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baja_patient
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Hi all, I have been working on a project for a fair while now, and I'm starting to see light at the end of the tunnel. As you can see in the attached pictures I started out with an unflanged mould in sight of using a wet lay-up technique.   Due to wanting cosmetically perfect parts and after consultation from the EC staff I decided to go for resin infusion instead. I modified my moulds so there would be sufficient flange space by adding a frame and a high-gloss surface to ensure that I can pull 100% vac. I am just about ready to start my first infusion and would like a few tips. The first mould I want to do is 70x40cm and approx. 7cm deep at its deepest point. I am planning to use 2 layers 200g carbon cloth and 2 layers of approx 150g e-glass. Is this a good combination and how much IN2 resin will I need based on the information? There is breather material included in my starter pack and it is also mentioned in the instructions, yet not in the video. I assume I should be using it. One more question (i hope): Can the reinforcement be cut smaller than the edge of the mould, or does it have to be almost at the gum tape? I hope I've formulated myself correctly!
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Joe
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Hi, When all your fabric is cut to size, you need to weight it. Then, ideally, you would want 40% of this weight in resin. BUT, keep in mind that your resin feed line, infusion spiral, distribution mesh etc will consume resin too. So mix a little more resin that what the fabric layers should take. Breather material is not needed if you go for the infusion. Usually in infusion, the stack is: mold, release agents, fabric, peel-ply, distribution mesh, vacuum bag. Breather is used when you hand wet your fabric in your mold and then put it under vacuum. Breather will act as uniform pressure distribution as well as soaking the excess resin thru a perforated release film. The reinforcment should "stop" anywhere between your part flange (to have enough material to trim your part) and your gum tape. I usually leave fabric at 1 inch from part flanges, and 1 inch from the gum tape. Hope it helps.
 A $1000 electronic device will always protect a 10 cents fuse
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baja_patient
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Thanks alot Joe! It does help indeed. I am fairly new to infusion and still learning everything I can. I was fixed on the resin ratio table and it totally slipped my mind that I could calculate according to weight of reinforcement and a little more. Thanks for the great tip. I will use this method. Roughly, could you recommend percentage-wise how much extra should be included for the consumables? around 10-15 % or is that not enough? I understand what you mean about the breather fabric. I remember now how it was explained to me. Where the vacuum line exits to catch pot, some say to put a strip of the breather under the silicone connector to catch excess resin which would otherwise land in the catch pot. Then others say just a couple strips of infusion mesh on top of each other under the connector. Some only use one strip of mesh and then the connector. What would you suggest? I am looking towards one or two strips of mesh and then into the pot, at least for my first go. I have bin through the trial and error stages with my moulds and have gotten them close to perfect. It was just so much work so far, but I enjoyed almost all of it thoroughly. I really want to get a perfect infusion the first time round and am taking my time and minding all the precautions.
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Joe
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Honestly, I have no clue how much more resin you should mix. I really think it depends on your consumables: how long is your feed line, how long is your spiral etc. What I personally do in a new part is weighting a little more resin that what the fabric takes. Say I mix 300 grs when I have 270 grs cloth. Then I look at the resin feed liner and if I notice I wont have enough, I clamp the resin feed, get a new liner, and mix a bit more resin (be carefull if you use fast catalyst not to take too much your time doing this). Then I pour it in the first liner when my feed line is. The second liner / pour method is used to mix the second batch of resin to avoid entrapping air in the feed line. So next time you know how much resin weight you need. I keep track of everything in my computer so I know what I need exactly for this or that part (resin weight, feed line lengths, spiral length etc etc). I use double layer of distribution mesh under my vacuum line connector, but I'm not saying its the best way. Thats just how I do. Dont forget the pics when you're done 
A $1000 electronic device will always protect a 10 cents fuse
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baja_patient
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So, first things first, Easycomposites makes everything look so easy lol!!! Great instructions, videos and tips on the forum! Had the whole procedure learned and in my head. It was quite a challenge to lay the stack to my odd shaped mould. I applied easy lease and built the stack. My masking tape would hardly stick at all so I used gaffer tape on the infusion mesh. I hope that was okay. Regardless, I stuck the first bag, it was a tad small with the pleats, so I used another, plenty big enough. I am using the flow indicator vane, and after a pushing down on a couple bigger leaks I managed to pull full vac. The problem was, after the drop test i heard a tiny crackle here and there and lost a few marks on the gauge. Pushed and pushed hard all over the tape, checked the connectors, re-did one of the connectors and tried again and again, the gauge kept changing. I watched the gauge drop 1-1/2 marks over aprox 20 mins. Vane not moving at all. I checked the next morning and the bag was still quite tight and the gauge was at about 1/3 vac. I was quite frustrated, but happy I didn't infuse. There must be some tiny tiny leak somewhere, but I checked and checked and didn't hear any leaking, it is too small. Also I couldn't get it sealed. Are there any other methods to check where the leak is, smoke or something? Thing is I have a busy schedule and don't always manage to get to the workshop, but I reckon I will just use a new bag and new tape. I will measure my pleats and make the bag exactly bigger to accommodate them, so I don't have too much and wont have to worry about having too many wrinkles. Any tips on how to best put the bag down? Anyway, I got really excited to see it pulling vacuum first time, only to be set back. Oh well, I'm not going to give up after coming this far.
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SebRS
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Hi Baja, I'm not a composite expert at all, but i notice that you gum tape is not directly positioned on the vinyl gel coat. Maybe your leak come from the wood/mould junction? did you add something on this junction to ensure a perfect seal? Regards, and good luck for your drop test! Seb.
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Joe
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Hi, If your leak is too little to be noticed, what about wraping the whole mold in the vacuum bag? Then even if your mold has tiny cracks, the bag will enclose them. If you do so, be careful with sharp edges on your mold that could damage the bag. Good luck !
A $1000 electronic device will always protect a 10 cents fuse
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baja_patient
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SebRS (04/05/2012)
Hi Baja, I'm not a composite expert at all, but i notice that you gum tape is not directly positioned on the vinyl gel coat. Maybe your leak come from the wood/mould junction? did you add something on this junction to ensure a perfect seal? Regards, and good luck for your drop test! Seb. Thanks guys, Yes I know what you mean, but I extended those flanges on purpose, its plywood with a layer of glass fiber and then a gloss coat of epoxy. I really hope that its air tight, I assume it is though. The joint is epoxied and then the subsequent top layers. Thanks Joe, I hope that the mould is tight. I was also considering bagging the whole thing in a tube, I would need to sand and/or apply some sort of soft fabric around the wooden sides and the bottom, because the bottom is pretty rough due to the putty and fixing method of the flanges. It seems like a whole lot of extra work. So before I consider doing that and before I remove the the stack, I will give it another go with the bag on top as instructed on Monday, hopefully it was just a first time bagging error and I will get her to seal. cheers
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Warren
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Use this Guide to resin usage to work out how much you need to infuse.
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baja_patient
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Thanks for the tips so far. Status update. I managed the infusion, didnt come out quite as expected but I have definitely learned A LOT. I bagged it up perfectly with one small leak which I sealed in seconds.The mould was airtight as expected. I calculated the resin quantity according to a 60/40 ratio and some more for consumables and began the infusion. It was fast, very fast.
The 250 grams of resin which should have been perfectly adequate were used up in about 30 seconds. It was all a bit hectic and I got some air into the infusion before I could top up resin. I knew it would cause problems in the surface and was very annoyed at the time. It was only one of my problems in hindsight.
I cured at elevated room temperature of about 33 degrees for 24 hours and went to demould. The easylease did its job perfectly, yet the part was very difficult to de-mould due to the high quantity of resin. I ended up using about 500g.
The reason I needed so much resin became apparent as soon as I demoulded.There was no bridging in the bag whatsoever, it was tight all over the surface and the pleats did their magic. The problem was I had voids underneath the carbon, it did not reach all the recesses of my quite complex mould. It was a bit of an ambitious mould, deep and recessed in multiple ways as can be seen in the attached pictures.
I have noted all my mistakes and will not be repeating them next time round.
Couple of questions, I think I will need to tack the carbon cloth into all the recesses beforehand (pre-preg style) I will be using profinish for my top layers from now on. How do I best go about doing so? Is it even possible? Shall I put down a tack gel coat, shall I use 3M spray glue (if so, which one) or equivalent? Or is there a special product to tack the cloth into all recesses?
As you can see there are quite a few large and small air bubbles, due to the fact that air entered the feedline because the resin was busy filling the huge air voids very quickly.
I will be extra careful next time, not to let it get too low. I have included pics of the mould, infusion, finished part, and a pic of how the body should look when its all trimmed and finished (in carbon)
thanks alot everybody, any tips whatsoever are very welcome. cheers Fabian
           
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