Good morning

When I used to work in a composite shop we used to use silicone rubber 2 part mix for making insert/formers that we would make to make shapes by adding the soft mix (plasticine texture) to the awkward parts of a mould let it set to a flexible rubber state and use it as infill pads/inserts ON TOP OF the prepreg carbon during the Autoclave curing process to help prevent bridging in awkward spaces and with it being a type of silicone it didn't stick to the resin and it was easy to remove afterwards and was reusable.

Do you have a product like this that does not need curing with temperature that I could use  as a reusable insert with wet layup carbon and your EL2 epoxy laminating resin and no vacuum .

Regards

Ian

Hi Ian,

Pretty much any RTV Silicone will do the job.  I would recommend our Addition Cure Silicone Rubber as it is tougher and has a higher tear strength compared to other silicon products such as Condensation cure silicone.

Depending how tight the corner is and the number of layers, you may need some weight or force applied to the silicone intensifier to ensure it stays in position.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

Related question; I need to make some pre-preg parts that would benefit from having a smooth surface on the b-side. Not glossy as such, rather just smoother than the creases and bumps that regular release film and vac bag pleats create. 

Look at vac innovations site they do a heat cure silicone sheet

about 10mm thick and about the size of 3 sheets of A4

there is a minimal amount of shrinkage after first cure

so if your laminate isn't too thick you can mould your former into your bare mould ( its just like plastacine) and cure and you should be able to fit back into your mould with a thin laminate

we always use release as it just gives you that extra bit of "slip" when you come to strip out.

Also handy to give the laminate a debulk to consolidate the laminate an makes sure you don't push any of the laminate down when you push the silicone in

there are a multitude of uses for it once you start playing with it

Thanks Rob, I'll have a look but it's quite likely impossible to get here or at least unreasonably expensive. 

You can use it without release,we use to make the turbo/intercooler pipes for the Renault v6 on the f1 cars that very way many years ago

Also has the advantage you can put 1 ply in your mould as your cosmetic ply the others can be laid around your silicone former with all the material joins staggered (butt joints of course)

Obviously silicone tube was hollow an was internally bagged

Current practice everyone uses 3d printed pipes

they can be rubbed down to a perfect Finnish,sealed an released

As you cook an have a dwell at 80 deg,just as your resin starts to flow an gel the 3d also softens enough to allow consolidation of the part

once cured an stripped from the mould heat to 140 an the 3d turns to a rubber like consistency and is easily pulled from some very complicated pipe shapes

Thanks Rob, appreciate your input as always. 

Hey Hanaldo

Thanks John, 

The silicon / rubber intensifiers I used to make were from a roll of white uncured rubber, that we kept in the freezer but we all had a stock in our toolboxes. Its not cheap by any means but its ideal for getting consolidation in small pockets and internal cavities. And it can be re-used several times as I re-used the intensifiers on some seat back moulds at least 100 times.