How to inspect your cultured marble mold
A cultured marble mold has to produce many parts over the years so the construction of the mold is very important. Any defects in the mold will be reflected on the parts it produces.
The best thing you can do for yourself is inspect the molds before they are shipped to you or get someone to do it for you as it is hard to rectify any problems later, that's if you can get the company to admit there is a problem.
Some companys such as Tiffany Marble offer warranty's up to 18 years on their molds don't be mislead by this, if you think about it you find a fault with your mold, they ask you to crate & ship it back to them & at their discretion they either repair or replace it then you pay for return shipping this would never be costworthy.
Even if the warranty states that the molds are inspected before crating I would still recommend that you inspect them yourself as their version of a good mold may not be the same as your's.
All this advice is useless if you do not know what to look for in a decent mold & what defect's are.
You could be forgiven for thinking this mold is ready for the scrap heap it was actually new when this photo was taken
If I had inspected this mold before it was shipped to me I never would have accepted it.
A visual inspection may not be good enough as some of my molds looked ok until I started polishing them & poked my finger through the gelcoat into a void below, so don't be afraid of poking around, it's better to find any faults before they are shipped to you.
maybe I shouldn't polish so hard.
This is a window sill mold. Have a look down the length of the mold it should be straight not curved like this one as the part will be a replica of this. Also the rippled surface will be reflected in the part. This type of window sill mold should be avoided as you can not mask off the front edge of the lip when gelcoating. You will also not be able to stand the mold up to pour the lip unless you pack it & risk the packers falling out whilst vibrating
The crack on the edge is an obvious defect that would be seen on a visual inspection.
There is no excuse for molds of this quality if you see a mold like this on your visual inspection reject it.
The same mold lit up from below showing the missing gelcoat along all the edges.
How many cells in a honeycomb?
Another thing to look for is fibre pattern as illustrated on my deck mold here this pattern will be transferred to all parts that come off the mold.
more fibre pattern.
Have a look down the mold lengthways as with the windowsill mold, it should be straight not curved like the surface of this mold.
if not too sure place a straight edge along it. A mold like this will cause you big problems as you try to level one end you will send the other end further out of level also if pouring a long part it will end up thinner in the middle as the matrix finds its own level.
check that all edges of the molds are covered with gelcoat.
Here the gelcoat was not thick enough where I had to repair some craters that appeared through the gelcoat while polishing.
Check the gelcoat there should be no air bubbles in it like these on my trim molds. These will be replicated in your parts which will have to be sanded then buffed every time.
Also another defect at either end check that there are no marks where the plug has been prised out as these will also be reflected in the parts.
Check that the doors fit properly as this will cause you major problems with matrix spilling under the door then if the part shrinks before you can open the door it will damage the top of your backsplash. This door cannot fit correctly because the mold is curved & not straight.
