1st Lay up

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#1

just done my first lay up .

1, glass sheet
2, rain x (release agent)
3, resin (sp106 slow)
4, 200gsm carbon
5,little more resin
6, 200gsm carbon
7, Release Film
8, breather fabric
9, vac bag
10, vac for 5 hours
11, left for 14 hours to cure

the end result was good but a few to meny bubbles ( pockets ) with no resin but on the release film side the finish is perfect, also the breather fabric had an even amount of resin on. can you have to much vacuum or was it the ran x dispersing the resin ?

#2

Pictures?

I never heard of using Rain-Ex before, where did you come by that idea? Did it release ok?

Sorry for all the questions…

#3

i assume the rain x worked well for a realease but i wonder if the silicone in the rain x caused a reaction to give you air bubbles. Minwax works really good also as a release agent, you can get it at any lowes or home depot in the wood floor dept, just don’t cure anything over 145F if you use it.

#4

i read it some where on this forum i think, yes it did release very well almost fell off!! i have tryed to take a photo but it doesnt show it well enough

#5

Welcome to the incredible world of composites. Keep practicing and you’ll be able to make some good parts.

My advice, start with the proper materials. Get some actual mold release, and do a few wet layups and let them cure with no vac.

#6

just got some TR108 going to try on some glass , and see how things go

#7

Use plenty of resin ( if you are vacuum bagging the flat panel) and a layer of breather over peel ply or a layer of breather of perforated release film. If there is excess resin the breather fabric will pull it out.

#8

using plenty of resin is a bad idea. When you vacuum bag a part that is resin rich your breather will sufficate and you will loose vac pressure and will trap air. your breather should only have very tiny dots appear once full pressure is applied. Really all you need is just enough resin to get the fabric wet which is still too much. there should be no excess puddles or glossiness too the fabric. I achieve a 32% RC(on average)in my vac bagged carbon parts.

#9

How are you measuring/calculating this? Seems awfully low unless you’re using uni and/or autoclaves.
Our infused parts are generally in the 34-38% range, as tested by an actual lab. The autoclaved parts we’re getting close to 30%.

#10

its calculated on test panels/actual parts cut in to a square foot and weighed. Solid laminates on average are 32-33% and cored sections 33%-35%. These are vacuum bagged parts not infused. Infussion I have gotten as low as 30% but with bad cosmetic surface, and highest was 40% with excellent surface finish.

#11

you are calculating by weight then? Not volume? Volume you neeed to take the density of both materials into consideration. I don’t have the equation with me, but when looking at FVF, it’s volume. Which I THINK is the normal way to tell how much resin is in a part.

#12

Yes, by weight. I found the formula on google. Thanks for informing me! I will have to run some new calculations this week.

#13

Yes, what needs to be measured is the Fiber Volume Fraction. The lab puts our panels in a furnace to burn off resin.

#14

I have now use some tr106 mould release made some flate plate and some control surfaces for one of my radio control gliders they all came out good with only a little air bubbles. still need more pratice, next iam going to make a mould

#15

how do you deal with the carbon oxidation loss for burn off? I heard to just add a few % to it? Or do you use a N2 burn off environment?

#16

Right, the resin is actually melted off, not burnt.

#17

how high do you burn off? we do at 570-600c

#18

Have no idea about actual temps. I know the lab changes it depending on material being tested.

#19

hmm, not to be picky, but I thought for thermosetting plastics it would not return to the melt by an increase in temp… I imagine an N2 burn off environment wouldn’t be to difficult in a lab setting, so I bet that is what they are doing