What material can I pour into a 1" x 1" x 1" mold (a cube without a lid) that
will solidify into a rubber-type consistency? I need to make a part for a
microphone that has not been manufactured in 50 years. It would be best if the
material did not harden like acrylic. However, I'd use that as a last resort if
I knew where to get it.
I've never done this sort of thing, so I have no idea what material to try to
find or where to search for it. Since I only need a small amount, a suggestion
for a material that is only available from a wholesale-only industrial supply
house would be hard to follow.
Is there some sort of silicone that meets this requirement? Is there such a
thing as liquid rubber? Here's hoping!
Silicon RTV adhesive or caulk would cure eventually but an inch is a
On the outdoor channel the other day I saw a guy having ear fitting ear
plugs made by having liquid rubber injected from a syringe right in his
ear so there is such an animal.
This mold builder stuff might work with enough coats:
I think silicone caulk would do it in about 3 days. [for about $5]
G-flex epoxy would give you more of a polyethylene plastic in about 5
minutes- for $20 or so from a boat store.
I'd give Devcon a call and see if they have a rubber 5 minute epoxy.
If the part is to be greater than 1/4" thick, regular silicone caulk
will not work since it will not cure properly. For thicker parts a
catalyzed silicone material is required. Look at McMaster.com for
various castable silicones, urethanes and the like.
Tin-cure RTV silicon rubber sounds like the best material for this. Noone (I
know) sells such small amounts for a 1" cube and besides, it will be really
difficult to properly measure 10:1 ratio of components if you only need
1cu.inch. It is sensitive to proper component ratios. 1 cu. inch is usually more
than I have leftovers after a mold is poured - this could have been easily done
from someone's leftovers if you can find a sculptor or a builder or another
specialist, artist or hobbyist in your area working with RTV molds.
Smooth-On sells very nice RTV silicons. I use mostly MoldMax 30 but it's pink -
do you care what color it is? MoldMax40 is light green, and they also have
translucent versions of all of these. Here is the page at their site about the
They do sell online, including trial size packages for about $25 but at 2.2 lbs
it is still more than you need if you only need one of these cubes. Arts and
crafts stores like Michaels also sell similar silicones (I think they are
similar) but they are about 4 times the cost per weight unit, so I've never
bought from a craft store, can't vouch for their quality or workability.
I guess for a small cube any RTV you can get your hands on will do, but for any
serious work I'd use Smooth-on product.
I found the trial size costs about $25 . Mold max 10 looks like plenty of
goo for 1 inch square.
What I have used is sylgard.
Mold Max 10 is very soft - the hardness goes up with the number. I imagine the
OP might need harder ones - 30 or 40 if this is used to hold any considerable
weight firmly. It would be interesting to learn which exactly part of the mic
would be made from rubber (-like material). Last time I've been inside old mics
was a very long time ago but I cannot recall a large elastic part like that.
I use to use silastic products, but costly.
You might try dynaflex 230 into a cube if silicone rtv does not work. I
don't know how 230 will set up in a cube, worth a try. Heat it up for a
couple days. Rtv should also set up with heat and time. It used to be easy
to buy the runny stuff for windshields, but I have not seen it lately.
Does it have to be all rubber?
Can you mold most of it out of Sculpy and use sheet rubber for the springy
There's stuff called "Great Stuff" that's used for plugging up
air infiltration in buildings.
The cheap stuff gets pretty hard. The more expensive version
Can get it at Home Depot.
Don't know if it has the mechanical strength for your application.
Any craft store should sell silicone based molding material. Since you
need such a small amount, save some time and shipping costs and just pick
some up at a craft store like AC Moore, Michael's, etc. You won't be making
a mold but you can use it to fill a small one.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.