Backyard Foundry - oil burning furnace - moulding and casting a spider

Hi Fellow foundrymen... I took some time off my day job to get some casting done this week and am putting together a few videos. Dave’s original post was inspiring! I thought I would start with a short video on melting fines for bar stock…

Hi Luker,I need to cast bronze barstock but the last time I tried it [a few yrs ago] vertically it was great on the outside but after turning it it was full of porosity,inside so I cast some horizontally with sprue & feeder & they came out ok but a mess on molding them, this of course was before & knew about your inoculant which I've just used[big thanks] perhaps I'll try again vertically.,saves time .

Hi Graham, the trick to stop that is the dusting with coal dust. The inoculant won't prevent porosity or piping from happening. If the top freezes first you likely to get porosity or piping in the bar. The idea is the coal keeps the top surface hotter for longer and the draw is from the top surface not the middle. I cast all my bars vertically.

Hi Luker thank you for that info [priceless!] it's a faff on 2 part molding from bar I'll get the furnace fired up this week.& see how I go,.

Hi Graham, my pleasure. Please let us know how it goes (pictures are always nice!). Here’s another video I took the day before of me moulding, with the sprue on the parting line to improve the quality of the outer surface, and increase the head in the mould. My neighbour was interested to see me moulding and casting and asked if he could watch me mould a pattern. I explained what I was doing and we had a good old chat. The video is long (20min) and is probably only of interest to guys that have moulded cored-split patterns in green sand. The casting is copper chimney caps for my current build.

Any foundry men in north Devon I wonder, time I got into it

Hi Luke, in the first your pouring brass ? there seem to be plenty of fumes ! It was good to see another tradesman at work ! To cut the gates may I suggest you take bit of tin plate cut from a 5L metal can about 3"W X 4"L and bend it into an S so the top part is 1/2" dia and the other end is 3/4" dia, this will cut the sand as clean as a whistle up to the pattern and then use a 4" hat pin or sharpened hard wire to clear the sand right to the pattern side. Always cut down so that you do not brake away the edge as you exit the sand, so down 120* round and then from the opposite side 120* round. The same when using the pasterers tool to cut the runner, cut down from both side so the sand is in compression, it's much quicker and reduces the chance of broken edges. An easy way to make good heavy mold boxes is to visit the local scrapman and but a yard/metre of LARGE box section and cut it into suitable matching lengths, add handles of 10mm round and locating pins. Have you tried using an insulated sleeve to help control shrinkage ? Best wishes Noel.

Edited By noel shelley on 24/02/2022 16:42:28

Hi Noel, thanks but technically I'm not a tradesman, just a guy who plays engineering in his back yard . Those were fines so they do get cast at a slightly higher temperature. I have found the loss of Zink is negligible for all the castings I've tested so I don’t worry too much about it. I've set my furnace up in such a way that the exhaust acts as an extractor for the immediate area which clears up very quickly.

I’ll give your ingate maker a bash, thanks for the tip!

Unfortunately buying from the scrap industry is very difficult with all our legislation. Lucky my boxes were made some time back. I do like your idea for a box though…

I have experimented with home-made insulating risers and even hot capping (that can be a little dangerous if you get the calcs wrong), but to be honest I don’t bother. Most of my casting issues can be solved with proper risering or mould orientation. BTW here’re some pictures of the one piece in the video. It’s been machined and gone over with a little emery, just needs to be polished…

Another excellent casting video Luker, I modified a couple of my flasks a good few years ago as I had a number of

"claw feet" to cast for a large alter cross for our local church that had "lost" them,[traditional

brass casters flasks] they all came out well,cast like this, brass is a "dirty metal" to cast, bronze being much nicer,as an aside I have a great supply of zinc, the garage in our village get's the odd machining done by me & as well as getting alloy from him he saves me all the wheel balance weights as they don't use lead now but steel or zinc,& they usually have zn cast in them so I sort them & make nice clean ingots.

Graham.

Thanks Graham. Brass isn't one of my favourite metals to cast and I only need it for the ornamental fittings for my builds (which were quite numerous for the old loco's). I sometime battle with scrap here which is why I’ve had to develop certain replacement alloys and methods of refining fines etc. When I built the American loco I had very little bearing bronzes and ended up making most of the components from cast iron including the eccentrics and straps. It actually worked quite well in the end.

a thought comes to me, why not try mixing your own bronze, copper brass and some zinc, or maybe some Aluminium for ali-bronze it would solve the problem would it not, worth a try.

Hi Luiker the local jobbing foundry where I go to [not many of those left now] don't like brass either also ,they use co2 sand & many years ago I asked for some greensand [mansfield red] & they said "go round the back" & dig as much as you like,needless to say I dug a few cwt up along with grass & weeds I riddled it & still use it, occasionally adding a handfull of "fullbond 100" bentonite to keep the bond,. Roger when I first started I thought I would make some home made Aluminium Bronze 90/10 mix needless to say I got the mix wrong with too much alloy & it turned out absolutely rock hard in lumps,, never bothered again, bronze would be easy enough to make but not with zinc in it, fortunately over the years folk get to know you & I've built up stocks of brass/bronze & alloys for odd jobs I've done for people so I'm ok for "pot fodder"

Beautifull,brass castings not a blow hole in sight.

I do mix many of my own alloys, or even shift the composition of alloys to what I'm looking for. Mixing base metals can be tricky and unfortunately most of the information isn’t easily available or common knowledge. A good example is the copper alloys. Copper oxide has a melting temperature relatively close to metal copper meaning it goes into solution, instead of the slag, which comes out as porosity in the mould. Graham mentioned ALBr which I have mixed quite extensively the last couple of years as a replacement to the tin bearing alloys (the composition varies depending on the properties I’m looking for). I mix my own free machining version but you can’t just add lead, because this causes hot tears, you need to add silicone. Cast iron properties can be shifted around from a ductile version to a harder wear version for wheels etc. this is easy when mixing from pig-iron.

Hi Luke, since you do not feel that the term Tradesman is correct, then may be a metallurgical scientist is better ? I for one would like to thank you for sharing freely your knowledge of the vast field that is foundry work, I hope I can speak for others on this point !

Making ones own alloys in small quantities is seldom going to be worthwhile in europe or the US since A) there is a good chance of failure and B) the right material or alloy will be comercially available though neither has a bearing on the third option - you want to do it for fun or out of nesscessity ! It is true that my opinion is biased as I work in an area where bronze, alli, lead, copper and brass are all freely available

IF any body knows of any Manfield red sand as used in brass founding, even that covered in weeds please let me know, 100Kg would be good 1 tonne would be even better, I will pay and I will travel to collect ! Noel.

How the other casting came out....

Thanks Graham. Yep I keep sanding and polishing outside my workshop! Roses in wood sounds interesting, please could you post some pictures. I'm always looking for gift ideas for my better half!

Good morning Gentlemen, a beautiful sunny day here in Norfolk. On the subject of polishing castings an easy way to make a polisher is to find an electric water pump, Say 1/2 to 1.5 Hp normally they will be 2pole 2850RPM single phase. Often scrapped as the pump or seals have failed or simply as the system is being upgraded. Dismantle the pump and disguard BUT keep the impellor.. IF flange mounted then mount on a heavy piece of angle iron or such or strap to a C shaped cradle that can be bolted down. Some alli cased motors have small cutouts that hold a nut enabling a foot to be bolted on. Buy a pigtail, the pointy bit with a screw thread, but make sure you get the right hand so the polishing mop screws ON not OFF !!! Take the pump shaft and measure it and check the thread, now drill or bore in the lathe, may be 1" deep then tap to suit thread.. Screw on pump shaft and check for truth. with the reads running the right way there is no need to grub screw or loctite. DO NOT reverse the direction of rotation as this will allow the pig tail to unscrew OR you will need to secure !!!!

As always the Lord smiles on the righteous, one day awhile back I found 3 dumped, from a swimming pool, one even had a new 20m 2.5mm extension on it., all were 2Hp It did matter as I already had made one years ago but good stock ! If dumped because it was noisy it will have an easy to get bearing set so worth fixing..

The polishing Shop are very helpful for pigtails I would go for about 1" (25mm) dia and 3 wheel types in 6" x1", sizal, stiched cotton, and loose leaf. Each used with it's own grade of soap, coarse for as cast, medium for a good lustre, and fine for a super finish. Axminster also supply all you will need. ( I have NO connection with either firm )

Polishing is a VERY DIRTY job and can be dangerous !!! Sharp edges should ALWAYS face away from the wheel. On finely detailed work it may be a compromise as the buffing soap is very agresive and will destroy detail. DO NOT dwell on a single point, keep the work on the move and avoid allowing the wheel to funnel into a corner or it will cut grooves.

Have Fun. Noel

Edited By noel shelley on 08/03/2022 10:45:58

Hi Luker, sorry about the delay re "yorkshire rose" these are traditional yorkshire roses not with lots of separate petals [& they have to be displayed the right way up!!] & a few other snapshots of castings I've done.in the past.