SSB's General Log

[mangozac]

Oh wow I didn't realise it was silicone - I thought it was a proper vulcanised rubber mould!

[SSB]

[Deadmeat30]

There are 2 types of material for making metal moulds, First is natural rubber, which is normally black in colour, then there is Silicone. I have a picture somewhere of my silicone mould i made while running some spin casting tests a while ago.

[SSB]

I have a strange question...
Seen the price of the high CFM vacuum pumps, and the fact that I have now a 5 gallon pressure pot...
An idea has popped into my head... (more than one actually)

What would happen if you plugged 2 vacuum pumps on one pressure pot ?

What if the 2 vacuum pumps are as powerfull ?
What if one of the pums does a deeper vacuum than the other ?

Same question for 2 air compressors...
(In my mind there is no problem with that solution...)

I have a 8CFM vacuum pump.
I am actually looking at a gorgeous 12CFM vacuum pump...

[mangozac]

I can't think of any reason that two pumps and/or two compressors wouldn't work...

[SSB]

It's better to ask before doing something stupid...

[fnarfbargle]

[SSB]

Interesting !

As a matter of fact, both vacuum pumps will have the same maximum vacuum of 15 microns. The only difference between the two is that one is 8CFM and the other is 12CFM

Have you been able to (or have you any idea) evaluate the speed of the oil pumping in the hoses while doing vacuum with both pump ?

The point is :
I will always be supervising my vacuum set up while I use it. When I reach vaccum (My gauge seems aproximative because it is small and is comprised between -30Hg and 100PSI) I close the ball valve to the pressure pot and then I shut down the vacuum pump.

I think there would be between 0 and 30 seconds of maximum vacuum reached.
Would 30 seconds be sufficient to cause any pumping of the oil ?

If not, then I'll consider myself safe !

Here is the schematic that would be used for the set up :

[fnarfbargle]

No, I haven't watched it happen. Once was enough for me.

Frankly I think you'll be fine. It won't be a fast process while both pumps are running and the sort of times you are talking about just shouldn't be an issue. Just make sure you break the vacuum before switching the pumps off.

[mangozac]

Yes, this is interesting and I can see how it could happen. But I agree it's unlikely to be a big risk here. If really paranoid you could put a nonreturn valve on each pump (so that air can only move towards the pump, not back).

[SSB]

Let's say I am, we are, paranoid...

Is this kind of valve adapted : http://www.ebay.com/itm/Bspp-Non-return ... 19e229f2fd

Is this kind of valve adapted ?
(if it isn't, could you give an example and/or characteristics of one that would do the work ?)

Doe the arrow indicates the direction the air can flow ?

[mangozac]

That seems correct. I'm not 100% on the intricacies of it but for that price I'd give it a go

Yes, the arrow should indicate the direction of air flow, so you'll want it pointing towards the vacuum pump.

[SSB]

Hello fellow addicts.

I haven't posted on my log for a full year. But, nevertheless, I am following the discussions now and then and my addiction is not cured at all. It's just getting worse.

I will bring my contribution to that forum in a while (don't know when). As I am becoming skilled in metal casting, I will share with you the techniques I learned. They are a bit different from resin casting and the tools are far more expensive, but I am sure you will enjoy the knowledge.

A small question. Anybody knows if Chris, of wasteland game studio comes around here ?

To share just a bit...

My addiction palace : (a bit messy when I took the photo)


And there, the silicone and PU resins I find and buy in France.
(I gave up smooth on products, too expensive and I had a lot of sticky results)

The silicone I use for resin moulds :


The 2 resins I use :

White one :


Ivory one :



Be sure I WILL be back for more...

[mangozac]

[SSB]

I'll post some things I found on his blof that I find interesting and intriguing...