts? Like, a big reference book, where you can look up "Fuel injector" or "Wheel bearing" and see an average expected service life (in hours or kilometers) for ideal conditions.

I'm sure OEMs have this information as a result of their decades of testing, but I doubt they'd be thrilled with the prospect of sharing their hard-earned knowledge.

The reason I ask is that this information would help me predict when I might start to expect issues with a given system. I like to be proactive with my vehicle maintenance, but I don't want to start replacing things that have plenty of life left.

don't they do the same thing? and doesn't the feed rod already have a transmission? can't the feed rod do the same thing lead screw does by varying the speed?

My window AC is designed to cool spaces up to 150 square feet.

According to the label: Voltage-115 Amps-4.6 BTUh-5000 Horsepower-1/12

1. If you do the math with the voltage and amps to get the wattage, it’s 529watts, but 1/12 horsepower is ≈62watts. What’s the horsepower label for?

2. How much does the compressor influence energy consumption (please remember my unit is small)

3. Is the compressor triggered by the temperature of the air it’s pulling from outside or is it triggered by the temperature of the room?

Edit: formatting

I would like to make an industrial cyberpunk PC case using slotted steel angle and expanded steel mesh. One feature I've noticed a lot in cyberpunk games and movies is large, backlit, slowly-rotating fans and I would like the front of my computer case to feature such a fan. I'd like a ~40 cm fan affixed to the front of the case, able to rotate between 12-24 rpm (for aesthetic) at its slowest rate and then increase speed to 240 rpm (for effect) according to a PWM signal received from a fan header on the motherboard. Whatever motor I use will operate at a higher speed but I will use a gearbox of some kind to reduce this.

According to my reading, most PWM PC case fans go down to 10% of the top speed but I did find some Arctic fans which can go down to 5%. If I can go down to 5% then my ideal range would be 12-240 rpm, otherwise 24-240 rpm.

I found some cheap radio-control BLDC electronic speed controller modules which my reading suggests expect a 50 Hz PWM frequency. Meanwhile, a PC motherboard fan header outputs 25 KHz so I can't simply connect a geared down BLDC to my motherboard via a random BLDC ESC. Maybe there's an easy way to reduce the frequency of the PWM signal from 25 KHz to 50 Hz without altering the pulse width?

Having spent a few hours not really getting anywhere, I've come to ask for guidance on how to achieve my goal reasonably simply and cost-effectively. Here is an image of the sort of fan (some kind of vehicle fan) I envisage using: https://s.alicdn.com/@sc04/kf/Hc0896ad485174bd68258195a052ce328k.jpg_720x720q50.jpg - the motor housing is on the outside of the fan cage which is not ideal but I haven't found anything more fitting yet.

I want to make a bunch of cable reels for all of my industrial stick welders using 1-0 or 2-0 cables for hot and ground. I’m not looking for any kind of Jerry-rig setup, I want something somewhat reliable and somewhat attractive.

Similar products on the market are around $1,500 and they use Liquid Metal for constant contact, but I’m wondering if I can DIY them cheaper as I need a bunch of them. Not sure why my phone is capitalizing Liquid Metal so let’s just deal with it. The ones on the market are bulky, I want to design it somewhat flush with the cart wheels that stick out (less probability of somebody whacking it with a fork lift).

I don’t need it to have a steady contact as the reel is spinning, but I do need to be able to reel in a cable without disconnecting it because my iron workers will eff it up if it’s not iron-worker-proof (aka touchless because they break everything they touch)

I am an engineer with as much field experience as I have design experience so the design and functionality part of the project isn’t the issue. The issue is that there’s a special piece of hardware out there somewhere that would be exactly what I need to design a single pole slip ring that can handle 250A but I don’t know what it is.

So far, my research has led me to brass graphite bearings? The Mercotac 1250 is a mercury slip ring that would handle it but I’d rather have something simpler because they WILL break it and I’d rather not have a chemical spill.

When making drill pipe connections, why is circulation head connected periodically to pump in mud into the well, and later on removed to continue making a connection of drill strings, and the procedure keeps on repeating?

What's the "why" behind the common things people do to make suction cups stick longer to surfaces?

1. Swabbing surfaces with alcohol (why not just water and let air dry?)
2. Vaseline
3. Placing the cup in boiling water for 30 seconds

I'd also love to know why when I try method #2 the cup just ends up sliding across the surface.

Hi,

Im working on a project that requires like a rotation part but I need it to be biased towards one side, so I want it to be spring loaded.

To further clarify what I am looking for:

- Think of a roller bearing or a ball bearing, it has 2 concentric rings with balls in between.

I want to have basically that, but instead of balls between them a coiled flat spring or something that allows the inner ring to rotate, but when "let go" it rotates back to a set position. This may already exist as a product as it many times is with things Im trying to build from scratch.

I cannot find anything similar anywhere. Any ideas? There are 0 threads on the tip. It has a 5/16” hex head with an overall length of 2”. Picture link below.

https://imgur.com/a/WNLgj1g

Cant post images which illustrate unfortunately so you'll have to make do with my description!

I have a travel cutlery case that is clearly an aluminium extrusion, that is then cut to length and finish machined to add end profiles etc. The Whole case is matte anodised and looks great but the chamfers have a gloss finish.

How do they do it? Is it simply surface prep that they blast the extrusion and then leave a smooth finish with the machining?

Same question but for a pen pot I have - the pot is black anodised but the chamfers are raw metal. Are people really machining parts, anodising, and then machining chamfers on just for aesthetics on a $6 pen pot?

I am taking both thermo and polymers this upcoming semester and I have heard some pretty scary things about both of them. I am wondering what tips and tricks everyone has to understand topics and study for exams. Are there any specific instructors on you tube that I should look into? Or in general guides online? Honestly anything you all could recommend would be great so that I can hopefully get a jump start on content before the class starts.