Brand New and looking for advice

[BeyondDoubt]

Hello there,
I am UK based and have been reading this forum and watching a few youtube videos for some time now and it's high time I actually got going with resin casting, rather than just thinking about it!

I intend to do some basic recasting of existing items, ranging from pieces up to 25cm x 9cm x 4cm down to shoulder pads.
I will also be casting from new 3D scuplts and new base designs.

I'm onboard with the need to have a pressure pot configured for both vacuum and pressure, but would like some pointers as to where best to buy the required equipment from.
e.g., is this a good setup at a good price? http://www.pressurepots.co.uk/resin-mou ... nk-10.html
What spec vacuum pump is required?

I have a compressor from an air-brush setup; will this suffice, or do I need more dedicated gear?

The more advice the better, and rest assured this is something I intend to see through.
I've already got a range of items on the bench waiting to be covered in silicone!

Thanks in advance.

[mangozac]

Hi, welcome to RA!

That doesn't seem like a terrible price for a ready to go casting chamber like that. Looks pretty solid!

Is your compressor an airbrush compressor, or a larger compressor being used for airbrush duty? You really need a compressor with a 20L+ tank for rapid transfer of air from the compressor to the pressure pot, otherwise the resin could start to set before you have finished pressurising!

Vacuum pump wise, we recommend 7CFM+ for that size of pot. The absolute vacuum level the pump can attain isn't too critical, so long as it's up around 99% vacuum.

[Fleafa]

What Zac said. I have that pot and I am very happy with it so far.

[BeyondDoubt]

Thanks for the welcome and responses.

Well, between making the first post and now I had done some more reading of older threads on this forum and found a recommendation for using the pot as both a vacuum and pressure. I wasn't sure if the item I had linked to did both, or was just geared up for pressure.

So, I read some more about converting a paint pot and decided to start there instead.
I have picked up this for £50. Inside is 24.5cm diametre by 22cm deep.
Not quite big enough for the largest piece, unless I get creative with the mould and have parts at an angle!

If it's not going to work, then break it to me gently.

So...
To double check, is vacuum and pressure in the same pot actually a recommended process, or is it better to keep apart?

The compressor I have is a 3L tank, and moves 23L/min... so probably not enough by the sounds of it.

Do you have any recommendations for a good manufacturer of a suitable compressor and vacuum pump?

Thanks in advance.

[mangozac]

That looks pretty standard like the rest of us have converted
Conversion is easy and for 50 quid is a good price!

Having vacuum and pressure in the same chamber is preferable for resin casting. It's not ideal for degassing (generally silicone), as you need to be able to watch the process. You can however build an additional clear lid for vacuum use.

3L is definitely too small for the compressor. You just want a standard unit sold by hardware/automotive stores with a tank >= 20L.

[BeyondDoubt]

Simple thing first then...
Would a 5mm sheet of clear acrylic suffice as a clear lid?
How would I know the max vacuum limit for a 5mm sheet; would a 6mm or thicker be required?
A3 sheet is around the £8 to £10 mark on eBay, so would be good if it was as simple as that.

[mangozac]

Not even close! You want a minimum of 20mm thickness for that kind of diameter

[BeyondDoubt]

Haha, ok, thanks.

So 20mm thick by 300mm x 300mm is around £31 to £35 on eBay.
That will cover the pot diametre, with a limited overhang.
Would that be an issue, and would I be better off with a larger overhang do you think?

Cheers

[mangozac]

You only really need about 10mm overhang. It's not that important. I got a piece of perspex CNC cut in a circle with a rebate for locating on to the lid and it works really well. But I was able to get that job done at a cheap rate from the plastics people we use at work

[Fleafa]

I bought a lexan polycarbonate sheet 12mm thick. Not tried it yet...

[RageofAchilles]

I didn't fancy messing about so bought a degassing kit off ebay, with vacuum pump and pot with clear lid.

I bought my 25ltr compressor off Ebay too for around £75

The pressure pot you bought was a bargain! It's good that your looking through old threads here since many of us ( myself included) are relatively new to pressure casting, so you will see the hurdles we have jumped over the last couple of years, hopefully you will have an easier time setting up because of it

[BeyondDoubt]

Rightio,
A long delay there... I won an eBay auction for the following air compressor for just over £40, but the seller reported it broken and refunded the money. Talking to him he sounded a genuine guy who was going to fix it before handing it over.
This sounded out of line with most eBay auctions, so I sceptical, but because he sounded above board I hung on.
Anyway, today I rang him and went round to collect it.
Seems to be running fine, so I may have found one of the better people on eBay.


So, now the clear acrylic sheet (eBay £31 for a 300mm square sheet at 20mm thick).

And then to begin the search for a vacuum pump!
Any guidance on spec. / advice on what to look for gratefully received.
Honestly... this pump seems to be the hardest thing to find!

What is the reasoning behind recommending the 7CFM+ pump?
I have looked on eBay at a variety of kits (pump and chamber together) and they are often in the region of 2CFM for just under 10 litre pots, and 3CFM for just over 10 litre.

[mangozac]

Nice one!

The reason you need a 7+ CFM pump is so that you vacuum the resin quickly enough. If the vacuuming takes too long the resin will set while it's happening.

[Blindhorizon]

I have the exact pressure pot you got. That black lump of crap on top is garbage don't even consider using that in your pressure set up it is of no use for your purposes. Personally before you go and blow money on a vacuum chamber and vacuum set up i suggest you convert your pot and try some test casts. You don't really need a vacuum set up unless your going to try and do some retail sales in my opinion, where 99.5% is what i get without vacuum you'd want to give 99.99% to customers for retail(i have been told my casts are on par with forgeworld). I don't know if money is in excess for you, but not having to spend that extra cash could go towards silicone and resin for more casts.

When pouring your molds you can leave them in the pot under pressure, i leave them sometimes for upto 48 hours under pressure. When it gets cold here it takes an 8 hours set time silicone over 24 hours to set i leave it for 48 to be sure. I had pulled one to early the whole thing blows out after an hour and looks like swiss cheese, wasted silicone and time. If you are suffering from leakage you can leave your pressure pot hooked up to the compressor with the regulator set to the proper pressure and it will keep it topped off. (Leaving something under pressure is dangerous i make sure to let everyone in my house know not to touch my pot, so if you have small children be careful with this).

[chinwag]

Hi Everyone,

Sorry to bump and older thread, especially with my first post here but I've been reading about pressure pots and this thread seemed like the most recent/useful one for me.

I just wondered if any of the UK heads here would know if the post mentioned at the start of the thread;

http://www.pressurepots.co.uk/resin-mou ... nk-10.html

Would still be considered a good buy, or is converting a pot better? I'm keen to get up and running and everything I try to cast seems to be full of bubbles at the moment!

Thanks.