High / Low Beam Switch

[DiverRay]

How about two threaded studs, so they also hold the mold together? Just throwing out ideas. With my sinus headache, they may NOT be good ideas, but hey, I'm trying to help...

[CRXSi90]

Yeah, I haven't worked out the details on how to align and hold it together. I was thinking maybe a couple dowel pins plus a bolt/machine screw, or studs.

I have to do a little more thinking about how to incorporate the tab. Right now, it would land right in the middle of the center block, which isn't really a machineable way to do it. I could replace the center block with three pieces (two flat and one with a cutout for the switch), but I need to think a bit more about the options.

[Schming]

Yeah, I haven't worked out the details on how to align and hold it together. I was thinking maybe a couple dowel pins plus a bolt/machine screw, or studs.

I have to do a little more thinking about how to incorporate the tab. Right now, it would land right in the middle of the center block, which isn't really a machineable way to do it. I could replace the center block with three pieces (two flat and one with a cutout for the switch), but I need to think a bit more about the options.

Wouldn't the middle block have to be the thickness of the switch tang and incorporate the recesses for the main body into the outside blocks ?

Or add the switch tang to the middle block and then split the middle block in the center so it can release.

[CaptonZap]

Since you seem to be almost to the place where you can start making molds, here is some info to give you another few days of web surfing.

http://www.instructables.com/id/Home-Injection-Molding/ About a third of the way down is an interesting picture.

In fact, go here and waste a week;

http://www.bing.com/search?q=diy+plastic+injection+sites&qs=AS&form=QBLH&pq=diy+plastic+injection&sc=4-21&sp=2&sk=AS1

Enjoy, CZ

[CRXSi90]

Or add the switch tang to the middle block and then split the middle block in the center so it can release.

I think I'm going to do something along these lines. Looks like it will take 4 blocks to get it all done.

And yes, mini plastic injection molding the parts does sound interesting. I will have to take a closer look at some of the plans. I've heard of people doing it with glue guns and such, but I don't think EVA-plastic switches would do it for us.

As a side note, does anyone know if the Mike's XS switch assemblies are factory parts or reproductions? I haven't seriously looked into tracing back the manufacturer of the switch assemblies. Someone, somewhere, had a mold for this little switch part.

[CaptonZap]

Someone, somewhere, had a mold for this little switch part.

And we can only hope that it was not in a society that fostered the notion that "if I don't know what it is, but if it is made out of metal, I'll sell it to the metal recycler."
I keep wondering how much metal, product of how many man hours of labor, gets sold for ten cents a pound.
CZ

[CRXSi90]

Yep, I agree, a lot of interesting things get scrapped. I like making metal art, and it's surprising what interesting things I find being discarded. Sometimes I feel like I'm committing treason while cutting and welding on some of these things. But it makes me feel a little better knowing that the things would have just ended up scrapped, and I'm giving them one last shot at life.

A local guy ran a salvage/scrap business. I'm sure he saw a lot of things go through which were interesting or had value to someone. He made some fantastic art pieces out of salvaged material, and I have a hunch he had some similar feelings about the abundance of things being scrapped.

http://worldofdrevermor.com/

[CaptonZap]

LOL,
Howdy Ken,
I like the web site. If you are ever in the Fort Collins, CO area, just east of town is a place called Swetsville Zoo.

http://www.roadsideamerica.com/story/10787

Well worth a couple of hours of your time.
CZ

[CRXSi90]

Cool, I'll keep the Swetsville Zoo in mind if I get that way. A friend in Denver invited me out to visit. I would love to do that as a motorcycle trip, but unfortunately it would probably take more vacation time than I can afford. My guess is that the trip would take 4 days or so, or more if I packed on a few more destinations (Sturgis, SD is on the way....kind of).

Doc Evermore's sculpture park has a Roadside America page too. http://www.roadsideamerica.com/story/2239

Added in the switch tang to the mold. Not sure if I should mold in the hole for the self-tapping screw, or just leave that to be drilled for best fit.

Also added holes for some sort of guidance/alignment. I'm thinking of using dowel pins, but I haven't done a lot with dowel pin fits. I know people often ream holes to get the appropriate fit. I think the ideal situation would be to have a press-fit into one of the blocks, and a sliding fit on the other three blocks. But it would probably work out okay if I just had a sliding fit for all the blocks, and just made sure the dowel pin was in place.

I'm still thinking of using epoxy, at least for the first go around. I'm not sure how to fill the cavity, though. I could just slobber the epoxy in there, and then close up the mold, but that sounds messy. I could inject with a syringe, but I think I would have trouble venting to make sure there are no bubbles. I could vacuum degas it after filling to remove bubbles and cycle the vacuum a few times, and provide an epoxy reservoir so each time the bubbles collapse, it is supplied with epoxy. Hmm.

Another thing that worries me is the part not releasing well. I will have to look into what mold releases are available.

[CaptonZap]

Poly vinyl alcohol, PVA, is the stuff you want for mold release. It can be sprayed on with an air brush, or painted on with a regular brush, or dunk and drip applied, although the latter method is not recommended. Any FRP supply store will have it. The down side is that it comes in quarts , gallons, 55 gal drums, which you would be forever using.
They might have it in smaller quantities, my supplier doesn't.
Good luck, CZ

[CRXSi90]

Thanks, that's interesting. It looks like I can get a 8 oz bottle of PVA for $8.99 at O'reilly Auto Parts. http://www.oreillyauto.com/site/c/de...5685/N0486.oap

I just watched a short video on PVA. http://www.youtube.com/watch?v=lKHGNh6UvZA

So coat with PVA for each part molded?

[CaptonZap]

Yep, thats the stuff.

i'll have to check the O'Rielly's here.
I've found that you can get the PVA to go on carnuba wax without beading up if you spray it.
Good find, CZ

[Schming]

Now yer cookin' with gas !!!

Great work on the design.

"Added in the switch tang to the mold. Not sure if I should mold in the hole for the self-tapping screw, or just leave that to be drilled for best fit."

JAT, could you add a centering tit, for the switch handle screw, to the far right section of your mold, to be "premarked" for post cast drilling ?

[DGXSER]

I would agree, you would want some sort of centering indent if not a smaller starter hole for drilling out the screw hole. Then again, if you have the tools to make the rest of that jig, drilling a hole on center should be a piece of cake!

[clcorbin]

FYI: I have access to a small ABS injection molding machine. It is the perfect size for making parts like this. The only downside is that we only have RED plastic for it, so... Once concern I have is how well it will handle the complex shape of this part (lots of places for air to get trapped).

I'll try to find out what the dimensions of the molds this machine can take. But I am about 99.9% sure that these molds for this part would work perfectly. The molds would definitely have to be aluminum to handle the forces and heat involved.

When the CAD drawings are done and verified, I could also see if Jason would make a set on the Fadal so we could give this a try. It would also let us make any changes to the mold body to better fit the injector.