We still do not know the exact specs of the materials you use… Hard to give new tips then.
@Herman,
Glass fibres followed by stitch peel ply A, then a release foil and finally with enka fusion resin distribution medium from AIRTECH. My resin is EPOFOAM A and EPOFOAM B with viscosity of 550.
As for my previous questions, I still get about 1 percentage fibres with incomplete impregnation, I do not know what is wrong??Also, uneven thickness around the circumference of the cylinder. How can I rectify that? Is there any way to control this unevenness.
Which perforated film, which pattern of perforations. The peelply should not give you trouble.
And Enkafusion from Airtech? Both are different companies and have their own infusion media. Can you point me towards the stuff you use on www.airtech.lu?
Also, can you direct me to the EPO Foam epoxy website or datasheets? I could not find them.
http://catalogue.airtech.lu/product.php?product_id=247&lang=EN this is the resin medium
http://catalogue.airtech.lu/product.php?product_id=130&lang=EN this is the peel ply.
As for the release film, the perforations are in the form of triangles. It is yellow creamish in color. I cannot give u quite a lot of information in that regards. Sorry for that.
For the resin, I dont think it can be an issue as I have previously received better impregnation than the ones I got last week. I think using Polystyrene mold could be a problem as I pin my fibres and materials on it which create a hole in it and maybe are introducing the air in the sample???Just a thought…
However, I was using Polyurethane mold previously and it was giving me a problem of drilling the mold??
When I removed the peel ply, it peeled off a little fibres also from the top most layer. Strange and completely beyond understanding in my experience.
I understand too many questions but can anyone help
I use the reinflow 75 from Airtech and Stitch Ply A from Airtech.
Will repeated compaction help me in removing these dry spots??Or if I leave the preform under vacuum for more time (like 24 hrs) before I do the infusion.
Mgz
Please take some photos and post them. A lot of people here are good enough to identify layup materials, even with tiny internet pictures. If we can see what you’re using and how it’s being used we can help you much more easily.
OK, we are getting somewhere.
peelply: should not disturb infusion in any way.
perforated film: I cannot comment, but if you choose the wrong one, you can have trouble. especially in combination with fast infusion media (actually all Airtech media are too fast, resinflow75 is no exception and on the faster side of the Airtech range).
You want a nice resin front, with not too much difference between the impregnation under the perforated film, and the “impregnation” of the infusion mesh. If you look carefully, you see the resin seeping through the perforated film, but in the mesh it moves further already. 4-6cm difference would be ok. Perhaps 10 or more when doing large infusions with thick laminates, but even then I would like to see that only in the very start of the infusion, when speed is still high.
I think the combination of a perf film with too little perforation and a too fast infusion mesh is the problem here. A lot of companies have been producing infusion mesh over the last years, but never really dived deep into the matters. They plainly thought speed was everything. But what is the advantage of infusing a part in say 10 minutes, if it comes out crap? I rather spend 30 minutes or an hour. Infusion speed can be influenced by other, more healthy means. (spacing runners more closely, for example)
If you need materials that work, see the materials at www.resininfusion.info/webshop (it is in the process of being constructed, but I wanted to mention it anyway.)
As for the peelply stripping off fibers as well:
Your resin is not cured enough yet. Warm curing epoxy cures through a “B” stage where it is brittle. Adding heat makes the epoxy far more ductile, stronger and more impact resistant. I guess this specific epoxy needs some heat to survive stripping the peelply. This is not uncommon. Try and stick the part in a box, with a 60 or 100 watt lightbulb in it. This is the most simple oven you can make, and relatively safe.
About your mould: Are you saying your mould surface is polystyrene??? Keep in mind that neither PU nor EPS is completely airtight. For infusion you really need an airtight mould. I suggest wrapping the whole mould in a bag, or using something else. This also can contribute to your problems.
Hi Herman,
I think it is not the curing because the peel ply has come off easily in the past and with good impregnation for the same amount of curing time (it is only cold curing resin). I am sure about the curing issues as after 8 hrs in the bag I can see it the impregnation as perfect with transparent part as I can see the inscriptions I make on my teflon sheet clearly. I could be wrong here. To remove the porosity issues, I left my bag overnite today and will do the infusion tomorrow morning and lets see if it makes a difference.
Previously I was infusing with the resin at temperature fo 50 degrees and I stopped doing it now so maybe after the bag is full the resin is too viscous to enter into the part. I am not so sure about this though. Also, I hate to use a centrifugal pump at the resin injection side so I stop the pump after 5 mins. I doubt if these 2 are the reason for the peel ply behavior.
I used a little mold release wax on the peel ply and see if it helps removal of the peel ply easily which remains the only issue as of now.
One last question is how to control the uneven thickness of the cylinder along the circumference??I can use a double vacuum bag but that would only make the fibres more compact and resistant to the flow of resin in my opinion. Are there any other alternatives to control the relaxation of the preform besides repeated compaction.
Thanks