help needed please

[tammynjames07]

Hi everyone,

I had a idea using some box section but have no idea of the sizes it comes in. What I need is something about 4 inches wide but not as deep and about 8 inches long? Also as its only a small length any ideas where I may be able to get hold of it? It's for a small project i'm working on.
Thanks in advance
James

 

[astro_al]

Metric equivalents of imperial sizes are what you buy - so you want 100mm box section, but the smaller 2nd dimension makes it 'rectangular hollow section' (instead of 'square hollow section'). The final dimension is the wall thickness in mm - typically 3, 4 or 5 in that kind of size.

Look on parker steel (google it) for an easy idea of available sizes.

That is a tiny bit though, so just call around a few local fabrication firms (or better yet, pop in with a fiver in your pocket) and see what they've got in the scrap bin - you're bound to find what you need, even if they need to chop a bit off for you.

If you're really stuck, I have some 100 x 50 (4" x 2") that I can post up to you - or you can pick up if passing.

Al.

 

[tammynjames07]

thanks for your quick response I will have to try and find some local firms. I will keep your offer in mind
James

 

[the snooper]

you could also try your local scrap merchants they will sell the scrap

 

[Hitch]

Both 100x50 and 100x60 should be easily available, 3mm wall probably the most common, although others are available.

Austen Knapman sell it per metre.

Let me know if you get stuck.

 

[tammynjames07]

Thanks for all your suggestions, I will let you all know what I wan't it for. Basically I thought about adding some steel each end to make it a solid box then adding two ports to use as a back boiler for a woodburner I am constructing. This is to heat water for the radiators.
Any suggestions on wether this is the best route, my other idea was a coil of 15mm copper in the very top of the burner?
Advice is appreciated.
Thanks in advance
James

 

[astro_al]

You can do either, but I don't think 100x50 will be big enough to get much heat into the water before it has passed. At that size you'd defo want baffles to channel the water in a zig-zag to give max heating time.

Copper spiral can work well - better contact area (surface area to water volume ratio).

I'm about to rebuild mine before the winter - get as much contact with the back / sides of the firebox as you can manage. Maybe start a thread in the projects section for advice.

Al.