Tips/Techniques Super easy durable cast aluminum match plate patterns

[Tobho Mott]

I've seen people cobble together steel spacer frames and backfill the seams with sand and pray to Vulcan for no leakers in order to cast metal match plate patterns before (Mr. Pete has an old series on his youtube channel showing this way), but the hack I came up with to save time and effort is to simply use a spacer made out of a scrap of precut drywall instead. It stands up to the molten aluminum well enough that I've been able to reuse the same frame to cast multiple match plates the same size. As far as I know, using drywall for the spacer is my own original idea; I haven't seen anyone else try this. But it works great for me.

I have a bunch of nice light 6.5" x 8.5" flasks I really like using, and a 12x12 flask is big enough to cast matchplates for those.

Here's how it works.

I ram the parts up. In this case it was my split pattern for casting pattern rappers, and a cast copy of it since there's room in the flask for two. It was much faster to simply cope down on the cast copy and use it as a pattern rather than print out a second split pattern.

Then I place the spacer. Obviously, the patterns have to be positioned very carefully to make sure they'll be cast with the right clearances from the edges of the matchplate and from the smaller flask walls. So they were traced out on the molding board before I began.

Then I place the cope on top of the spacer and pour, simple as that.

Once it cools off, the mold is opened and the spacer carefully removed to reveal the raw matchplate casting.

Runner in the drag, gates in the cope. All that remains is to cut off the sprue and drill the holes for the alignment pins. Then I can start cranking out castings much faster than molding loose patterns one at a time.

I drill a small hole through the matchplate from the underside of the runner where I want to sprue down from above, to show me where to drill a bigger hole in the cope side to fit my sprue pin in the right place

All done, ready to ram up. Next post will show it in use.

I have a few videos on this process if anyone found this interesting. This one is about 20 minutes-ish long, but these pix are all screenshots from it, so if you give it a pass you're really not missing anything.

Jeff

 

[Tobho Mott]

The matchplate is sandwiched between the cope and drag and the drag is rammed up first.

Meanwhile, the muller is running, processing the sand from the matchplate casting session.

Once the drag is made the cope is rammed up, with the sprue pin in place. After the pin is pulled and the cope struck off, I cut an offset pouring basin as close to the edge of the flask as possible.

Then the matchplate is de-molded, and aside from a little brushing and getting any loose sand grains blown out, the mold is ready to close back up and pour. Fast and easy.

I poured 3 sets this session .

There's a fair bit of flash on these, but it's barely more than paper thin.

i'll spare you the video link to that one, the audio is terrible!

Jeff

 

[Tom O]

I’ve never tried a match plate or cast anything that requires the middle section between the cope & drag.

 

[Dan Dubeau]

Looks great. I'll file that away as it seems like a pretty quick and easy way of making a matchplate pattern.

 

[Tobho Mott]

I’ve never tried a match plate or cast anything that requires the middle section between the cope & drag.

Really, I was just playing around with production patternmaking here for fun, I'll never cast enough pattern rappers to justify making this permanent production pattern. Or even mounting the patterns on a wooden matchplate for that matter.

I have another one made the same way for making sprue covers, to keep dust and bugs from getting into my molds. That one I actually do use sometimes, it's so fast to ram up a pair of them and it's handy to have extras around, so I use them almost like ingot molds. But even there, a permanent metal pattern is totally overkill..

Jeff