Tech Spam thread - because 1/4" BSP gets 5 hand spans to the jiggawatt

[Carsnz123]

I was taught that a fuse can carry 80% of its rating happily. So 10a fuse will carry 8a all day. Going off that I usually fit a fuse 125% of the max load if a fuse isn't speced by the manufacturer. Another consideration is the wire size. No point fitting a 10a fuse to wire that can only handle 5a.  

[Mof]

4 hours ago, RUNAMUCK said:

Obviously a 10a fuse with a 10a draw doesnt leave much room for error.

Yeah that makes fire 

[RUNAMUCK]

Wouldnt it make a blown fuse?

[Mof]

Yes ok, but above that 80% it makes essentially a hot wire

[Adoom]

Does anyone know stuff and things about how much I can load a beam?

So I want to make a mezzanine... erm I mean "A shelf" in the shed. It would be 3.8X2.8M

Here is a quick scribble that is not to scale.

Red is the existing steel frame posts and walls.

I'm thinking that I can just bolt to those existing posts, and maybe bolt some 50X100 framing to the steel posts to give the perimeter of the mezzanine something to sit on.

I'd like to have only the one blue post in the corner.

I could add an extra post on the short side that's against the wall if it's needed.

The 'floor' of the mezzanine would be 150X50 joists at 450 spacing on top of the perimeter frame, then 19mm ply on top of the joists.

But I'm not sure about the perimeter frame, especially the two unsupported sides.

I initially thought about using 300X50 framing.... then I found out how much it costs.

But I do have some 100X50X3mm steel RHS.

What if I made the perimeter frame out of that?

Would it be strong enough?

Do I need to double up the RHS so it's two high? I'll do this if it needs it, but if not, I don't want to 'waste' the steel.

How much weight could my "shelf" support?

I'm not thinking of putting heavy stuff like engine blocks up there, but lots of light things will add up....

 

 

[Sunbeam]

I spanned 3.6m for my mezzanine with a double 240x45, and used 190x45 joists with 21mm strand board flooring. It’s slightly springy, but like you I balked at the price of 300x50.

[Bling]

I'd start the design by looking at the deck building guides on Bunnos / M10 / ITM websites. They often include the building code sections relating to beam sizes for spans and spacings etc. 2.8m is a fair span, especially if you are piling your junk up there. Adding that extra post on the 2.8m length and one against shed wall, with a double beam between them could cut down on timber needed. 150x50 would probably be decent for 1.4m spans with the loading. Like I say though, the guides have the code that will be super handy for working it out.

[Sunbeam]

Also, I came to ask a question. My trailer has LED lights and I never had an issue with them. My latest tow rig, a beeeemer X5 has a conniption fit when I plug the trailer in with fast flashing blinkers and bulb failure warnings for Africa. I suspect the trailer light module was not intended for use with LEDs and thus the low current draw is causing the strange behaviour and failure messages. I don’t want to change the lights, so is there anything else I could do? Fit resistors? I’m a numpty with electrickery….

[Adoom]

I finally found this. https://sunsetpatios.com.au/beam-deflection-calculator.php

If I double up the RHS on the 3.6m side, and call the static load 100kg, I can load it up with 400kg it should bend about 3mm.

[smokin'joe]

someone will adjust this for current, if it isn't, but
make the 'clearspan' between fixings 3.55m ?, use 190 X45 SG8 at 400mm CRS, connected to 2X 245 X 45 at 2.8m long

[Adoom]

10 hours ago, smokin'joe said:

someone will adjust this for current, if it isn't, but
make the 'clearspan' between fixings 3.55m ?, use 190 X45 SG8 at 400mm CRS, connected to 2X 245 X 45 at 2.8m long

I'm gonna need a picture.

[mjrstar]

14 hours ago, Sunbeam said:

Also, I came to ask a question. My trailer has LED lights and I never had an issue with them. My latest tow rig, a beeeemer X5 has a conniption fit when I plug the trailer in with fast flashing blinkers and bulb failure warnings for Africa. I suspect the trailer light module was not intended for use with LEDs and thus the low current draw is causing the strange behaviour and failure messages. I don’t want to change the lights, so is there anything else I could do? Fit resistors? I’m a numpty with electrickery….

You can buy led trailer interface adapters which should eliminate the issue.

[h4nd]

15 hours ago, Sunbeam said:

Also, I came to ask a question. My trailer has LED lights and I never had an issue with them. My latest tow rig, a beeeemer X5 has a conniption fit when I plug the trailer in with fast flashing blinkers and bulb failure warnings for Africa. I suspect the trailer light module was not intended for use with LEDs and thus the low current draw is causing the strange behaviour and failure messages. I don’t want to change the lights, so is there anything else I could do? Fit resistors? I’m a numpty with electrickery….

 

1 hour ago, mjrstar said:

You can buy led trailer interface adapters which should eliminate the issue.

If it's 12V (it's not, but prob near enough) and expecting e.g. 10W bulbs, 15 ohm 15W resistors would be worth a try (temp hookup with clip leads?). 12V / 15ohm = 9.6W

Of course, your Alt is set to 14.5V so about 1A, so about 14.5W in the real world.

 

[smokin'joe]

14 hours ago, Adoom said:

I'm gonna need a picture.

run joists 90 degrees so they do not tie into longest span. 
don't ask drawings..... i can barely write legibly

[Adoom]

I'm thinking of building an outside brick fire because I've got a whole pallet of bricks left over from the house. It's primary use will be the heat source for a water pipe loop that will run along 15m of grape trellis wire, and back to the fire to hopefully radiate enough heat to stave off the late season frosts that keep fucking up the early shoots.

I'd want it to have a bunch of thermal mass, so I only want to keep the fire going for a few hours and the residual heat would keep the water thermosyphoning for hours more.

It would be a fire with a door.

So... can I just use normal cement mixed with builders sand? Or do I need to use refractory cement? If I do, do I need to use it for the whole thing, or just the layer of bricks exposed to the fire.   

[datlow]

I'd Google pizza oven diy stuff

Pretty sure you'll need fire bricks and mortor for the inner

 

[Bling]

Sell bricks,

buy old wetback, 

????
Profit warm vines

[Adoom]

15 hours ago, Bling said:

Sell bricks,

buy old wetback, 

????
Profit warm vines

It will cool down too fast I think. I'm not staying up all night to keep it going.

I suppose if I can make a system to automatically light it.... using an arduino and a temperature sensor and one of those piezo lighter

I do have an old pot belly, but it's super fucked, the door fell off and the chimney hole broke and it's kinda too small I think. But then.... I could make a steel spacer sleeve to make it much taller. And it would look like a okay garden feature.

[smokin'joe]

29 minutes ago, Adoom said:

It will cool down too fast I think. I'm not staying up all night to keep it going.

I suppose if I can make a system to automatically light it.... using an arduino and a temperature sensor and one of those piezo lighter

I do have an old pot belly, but it's super fucked, the door fell off and the chimney hole broke and it's kinda too small I think. But then.... I could make a steel spacer sleeve to make it much taller. And it would look like a okay garden feature.

drip fed oil burner.
max heat obtained from hydraulic fluid/ ATF

[tortron]

What does a top switch/high gear switch do on a manual gearbox. 

Obs. it's activated when it's in top gear. Tell the ecu to change something like lean burn or timing?