Inliners International Forums General Discussion Tech Tips pattern makers

Any one have any pattern making experience? Like to talk if you do.

"No answer!" came the stern reply...

I haven't done, I've talked to people about it and had castings done using a simple pattern a friend loaned me.

Worse, I'm about to get right into it... so if there is anyone can pass on any gems I'm listening too!

I'm no pattern maker, but I have a few nutty ideas rattling around in my head I would like to try. So I would like to know what you guys have read (I expect there are books on the subject).

How dificult is it to find a foundary that is willing to make one or two of a part? To the best of my knowledge there isn't a commercial foundary here (some hobbyists I'm sure, they seem to be everywhere, in small numbers).

Sorry I am of no help to you both, If I knew anything about it I'd tell ya.

Are you looking to make your own castings? In what material?
I'm not a pattern maker per se, but I have some experience with casting zinc in permanent molds, and I've messed some with patterns for sand casting.
If you're only going to make a small number of parts a loose pattern should suffice, as opposed to putting it on a match plate. Anything with cores is much more involved. Draft (release angle) should be a minumum of one degree everywhere, more is better- like 2-4 degrees. If you're casting aluminum, plan on a shrink of about .012 per inch. In other words, if you want the finished part to be 4" long, make the pattern 4.048" long. Softwood is ok, laminating it will help prevent warpage. Try to not create sharp edges or corners. You can buy fillet wax by the roll, it's like a strip of wax in the shape of a cove mold. Press it into place, the pros use a ball bearing silver soldered to a steel rod to burnish the wax, you could improvise something. Heat the tool, rub the wax to stick it in place and make the fillet consistent. Finish the pattern with urethane or something like that. Check out this site: http://www.kindt-collins.com/
I used to have some dealings with a foundry in Cambridge,Ontario, but it's been years... Probably best to first find a foundry that's willing to cast your parts and seek their advice.

That's more than I knew when I asked. Thank You.

For me, I have a couple projects I would like to try in Aluminum, and a couple more in Iron. The last two are the ones I figure will be the most difficult (because it's Iron). I figure I could cast simple Aluminum parts like covers and what not here. I would be hard pressed to generate the heat (BTU's not just degrees) it would take to melt the Iron.

You have a famous name, Eric... you don't have a daughter named Sandy do you?

I'm embarking on a project to cast inlet manifolds for a V8. So I'm right into complexities there... I plan to have a good chat to the foundries first, learn their latest preferences and work from there.

I remember that we made some fairly big stuff (mine was about 18” X 24”) in art class in high school. We melted the aluminum in an old ceramic kiln and made the patterns out of Styrofoam which vaporized. Being an art class, we weren’t too concerned about finished dimensions but the same technique could be applied to something that wasn’t too complex. It would require more finishing obviously.

Whoever the famous Eric Jackson is, I assure you I'm not him... And two sons, no daughters.

Casting V8 manifolds will be a huge job- stepped parting lines, elaborate cores and core boxes, gating and venting will be critical to get good fill and feeding. Fixturing for machining will be involved also. Best of luck, you're braver than I am.

Lost foam casting is common, it uses the same basic approach as investment casting. The pattern is made of sacrificial foam, dipped in a ceramic slurry to create a hard candy shell, the foam is vapourized by the heat of the molten metal. Investment casting uses wax for the pattern, often lots of small parts on a christmas tree- like sprue. The wax is vapourized by the metal, the ceramic shell contains the metal until it solidifies, shell breaks away to leave parts. Lots of jewellry is investment cast.

For onesy- twosies, I gotta believe sand casting is the best route. IIRC, .004 per inch is the shrink rule of thumb for iron.

efi-diy
Talk to a good freind of mine today, he is a Pattern Maker by trady and a big Gearhead. He is sending me his e-mail address. he said for me to have you e-mail him and he'll help you with your questions. It will be a few days before he will get back to me, but as soon as I get it I send his address to you.
Luke

He is a good friend even if I can't spell it right.

Good job you're not, Eric... his daughter's name is Jackie...

He was a Ford works rally driver in the Lotus Cortina days and set a record from London to Capetown driving a Cortina to race an ocean liner over that distance.

Sorry, off topic, but I had to ask.

Luke any updates on this ?

Horsepower TV recently had an episode where they showed the processes used in an Edelbrock foundry. They showed the cores that they used for the passages in the cylinder heads, it was three pieces that they stacked together. It might be on youtube.

These guys have made patterns for me in the past and are very competent and deliver on time. They have been around from the late teens and know cars. To give you an idea on cost I looked into making a head and rough quote was about 15K for the pattern and about $350 for the un-machined casting. www.kearneyfoundry.com

Kearney looks pretty neat, thanks for posting.

efi-diy
I'm sorry I haven't gotten back to you before this. My friend took off for a month vacation down south in the sun. He is to be back next week and I'll get that e-mail address for you.
Luke

efi-diy
Sent you a PM with that e-mail address
Luke

Thanks,

I dropped an email to him. Waiting for a reply.

efi-diy
Did Craig return your email?
Luke

hello,
you might try this stuff to melt/supply iron for your casting job.
once lit,it is self sustaining and gets REAL hot.
a couple of links for your information.

http://www.youtube.com/watch?v=nR6K90cR8Lg

http://en.wikipedia.org/wiki/Thermite

if your job only needs small amounts of iron to cast,this may help.

regards,Rod

I have made some patterns and molds before for simple things. I found this website containing a DIY home style foundry, showing much detail in making the pattern,core boxes and everything needed to make simple aluminum castings. This guy made side covers for an Indian motorcycle that are very hard to find in usable condition. This shows step by step him making the patterns and everything, it answered a lot of ????'s I had about draft angles and such, maybe it will be useful to you as well, heres the link: [url=www.virtualindian.org/3techcasting.htm][/url]

A friend of me has built himself a small foundry at home.

He made his oven out of a big steel-tube aproxx 15 inch wide and 35 inches high,cemented some bricks from our little local steel-works (Sandvik Corp)inside and made a lid of concrete

He gets the heat to it from and old oilburner that he took from his house-heating pan and runs it on diesel,gets hot enough for aluminium to melt.

He uses old alternators ,carbs and other junk-stuff and some much needed chemicals,poors the metal into sand-molds and out comes a finned ignition-coil cover and some other things like foot-pedals T-Ford window-posts and such,he's self-learned and hes getting better for every time he's at it.

And his nabour is a model-carpenter so he makes all the molds for him in wood,took them sometime to figure out angles and such before they got it to work as it should.

/Speed Swede