Just pulled it out of the mold, it still has bubbles. The bubbles seem to be in the second application of epoxy (after the gel coat and before I put down my first layer of carbon). The bubbles are clinging to the carbon. Doesn’t make sense because I know for a fact I popped those bubbles with m y heat gun before laying down the carbon. Is it possible that my vac pump is making these bubbles? I switched to vac bagging because I thought it would help me avoid bubbles and voids! I failed at hand lay up, I suck at vac bagging, I really don’t want to move onto infusion until I master something! Well I’m going to try spraying the clear into the mold next. First I have to fix m y mold, there was a spot I heated up too much that my lay up stuck to!
Good results in infusion are much easier. Handlayup needs a lot of experience to get good results. And I don’t want to talk about perfect results.
Write me a mail with all your materials and equipment you have and I will take a look if you can use it in infusion. If that is possible and you will work 100% by the way I tell you I promise you will get perfect results, If not I will pay the materials you wasted!
With infusion of carbon visual products, a couple of things are important:
-really good vacuum
-airtight bag
-degassed resin
-dry materials (materials can be dried by keeping them under a good vacuum (less than 20 mbar, preferably 5 mbar) for a while. Epoxy + water = gas
-MTI hose
-No bridging.
The skill to produce good quality parts moved from laminating skills, which are highly dependant on materials and just plain practice, to tayloring skills, some flow front prediction (which for smaller simple parts is not difficult, and you can always ask) and leak chasing.
The fun thing is that you can tweak things with unlimited time, and only after you are happy you mix the resin and infuse the part. So much less stressful working conditions, and a lot cleaner as well.
I would definately accept the offer of Dominik, and I am sure you will produce high quality parts using a bit of his material and help.
I have had the same poor and frustrating experiences before I came across MTI a year ago. There is no better way to produce bubble- and pinhole free appearance parts. Here is an example of my latest project: http://youtu.be/EyLHBz-2Cj8
So bottom line is I have to switch to infusion? I created a smaller mold for a smaller part and tried again with the same results. Bubbles and micro voids in the corners. Also with de-gassing, I put a small cup of resin in a glass jar with 29 pressure on it and it bubbled and then the bottom part was clear but a thin layer of bubbles on the top. How do you get these bubbles out? I’ve got about 2-3 weeks before going back to work and I won’t have time to play around with this stuff but I think when I do get time I will try infusion. Has anyone had luck with wet bagging? Seems like I can make parts just not carbon cosmetic worthy parts.
Unfortunatly, I can’t help you. I am having the same problem you are and will probably switch to infusion. It seems the atrs must be perfectly aligned and you must be a unicorn whisperer to achieve perfection with wet layup bagging. Let me know if you come up with a solution.
You may have tensions when you put layers.
Your result seems to be good on plane surfaces, the problem is in corners.
How do you put your first layer ? Do you use a spray glue ?
Be really carefull with the peel ply, be sure to not have tensions. Your bagging film must be larger (30%) than your mould.
Do you use MTI Hose for your infusion ? It can help to give you a prefect result if you are sure to not have tensions on the different layers.
I don’t think he is infusing. But you are right, there does appear to be bridging in the corners.
If you remove your epoxy or resin from your degassing chamber and the bottom is clear but the top still has bubbles then you’re not pulling enough vacuum. I had the same issue before when my chamber wasn’t sealed correctly.
Here’s how to fix this.
- Make sure your chamber is air tight
- Make sure your pump can pull the right amount of vacuum “I use a robinair pump”
Here’s some tips on how to degas
- Make some type of toggle switch to ambient air “this is if you have an epoxy that’s hard to degas and you don’t have a large container”, toggling the switch keeps things from over flowing
- Degas in small batches, let’s say you use 260grams of resin total. Take another cup and pour some in there, maybe 100 grams, then degas that one cup, then pour the rest in that degassed cup, and degas more. You can vary the amounts depending on how annoying your resin is
- If you’re using something that has a longer cure time you can stick your hardener and resin over the heat vents of your house BEFORE you mix. This helps if your house is cold and you want to heat it up just for the infusion or lay up.
- You should see zero bubbles after degassing. I usually do this for 3-5 min after it starts to boil. Some people do it longer but I’ve never had an issue but I only have used the MTI hose…
Good tips sduffass. Should be added to the tips and tricks section.
Give the degassing chamber a good toss while on vacuum helps as well. My colleague is pretty aggressive on the chamber at times.
Also, a wide container degasses better than a high container.
Sparging (adding air into the resin during degassing) also helps (sounds crazy, I know). Degass while sparging for 5 minutes, then keep the vacuum on for another 10 minutes.
Adding a scotch brite on the bottom of the container helps.
Pumping the resin round helps. (perhaps the sparging idea works on the same principle: getting the resin moving)
Herman. What’s Sparging and how do you add air into the resin after it’s already inside the chamber? You’re talking about adding air into the resin directly or just letting air in the chamber?
Also for containers yeah wider ones work better, but my degassing chamber isn’t the best…
For containers though I picked up about 500 clear thin wall quart containers from a restaurant supply store. Cost me around $50 and should last me forever.
Scotch brite is a beautiful idea…I tried with a wire mesh but it doesn’t work. When I degas, I move the degassing chamber, and I beat it on the floor 
Resin degas a little better like this
Sparging is a way of adding air in the resin while degassing…for this you need a tiny inlet of air going from outside the chamber to inside the cup of resin…just a tiny air inlet anything else will make resin bubble uncontrollably… Using a scotch brite is way easier…you just have to deep it inside the cup…Because it’s a sponge it has air within it.
“…Adding a scotch brite on the bottom of the container…”
Hi!
Could you explain in more details please, how is this done, how it works. I have similar problems with degassing of the resin. I’m appling enough vacuum, I think (-0.89 - -0.9 bar), adding vibrations. The epoxy is low viscosity (Letoxit PR 227, 300-700 mPa.s at 25 degrees Celsius), I can see that the bubbles are forming and rising, lot of them will pop, but I still have lot of them in epoxy after 10-15min degassing. Somewhere I’ve read that this problem may result of polluting agents, which increases the surface tension of the resin-hardener mixture. (Otherwise in appearance it seems perfectly clear resin 
) I’ve an idea: immediately before puting the mixture in the vacuum chamber to spray the surface with acetone, or alcohol, or ether ,or something else. And that will be my last try to degass this bloody mixture. Ultrasound is the only thing that I have not tried yet. Thanks!
Your vacuum is not good enough. Aim for at least -0,995 bar (5 mbar abs)