Vibrating table for mold making and casting

Chris Ellerby

One thing I'd like to add to my shop is a vibrating table to help reduce trapped bubbles when making molds or casting.  There are a few existing models on the market, but they tend to be a bit on the expensive side.  There are some nice models used in dentistry, but they are a bit small (usually 6"x8" at the max) and i''d like something more like 12"x24" or a little smaller.

I found this model on eBay, but it's also a bit expensive:



I like the vibration dampers they are using, but I've not been able to find any like them online, aside from shock absorber covers (which could be what they are)

I've also been looking for good variable speed vibrating motors, but have not found the right model just yet.

I figured I would share this here so others can follow my progress, but also so you guys can suggest your own ideas.

I've seen vibrating tables made by bolting a vibrating sander to a piece of plywood, but I'm hoping for something a bit more elegant and adjustable.

What do you think?

/Chris

Joseph Humpston

That's Nice Chris! You care to post some plans?

Chris Ellerby

As I find the parts I'll post what I find and will share the build.

I still need to find the right variable speed vibrating motor (looks like some folks are using parts from massagers) and the right vibration dampers.

Still searching!

/Chris

Chris Ellerby

I've been looking at motors from massaging chairs and similar products.  Hoping to find one with adjustable speed.  I've not found the right one yet!

I've also found this product for $120:



http://www.amazon.com/DENTALNY-Denture-Vibrator-Medium/dp/B00CB1ZV4Q/ref=sr_1_1

That price point is not bad at all, but at 6"x8" it's about half the size I want.

/Chris

David Boccabella

Hi Chris.
Could you not bolt a larger top onto it. 

Chris Ellerby

You can, but there would be some power loss and the vibration would weaken the further out to the sides you get.  

I could put a larger top on and then move the mold around over the "sweet spot" where there is more vibration, but ideally I would like a larger vibrating table that has enough power at the edges to do a couple small molds at once.

/Chris

Chris Ellerby

I was able to find an 11"x8.6" mold vibrator for around $223, which is roughly the size of a sheet of paper.  Still not super large, but I'll have plenty of smaller molds that would fit on it just fine.  And I might be able to slide larger molds back and forth over it.   Not buying it just yet, as I want to keep researching, but so far that's the best option.



It has the added advantage of 2 vibration frequencies and variable speed.  Most DIY solutions would just be variable speed.

/Chris

Stuart Mcconnel

I'm not sure what sort of vibration frequencies would be suitable for this, but could you perhaps use a transducer from an ultrasonic cleaner? They're typically around 40kHz, which might be too fast. But they can be had fairly cheaply.

Stuart Mcconnel

Another thought is to use a washing machine motor which typically already has a pulley attached. Add some off centre mass to the pulley by just screwing a lump of metal to it or something and hey presto, you have a vibrating motor. Washing machine motors are probably sturdy enough to withstand the vibration.
Bonus points if you can utilise the speed controller and motor driver from the washing machine!

David Boccabella

The vibration frequencies are pretty low, usually around the 50-100hz.  Definitely not ultrasonics as that might cause cavitation which is definitely NOT what you want.
An motor with an off balanced pully is usually the best

Dave

Chris Ellerby

I did toy with the idea of just using a DC motor with a off balance weight.  There are also a number of variable speed vibration motors out there, but most are quite large (more for vibrating big concrete molding tables)

Ideally I think a 12"x24" vibrating table would be perfect for my shop, but the only pre-built model I've found is over $800, which is horribly over priced.  It's intended for chefs who work with chocolate, so they inflate the price to a ridiculous level. 

I may settle for the 11"x8.6" model I found, but for now the search continues!

/Chris

Stuart Mcconnel

I hope you find what you're looking for
And for the record, for anyone else reading this thread, be very careful when searching for the 11" x 8.6" model that Chris posted an image of. Googling "Big vibrator" is quite risky lol!

David Boccabella

@Stuart Mcconnel   Whatever does the job of getting the bubbles out works.  I've seen stranger things reused for purposes that they were not designed for.

Chris Ellerby

Haha.  Trust me, this endeavor has produced some rather unpleasant search results.    Search terms such as "mold vibrator" are not for the feint of heart.  

/Chris

David Boccabella

I remember reading an interview from Robert Picardo - who played Eddie in 'The Howling'
He was not expecting to have male prophylactics strapped to his person and inflated.. Some until they exploded under pressure - during the scenes.
It was the classic werewolf transformation scene which in my opinion is still one of the best...
Needless to say Robert went on to many other great roles like the holographic doctor in Star Trek Voyager, and Richard Woolsey in Stargate Atlantis.

Chris Ellerby

Loved him on Voyager and Stargate Atlantis (miss that show!).  I've not seen The Howling in years, such a classic.  Really need to see that one again.

/Chris

Mikey March

@Chris Ellerby I spent hours looking for what's called an "e-ring" to keep rods in place (my roto caster). At the time, it looked more like a 'C' to me.. c-lock, c-clamp, c-ring? Google's and eBay's c-rings were not the c-rings I was looking for.

Chris Ellerby

@Mikey March Too funny!  I've had to search for e-rings (aka retaining washers) before as well. I'm using them in my animatronics projects where shaft collars eat up too much clearance.  McMaster Carr is a great source for them.

/Chrsk

Dennis Heinzeroth

Dang! Looks like I haven't been here on the forums in quite a while. Anyway.....you can also look for paper joggers used by printshops to neatly "jog" stacks of paper. They come in a number of sizes and prices can be high, but sometimes you can find a good deal on them. Variable speed and can handle a good bit of weight, depending on the size of jogger you get. 

Dennis

Wolf Reicherter

Anyone thought about using these things?
http://www.bassshakers.com/faqs/aura-bass-shaker-versus-buttkicker/

They re used extensively in the so called 4D theaters to create different feelings in chairs and as far as I know you can adjust seamlessly

Chris Ellerby

That could work Wolf.  I guess the challenge is what drives that device, and if it operates in the ideal frequency for different casting materials.  Worth looking into for sure!

/Chris