Dry patches using weave pattern

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Dry patches using weave pattern

Author	Message
Lester Populaire	L Lester Populaire posted 6 Years Ago HOT Post Details
L Group: Forum Members Posts: 311, Visits: 13K	+x Dromilious - 2/26/2019 11:08:36 AM +x Lester Populaire - 2/26/2019 10:36:27 AM +x dcfoster - 2/25/2019 11:30:55 PM Im having a similar issue, but its also leaving some of the epoxy on the mold surface. Ive added mesh to increase flow upon entry and created a resin break to slow down exiting epoxy into the catch pot. Also im using an infusion epoxy yet I keep getting dry patches. Im using a blue carbon/nylon cloth for the visible layer and then a +/- 45 biax for the underlayer. This is for a fuel door for an Acura. Ive never had this issue before, even with small parts but I keep getting it with this. Could it be since its winter that its too cold? I made sure to put my epoxy in front of a heat source to warm it up and noticed it gassed alot less when mixing, I also let it sit to degass for the 15min I usually wait to make sure the infusion molding is properly sealed and not leaking (the epoxy I use has a long pot life). Yet it only made less dry spots but still have them. Pics included. Original poster. sorry to thread jack, figured since you already have a thread open it just makes sense to keep all the 'dry fiber' issues in one thread. I would guess it's related to the spray tack. Either too much or a kind that does not dissolve properly in epoxy. To the original poster - could you share a picture of the vacuum setup? Normally this kind of things can be solved with the right infusion setup... i don't think it is from the spray tack. I don't use spray tack and i had once the same problem. I'm not saying this is the only explanation, but this is typically what i see when an intern is a little trigger happy with the spray tack on the first parts.
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dcfoster	dcfoster posted 6 Years Ago HOT Post Details
Group: Forum Members Posts: 32, Visits: 100	I didn’t use spray tack at all. I put at least 4 layers of meguiars mirror glaze mold release wax. Maybe I should go back to using the regular carnauba wax. Seemed like the mold release was better with standard carnauba cleaner wax.
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Philippine	P Philippine posted 6 Years Ago HOT Post Details
P Group: Forum Members Posts: 4, Visits: 14	+x Lester Populaire - 2/26/2019 10:36:27 AM +x dcfoster - 2/25/2019 11:30:55 PM Im having a similar issue, but its also leaving some of the epoxy on the mold surface. Ive added mesh to increase flow upon entry and created a resin break to slow down exiting epoxy into the catch pot. Also im using an infusion epoxy yet I keep getting dry patches. Im using a blue carbon/nylon cloth for the visible layer and then a +/- 45 biax for the underlayer. This is for a fuel door for an Acura. Ive never had this issue before, even with small parts but I keep getting it with this. Could it be since its winter that its too cold? I made sure to put my epoxy in front of a heat source to warm it up and noticed it gassed alot less when mixing, I also let it sit to degass for the 15min I usually wait to make sure the infusion molding is properly sealed and not leaking (the epoxy I use has a long pot life). Yet it only made less dry spots but still have them. Pics included. Original poster. sorry to thread jack, figured since you already have a thread open it just makes sense to keep all the 'dry fiber' issues in one thread. I would guess it's related to the spray tack. Either too much or a kind that does not dissolve properly in epoxy. To the original poster - could you share a picture of the vacuum setup? Normally this kind of things can be solved with the right infusion setup... These are the photos of my setup. It's the only ones I've got unfortunately. The first one is before reducing the mesh size and with the silicone spiral. The second one is the last one that I tried where the resin took 45 minutes to cross the sample entirely.
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dcfoster	dcfoster posted 6 Years Ago HOT Post Details
Group: Forum Members Posts: 32, Visits: 100	I will see tomorrow once roughly 24hours have passed since infusing the part. I let the Epoxy and Hardener sit in front of a space heater rotating every 5 min or so to warm it up. Then after mixing I sat the mixing container in front of the heater as well rotating it to speed up degassing. Was the clearest and runniest Ive had it since starting products this winter season (its 20-40F here in the western US). After the part wetted out I mostly closed the vacuum valve to slow it down. Then I shut it off and allowed the pressure to pull some resin and bubbles (presumably from degassing) through into the catchpot. Then I capped off the exit and left the feed open for a moment, then capped it off as well. Before hand I waxed the part 6 layers and really took my time with it. Hopefully this will make the difference.
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Lester Populaire	L Lester Populaire posted 6 Years Ago HOT Post Details
L Group: Forum Members Posts: 311, Visits: 13K	Ok now that i see the setup it's pretty clear - cut the flow mesh short of the an inch short of the end of the fabric. The flow in the mesh is very good, in the much more compact carbon fibre not so much. It therefore takes some time to impregnate the fabric stack vertically through all the layers. when cutting the flow mesh short of the end you will force the resin to flow through the fabric rather than just flowing through the flow mesh and out of the vacuum line on the other end while trapping residual air underneath. When having no flow mesh at all the infusion speed is so slow that capillary effects start to take over and you do not get a very reliable result either. and another detail which i do not think is critical in this part, but a good habit to take is to have the resin inlet on one corner and pull the vacuum from the opposite corner. As the resin is slightly arching from the entry point the corners in your layup are the last areas which are not impregnated and you should pull the vacuum in those two spots. Placing both lines in a corner is the easier solution.
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dcfoster	dcfoster posted 6 Years Ago HOT Post Details
Group: Forum Members Posts: 32, Visits: 100	For me I have yet to confirm, but I talked to the Carbon/Kevlar supplier. Was told my part/mold is too cold, so its causing flow issues with the epoxy.
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