Casting Runway Landing Lights Part 1 The threaded shell sand cores 

Veg, Wot me patient? Never! Its a case of lie back and think of the money! (and hope there is some novocaine in the Vaseline :-))...Martin

Head, Yes shell core is a great process good dimensional accuracy too... Martin

Law, Seems YT are not all that good about informing re comments so I am sad to say I missed this one of yours. As always sharing is my pleasure, I am glad that you enjoyed the video... Martin

Thomas, Sorry, only just came across your comment. Glad that you liked the video, more on the way, Thank you for your comment... Martin

Big stack, Yep, it makes a nice core. If you need good strong stable storable cores this is one process well worth looking at I strongly favour it over other core making methods.... Martin

Daniel, Glad that you liked the video and that you feel that you have learnt something from it, that was my intention....Martin

Nathan, Yes it is a very interesting process, The resin coated sand is cheap and easy to use just need a metal core box. It is a very versatile process too. Commercially the sand is often blown into the core box using compressed air and this improves the definition way and above what I get..... Martin

Joe. Wot me a craftsman? Naw! Just a silly old bugger who has been at it a while. Than you for your comment.

We tend to put ourselves down all the time, and find it hard too accept praise, it's those warm fuzzies that keep us going and keep our onboard batteries topped up compliments of the season have a great Xmas and New year Tony from Western Australia

Joe, Great to see another Ozzie out there! You are right, those warm fuzzies are a boon. Thank you for your good wishes - may the silly season treat you most kindly too... Martin

Shotgun, Glad that you liked it, Thanks for the comment.... Martin

Amal, In one of those examples of the mysteries of YT some of your comments are not appearing where they should so I will answer the one about parting agent here. No I do not use talc. I am aware that many people do and I guess its very convenient as you can get "Baby powder" anywhere and it sure seems to work OK. But you need to be aware that some, most, all??? Talc contains fine silica and breathing that in is not exactly clever in fact some medical advice is now that one should not powder babies bums with it for fear they may breath it in. Also talc is closely related to asbestos and some talc used to actually contain it although I understand that those particular talc sources have been closed down. The parting agent that I use is a commercial one but it is nothing more than very finely ground limestone. Apparently the human body can tolerate this quite well having the ability to dissolve it, and a little extra calcium is probably no bad thing. Talc costs about $10.00 per Kg at the supermarket while I payed $65.00 for 25 Kg parting agent which was clearly labelled "calcium carbonate" This will last me 5 to 10 years so I guess it would be a lifetimes supply for most people. Thus the calcium carbonate is cheaper healthier and does not have that annoying cheap perfume smell! Which ever one you use shake it on from a calico bag like I do, don't shake it on from the can! In a pinch an old sock will do.... Martin

Olfoundryman, I apologize for that. I found in a later video you explained what you used. I felt a bit silly about it and I went and deleted my comment. Thank you for the thorough and well said explanation, makes much more sense to never use talc.

Nathan, Naw, I am the most impatient bugger around just ask the wife:-) I do not do well at repetitive tasks but it one foot in front of the other stuff - You know, lie back and think of the money! (and hope that there is some novocaine in the Vaseline!) Glad that you like the videos.... Martin

Rupert, No problem... Martin

Wayne, It was over many years so spread out like that it was not to bad, but could not do it again though just too old now 😰.. Martin

Michael, Not really much to show! Just castings being placed in an oven and taken out some hours later! The heat treatment that I do is a T5 process. It is an age only process there is no prior high temperature soak followed by a water quench. This T5 involves 6 to 8 hours at 165 to 170 deg C, In a fan forced oven. A domestic oven will do. In order to improve the response to this treatment I cool the casting as quickly as possible after casting. In the case of gravity die work the die pretty much takes care of that but for sand work I break the castings from the sand mould immediately they are just solid enough to handle and water quench them. This T5 is just to make the castings harder so the machinability improves. If the castings were for more critical work , wheels for example, I would not do the T5, but would tell the customer to get a full T6 treatment done. I don't do T6 as its too difficult to control the temperature accurately enough. Note than not all aluminium alloys will respond to heat treatment. The alloy that I use we call 601 but in the US its known as 356. It responds well to this heat treatment.... Martin

Stefan. Thank you for the comment - hopefully I will have more video up soon...Martin

i like watching your vids, I want to start doing casting more as a hobby and your stuff is prefect to learn from, much better then a lot of other vids on the tube right now

Chris, Great process to have in ones repertoire. Makes a lovely core, dare I say almost the perfect core and so easy too no messy sand mixing just tip the precoated sand into the hot die, only drawback is the need for a hot metal die which sort of limits it to jobs where a lot of the same cores are used. Well worth getting into even if only to make standard sized cylinder core to just have on the shelf. I have never used it with iron but only because I don't do Iron. My understanding is that these cores, often as whole moulds find extensive use in the iron industry..... Martin

Olfoundryman good to know

douro, Many runway lights are now indeed made from some sort of yellow (yuck) plastic but these don't seem to like the UV in Australia hence these lights - which are available in (yuck) plastic - are cast in aluminium and powder coated the required yellow. I have cast a few other designs over the years too... Martin

Mite, It was called ISOMOL 185. Strangely some books claim this to be a graphite based material but its colour would indicate otherwise. The tin of it that I have (25 Kg) is clearly labelled with the name and lists its main ingredient as Zircon! It does come from Foseco and is often used as an anti veining compound i.e. to stop metal penetrating joints in cores. The resin coated sand does NOT come from Foseco as far as I know they do not sell it. From the mention of a "Holden grey motor" in one of your vids I take it that you are in Australia. I am in Melbourne and I get my resin coated sand from "Beckwith Macbro Sands" It costs about $10.00 for a 25 Kg bag. I would imagine that if you went prepared to take what grade was in stock you could pick up just the one bag if that's all you needed. I buy two grades 2% and 4% resin content both 70 AFS grain size. For most of my work I mix 2 of the 2% and 1 of the 4%, but for some jobs I use the weaker 2% as it is easier to get out of the casting afterwards although breakdown is good even with the 4% and for my riser extensions I use 4% as I get more uses from them when made in this stronger sand. Wherever you are in Oz just google "resin coated sands" and confine the search to Australia. You should have no trouble finding it as it is a very common and much used material. I am very glad that you like the videos... Martin

Thank you Martin for the info its very informative. Yes I'm in Oz, just north of Brisbane to be exact. I was and still am on BYMC but every rarely post on there anymore. I remember you from when you were a member. Back then you were always trying to get me plus others to stop using alloy wheels, heads and such, at the time I always said ingots were to expensive and to a point ignored your advice, BUT, I now use ingots only, I save all wheels and heads I then cash them in and buy ingots, sometimes it takes awhile for good advice to sink in ;-)

Mite, Ah, the good old BYMC days, not my finest hour. But I did learn not to get involved in forums as they are way too time consuming. Seems we remember my advice just ever so slightly differently. If I recall correctly (unlikely at my age) I urged people not to melt any wrought materials particularly cans and also to avoid pressure die cast parts any unknown alloys generally, this would include just about everything EXCEPT wheels. These are 601 alloy (356 in the US) and are good stuff. So if you can't afford or find a source for ingot then get alloy wheels from the local scrap dealer and melt them. Just check with nitric acid or acetic acid (vinegar) (These will attack Mg but not Al) or with caustic soda (will attack Al but not Mg) Just to be sure that you have not accidentally picked up a magnesium wheel. These are rare but you don't want to try and melt one down , big bad fire can't be put out, bad news. However it is preferable to buy certified ingot as you know exactly what you are dealing with and this is what I do. Pistons are perhaps a bit of an exception because piston alloy here in Australia is only available in 1 ton lots (That's a lot of pistons). So if you need to make any pistons you will have to use old pistons as a source of metal. Most pistons are marked inside with the alloy designation so if you stick to ones with the same designation and remove any steel inserts (may be cast in) and old piston rings etc you should not be too badly off. Your practice of selling all the scrap and then buying good known ingot is to be commended, I will bet that a lot of your problems went away when you started this practice. I note that Myford now seems to use cut up wheels, perhaps he too heard my voice, but doubt he would admit it!... Martin

Hi Martin, yes a lot of my problems went away when I started using 601 ingots, I still think a lot of my practices do leave a lot to be desired, BUT as a metallurgist once said to me "how we get there is not the problem, as long as it all works. This person has spent his life in casting has told me to call him anytime that I need help, but each time I phone we spend about two hours on the phone with my head damn near exploding from information over load LOL but its great that people with the experience are prepared to share with us hobbyist, I thank you Martin :-) . with regards to using Alloy wheels, it can get very exciting breaking them down with a 9 inch cutting wheel, its so much easier to put a ingot on my metal cutting band saw;-)

Spewe, The sand has been precoated with a resin. There is around 3% resin in the sand. The mould that I pour it into is at around 180 deg C and this first melts and then cures the resin thus binding the sand. This "resin coated sand" seems to be available world wide, it is quite cheap and makes a very good core. One of the processes great advantages is that you do not have to pack it in. Commercially they often blow it in with compressed air but as you can see simply pouring it in works quite well. The main disadvantage of the process is that you have to have a metal mould because of the need for it to be hot.. .. Martin

Spewe, No I did not make the die. Cutting the thread was a bit beyond me! However I know a very good pattern maker who I got to make it.... Martin

Hull, Quite simply I buy the resin coated sand. It is reasonably cheap. And is available just about world wide under the name of "resin coated sand". It is available in different resin strengths (I use 2% and 4%) but 2 to 3% is a good starting point. Simply Google "resin coated sand" in your locality. I understand that making it oneself is not that easy as the sand has to be hot coated with the resin precursors and its so cheap that it would not be worth the effort... Martin

Thank you so much for your quick feed back. Building a 6kw electric furnace to cast some parts I need for a couple projects so I don't have to do machining on a full 16" by 6" by 6" block.

Hull, Electric is a good way to go - slow - but it can produce better metal quality than fuel fired. Hmm, the cost of 16 *6 *6 block would be a bit prohibitive too! It would have to be close to 60 lbs. Well north of $300.00 here in Australia I would think... Good luck with it all. If I can help with advice etc please do not hesitate to ask...Martin

Michael, Yes, its more than a hobby. I managed to keep the bank manager at bay and feed the family by doing it since about 1990, for many years before that it had been a paying hobby conducted at weekends and other holidays. Now days age has me slowing down quite a bit but it still contributes to our survival as well as being simply "what I do". The shell sand process does make great cores, there are other very good processes out there that also make wonderful cores but for ease of use and providing the job will support the trouble and expense of a metal core box (often cast them myself) I will go for shell every time.... Martin

Mite, I aim to have the moulds for the shell core above about 165 deg c. And colder and the resin in the shell sand sets off too slowly but if the moulds get up to 190 to 200 deg C they get too hot to handle comfortably with the loop type cotton gloves that I use. Note that these figures are a bit of a guess as I do not actually measure the mould temp, but years ago I did measure and found that 165 deg C was the minimum. I have no real idea as to how hot the electric heating plates get but obviously its somewhat above the mould temp. I control the temp just by judging if the mould has got to hot (I start to get burnt through the gloves :-)) and simply turning the heating plates on and off accordingly. Many people who make this sort of core use a gas flames for heating - its a pretty forgiving process. If the mould is on the hot side the core will start to go yellow then brown quite quickly. If on the cold side the core will barely go yellow and even that only slowly. Once you get that hang of the process it is very easy to do. Years ago I had a temperature controller worked by a thermocouple in the core mould, but such sophistication is not really necessary and frankly proved to be a most unnecessary complication.... Martin

Thanks Martin, with it being a very forgiving process I think I'll use gas when I start to use resin sands, I'm waiting on a email from Cast Metal Services on price and the MSDS for there resin sands

Mite, You may find it a bit harder to control the temperature of the mould with gas. With electric I just turn it on and off at the switch on the wall as required but throwing a switch is a bit easier and more convenient than lighting a gas burner. However many people do use gas and seem to have little trouble once they get the hang of it, probably a direct result of the forgiving nature. Let me know what CMS say, I suspect that they get their sand from the same place I do! Also please let me know how you get on with the process... Martin

Hi Martin, I pick up a bag of resin sand tomorrow Friday, not to sure on how long for me to make a metal mould for the core as I'm a little busy at the moment, luckily I'm retired, but I find I get rather busy just doing stuff LOL

Mite "but I find I get rather busy just doing stuff" You have been reading my mail! Life just seems to be like that and the older one gets the more like it, it gets. I should be retired too but foolishly (perhaps) still struggle to make the odd dollar. Things just seem to take longer than they used to and everything is heavier than it used to be. In short, old age is a crock. Good luck with your shell core efforts, please let me know how you get on and send me some photos (PM me for an email address) I am keen to see.... Martin

Raschelle. olfoundryman@gmail.com .... Martin

Worldtraveler, Yep, sucks indeed. Boring, boring, oh so boring, but I long ago learnt that you make your money when you are bored witless and not when your are excited by the one off. Its just a question of "Lay back, think of the money and hope there is some novocaine in the Vaseline!" But oh yes, it paid Ok.... Martin

Yes production work is very boring and Its all I've ever done, but whenever I make something thats a good product everyone says why don't you sell them, I tell them after doing 15 years of production involving concrete products such as water tanks, cattle troughs, septic thanks and such, then 5 years making concrete masonry blocks, then 27 years in plastic extrusion makeing pipe, I'm well over production work. I get a lot of enjoyment on getting an idea, making a pattern, getting it sorted so it casts, and then for the most part patterns just sit on the shelf while I wait for the next idea. Wife does get a bit sorta upset at times because she sees money going out and none coming in ;-)