Epoxy Mold... what to use as Epoxy Mold Surface Coat?

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#1

Plug is almost done, then it will be sprayed with Duratec Primer, sanded, polished, wax’d and pva’d (flange added of course).

I have decided I am going to build my Mold(s) out of Epoxy (please lets not turn this into a “why not use a polyester system”).

My questions pertains to the Mold Surface coat.

I see Fiberglast makes this product specifically: “Epoxy Surface Coat” http://www.fibreglast.com/product/Epoxy_Surface_Coat_1099/Epoxy_Resins

Is this something I could “freestyle” myself, say using US Composites 150 thick epoxy system and pigment: http://www.shopmaninc.com/epoxy.html ?

Any other Epoxy Surface Coatings anyone is using?

A buddy of mine actually has been using Duratec as a Mold surface coat (put it on thick), let it dry, sand with 80 grit and continue building up his layers. Has been working quite well for him but I rather avoid the time to let it dry, sand, etc.

Thanks for anyone’s input!

-Andrew

#2

I do a lot of epoxy molds, use carbon from many of them too. I’ve never used a real surface coat product, instead I usually use RAKA 900 (med vis) resin with their 631 5:1 hardener. I add some pigment and filler to thicken it and it works great for me. I’ve tried a few fillers and can’t say one is better than the other, even talc makes for a very good hard surface.

#3

I used to use a 600cps epoxy, added calcium carbonate, fumed silica, and dye. It was too thin… my recomendation if you make your own surface coat is to start with an epoxy that is around 1200cps… thicken accordingly. You can also buy aluminum powder that will help create a hard surface that is also polishable.

Resin Services Inc recomended their high temp surface coat… it has aluminum powder in it. It depends on if you want to ambient cure your parts or oven cure. If oven curing parts your mold will need to be vacuum bagged and oven cured also, and epoxy resin ramp schedule followed.

All epoxy molds should be vacuum bagged.

#4

Why is this, Fastrr?

#5

I’ve used epoxy surface coats. Works fine. If I am only gonna pull a small number of parts from a mold I use Duratec vinyl ester primer. I like the Duratec cause it’s just simple to spray up and use.

#6

most suppliers say to vacuum bag epoxy molds. You want an air bubble free/void free laminate… especially on the first two layers next to the surface coat. Those air pockets/bubbles will expand and blister with temp changes. I have seen this on epoxy molds i made that were not vacuum bagged.

#7

x2. I dont like epoxy molds because of the extra work needed, but its worth it for a mold that could last a life time.

#8

I am just receiving my materials to make a “ceramic laminate” with epoxy gelcoat.

The steps:

apply epoxy gelcoat
let cure for an hour or so
apply special bonding layer
apply ceramic laminating resin (Acrylic One)

Let cure for 4 hours.

Presto, your mold is finished. No shrinkage, no bubbles, no vacuum. In 5 hours time you can have a mould. Amazing stuff.

Will be able to report on it later.

#9

Can you provide a link for the ceramic stuff? Doesn’t it make the mold a whole lot heavier? I guess that does not matter though?

#10

Who cares about the weight of a mould?

A link is www.acrylicone.com, but keep in mind that I am still working on documentation. As soon as I have something, I will post it.

#11

most curious to see your write up!

it would be SO awesome to avoid resin and cloth all together on the molds!

weight, i agree, who cares.

what is the cost / source of this material?

#12

It is a product that we manufacture ourself. We produce Acrylic resins (www.acrylicone.com) and combine them with different aggregates to produce laminating ceramics.

My collegue is supposed to supply me a write-up for the mould system within a week or so.

What I know is that it consists of a normal temp and a high temp epoxy gelcoat (choose what you need), a bonding material, and the ceramic.

Photos soon… (need to insert the photos into my catalogue, and will make a PDF out of that.)

#13

^ I cant wait to see it! Any pictures of finished molds?

#14

5 hour mold? That’s awesome, the only question I have is how tough is the mold? Will it crack if it was dropped on a shop floor or inadvertently hit?

#15

I have some questions on this topic

  1. Why do we even need a surface coat if using an Epoxy based system and using a vacuum bag to make the mold? Does the epoxy surface coat have better properties (hardness, durability, etc) then the epoxy resin used in the laminate? Or is really just there to make it easy to conform to the plug, which is what the vacuum bag would essentially solve?

  2. What is the proper technique for making an epoxy mold using a vacuum bag AND a surface coat? Do you apply the surface coat and let it setup after a few hours, then start applying the fiber and resin and vacuum bag as usual?

#16

  1. The surface coat will be filled with aggregates, making it more scratch resistant, temperature resistant, and better gloss retention.

  2. You are right.

#17

Herman, are your products available in other countries?

#18

Contact me with whatever materials you need, and either I can supply it, or I can redirect you to others.

#19

I’ve been using PTM&W 1935. Their web site has a pretty good write up on mold construction. I use 2 thin coats of 1935-- the first allowed to gel before applying the second.

#20

what is the name of the company?ptm&w?im looking at building my first epoxy mold.i cant seam to find solid answers to what surface coat to use and layup schedule.