G'day From Col.

Only two days ago I suddenly woke up to the fact that the ezine is due out, blimey, it's the 10th of May, I better shake a leg and get stuck into it otherwise you might be wondering where the heck the May ezine is. So here we go, sorry the ezine is a little late, we've been snowed under the last couple of weeks.
Welcome if you have just subscribed over the past few days, you are one of the many people out there who want to learn how to cast metal, and why not, the technology is there and the basic equipment is not that hard to build, as long as you have some instruction & guidance.

And if you ask anyone who has been at it for awhile, they will tell you what a thrill it is when you get to pour your first casting, and who gives a damn if it's not perfect, very few first time pours are... unless you're an expert, but then, you wouldn't be called a hobby caster would you, and that's what we are about, helping people make a success of their metal craft.

Cripes, I still remember that old pile of rough bricks which was formed into a circle outside of the workshop which was my first furnace, it had a lump of 15" long X 1.75" Dia rusty pipe placed on the ground leading into the middle acting as the air blast pipe to the charcoal and coal based briquettes I used as fuel to heat up the alloy in and old home made steel pot, yep, it was as agricultural as all hell, but it worked surprisingly well, the good wife even let me use the home vac (in reverse of course) for the blast... until I got caught one day when it was still on suck???? Yikes... how would you like a new vac darl? This one is kinda stuffed!

The foundry learning journey is slow, until the jigsaw bits all fit together and then suddenly it clicks and you are away, the confidence level zooms to new highs, and you find your self attempting things you wouldn't have previously. I have followed several of our ebook client’s progress closely and once they have conquered the basics, they have really moved forward at a rapid rate. They're happy, and we're happy to see and share their success as well.
The realisation that you can make some pretty cool stuff with metal casting hits home with many people..

If you are one of our valued ebook customers you will receive an email shortly where you will be invited to join a special list, membership of the list is by invitation only and you must be an ebook customer to become a member, we have an extensive data base from when the very first ebook was sold, of course we don’t expect all of the email addresses to be current but we will send out an email to all addresses we have on file, when you receive the email from our list server all you have to do is accept that you want to join the list and you will become a member.

The advantage of being on the list is that you will be notified of any new free updates to any of our ebooks, you will also have first offer on any new release products we develop, and we may need to notify you from time to time about various hobby foundry matters.
You do not have to join the list if you don’t want to, but you may find it to be an advantage to do so.

There are no profiles about hobby casters this month, but what we have decided to do is feature some of the stuff we've been doing, but dont get me wrong, it is not intended to be a brag session,  just a talk about the methods, techniques etc. I hope you enjoy the read.

Sponsor Message.

                   Home Foundry Projects.

                
                    
                            MDF Wheel Rim Patterns

           The fun you can have in a hobby foundry.              covers and bronze tappets.

       
             
                   Split Rim Alloy Go-Kart Wheel.

 
                         Reproduction Alloy Rocker Box.

                    
           Pipe clamp mounted patterns & raw castings.

                                             Sand Core Steam Blow.    

MDF Foundry Patterns.

Ever since this fine-grained, compressed particleboard became available many years ago, it has been extensively used in the professional and hobby foundry pattern shop alike. It is easy to work with, machines well, and can be finished with shellac or polyester lacquers to provide a hard smooth surface finish that wont snag and pull the moulding sand when lifting the cope or removing the pattern from the drag box.
To make the kart wheel rim patterns, about five or six squares of 3/4" thick MDF board were glued together with PVA and allowed to set overnight, the blocks were lightly clamped in the garage press, but a large "G" clamp would do the same job.
Next step was mounting and centering the MDF block in the four jaw lathe chuck ready for machining, the inside cavity was done first and then the block was removed from the chuck and the four jaw chuck was replaced with the three-jaw self centering chuck, the block was then gripped on the inside bore while the outer part of the rim machining was done.
Plenty of material was left on the pattern to allow for shrinkage and machining later on. The MDF patterns were finished with shellac, which was a little slow, but the finish was superb, shellac provides a hard surface that can be sanded between Coates. After the final coat has been applied and also sanded back with 600 wet or dry, it can be polished with bees wax and then rubbed with graphite to give a super smooth finish. 

Cast Alloy Wheel Rims.

The kart wheel rims were one of the first major projects I made with my home foundry, there were no fancy gas fired furnace, a silicon carbide crucible was used, I had a good supply of green sand, but hey, geez, I hated reconditioning that stuff by hand (the reason why a motorised gyratory riddle was built) So we actually melted any old scrap we could find, old auto pistons featured in the mix. And this was back in the days when I knew nothing about degassing aluminium, and you can tell when you look closely at the wheel rims, the porosity is quite noticeable, but it has not harmed the integrity of the wheels. But I would not make them again with out a degas treatment of the alloy.
Machining of te rims was almost similar to when making the patterns, the outer internal dish was machined first then the rim face where the tyre locates was machined as well as the inside surface where the other rim mates up to it. There is quite a bit of machining to do, but they did not take that long to make. The rims were made to fit domestic ride on mower wheels. The kart was built to a tight budget, casting our own wheel rims enabled a set of front and rear wheels to be made at a very low cost, and was also a great learning experience, as you can imagine I was hooked on metal casting after the success we had with the wheel rims. 

Reproduction Alloy Rocker Box.

Well here is a challenge if ever there was one, an acquaintance had an old ford Cortina which was being rebuilt, unfortunately the nice rocker cover that came with the engine was badly damaged with broken fins etc, some repairs were done and the original rocker box was sprayed with several coats of hi fill spray putty and then carefully rubbed back when cured. The repro rocker box was cast in green sand. Using an original part like as a pattern is a very difficult way to go. The hours spent making repairs and then preparing the part to use as a pattern was not really a viable proposition. It was certainly a challenge and one that was eventually won on the third casting attempt... then we called it quits, no more I said. If a new cover had been available my friend would have bought a new item. One of the problems with the job was trying to get the green sand inner core to stay with the cope mould, the cover was cast with the fins facing down, the clever use of soldiers (Soldiers are wooden sticks with several small grooves cut crossways along the sticks, they are imbedded into the green sand where required, to help keep the sand core attached to the rest of the mould). Another problem was  the sand that remained trapped inbetween the fins on top of the rocker box, the battle was eventually won with some carefull work and attention to the side draft of the fins and also making sure that there were no rough spots where the sand could snag and pull with the pattern.

Pipe Clamp Patterns & Castings.

The foundry mans curse.... steam blows in the casting, and the sand core was the suspect here, the core appeared to be dry, but it had absorbed quite a bit of moisture. Looking at the raw casting from the outside, you would hardly know what kind of damage the steam blow had caused internally, needless to say this one ended up back in the pot. This casting was kept and cut in two to reveal the steam cavity inside. The raw casting is the basis of a clutch slave cylinder we manufacture for a company that rebuilds and supplies parts for English cars.
This slave cylinder project caused more than it's fair share of problems, one of the major irritations was the age-old problem of porosity. The original alloy cylinders were manufactured by the pressure die casting method which produces an incredibly tight grain structure, but, we could only produce them with the green sand casting method, and it took quite some time to solve the porosity problem. But with careful attention to degassing, and the use of steel chills soon resulted in a high success rate and production of high quality pressure slave cylinders. You wouldn’t believe the rate at which porous aluminium weeps and pisses so much fluid when it is under pressure. This little item has been quite a nice cash generatiing product. Maybe you have a product that you can make and sell. Just recently I had an email from a client in South Africa who manufactures cast bronze and aluminium items to sell at craft markets in his area. There are all kinds of opportunities to profit from your metal craft skills if you want to.

I hope your projects are going well.

Cheers
Col Croucher.