First Time Infusion Major Fail...Need Advice/Input Please

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#1

hey guys,
So today I was feeling bold and decided to try infusion today. It was a major disaster and was wondering if you guys could give me tips. Here’s the setup I used today…

1.5 cfm robinair vacuum pump
1 layer 2x2 5.7 oz twill cf
1 layer 6 oz fiberglass
1 layer airtech peel ply b green
1 layer airtech green flow 75 flow media
1 layer nylon bagging film
polyester clear surfboard laminating resin

2 1/4" vacuum t fittings
1/4" resin in/out lines
spiral tubing on both sides

  1. I wasn’t able to get a vacuum on my own without the help of the pump being constantly on. I spent 1.5 hours trying to find the leaks. I noticed some of the leaks were due to the spiral tubing ends cutting the bagging film. I found those and put gum tape over the spots, but there continued to be a leak. I even used my old nursing stethoscope to find the leaks and somewhat found some. But after all that i couldn’t find the rest and just infused at 27 mmhg. Is it the flow media cutting into the nylon bagging although I couldn’t find any cuts? I smashed my tape down over and over around the edges, but that didn’t help, but I could hear hissing with my steth when placing it over certain areas of the gum tape, but that didn’t really help. I covered the inlet/outlet tubing with more gum tape but didn’t work.

  2. When I degassed my polyester resin before adding the MEKP catalyst I was able to remove the bubbles. The only problem is that it made the resin on the bottom kind of gelled. Why is that? I opted not to infuse that resin. I just made another batch of resin and did not degas it (see next question).

  3. So when I infused the resin, it did not flow like the videos I have watched. It infused, but it had so many fast moving bubbles come out of the spiral tubing. Kinda looked like the bubbles rushing out of a scuba person’s mask.

Currently I’m in 1.5 hours of the pump being on and it’s holding 27 mmhg. Since the polyester resin has pretty much set in, I’m gonna turn the pump off at the 2 hour mark.

Can someone give me tips on how I can avoid these problems?

Thanks in advance…

#2

Don’t try again until you have full vacuum. You’ll just be wasting time and materials.

What type of clamps and hose are you using and are you sure they are properly sealing your lines?

If your spiral is cutting into your bag, wrap the spiral with some release film.

If you’re still having issues with leaks, get a thicker bag and/or double bag. You really need to make getting a leak free system a priority.

Get a slower hardening resin/epoxy, or lower the temperature of the resin/epoxy. When you degas, you speed up the pot life. Your pump is very weak, so it probably takes a decent amount of time to degas. By then your resin has already kicked.

That’s because you were using a laminating resin and not an infusion resin. Chances are, it has a higher viscosity so it won’t flow very well. If you have to lower it’s temperature to get a longer pot life, it will be even thicker and flow even less. Get a resin/epoxy with the longest pot life you can (200-300 minutes) until you know what you’re doing. This will give you more time to degas and ensure your resin doesn’t kick before you’re ready.

Degassing will help with bubbles considerably, but you’ll still see some bubbles flowing even if you do degas. Fix your other problems first, then you can start trouble shooting the bubbles.

#3

I’m using brake hose clamps. I tested it out with a piece of tubing attached to my resin pot and the clamp was able to hold and achieve 29 mmhg.

I guess I’ll wrap my spiral tubing more in peel ply.

When you say double bag, do you mean just cut one bag slightly smaller and then have the larger bag over it? Or do you mean just sandwich the two bags?

I guess as a beginner to me it flowed well. It actually flowed faster than the resin in the easycomposites video. Sadly, there isn’t much choice of resins down here. The only thing that has a longer working time is a polyester clear casting resin which is a no. We do have epoxy down here, but my mold is from a polyester gelcoat so that’s not an option. If I remember correctly you can’t use epoxy on polyester gelcoat?

Keep the information coming. I’m at a lost. Aside from the leaks, it seems my problem lies within my resin but don’t have other options aside from remaking all my molds with epoxy and doing it that way.

#4

I used those when I first started too, but had problems with slow leaks. I switched to legit clamps and no more issues.

A second larger bag over your initial bag. It’s an insurance policy against small leaks. A second layer of bagging film and some tape is a lot cheaper than losing carbon/epoxy due to failure.

Technically epoxy will stick to polyester, but if you seal it and use a good release (semi-perm) I don’t think you’ll have any issues. But you should get clarification on that. I’ve never tried it before, so I can’t be certain. We use epoxy for our molds.

Just keep at it, you’ll get where you need to be if you stay persistent.

#5

Ok so just pulled part from the mold. Is this the result of infusing with a small leak? It pulled both my resin and the air from the small leaking causing those major bubbling while infusing (kinda like bubbles boiling in a pot)? Seems like some of the resin didn’t catalyze since the resin that is still in my mould is still wet/tacky. I’m gonna try give this another whirl today, but any advice before I start would be helpful. Thanks a bunch!


#6

considering your issues it looks decent

For clamps I just buy some vice grip type clamps, though I use cheapo ones not real ones, and they do me right. Just don’t close them so tight you snip the plastic tubing.

If your mold is made of polyester, you can use epoxy so long as you release the mold… which obviously you did.

Though epoxies can be fairly thick, even infusion epoxies. Though honeslty your part is so small it should easily wet out. Also since your mold is so small you can bag it then envelope bag it to be sure you have no leaks. You must have no leaks or else you’ll get air in the part.

At home I don’t degass. Probably better to do it but I don’t have a degassing chmamber at home. If i were you I wouldn’t degass yet. Just mix the resin while trying not to get too much air bubbles in to the mix and then let it sit for a few minutes, tap the sides. I don’t usually have a major issue with bubbles from the resin. but for these first few parts, keep it simple.

really if you can afford it though, switch to epoxy. The cure on polyester isn’t so great and the epoxy is much stronger and you don’t have to mess with MEK-P. I’ve not infused polyester but have used vinyl ester and have had issues with it degassing in the bag after infusion creating bubbles. I would imagine polyester is similar in this respect.

#7

Thanks Sammy. So all the big cracks in my resin is due to air? I know I got frustrated yesterday and infused it at 27 mmhg with a slight leak near the resin inlet. Is that the cause of the cracks of resin in my part?

Thanks a bunch. You guys are awesome!

#8

You can’t have any leaks… you should be able to clamp off the vac line and then go and have a coffee and come back and have the bag nice and tight. Really you should do a leak down test. I personally like to have 0 inches drop. On small parts I’ll double bag so I don’t have to worry. Big parts a bit more of a pain but, one leak and your in trouble.

I don’t see the cracks… but if you know there was a leak, you’d see the air bubbles getting into the bag/part. If there was a leak the part may or may not be scarp, depending.

It’s also possible for the mold to leak, which is PIA. Infusion is good when it works, and leaky when it doesnt’. I’m trying to make the move to prepreg… just need to build my damn oven! :smiley:

THe part looks pretty good though, keep at it and I’m sure you’ll get it.

#9

Sorry I meant where the resin is entirely missing. It’s basically the entire center section.

#10

Hi
Just a few thoughts that will help and i use all the time, trim down the mould until you have a flange width of 70-80mm then sand the back of the mould to a smooth finish and envelope bag the part. This will reduce the chance of a bag leak considerably and I never have a leaking bag with this method. I also cover the back of the mould with breather fabric to remove the risk of bag damage on any sharp edges.
Regards Chris
carbon fibre works ltd

ps always make you envelope bag on a clean and smooth workbench.

#11

I think you have a number of issues going on. First, your mold is not what I would really call good. Packing tape and clay to build the flange? Your mold should be cleaned up. Actually, I’d start over. The surfaces of the flange should be smooth and shiney. All those pits, cracks, and crevices are potential paths for leaks.

Next, it looks like you have some bridging of the carbon. Those are areas that collect either air or resin (depending on the quality of the vacuum seal). You should make sure the materials are in contact with the mold surface before bagging and after you bag before you apply vacuum and finally after vac but before infusion. Once you let the resin go, it’s pretty much too late to adjust anything.

Your vacuum integrity should be good before flow. Otherwise, you end up with a part like you built. If air is getting in, it’s staying in.

Misc points:
Laminating resin is not infusion resin although it can work for small parts where the flow path is short.

Polyester tooling can be used with polyester, vinylester, and epoxy, you just need to use an appropriate release agent.

You mentioned that some of the resin didn’t seem to cure. One of two things is going on, either you didn’t mix thoroughly or, and more likely, you are seeing styrene and thinking resin. Polyester resin outgasses as it cures and the majority of that is styrene. With an open mold, the styrene escapes to the atmosphere. When you are closed molding, the styrene normally has no place to go so it crosslinks in the matrix. However, if you have voids, the styrene has a place to go and so it outgasses and collects in those voids.

An envelope bag can solve your leak problem with the current mold. Just make sure you follow carbonworks suggestions. In addition, when creating the bag, make smooth seams and you won’t have to worry about leaks at wrinkles. If you do the envelope correctly, the only possible leaks will be where your lines go in, making finding them much easier. Well, there is one other path, holes in the bag. Be careful with the film.

#12

Thank you all for your helpful responses. I will be remaking the mold and switching to epoxy in the near future.

So I infused yesterday. I really took my time and was able to get a decent part out of it. The only problem I’m having that you can’t see in the pic is very tiny bubbles along the edges of my part. Is this due to air still being leaked? Is it not degassing properly? Or is it what Roger said where polyester resin outgasses and there’s nothing I can do?

thanks a bunch everyone…i’m getting closer! I hope…:slight_smile:

](http://s302.photobucket.com/user/Kanklesdod/media/imagejpg1_zps105772f5.jpg.html)[/IMG]

#13

Good work, you’re getting better.

I can’t speak for you on the polyester, as I haven’t used it in an infusion system. But it doesn’t look like a leak to me. A leak would leave voids in the surface area, similar to what you had before but smaller pinholes on the surface in a texture like the fabric (so tiny gaps of air in the gaps of the weave).

#14

Hmm…so I’m running another one as we speak. I found out that my vacuum chamber wasn’t holding pressure…brand new go figures. So I spent half my morning taking apart the valve. Teflon taped the threads and am now back to holding 29 mmhg. So hopefully this time it works.

But those bubbles look like they were from the resin that got trapped. If this is the case, I’m gonna stop using polyester resin as it only has a working time of ~10 minutes before it starts to cure. Not enough time to degas as I degas the resin before I add the MEKP catalyst and that takes around 30 minutes. Didn’t try to degas after adding MEKP though.

#15

I’d also suggest a few dabs of silicone around any handle bolts on the inside.

I don’t think you’re doing yourself any good degassing before you mix the MEKP. Mixing the catalyst or hardener adds air to the resin or epoxy, which is why you’d degas after.

If you only have a working time of 10 minutes, thats probably the main issue. Switch to a 100-200 minute epoxy. Then you’ll have familiarity with it when you’re ready to infuse bigger parts. I’d suggest going as slow as possible if you can, as you live in a warmer climate. Unless you’re working in a climate controlled area, you’re going to want as much time as possible for your infusions.

#16

I noticed when I pour out the polyester resin, there are a lot of bubbles created so I degassed the resin so that when I mix the MEKP, I will have less bubbles than before. But nonetheless you are right.

I think I’m going to have to rethink the resin. It seems to be my issue. Sad thing is…again hawaii. We don’t have much selection of epoxy down here. Can you guys tell me which epoxy I should be using for infusion from the link I’m gonna post? I’m not sure which I can use, but that’s basically all we have down here.

http://shop.fiberglasshawaii.com/resin/epoxy_resin

But yep, I tried degassing after I added the MEKP. It seemed to work well. Then as I opened up the line, it gelled as it went into the mesh. So pissed that I wasted half a day doing this for nothing :mad: Third infusion with only 1 partial success. Frustrating but I ain’t going to give up just yet :slight_smile:

#17

If you can find out exactly what viscosity that Aluzine resin is, that sounds like a good bet. They state it is low viscosity, so if it’s below 300cps/mpas then it will be perfect. 180-200cps would be ideal, but I frequently use a 300cps resin for infusion and it’s fine.

Otherwise I think you will possibly get away with using the System Three Silvertip epoxy with the slow hardener. It’s got a viscosity of 675cps, which is a bit thick for infusion but it may still work, albeit slower.

#18

You can just leave the epoxy out for an hour after you pour with a piece of paper over it (so no bugs or dirt or whatever fall in) and it will degas on its on without using the chamber. I’m not sure if degassing before you mix in the catalyst speeds up the pot life but I know degassing after you do does.

Nothing on their website has the technical data sheets, so if I were you I would either call them or go to their store and talk to them. Tell them what you’re doing and tell them you need something with a lower viscosity and a much longer pot life. They might not have the perfect epoxy it in stock, but chances are they can get it for you and cover the freight costs with their next order of other supplies. They can also probably provide you with a small sample of their Aluzine to see if it works for your application, as it appears they manufacture it.

Bingo.

It happens. Just make sure when you have failures you are understanding why you failed, so you don’t continue to make the same mistakes and waste time and material.

#19

Hey whitecel,

So I use these guys resin systems at home: www.entropyresins.com

they make a uv stable clear infusion resin that is partly bio based and it works pretty damn good. I like it. I chekced their website and they list this guy as their hawaii distributor:http://franceseider.wix.com/kbshapes/about

ANd degassing doesn’t reduce the pot life of epoxy. If your polyester resin is curing in 10 minutes, you really need to reduce the percentage of mekp. You can go down to like .5% or so. You just want to catalyze it and then get it out of a cup asap. In mass it will exotherm and heat up, heat will make it cure faster. ALso if your in hawaii and it’s 90 degrees that will make it cure faster.

If you use an epoxy you will still have this issue of exotherm but, epoxy is a lot better for this. Plus your part is very small and you shouldn’t be mixing up much? WHat like 200 or 300 grams or so?

The epoxy should be like 300 centipoise, which is good for infusion. Not sure what your polyester is?

Again, degassing shouldn’t be necessary initially. If you mix carefully and then let the resin sit for a bit you should get a good amount of the bubbles out.

Do a gel time test with your polyester. Pour 100 gram amounts into small cups and then catalyze them at .5%, .75%, 1%, 1.5%, and record the time until it gels. You should generally do this when you get a new resin. It’s called a gel time test and pretty much anyone who uses resins does this, or should do this, before implementing a new resin system into production. That way you will have a better idea for how much mekp to add.

keep at it man, you’ll get it. A lot of this stuff is just using the right materials first, and then using the right process second.

Keep at, your very close!

#20

I’ve not found this to be true. In all of my tests on several of the epoxies I use, both thick and thin, degassing has significantly sped up the pot life.