I'm a new member from Germany. I already tried some Bits casting some time ago. I used "2 pieces fold mould". Which means I create a two part mould which is rather even, fill the two halves of the mould with resin, wait a Little and then bring it together having something heavy on top of the mould. This worked but not really well and only for solid and simple parts.
Now I have created a vacuum Setup which I used the first times this week. Unfortunately the results are also bad. I have made 6 Tests until now for some heads with 2 part moulds bringing the resin from the top (with a Reservoir). Results: big bubbles or many small bubbles. The last 2 attempts additionaly had "bloody" parts where some not hardened resin came out of the bubbles.
I will try to generate my own FAQ which I want to share then.
So hopefully I will get some Support to find the traps and come to satisfying results.
Resin: TFC PU Giessharz Resin 9min 1:1 500g+500g (https://www.trollfactory.de/Giessmassen ... g500g.html)
Silicon: TS-PK-Sil-Mint-Silikon-A20 (https://www.pk-pro.de/TS-PK-Sil-Mint-Silikon-A20)
Vacuum Setup: ca. 10l pot, Kaleep 1stage vacuum pump, Free Air displacement: 2.5CFM, Ultimate vacuum: 5Pa. On my Manometer I managed to get -13 PSI (-0.9 bar)
I do not have preassure Equipment at the moment. I want first to understand what I currently have and maybe later.
I did not use any release Agent ( will try to buy Baby powder by today)
I have a two part mould with a big Reservoir on top from which I also insert the material. Looks similar to what mangozac is showing here on the right picutre:
The Reservoir is not cubic but becomes narrower towards the Elements beeing cast (sorry do not know better to explain)
a. still some bigger bubbles where the resin is not flowing completely in the mould.
b. a lot of small bubbles even if I squeeze the mould and degass it 1-3 times (somewhere in between -0.5 / - 0.9 bar for 30-60 seconds)
c. in the last 2 attemps bloody areas where the resin did not react to solid state (I assume this Comes either from not having the right Ratio between the 2 resin components or from older component B in my mixing pod. I regognized some White film when bringing the resin to the mould in my latest attempt which is currently hardening) in this attempts I did the Maximum vaccum of -0.9 bar at least 1 time per attempt for around 30-90 seconds. Maybe this is the Problem?
1. If I only have access to vacuum setup, how to degass?
1.1 Maxumium possible vaccum?
1.2 How Long /often should I degass?
Currently I'm also reading a lot of threads here in the board but I hope you will help me here in my learning by doing thread.
Cheers
Thorsten