Casting resin parts in 1/72

Micro Mark sells a good all-in-one resin casting kit, as well as individual replacement supplies.

It works well, has good instructions.

Smooth-On  (Smooth-on.com) makes multiple products for resin molding & casting.   Check their website.  On it there is a series of video tutorials including one, How to start resin casting and live to tell about it.   

Check too their distributor list for one near you.   I have one nearby and I can buy over the counter.  They are also helpful in answering my questions

They offer a starter kit which includes OOMOO-30, a 30 Shore weight RTV, and a 5 minute white resin.  Also included are some spritz bottles of mold release.   Regarding Shore weight the higher the number the stiffer the RTV.   Shore 60 is too stiff for resin but may work well for concrete.  Shore 20 is too flimsy.   30 is a good compromise IMO. 

Smooth On is 1:1 volume mix so you don’t need to mess with weights or smaller volumes.  

Hobby Lobby has casting sets.  Using one of their 40% coupons might be a way to get started.

Here is my experience with RTV molds and urethane resin.  Biggest issue is design of mold. If you design mold right you do not need vacuum equipment.  Main source of air bubbles is not in the resin itself, it is air trapped in the mold.  You must leave a way for the air to leave the cavity without conflict with the incoming resin.  I find a J-shaped channel for bringing the resin into the mold, along with vent tubes rising from each local high spot in the cavity makes for a good mold.

Also, the resin itself seperates when it sits for awhile on the shelf.  So it is important to mix the resin itself well even before adding the catalyst to it.

Ahoy Matt.  I've got the itch to try my hand at resin casting also.  I found this good, short video from none other than FSM's own Aaron Skinner.  He makes it look simple and painless and it answers some of the basic 'how to get started' questions.  When you've finished part I watch part II.

https://www.youtube.com/watch?v=vr4OlQIARc8&t=16s

https://www.youtube.com/watch?v=Md1acWONuRQ&t=16s

Thanks Strongeagle. Watched both of them and I must say that it seems pretty straight forward.