Hi,
I have problems with mould release agents.
I’m using prepreg vacuum bagging technology. Product is produced on male aluminium mould.
When I’m using PVC film to release mold everything is OK, the surface is very fine ant glossy, but when i’m using Loctite® Frekote® 770-NC, surface of product is mate and with some lacks of resin. (I have attached sample photos)
Prepreg production terms with PVC and Frekote are the same and mold is the same.
Any suggestions? Where is the problem?
That is very peculier. I would stop using the Frekote;)
Some release agents are designed to give a matte finish. We use mainly Frekote for the prepreg work, and have no problems.
Lack of resin is most likely due to removing too much resin or por bagging technique.
i’ve used frekote too, but on a super glossy mold, it dulls it just a little bit, barely noticable. how about posting a photo of your mold.
Well any tooling quality will transfer to the part. If the PVC film (didn’t konw you can GET PVC film…) is more shiny than the normal tool, then yes, the part will be shiny. Frekot will just cause whatever the part surface is, to look like the tool.
Now, the pitting. Are you following directions exactly? Let it flash off for 5-10 min? I would suggest heating the mold if you can afterwards to drive off any left over release agent. I’m using 700 now, (not sure about 770), and it leaves droplets on the tool, after 10min. I just throw it in the oven to bake it a bit.
If there is extra wet agent on the tool, then it might cause an outgassing then baking the part.
You say the bagging is exactly the same for both cases?
I used to use aluminum molds and prepreg all the time…I was never fully happy with the pits in the part. maybe it’s just pre-preg.
Hi,
Thanks for your answers guys. I will keep experimenting. I must eliminate PVC from this process because it costs to expensive.
Just a question, granted I have no clue what you are doing(as far as size goes), but have you considered using mold release wax? I am going to guess that its something big, as you didn’t mention trying that, but im curious if it would help you, if its a large project, you could probably apply with a buffer on a really low speed? I probably sound dumb, but just trying to help as it looks like the two forms of release agents you have used are not working out for you because of cost/issues with wetting out.
We produce small things http://www.orthobaltic.lt/en/orthoses.
Currently we use male aluminium moulds. Those moulds are expensive, old and I need to change form of shape of the mould. I have 5axis cnc milling machine which cannot mill aluminium (only wood, MDF, PU, PE, etc.). So I’m trying now some mould materials from RAKU-TOOL (WB0-700; WB-1700) and Coastal Enterprises (PBHT30). I plan to use those materials to produce new moulds and problem is mould releasing without PVC bag.
Semi Permament mold release are so you don’t need to wax the mold each and every time. I love them!
Coastal Ent. (PUR foam people) are great people to deal with!
PP can leave air pockets if it is getting old as we used some 1 year old material in the former classroom and if they didn’t get the right heat and time in the oven, the PP epoxy resin wouldn’t flow right.