Making metal boxes

Sparky1 · Post by **Sparky1** » Mon Jul 13, 2020 8:23 am

I've got a couple of projects on the go, which would benefit from doing some basic metalworking.

1. I want to make a metal door to fit inside a wood-fired oven in the garden. The idea is to cut the door from a metal sheet and make a box to the shape of the door. It needs to be a box so that I can fill the void in the box with Vermiculite granules to act as a heat insulator. The dimensions are 25(D) x 250(H) x 400(W)mm, with a curved top.

2. The second project is an ash box for a home-made BBQ and the dimensions are 75(H) x 35(D) x 65(W)mm.

For both, which would I best work in, mild steel or stainless? What sort of thickness? Which is easiest to work in? Can I make the joints by folding flaps and screwing them or should I get them welded?

I've only got basic metalworking tools but I have access to a compressor and nibbler.

Is using galvanised material next to heat a problem? The heat for the wood-fired oven is going to be in the region of up to 600C but the BBQ ash box could be higher. Someone told me that galvanised sheet gives off toxic fumes when heated. Is this true?

Any help or guidance would be appreciated!

Chippo1 · Post by **Chippo1** » Mon Jul 13, 2020 10:18 am

Galv won’t last two mins at those temps.

Zinc does give off Toxic fumes when very hot , I can’t remember the temperature that this happens at, but welding galv materials you can get wisp of white smoke which is the Zinc , if breathed in it was known as metal fume poisoning , as I recall symptoms like the flue. God dug that out of the memory banks learnt that at college in the early 1970s.

wine~o · Post by **wine~o** » Mon Jul 13, 2020 12:37 pm

As stated Galvanised will give off toxic fumes, IIRC only needs to be 250/300 Celsius.

Chippo1 · Post by **Chippo1** » Mon Jul 13, 2020 2:12 pm

If your doing it yourself just use stainless steel sheet

Nos · Post by **Nos** » Tue Jul 14, 2020 8:17 am

Chippo1 wrote: ↑Mon Jul 13, 2020 2:12 pm If your doing it yourself just use stainless steel sheet

Stainless is more difficult to cut and weld than mild steel. The best doors are cast iron, there is plenty for sale on the internet, and they seem pretty cheap, perhaps you can have a look there. Your ashpan as it's outside would be better in SS, you could fold and screw/rivet or bolt it together, the problem is folding it neatly and in a straight line, again Youtube has videos on how to do it without a bending machine. I know we all like to make things, but unless you have the correct machinery, it can end up costing you more in scrapped work. See if there is a friendly sheet metalworker based near by, have a chat with them.

Chippo1 · Post by **Chippo1** » Tue Jul 14, 2020 9:23 am

Yes welding SS you need mig or tig

Cutting , you would go through jigsaw blades like they had gone out of fashion , hacksaw works ok if you can support the workpiece properly. Thin metal cutting discs in 4.5 inch grinder work well to.

But yes find a small local fabricator who does a bit of SS work but the material from them and get them to fold what u need for cash !