Are there any Patternmakers browsing this site?
If so, i would to hear from you....

Klox

:D You got one,

Castguy, we've met on the casting forum, hi again!
As i understand these days Patternmakers are hard to come by. I presume that your one of the guys that can still make a pattern by hand for sandcastings....
May i be so bold to ask if your interested in giving us some background on moulds (the making of), feeders, risers etc....?

Thanx

Klox

I got my start back in the early 60's working after school and weekends. Started a dual wood/metal apprenticship in 1969. I am what is known as a Master Patternmaker, meaning I can take a concept from drawing through complete tool.
Up until 1988 I worked the "old fashioned" way with chisels and gouges for wood and manual machines for metal. Then my shop got it's first CNC mill. By 1990 most patterns were done to some extent on CNC.
In the late 90's I left the shrinking pattern trade and went into casting and tooling engineering.
Throw your questions at me.

We've got a bit of a quality problem in South Africa when it comes to foundries doing small batches(read sand casting moulds/patterns). (Anoel, NeoMoses i'm not bashing anyone here!). A (potential) client ask me if i could look into casting jail keys. Currently they take wax patterns from a master pattern and then cast by gravity. I assume the shape is a bit complex as i haven't lay eyes on a sample key yet.... Is it going to be better to go the high pressure die cast route or are there some "hurdles" to overcome i don't know of yet? I presume the matl would be steel/ iron.

Thanx

Klox

If you already have wax patterns the route to go would be investment (lost wax) casting. The individual wax patterns would be fastended to a wax "tree" which is really the riser and runner system. The resulting assembly is dipped in a ceramic slurry and dried resulting in a ceramic shell. This is the actual mold. The wax is melted out and the ceramic shell is fired to about 1800-2000 deg F then the molten metal is poured into the shell.
Just about any steel brass ort aluminum alloy can be poured. The resulting casting is "near net shape" meaning very little or no machining is required.

I agree with Castguy that wax investment would be a better thought..

My thought comes As I started in the machining industry as a Wax investment tool maker and even worked as a tool maker for one of the big foundrys out here.

Still help with some of the programming for all kinds of mold shops out here at times.

Castguy,

I'm a potter who wants to broaden out to metals. Can you give me some pointers for a ceramic slurry recipe? Lets say for wax models. It needs to be virtually no shrinkage, right? I expect you will use a finer mix for an initial coat and then a dry sandy sprinkle? What is that stuff?

Wel it matters on the metal you want to pour to the shrinkage.
Lets say 6061 would be close to .025 per inch shrinkage.

Hmmm, 6061. Would that be an aluminium alloy? Do you mean that it shrinks on solidification? Nearly all clay formulations will shrink from wet to dry and again from dry to fired. Are you saying that the dry to fired shrinkage of the ceramic needs to match the solidification shrinkage of the metal?

Arnie,

If I may chime in...

The "Ceramic Shell" that is being referred to uses a colloidal silica binder with a fused silica refractory. It's a specialty product that can be a little touchy to work with - usually the binder must be constantly mixed to keep the colloidal silica in suspension. There are some products available, however, where you don't have to keep mixing. Shellspen, I think, is a brand name.

The other investment option is the 'traditional' one using mostly plaster, sand, and Ludo (sometimes spelled "Lutto" - old ground up molds used as a filler). Use the same wax gating system outlined above. These molds will need to be "burned out" in a gas kiln at around 1050 degrees F for a few days.

The finish right after casting can be quite good with a minimum of chasing.

Another option is to use resin bonded sand of which I'm much less familiar.

Good on ya Dogsione! Shellspen has a website and it looks like I'll find all I need to know there. I was starting to think it was a dark secret.

www.shellspen.com

I have come across the word 'lutto' before, I met someone who was casting glass and he was using an aweful mix of plaster, ceramic fibre and recycled plaster. Yuk! Oh well, it worked.

thankyou

Oh good, I'm glad I could help...

Creating the shell is only going to be your first hurdle - getting the wax out will be the next.

You could use a raku kiln to flash melt the wax and vitrify the shell at the same time, but it creates a ton of smoke which your neighbors may not like. We had this problem with a university set-up. Some are boiling out the wax first and than firing the empty shells. The advantage to that is that you recover most of the wax. Either way, make sure you have some refractory cement (or whatever the Shellspen people recommend) on hand to repair things.

What are you going to use to melt the metal? Believe it or not, I set up a system this semester to melt small batches of aluminum using one of those turkey fryers. Worked pretty well if I may say...:rolleyes:

LoL, a turkey fryer for a furnace!! Wait a minute, in really small print, the instructions say you can use cooking oil or aluminum. Well, it does pay to read the instructions :D

Hello,
Speedre here. I'm also a Master Patternmaker, wood, metal, urethanes and epoxyies. Started in 1968 right afert high school. I am still making patterns the old fashion way, by hand with manual tools. No cnc in any of the shops I've worked in for the past 35 yrs. I'd really like to get into that end of it but, traditional shops in my neck of the woods avoid it like the plague. Just thought I'd add my 2 cents in.
Thanks :cheers:

He showed me a pic and wanted a pattern made i tryied to mill a pic.
and it did not look like pic yet so back to the drawing board.... I dont know
if he got one yet???

Hi, have you tryed wit EPS/styrofoam?

I am a pattern maker in Winona, MN USA

But what would one expect to pay a master pattern maker with MasterCam (or similar) competence, 3 and 4 axis CNC Competence, Disamatic plate experience, intricate coring and core box machining experience????

Well a man with that much knowledge would , should recieve top rate. That is, whatever top pay is in his locale. It varies as to geography. Or he could have just priced himself out of a job. :o

Well a man with that much knowledge would , should recieve top rate. That is, whatever top pay is in his locale. It varies as to geography. Or he could have just priced himself out of a job. :o

$25-$30/hr for a top top top guy? More?

I'm in Michigan......Is that good or bad (from the job position that is :D)?

That's what I'd expect to be paid in my locale, New England area but. I've been paid as high $24.50 hr. in Mass. in the late '80's. My knowledge is wood, metal, plaster, blow mold core box, urethane reproduction, compression mold making, vacumm mold masters, fiberglass layup, foundry experience, cadd degree, machine shop exp., plastic fab. I work in a one man shop now, me and my boss. I do all the new work and he picks up the repairs and does all the leg work, picks up lumber and does job quotess, visits foudries. The trade in this area is almost dried up. Where there were once a hundred or more working job shops and many captive ones there are none left, all closed and history. So short story long, in Mich. if there's work and you get that scale don't ever leave. Get my drift? Good fortune and God Be with You.

That's what I'd expect to be paid in my locale, New England area but. I've been paid as high $24.50 hr. in Mass. in the late '80's. My knowledge is wood, metal, plaster, blow mold core box, urethane reproduction, compression mold making, vacumm mold masters, fiberglass layup, foundry experience, cadd degree, machine shop exp., plastic fab. I work in a one man shop now, me and my boss. I do all the new work and he picks up the repairs and does all the leg work, picks up lumber and does job quotess, visits foudries. The trade in this area is almost dried up. Where there were once a hundred or more working job shops and many captive ones there are none left, all closed and history. So short story long, in Mich. if there's work and you get that scale don't ever leave. Get my drift? Good fortune and God Be with You.

Thanks for the reply. I'm actually looking for someone to fill this position. I'm not nearly that skilled, I'm just a measly salesman. :banana:

Hi gang,

I'm new to the forum, and thought I'd chime in. I work at a Pattern Shop in Erie, PA. The trade is going away I fear. I mostly do 3d modeling and CNC machining of patterns and core boxes. Most of our stuff is for green sand molding, Disa, Hunter,Osbourne, etc. We use cast Iron, aluminum, plastic (machined and poured), and wood.


Steve

Whats up guys? I`ve been in the trade since 86. It does look like it may dry up. Worked in a wood cnc patternshopthe last five years if not for cnc router who knows what would have happened to our shop, just thouhgt i`d chime in