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Post by philby09 on Aug 8, 2015 0:47:26 GMT -5
Hi all,
I am trying to make plastic resin copies of some plastic spur gears that are for a old film movie projector, ben using amazing putty to make mold, but whether I rolls putty onto gear or press gear into putty, I just cannot get mold to be right as in the teeth are not 100% right and I cannot get mold thick enough.
Gear has seperators around their hole on each side, getting the other side one's in mold, is a issue, have tried a two piece mold, just cannot get them to match up.
This is a example of what it looks like.
shop.hpceurope.com/fr/produit.asp?prid=3283&lie=0&nav=3
Some may ask why not buy some, well I am yet to find anywhere on web inc Ebay etc that has right size gear, the correct number of teeth and that is important as there are 3 of these that set next to each other on this plate in projector that make other ones turn and in turn the sprocket wheels of projector turn.
If 3D printing was cheaper yeah maybe, but $100 plus per gear ain't viable.
Note I am using Amazing Casting resin to make part.
Any advice appreciated.
Thanks Phil
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Post by mike on Aug 10, 2015 10:05:16 GMT -5
I'd recommend a 1 piece mold using Amazing Mold Rubber and a piece of mold released glass or plastic as the back side half of the mold.
Adhere the gear down on the flat side to your mold base, then make a mold box out of a section of pvc pipe that is 1" bigger diameter than your gear. Seal the PVC pipe section down to the mold base around your part. Then mix Amazing Mold Rubber and pour over top. Allow to cure and you will have a perfect gear mold with no bubbles. Then mix Amazing Casting Resin, pour slowly in your mold until it is over filled, mold release a piece of glass and lay on the back of the Amazing Mold Rubber starting from one side and laying across to the other side, then apply weight to the glass and allow to cure (place weight on the glass until cured to avoid it from sliding or moving). Once cured, demold. Remove the minimal flash and you are done.
Thanks,
Mike
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Post by philby09 on Aug 11, 2015 2:40:11 GMT -5
Hi Mike, thanks for reply and recommendation, I give it a try, by Amazing Mold Rubber, that is a different product to the putty oh you say pour it so that would be liquid version, yes liquid version for mold would work better, Thanks Phil
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Post by mike on Aug 11, 2015 8:33:15 GMT -5
You are correct. If you have a Hobby Lobby near you, you can pick it up from there as they carry that product along with the Amazing Mold Putty in the aisle with polymer clay. Or simply place an order with us and we'll send it to you ... downside is you'd have some shipping costs compared to finding it locally.
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Post by mike on Aug 11, 2015 8:34:05 GMT -5
There is a product video on the box (QR code) or on our website that will walk you through how to use it. Would recommend watching that first as it will make the learning curve very short.
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Post by philby09 on Sept 1, 2015 22:34:13 GMT -5
Hi Mike, sorry for late reply.
I found a Australian importer of product,http://www.fishpond.com.au/ which arrived yesterday. I'll check out video,
Cheers
Phil
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Post by philby09 on Sept 8, 2015 22:08:34 GMT -5
Hi Mike,
Okay I have done a couple of molds, as the spur gear I am molding is only less than an inch in size, first mold I used a medicine cup, like one gets with the Amazing Casting resin, 2nd one I used a plastic cup, as I didn't think enough liquid mold got underneath gear, I don't have a glue gun handy or clay, I did try tape, but found gear would not stay level, I used a small bit of Blu Tack to hold gear in bottom of cup. Now for sure way better result than using the putty, but the casts of spurs gears while even both sides of their spacer is coming out well, the gear teeth thickness is not even, some are thicker than other.
I am theorizing here that not enough mold is getting underneath gear and hence not enough resin can when I cast.
Any suggestions welcome, wish I could upload some pictures here and you see what I mean, I see if I can get them on a cloud account I have and post link here later.
Also which way should I be getting orginal gear out, I am cutting base of cup way and accessing that way.
Thanks
Phil
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Post by mike on Sept 9, 2015 7:16:54 GMT -5
Please send your pic to world(at)alumilite(dot)com
We will take a look at the gear and let you know how we'd suggest tackling it.
Mike
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