Making your own Silicone Mould

[W3DRM]

Wow, my garage smells like an Italian salad bar!! :biggrin:

Just checked on the mold and the outside has set up nicely. Can't wait to open it tomorrow afternoon to see how the rest of it has done.

Charlie - I think I'll try using some shellac to seal the mdf and see how badly the silicone sticks to it. Will try a small sample first. Shellac creates a pretty hard and slick surface so the silicone may not adhere to it. May also add some furniture wax to make it even more slippery. If that doesn't work I'll try some mold release. I'll do anything to get out of having to put that poly wrap stuff on each time I want to make a mold. It's a PITA to put on and get the wrinkles out before putting the silicone in.

BTW, I sized my form so the entire mold has 3/4" sides and bottom. Assuming it will harden correctly, it should give me plenty of sidewall strength so they don't sag or bow out from the weight of the PR.

More pictures of the results (good or bad) later tomorrow...

 

[NewLondon88]

I'll do anything to get out of having to put that poly wrap stuff on each time I want to make a mold. It's a PITA to put on and get the wrinkles out before putting the silicone in.

A hair dryer set on high might help pull some of the wrinkles out. The
wrinkles can trap silicone which might tear when de-molding, and the
wrinkles in silicone can trap resin, which can pull and tear the silicone
when you remove the casting. DAMHIKT :biggrin:

 

[W3DRM]

I checked the mold this afternoon and it looked pretty good. Took it out of the wood form without any problems at all. It appears that the silicone had firmed up completely within a 24-hour period. I found no uncured silicone remaining.

Have attached some pictures of the resulting mold and think it came out quite nice considering it was my first attempt at such a thing. I can see some areas that the silicone did not get down into but none of them will impact making a block PR casting. You can see the wrinkling from the poly-wrap I used to cover the mold form.

My next attempt will be to apply a shellac base to the forms so I don't have to use the poly-wrap. Will also pay closer attention to filling the voids in the mold so I don't have any pockets.

Otherwise, I am very happy with the results I got.

 

[Darley]

Very nice and vell done ' BRAVO ' :good::good:
I didn't mix my RTV silicone with water but I think it will be the same, when filling the mould make sure to push down by hand the silicone, as for the wrinkles try to put the smooth part up and the fold saran against the mould, don't forget the smooth part is the bottom of your mould, to make the saran to stick easy on to the master ( wood or anything else ) you can spray with oil and the saran will be without wrinkles, I don't know the thickness of the out side wall but mine are 16mm or 0.630".

Again well done

 

[NewLondon88]

Sweet!

 

[JerryS]

Came out looking pretty good , they do make a mold wax . http://www.jamestowndistributors.com/userportal/show_product.do?pid=4124


I asked a question over on Meguiar's forums, one of the guys there should know if this would work .

http://www.meguiarsonline.com/forums/showthread.php?p=294049#post294049

 

[Glass Scratcher]

Came out looking pretty good , they do make a mold wax . http://www.jamestowndistributors.com/userportal/show_product.do?pid=4124


I asked a question over on Meguiar's forums, one of the guys there should know if this would work .

http://www.meguiarsonline.com/forums/showthread.php?p=294049#post294049

You could have just asked here. Meguiar's #9 Mold Release Wax is just that- a Mold Release Wax. I've used it and other waxes and mold releases for years.

It works great for Silicone molds, or on fiberglass or wood plugs. Just make sure you buff in several coats to ensure complete coverage.

 

[JerryS]

You could have just asked here. Meguiar's #9 Mold Release Wax is just that- a Mold Release Wax. I've used it and other waxes and mold releases for years.

It works great for Silicone molds, or on fiberglass or wood plugs. Just make sure you buff in several coats to ensure complete coverage.

Sounds like a good alternative to the cling wrap .

 

[W3DRM]

I notice the Meguiar's Mold Release Wax has carnauba wax in it. I have a block of supposedly 100% pure carnauba wax and will try that to see how it works for releasing the mold. Will put three coats on my mold pieces beforehand as in the Meguiar's instructions.

I am now working on building a wooden mold that I will use to make a finger-ring base to hold bottle stopper blanks. I have a customer who I made a red-hat bottle stopper for and she wants to make it into a ring. Should be an interesting project. Will post some pictures if I get it figured out.

 

[DurocShark]

Bleh. Nothing got the wrinkles out of my plastic wrap. I tried the hair drier, a real heat gun, stretching and pulling, nada.

Oh, well. The sillycone is curing. We'll see...

 

[NewLondon88]

Part of the job is getting rid of as many of the wrinkles as you can .. BEFORE putting
the sillycone in the mold. Maybe wrapping each piece of wood in plastic before assembly?
That would allow you to shrink the wrap with heat and not pull at the mold? Dunno.
I just finished one without the plastic wrap and it came out better. Wax and buff the
wood that will touch the silicone and it comes out easily.

Of course, it wasn't caulking, but it should work the same if the
caulking is pliable enough.