Talk Composites - The Forum for Advanced Composites

Advice on making Moulds for picture frames

http://www.talkcomposites.com/Topic14095.aspx

By Michael77 - 12/8/2014 7:56:38 AM

Hello. I would greatly appreciate advice for making moulds for picture frames. As you see in the photo attached to this post, I have a master that is made of acrylic. There are four parallel sides and a top lip that is perpendicular to the sides. I was thinking about casting it so that the top of the lip is exposed. this way i only need a one part mould. Gravity will level whatever material is poured into the mould to create a flat surface. But perhaps there are problems with this method that I am not aware of?

I want to make frames of various sizes cast out of various materials, such as epoxy, silicone, rubber, plaster, if possible. I would like to create a nice set of moulds for about half a dozen sizes that i can reuse for a long time, if possible. 

So, far, I have purchased some epoxy in styrene at my local boat store. I am ready to try this material but I am  nervous to try it and just waste my time and effort. I am interested in buying materials from easy composites if it means i will get better results. I await your advice. Thanks.

Size of acrylic "pattern" picture frame in photo attached here is 13x18cm. I want to make moulds and casts for picture frames all the way up to 100cm. 
By Matt (Staff) - 12/11/2014 2:32:12 PM

Hi Michael,

Sorry Paul's not got back to you on this, we have a training course on this week and he takes the course and therefore doesn't get chance to check back in on the forum. I'm sure I can answer your questions....

1. should i put the master into my mdf mould frame before pouring in the silicone or after? Does it matter which method?

It doesn't make a huge amount of different. I think the more common practice would be to position the master in place and then pour the Addition Cure Silicone Rubber around it. Don't forget to secure the master down, I don't think acrylic is lower density that silicone (which would cause it to float) but it's quite close and so not worth risking.

2. i love the look of this art that was made in the 60's by Eva Hesse, actually, this brownish yellow stuff is what originally attracted me, many years ago to resin casting. Do you possibly know what this is exactly, what materials create this color and where I can find this material?

It's difficult to say exactly what Eva's pieces are made from but certainly the appearance of them is very similar to the appearance of a cured sample of GP Laminating Resin. Once cured, the GP resin has that slight translucent brown tint and might be very close without any modification, however if you did want to tweak the colour then our box of 10 Translucent Tinting Pigments includes a 'Burnt Sienna' colour which is a really nice caramel brown colour.

It would also be possible to recreate a colour and appearance like this using a clear resin such as our Water Clear Polyester Casting Resin or even our Water Clear Polyurethane Casting Resin (although really this second resin would need degassing to remove air bubbles) and then just tinting them using the tinting pigments I linked to earlier.

3. there are little chips and dings in my master that need to be filled with putty and sanded smooth. what do you recommend for this?

If you're using silicone to make the mould then it won't really stick to anything so you can, effectively, use anything you want to patch-up your master. Polyester bodyfiller might be any option or, if you're careful, you might find that our yellow filleting wax, which can be shaped and smoothed incredibly easily, would be a simple option.

I hope this helps and look forward to seeing your finished pieces Smile

Best regards, Matt