Results 1 to 2 of 2

Thread: Lost wax casting

  1. #1
    Join Date
    May 2021
    Posts
    1

    Default Lost wax casting

    Hello,

    I am new to lost wax casting and had an unsuccessful first casting. Maybe someone could help me out with identifying my errors.
    I thought I studied enough, watched way too many youtube tutorials and prepared everything into detail but it still ended with non and partial fills.

    I built a little wax tree with wax injected earrings, charm and hand carved rings, covered the tree with Goldstar OMEGA+ investment which i mixed with deionised water 40:100, vacuumed and then after 2 hours burnt them out in a 3.15" x 4" perforated flask, in a paragon E12 kiln for 12 hours (started at 300F - 400F - 700F - 1350F - 1130F Casting temp i held for more than 2 hours)

    I used a KAYA cast for vacuum chamber casting, melted sterling silver until 1850F in an electric furnace and poured it in my mold, while it was in the vacuum chamber with full vacuum pressure on. After 5 min I quenched my flask and unfortunately just one charm made it completely (but also with some rough surface on the back). the bear charm was on the very top of the tree and the heaviest model. the top pair of earrings just filled half and the lower placed earrings stopped right at the sprues, same for the basic rings at the bottom of the wax tree. Now I figured as they were the smaller pieces they should have gone on top?

    see attached pictures of the final tree and also the wax tree, and separate earrings to see the sprues better.

    My guess would be that my sprues are too skinny and in the wrong placement? but they were like 3 mm which I though would be fine, also for the lower earrings I had 4 sprues attached to the inside of the earring to ensure the metal reaches the whole model. maybe too many or too complicated. They way I built up the wax tree must be wrong because I thought temperatures of flask and metal were fine.

    Thanks for your help, really appreciate it!
    Raffaela

    Click image for larger version. 

Name:	Screenshot 2021-05-04 at 11.04.10-2.jpg 
Views:	15 
Size:	43.8 KB 
ID:	13011Click image for larger version. 

Name:	Screenshot 2021-05-04 at 11.04.28-2.jpg 
Views:	9 
Size:	27.7 KB 
ID:	13012Click image for larger version. 

Name:	Screenshot 2021-05-04 at 11.04.54-2.jpg 
Views:	13 
Size:	26.3 KB 
ID:	13013Click image for larger version. 

Name:	Screenshot 2021-05-04 at 11.04.04-2.jpg 
Views:	9 
Size:	39.1 KB 
ID:	13010
    Last edited by raffacakes; 04-05-2021 at 09:09 AM. Reason: submitted too early

  2. #2
    Join Date
    Mar 2011
    Location
    Manchester UK
    Posts
    937

    Default

    the sprues look ok to me, I would start with temperature if the heavy item cast .I would up the temp of the flask and maybe the metal too. Is the machine producing a full vacuum ? Also with an electromelt the metal cools very fast you need to be very quick when you remove the crucible and pour it.

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •