Talk Composites - The Forum for Advanced Composites

XT135 Pinholes

http://www.talkcomposites.com/Topic27098.aspx

By Hanaldo - 5/27/2018 2:13:18 AM

Hey guys,

Is anyone else using XT135 yet? How have your results been and what materials are you using for your patterns? 

I have been trying to make some moulds recently, and have used a bit more than 1m of the surface and 2m of the backing ply just making relatively smallish moulds (8 different moulds in total), but I haven't managed a single decent result yet. Every one of them comes out with pinholes, not all over the mould but enough to render them unusable. 

I am sure of my seal and I am sure of my oven and temp stability, so the one thing that I am unsure about is that I'm not using the XT135 with epoxy tooling board as being in Australia I don't have access to the S120 board sealer. So I have been making my patterns longhand by creating an initial plug in the conventional method of PU foam etc, then making a vinyl ester splash mould, and finally using that mould to infuse a new epoxy pattern. The epoxy patterns are great surface wise and cured up to 90 degrees for 24 hours, so shouldnt be any concerns there. Any Easy Composites staff reading this, are you aware of anyone else using the XT135 in this fashion? Can you see any reason this would cause issues? 


Does anyone have a solution for repairing these moulds to salvage them? The user guide states that they can be filled with a high temp epoxy gelcoat and sanded flat, but then the surface can't be polished up again and the S120 is needed again to bring the gloss back - obviously not an option for me. Has anyone tried flatting and polishing the surface of XT135, is it worth an attempt or no? Anyone have any other viable ideas for smoothly filling these pinholes? 

Will post pictures when I get a chance.
By Warren (Staff) - 7/13/2021 8:33:10 AM

The EL160 is the resin system that you would be best advised to use as the low viscosity should fill in the pinholes better. You could use the gelcoat for bigger voids. Fill the pinholes after the 65 degrees cure allow to cure at ambient and then run the post cure cycle. Only run the suggested XT135 post cure cycle.