Can not get this infusion right!

So I have been working of these hoods for a while now. They go on a Kawasaki X2

I have made about 8 now with varied levels of success from totsl disaster write off to nearly perfect, but never have I popped out a grade A part.
This is my first project using vaccuum and resin infusion.
I will try to be as detailed as I can in my process etc and maybe somebody can help me.
First I will illustrate the problems that are plaguing me.



These pictures were taken of a hood that was not worth trying to save because the pinholes (I think thats the term) is so bad. In these pictured it is coated in a heavy layer of body filler dust from sitting on a shelf in my body shop, but the dust actually helps show the problem. It seems as though the resin isnt fully wetting out the fabric.
I am using US composites thin Medium 3:1 epoxy.

Few coats of Meguairs mold wax (part sticking to the mold has never been an issue)
Layup is 5-6 layers of 5.7 oz 2x2 twill. I am using super 77 to help keep the fabric in place. Then a layer of peel ply, then green flow over the entire suface of the part (the times I didnt use green flow over the entire part I ended up with massive dry spots.)
After the green flow im using a plastic “T” fitting with plastic spiral wrap wrapped in peel ply coming up the back of the mold at the widest points, and the “T” is then going into my feed pot. My vacuum out tube is at the front of the mold on one side. Then green stretchlon and gray bagging tape. Here is a crude depiction
After I finally figured out to take my time and be sure there are no air leaks, I usually get a nice even flow into the part. Occasionally, like with the part I did last night, for some unknown reason I had lots of very dry spots, as in the resin didnt even make it all the way to the first layer of carbon, but in that instance the layup was a combination of carbon fiber, fiberglass surfboard cloth, and fiberglass mat. Some of the part came out beautiful, but some was dry as a bone, with no logical explanation.
I usually dont get dry spots in the full carbon layups if I take my time setting up the bagging process, but the pinholes have never stopped. It takes me an average of 8-10 hours in rework time to fix the pinholes, and the parts never look perfect even when Im finished. I was told maybe I was infusing too fast, so last time I kept a kink in the feed tube to really slow down the resin, and it helped, but didnt entirely fix the problem. I am also degassing my resin how using a large piece of clear acrylic glass over a metal pot with a vacuum tube into it, so there are no air bubbles in the resin. To get rid of the pinholes I have been brushing on resin then sanding it back. Then clearcoating using mipa 2k clear. I do not use any kind of clear coat or gelcoat in the mold face. I tried it once using 2k clear and it just didnt stick to the part at all, peeler right off like cling wrap

Please please help me. I really want to start producing some top notch stuff out of this mold I spend weeks making.
Also, I am very open to alternate, stronger (but still light) layup schedules. The hoods right now weigh an average of 6 pounds but I could get away with adding a few pounds to really beef them up. There is an inner baffle/air bladder that goes up one side which adds a lot of strength but I would ideally like to include some type of core structure in the hood, but the thought of trying to incorporate that into an infusion terrifies me. Every time I mess a hood up is costs me about $200+ and I cant keep losing money on this project but I refuse to give up.
Thanks so much

A few thoughts:

The US Composites 635 (thin) isn’t a very good infusion resin. It’s viscosity is rather high. It also looks like you might be infusing too quickly which can leave voids in the laminate. Lastly, the Stretchlon 200 is notoriously known to be a leaky bag material for infusion.

Can you recommend an alternative resin and bag?

Stretchlon 800

IVEXC-410
http://www.ccponline.com/composites/compo_resins.php?submenuheader=1#/1/zoomed

Did you do a leak check? Using a basic vacuum gauge you should aim to get a "0"hg drop in 15mins. If you us a digital absolute pressure gauge a “0” mbar(better unit to use than Hg)in 5 minutes is good test to do. Vacuum integrity is the most important aspect to a good infusion.

OK,

Make sure that the bag ist absolute tight!
You need a brake zone, that means let the flow media end abour 2 inches before the part ends and before the evacuation hose.
Degas the resin to make sure that there is no air in the resin. Your resin seems to be ok, the whole part is impregnated so that is not your problem.
Also make sure that you have a perfekt vacuum of about 20mbar or 0.001inHG absolute pressure for infusion and always use an infusion resin.
Also the MTI hose can help you to get a pinhole free part and makes it much easier if you start with infusion.
You can read the MTI hose thread, if you want a sample contact me.

This is the guage I have been using, and it always pegs out to full vaccuum (28 inHg) on my guage. I know this guage is not ideal, but its what i can afford.
Back to the resin, is it good or no good?
I am very interested in the MIT hose, ill look into it. What is the best way to control infusion speed? Is my resin pickup line the correct size? (3/8")
What does the brake zone do? Every time I try doing that the resin just stops flowing and I end up with an incomplete infusion

Try to limit the amount of Super 77 you are using. If you apply it too heavily it could cause issues with the resin flowing through the thickness of the part causing dry areas. You may want to try some epoxy soluble spray adhesives like NuTack E. Are you using Super 77 directly on the mold surface to fix the first layer? Also, be sure to degas your resin before you infuse.

Yes i am using 77 on the mold surface.

I have asked DDCompound for a sample of his MTI hose, and from what I have read im confident it will help me. I would really like somebody to tell me a good infusion resin that can be ordered easily in the US and also a good spray adhesive. A link to where I can order both would be fantastic

-Hey Nick. That stretch o green is a no go unless you’re prepared to dbl bag. Use the 800 or something else. I’ll drop some bagging material off over at your shop here in the next few days. You’ll never win using that stuff. The air leaks are so small and will starve your infusion pretty much every time. That should get your problem taken care of.

-Problem two is the glass fabric. The glass will wet out much slower than the Cf you’re using. The only way to get around that is to experiment untill you find a suitable thinner resin or glass fabric that wets out better-or both.

-I suggest pulling vaccum from both ends of the vaccum side spiral wrap up at the top so that the resin front doesn’t choke the process towards the end.

Also, put the resin trap hose inlet higher than the mold effectivley otherwise the weight of your excess resin in the lines hanging below the mold will work against you.

The US composites resin: I found that using as short of a feed to your mold as possible is important and suggest using 1/2 inch id minimum tubing to keep from adding any more than necessary resistance to flow during the infusion. It’s definetly on the more viscous side but it’s do-able.

I’ll drop off an example with that bagging material.
Keep your chin up. Thats a difficult mold to work from.

Hey thanks for the advice Chris. The fiberglass was only in one layup the rest have been full carbon . No doubt that was the cause of the dry spots in that particular part. If i could make perfect full carbon stuff ill be happy. The pinholes (not even pinholes more really more like dry sections of the 2x2 twill pattern) are what kills me. It takes forever to get rid of them and is never perfect even after. It’s just not cost effective to produce that way. Thanks again for your help Chris, especially on my first infusion

You can try ProSet 117LV/229 hardener as well as Gurit Prime 20LV/Fast hardener epoxy resin for infusion applications. Each can be purchased from Composites One or a ProSet distributor with an online store is http://www.cstsales.com/pro-set_epoxy.html

Try ProSet 117LV/229 Hardener or Gurit Prime 20LV/fast hardener epoxy infusion resins both available from Composites One.

Most has been said:

-change bag
-change resin
-use MTI hose (in which case you do not need 2 vacuum ports, as the MTI hose will not choke)
-be very, very, very, very careful using spray glue. 3M 77 or super 77 are notorious for causing defects. Try something else (Airtac 2 for instance) and only use if you cannot go without. Treat the stuff like you need to pay for it from your beer-money. If I was to have a composite shop, I would deduct the cost of spray glue from the workers wages. (a great way to reduce spray glue usage, hehe)

Some additions to it all:
Do not use CSM (fiberglass mat) in the layup, especially with epoxy. It does not infuse well. (over here we call it “infusion stopper”)
5.7oz carbon is relatively expensive. Try and get hold of some carbon multiaxial, or even heavier cloth, to beef up the part. Use the 5.7oz for the exterior only.
Your inlet should be fine. I infused 12 meter (40 ft) boats with 2x 3/8" diameter hoses, without problems. I might even use a smaller dia, to slow down the infusion. (and give the resin more time to saturate the fiber).
I feel your mesh (the green hard plastic one) is also on the fast side. Try a knitted mesh, which is slower. Your laminate is “slow” so basicly your mesh should also be slow.

Great! Thanks so much for the advice everyone what a great bunch of guys

WOW there is quite a price difference between those resins and the stuff iv’e been using

A cheaper epoxy alternative is Resin Research Composite Pro. This is a very low viscosity epoxy that infuses well. It has a lower Tg/HDT though. They give a post-curing schedule to 180F but it’s utter BS. You can cook that stuff at 180F for a week and the HDT won’t get above 140*F. With resins you typically get what you pay for. The US Composite 635 that you are using has a higher Tg/HDT than the RR Composites Pro. The US Comp. is just not a very good infusion resin. Another option is the Adtech 820 epoxy. This has a higher Tg/HDT but cost a little more money and will require a heat treatment to boost the Tg. Vinyl Esters are always an option as they have a higher Tg with just a room temp cure. The downside is that Vinyl Ester resin has a very short shelf life.

Wyo, RR Composite Pro is definitely more in my price range. I appreciate your input.
Where is the best place to order all of my consumables in a one stop shop?

The problem is, when all the layers of a 5.7 get compressed, your pump can not pull the resin. That’s why you have dry spots. Stop using that 77 and get a Lantor Soric core.
You will make a sandwich between the layers.
3 layers of 5.7 then 1 layer of Soric and another 3 layers of 5.7., peel ply,flow media and 6 ML vacuum bag plastic from the Home Depot ( paint section) works great!
The lator soric will allow the resin flow in between.