Making a 10cc Whippet pattern

[bmac2]

Hang in there, I read in today's paper that a couple of hundred firefighters are on their way from Sydney and Melbourne.

Paul.

Paul that’s great news. In theory it’s an 18 hour direct flight but those don’t exist so with 1 stop it’s more like 24 hours to get to Alberta from Melbourne. So Then If I have my math right that’s:

(Government–A + Government-B) / 24 hour Flight = Murphy ’s Law

So by the time they get here it should be raining pretty hard. Rof}

Thank you RichD
I find that working on the pattern gets frustrating at times but a lot of the problem is that I over think it. While in a way I am working on a model engine the patterns really don’t have to be that exact. All in all it’s been fun and interesting even if my learning curve gets a little steep at times. But when I get frustrated it’s always fun to just melt something.

Hi Dougie
That’s a great idea. I was thinking of something along those lines myself but I was over complicating it. What sort of SS did you use for your cores? I might try for a video on my next pour. I haven’t done one for quite a while because I just don’t want the distraction.

 

[fourstroke]

Hi Bob
I used the foundry grade, the dark brown stuff you mention. I mixed it with kiln dried sand from the local builders merchant at a rate of 3% by weight and the cores came out of the mould rock solid in a couple of minutes.
Are you using co2 to set it?

Dougie

 

[bmac2]

Hi Bob
I used the foundry grade, the dark brown stuff you mention. I mixed it with kiln dried sand from the local builders merchant at a rate of 3% by weight and the cores came out of the mould rock solid in a couple of minutes.
Are you using co2 to set it?

Dougie

I just bake them in the toaster oven when I’m just messing around like this. If I am planning a pour I stop and pick up some dry ice and use that. I’d like to setup up a small Co2 system and looking around the paintball tanks are $30-$50.00 (12oz to 24oz) and cheap to fill but I think I’d have to bodger up the fittings and get a regulator together to make it useful.

 

[bmac2]

Hang in there, I read in today's paper that a couple of hundred firefighters are on their way from Sydney and Melbourne.

Paul.

Hi Paul
Looks like the Australians are all going to British Columbia (my second favorite provinceThm, has to be one of the prettiest places on earth.
On the news tonight they were showing some fire fighters that are up here from New Zealand getting their “introduction to the local wildlife and what to do if you see one” training. I’d never thought of it before but I guess in New Zealand you wouldn’t worry about it.

Swan Hills grizzly weigh from 140 to 450 kg (300 to 1000 lb.)
Average length of male cougar 1.7-2.7 metres, 60-100 kg (130 to 220 lb)

 

[Swifty]

Bob, there's not much in New Zealand that's going to bite you except sand midges, which are a real pest, they don't even have snakes. But us Aussies are certainly use to seeing snakes around, that's about the only thing trying to bite us, just try to avoid them.

Paul.

 

[fourstroke]

Hi Bob
I use the co2 bottle from my mig welder with a short piece of hose cut from the gubbins inside the unit, the regulator lets me adjust the pressure to whatever I need which is usually pretty low
Dougie

 

[bmac2]

Fourstroke : I’ve got a small mig welder but its flux core only. The dry ice setup I use works it’s just I have to plan ahead. With the sodium silicate I have the cores come out hard after gassing but feel wet so I have to bake them to make sure they are dry. One day I’ll find a deal on a bottle with normal fittings and get things setup. I know that most places around here won’t fill anything if it looks at all dodgy.

Paul: Yep, that’s the difference. Getting a bite and getting eaten.
Oh. And our weather forecast . . Murphy’s Law . . We’re getting rain on and off for the next week, starting tonight.

 

[bmac2]

As it turns out, like everything else not all bentonite is the same. There are three main types sodium bentonite, calcium bentonite, and potassium bentonite. And there are probably an infinite number of grades within each type. What you want and what I have for green sand is sodium or western bentonite I just don’t know what grade it is. When I mixed up my first batch I went with the ratios from the Myfordboy blog. I think that any recipe you decide to use is only good as a guideline unless you’re using materials from the exact same source. I’ve been slowly adjusting the ratios in my sand mix over the past 5 months (casting is nothing if not fast paced) and adding that additional 200g of clay this week has made an amazing difference in the overall feel of the sand. I’m going to have to go back through my notebook and work out just what my ratio is now. With the sand feeling this good I had to try it so I grabbed my little snap flask and rammed up the block pattern as before giving it a generous dose of venting.

 

[bmac2]

As soon as I opened the flask I started getting excited. When I pulled the patterns I could see a major improvement. The edges are much sharper and the surface of the sand looks clean and smooth. I also changed the runner and gates this time. I don’t know if it makes much difference but I’m really starting to like to ram in the runner and gates. I also like to scratch a number in the sand in case my pictures get mixed up.not that that could ever happen.

 

[bmac2]

The undercut for the cam gear mount pulled smoothly and the edges came out nice and sharp with only the slightest bit of tearing. I was feeling pretty good at this point. I even when and got my wife to show her the results. She was thrilled and said “That looks nice” and went away but brought me a sandwich. Always a good sign.

 

[bmac2]

I put the core in the toaster oven at 475 (as high as it would go) and fired up the troll. I really have to get to work on the new furnace one day.

 

[bmac2]

Once everything was up to temp and melting nicely I got the core positioned in the mold. I thought of trying to get a nail into it to keep it from shifting like Dougie suggested but was afraid of damaging it so I just go it in position as best I could and closed up the flask

 

[bmac2]

I tried to get a video of the pour and only got about 45 seconds before the batteries died. I thought I had a short pour as the risers didn’t fill but I could just see some metal at the bottom. The blob beside the riser was the vent I’d put in for the core. It worked well at first with a lot of smoke from the core coming out until it filled with aluminum. I’ll have to work on that. Looks like the snap flask got its first battle scar.

 

[bmac2]

If nothing else the shakeout with a snap flask is well . . . a snap. Pop it open and everything just falls out. Melting things is fun and pouring is just cool but the shakeout has to be my favorite part of casting.

[ame]https://www.youtube.com/watch?v=h9KcMn2SYmA&feature=youtu.be[/ame]

 

[bmac2]

This one came out a lot better and the core didn’t go walkabout on me. The finish is better with (to me) an acceptable amount of flash but it looks like my sand may have been a bit wet. Over all this one could have been a keeper if the pattern was finished.

 

[bmac2]

The overhang came out nice with a sharp edge. I am very happy with that and the inside looks cleaner.

 

[bmac2]

I didn’t do any setup for this I just wanted to see how it would finish up so I hit it quick and dirty with an end mill on the surfaces that need to be machined. 4L Nissan is nice stuff. It machined easily and the finish is pretty good considering the mill I was using. There are a lot on tiny pinholes but nothing that I think would make it unusable.

 

[bmac2]

The flashing cleaned up fast and easy with no sign of the file clogging up. It looks like a lot of gas entrapment in the top in the valve guide area. This may have been from the core but the top of the core looks clean so I don’t think so. It may be that it was too close to the sprue so it stayed liquid longer and had more time for gas bubbles to form. If this was a casting I was going to use I don’t think it would affect anything but next time I may try degassing the melt. The inside looks a lot better but I’m going to rethink that venting in the core to keep it from filling with aluminum.

Thanks for checking in.

 

[bmac2]

I decided it was time to stop playing in the sand and get back to work on the pattern today. I need to add a flange for the water inlet and a spot for the oil filler plug.

 

[bmac2]

I only need a little over ¼” for the water inlet but the shape looks so handy I made a piece about 5” long. I did this like all the rest by clueing two strips tougher with newspaper then glued the pattern onto each end and forming it on the belt sander. I can’t think of any project I’ve made where I’ve used this sander more than on these patterns.