Glassblowing Molds 101 With Glass Artist John Gibbons

[@Gibbonsglass]

⁠don’t get it wet and use hydrocal. Also use the acetylene , I have never used graphite but it might work? What are you making?

[@90snebula]

How did you make your plaster mold? Recipe and did you cure it?

[@Gibbonsglass]

@@90snebula sorry for the late response , I use 1/3 hydrocal plaster, 1/3 powdered silica , and 1/3 water by weight and a handful of fiberglass strands 1/2 inch. Let it get bone dry for a week or two then graphite powder or carbonize the the inside of the mold where it will touch the glass a blow in! Carbonize with acetylene gas, watch out, it is toxic!!

[@90snebula]

@@Gibbonsglass thanks I’ve been using the 1/3 recipe but not the fiberglass or graphite powder. The issue I’ve been running into is not being able to reuse the mold more than 4 times without the layers coming off with the glass. I also would keep it wet and it would dry out so fast and would get brittle.

[@NN-tk7uw]

Very nice tour of the mold world! How come the glass doesn't get stuck in the pineapple mold? Seems like you wouldn't be able to pull back out!

[@Gibbonsglass]

It does get stuck sometimes. You have to be quick, have the right temp and not stay in the mold too long.

[@jasonbowman7190]

I'm very meticulous at buying the perfect items, I'm told that I have great tast. Just bought a very beautiful supposedly antique lamp, but I'm contemplating about returning it. The kobalt blue cut to clear etchings are off. Would it be possible to send in the piece to a mold company to have a mold made without the etchings and have someone blow and etch to hopefully do a better job at the cut to clear 🤔. What is the rough price as well as the hoops to jump through 🤔. If I ever got into glass blowing I would probably make unusual abstract art 🎨, as I would really suck at it 😄 .

[@Gibbonsglass]

Just return the lamp, that would likely cost thousands.

[@420Rudiger]

Where can I find a pineapple 🍍 mold like the small one??? I’m not flying to Italy 🇮🇹 tho. I have a bunch of different optic molds myself. RamblezMarblez

[@Gibbonsglass]

I purchased mine from hobbyglass.com

[@robertmays3110]

Who makes your graphite molds?

[@Gibbonsglass]

G and G machine works, look for them on Etsy. Easy to deal with and fast! Do you make glass too?

[@rf4790]

@@Gibbonsglass Do you know how hot to pre-heat a graphite mold would be?

[@Gibbonsglass]

@@rf4790 I get mine hot by using them and making several pieces

[@rf4790]

@@Gibbonsglass Ok, thanks. So literally no pre-heating?

[@cloverhandmade6785]

🤷