Cheers folks!
Fired up properly last night, fuelled on petcoke mix (mixture of petcoke and bitumous coke). Found it lit easily using three large firelighter blocks and a little bit of gentle draught. Managed to get everything else ready whilst keeping a casual eye on the developing fire. Forge was soon up to temperature and what a temperature it was!
First observations: Being bigger than my other forge, it holds more fuel and because the air holes are spread out more, the fire is larger and the mass of heat is greater. This is pleasing as my intention was to be able to heat larger/longer stock evenly. I would have expected to use more fuel but to be honest, whilst it did use more, it didn't use as much as I would have expected in comparison to the smaller forge. Also, with having the larger amount of fuel in the forge itself, fire management was a bit easier and I didn't need to add fuel as often. Heating stock was quick, the fire bringing 10mm square to a yellow heat quickly. Whilst this is good, it does mean you need to keep an eye on smaller stock as it'll burn much more quickly as I soon found! Having the broader fire pot with the edges around it contained the coals better, although I think I'll cut some smallish cutouts at each end to allow longer lengths to lie across the fire. Having the tongs and fire tools hanging to hand was great too, better than having to turn round to where they used to hang on the door! Shutting down was simple enough too, just knock off the fan and then put everything away whilst the fire dies down. By the time I was ready to move the forge, the fire was just a glow and the forge, whilst still hot, was cool enough to move into the shed. All in all, a success I think. I've learned a lot (again!) and the next forge I build will be the better for it!
The original design criteria were 1. must be as cheap as possible! 2. must use reclaimed materials where possible 3. must be able to get decent lengths of steel into it. I think these have all been achieved! The long shape of the forge meant a good length of steel can be put in it, although I'll modify to improve this further by adding cutouts and maybe extension pieces to support the ends. The whole forge, apart from the lining materials and various nuts, bolts and screws, were made from reclaimed materials that were found by ferreting through scrap heaps and scrap bins. The lining materials (two pots of Screwfix No-Nonsense fire cement, vermiculite from the Allotment Association) came to less than a tenner. Factoring in welding electrodes and sundry items, I'd say the build cost was certainly under £15 so certainly cheap!
Finally, this is what I made last night - a hanging basket bracket! It's not quite finished, as it still needs a good wire brushing to clean up and a couple of coats of clear lacquer to protect it from the weather, but for the first product out of the new forge, I'm quite pleased with it.
Hope you've enjoyed the build and hope it inspires others to have a go at getting into blacksmithing!