mold release problem!

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#1

well I am having some issues with mold release! Today I made a mold of a mold essentially to create a female and had some serious release issues. The original mold I sanded down, applied a final coat of resin and then applied 4 coats of mold release wax over a period over 3 hours. when I bagged my mold and released it, it took me over an hour to remove the original and finally had to cut it off! This was quite the process and ended up with my blood all over the final, not cool!!! When it finally came off, part of the original was stuck to the final mold and part of the final mold came off on the original.

What am I doing wrong?

Respond ASAP would be appreciated as I need to get this all done tonight!!!

Thanks Guys!

#2

For a fresh mold I have heard some of the guys around here say that they use anywhere up to 10 applications of wax, and let dry over night/for an extended period. Also with pva.

#3

damn eh…guess i’m gonna have to wax a bunch more then.

Anything wrong with my process???

-Apply last layer of resin post sanding.
-apply mold release wax reasonably thick (can still see the color in the streaks) on paper towel
-wait for wax to dry (15-30 min)
-remove wax with microfiber cloth using round streaks.
-wait about 15-30 min the start over applying wax.
-after 4 layers, I waited overnight and then made my mold using gp poly resin with wax additive.

#4

maybe have a heat lamp on the newly waxed layers to expedite the drying… might be able to get a few more layers in then…

#5

This problem probably has something to do with sanding and applying resin to surface before waxing.

I have never had a single problem with release from new moulds, but do put considerable time into surface prep, and machine buff to a high polish if at all possible.

Finally have found that you can get good results with proper release waxes on new moulds with 4 or 5 coats applied over a period of an hour or so (as long as ambient temp is reasonable).

#6

so is it recommended to sand before waxing or apply resin before waxing???

#7

Obviously if you sand the surface before waxing, then this greatly increases the chances of the mould not releasing properly.

The surface of a mould should ideally be highly polished smooth finish…if its not then release may be difficult, no matter how much release wax is used.

In general after proper application of release wax, the next stage in the process would be gel-coat, and resin would only be used after the gel-coat.

#8

you said you sanded down the original mold and applied a final coat of resin. what was this coat for? was it to the back of the mold or the surface?

#9

I hear so many problems with waxing and getting the part off.
I think everyone should invest in a can of Frekot 700NC. we use it all the time on everything, and never have a problem!! parts just fall off sometimes.
I would never go back to wax and PVA even if I started up my own business again!

no, I don’t know how much it costs. It’s a Locktite/Hysol product.

#10

Waxing is a tried and tested process that has been used for many years, and is quite inexpensive. Seems to me the major problems relate to the way that the wax is applied, rather than anything wrong with the process.

#11

k…could someone tell me the correct process for applying wax then?

I have been using vinyl ester resin with more than enough hardener to make my part cure but it is just not happening. When it finally did get close to curing and I pried it off, it actually took the resin out of the fiberglass cloth underneath and transfered some of the carbon from the part to the mold.

How can I fix this?

#12

If parts are not curing then you need to look at tech data from the manufacturers of materials you are using, and be certain that they are compatible, and if you are a newcomer to laminating make sure you are using the correct ratio of hardener to resin. Also weighing the resin and dispensing hardener with a proper measure is always a good idea.

Seems to me the main problem newcomers seem to get with waxing, stems from buffing the waxed surface so hard, that most if not all of the wax is removed. The main reason for multiple coats of wax, is not to build up a thick film, but to make certain all of the mould surface is covered. Applying say 10 coats of wax and buffing each one so hard its almost removed, is less effective than 2 or 3 coats properly applied.