Casting Wiper lever

[M37-1952]

Hi all,
Nobody has a lever for the back of my vacuum wiper motor and they are rarer then square washers so I cast one. Made a mold of plaster from the one lever I have, melded some junk Al and made a lever. Filed and sanded for a half an hour and the pictures are below. The casting is on the left of the two levers.


Mark

P.S. Next to make the odd 3/8-24 bolts.

 

[Angus1]

Ahhh, Necessity. Looks Good.

 

[Boatcarpenter]

Very nice
BC

 

[clinto]

Wow, that's pretty industrious of you.

Good work.

 

[Hm2klie]

Very good idea, nice looking

 

[Junkyard Wars Crusher]

Top notch, sir. That's a restoration in which you can take pride. Making your own parts is the final step.

 

[alphadeltaromeo]

That's an excellent idea! I'm really impressed with your ingenuity...so thanks much for sharing. Now, what was the process of melting down the metal? Educate me a bit more please...if you would.

Andy

 

[M37-1952]

I work at Alma College and I'm the Science Coordinator. My job is to repair and fabricate research equipment. Alot of the time it is an idea drawn on a paper towel with a sharpey. For the lever, I looked up metal casting on the web and learned that cast plaster will hold up to molten Al. What I did was mix and pour plaster of paris in a foam bowl. I put 1/4 " tubing in the shaft hole and grase the whole thing in vaseline. I poked a hole thru the bowl when the plaster was slightly hard and used a 1/4" tube for the spruce for air release. I let it harden for an hour then grased the plaster and part . Miw and pour more plaster on top. Let harden 1 hour. Split and remove parts. Use a razor knife to clean upthe mold areas and to cone shape the pouring spruce.Dry overnight in warm oven or heat lamp to avoid steam explosion on pouring. Melt Al scrape in a ceramic crucible or plumbers ladle using a O2/AC torch or MAPP gas will work. Clamp verticle and pour molten Al in one spruce until it flows out the air spruce. Let cool for 1/2 hour. Split and sand and file. Finally buff to take out final marks.


Mark
1952 M-37 Starting to take apart to paint and restore.

 

[AN/GRC-46]

Good old American ingenuity. It appears the new casting is a little smaller than the original. Did it shrink when it cooled? I've done similar things but used broken automobile trim pieces (pot metal) to melt.

 

[JasonS]

Yes, they will shrink. There is a rule of thumb for shrinkage but I don't remember it. Not knowing that, you could look up the thermal coefficient of expansion of Al and use that to calculate the shrinkage from molten temp to room temp.

 

[IronPig]

Quite impressive. As Junkyard said, you've made it once you realize you need to make your own parts... and do so!

BTW- if you make two extra PM me and I'll send you the mailing address for the "extra vaccum wiper lever disposal depot" <grin>

 

[amanco]

I have had parts casted for antique engines. Most people who cast parts dip them in wax to make up for some of the shrinkage and create a smoother surface. Also to build up areas to be machined.