It appears Herman’s assessment was correct. I was meticulous in insuring things were flat. The results were good. Thank you!
So your stack of rejects is getting lower now?
Actually this monday I will do an infusion to show first of all my colleague, who has little experience in infusion, how to make a good looking carbon sheet. This is to prepare for someone making carbon sinks, and is having some issues.
I am really looking forward to it, as I will have the opportunity to do projects the size many of you are doing, and since a longer time do an infusion at all.
I will use MTI hose. Weight is not critical, so I will aim for a lower Vf, to make the carbon look more natural, and have the best surface possible.
I will also (finally) be able to test the 3 leak detectors that I have.
herman, how do you obtain the best surface possible? I tried with full vacuum (about -0.95 bar), today I tried with -0.7 bar…resin flow so slow, then stop without thoroughly soaked the mesh. I increase vacuum to 0.95, resin flow, then I decrease vacuum to 0.7 bar, and then close the resin inlet. The bag isn’t compressed, I can move it by hand, then I wait that pressure stabilize under bar, then I put in oven. I have just demold, there aren’t differences with full vacuum like surface…
question…how influence the cure temperature with surface finish? It’s the same cure at RT, or 40°C, or 70°C? Piece totally cured in the mold
epoxy resin (MGS RIM 235 + mix of rimh233 + rimh235 hardener)
how inflence the ramp temperature if the piece is in mold and under vacuum?
Best surface possible:
-if possible use a gelcoat of some sort
-degass your resin
-use as much vacuum as possible, preferably 20 mbar or less
-leave the vacuum on for a longer time, to get rid of moisture, before infusion.
-leak free bag and tool
-use MTI hose
-clamp of vacuum, leave resin side open and in pot
This will not give the lighest parts, but if it is about surface quality…
If you want light parts, apply a vacuum on the inlet port.
Depending on what materials I have available, I will try that as well.
-0,95 bar is too less! For infusion you always need a vac level between 1 and 20 mbar abs, perfect will be between 2 and 5 mbar.
To stop flatten the fabric use MTI hose, you can work with vaccum the whole time and let the resin feed line open. place the resin pot at the same high than the deepest point of the part.
Degas your resin, make sure your bag is 100% tight (includes a good bagging film), that you have a perfect vac level and use MTI hose. Than you will get a perfect part!
Poeple always tell me that they get perfect parts without these parameters, but nobody wants to show them to me. Most times they have only a few pinholes or some air in corners, or some resin less areas…
Ask herman how the parts looked like we have shown on the Composites Europe which have been just out of mould. And even people who said they have perfect parts could not believe that you can get that quality just out of mould.
I open a new thread, this is jap’s 3D
http://www.compositescentral.com/showthread.php?p=43142#post43142
The parts in the booth of DD looked absolutely perfect. I have not been able to find one single pinhole.
I believe to DD…I’m interesting to try MTI hose…but where can I find it in Italy? I haven’t VAT so many shops don’t sell me, and online composite shops sell for hobby use, and they have not MTI
Interesting Composites Europe? Yesterday I found that ford presented to composites europe a prototype of carbon hood for focus, made with RML or RTML if I understand right
Right! I have to agree. Dominik showed to be be a very competent, talented and gentle person.
It has been a pleasure to talk to him.