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ahender
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Tomorrow I will finally infuse the 12' canoe I have been working on for years. I'm going to preheat the mold and I want to elevate the temperature some during the curing process.
What is the ideal temperature I should aim for regarding the mold? The resin I am using has a cps of 600 so I think it needs to thin some once it hits the mold.
I also want to elevate the temperature once the infusion has completed. Is there a limit as to what this temperature can be?
Thanks again for offering such a great resource for those with limited knowledge in this area.
Alan
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Chris Rogers
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You want to get the right balance between resin viscosity and gel time for the infusion layout you're using. So, not knowing anything about your tooling, materials or resin... I'd suggest a few things: 1 - Make sure your resin and mold are the same (elevated) temperature - so heat the resin too. Just let the pails hang out in the hot room with the mold over night. If the 600cps is at "room temperature" the viscosity will be much more usable at 90F / 32C or even higher if you can do it - usually with epoxy uncomfortably hot is ideal. What is the resin system you're using? Some epoxy tooling systems are that viscosity and need to be infused hot (like 40C or more), but most general purpose infusion resins should be lower viscosity... 2 - Don't change / raise the temperature until the resin has all gelled - then you can ramp it up a bit and do a postcure. If you heat it before it gels, you risk changing the vapor pressure situation and potentially having bubbles form or other issues. Once it has gelled hard, go ahead and ramp it up slowly. 3 - I'd suggest leaving your vacuum on and (ideally) dialing it back to 20inHg or so after the part is filled. Leave the vacuum on through the full cure cycle - including the postcure. If you don't have the option of very high vacuum, it is sometimes ok to do the whole shoot at 25inHg or so and just throttle the fill so you don't have trapped air problems. If this is a very light laminate (canoe) then it shouldn't be an issue. Are you using core? 4 - Make sure you have good resin breaks so you don't have over-bleed issues as you wait for the resin to gel... Good luck! Please post some pictures of the canoe if you can.
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ahender
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+xYou want to get the right balance between resin viscosity and gel time for the infusion layout you're using. So, not knowing anything about your tooling, materials or resin... I'd suggest a few things: 1 - Make sure your resin and mold are the same (elevated) temperature - so heat the resin too. Just let the pails hang out in the hot room with the mold over night. If the 600cps is at "room temperature" the viscosity will be much more usable at 90F / 32C or even higher if you can do it - usually with epoxy uncomfortably hot is ideal. What is the resin system you're using? Some epoxy tooling systems are that viscosity and need to be infused hot (like 40C or more), but most general purpose infusion resins should be lower viscosity... 2 - Don't change / raise the temperature until the resin has all gelled - then you can ramp it up a bit and do a postcure. If you heat it before it gels, you risk changing the vapor pressure situation and potentially having bubbles form or other issues. Once it has gelled hard, go ahead and ramp it up slowly. 3 - I'd suggest leaving your vacuum on and (ideally) dialing it back to 20inHg or so after the part is filled. Leave the vacuum on through the full cure cycle - including the postcure. If you don't have the option of very high vacuum, it is sometimes ok to do the whole shoot at 25inHg or so and just throttle the fill so you don't have trapped air problems. If this is a very light laminate (canoe) then it shouldn't be an issue. Are you using core? 4 - Make sure you have good resin breaks so you don't have over-bleed issues as you wait for the resin to gel... Good luck! Please post some pictures of the canoe if you can. Thank you for the detailed response Roger. The resin system used for the mold is epoxy sanded to 1500 grit. Six applications of wax have been applied. The epoxy I am using is from US Composites. The fabric is 9oz/yard s2-glass. The peel ply, bagging film, and mesh are from Easy Composites. No core for this layup. One layer of glass all over, then an extra layer on bottom, bow, and stern. After cure, I will add a core, then separately another layer of glass. The canoe is designed to be an ultralight, hence the use of only one primary layer of glass on outer and inner layers. I do plan on dialing back the pressure after the infusion. The mesh will stop about 3 inches from the end of the fabric. There will be about 6 inches of just peel ply between the glass and vacuum line. So to confirm, you are stating both my resin and mold can be heated to 90 degrees F for the infusion? Then continue cure as the same temperature until the part has gelled? One question. Why does there need to be a vacuum after the part has gelled? Alan
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torsten Ker
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For my canoes I use epoxy infusion resin and infuse the part at 25C and a 30/70 mix of fast and slow hardener, once infusion is complete the temp of the mould is raised to 30C which shortent the gel time considerably, all of that under vacuum left for 8 to 12 hours, I lost vacuum on one after 3 hours and the tension of the laminate in diffucult places sepereated it from the core in some places, hence now I gel it at 30C to avoid that After that post cure for 8 hours as described in EC-TDS-IN2-Infusion-Resin.pdf2hrs at 40°C 2hrs at 50°C 2hrs at 60°C 2hrs at 70°C First time I did that I was really suprised about how strong the epoxy got that way, 30% is not far off
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ahender
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+xFor my canoes I use epoxy infusion resin and infuse the part at 25C and a 30/70 mix of fast and slow hardener, once infusion is complete the temp of the mould is raised to 30C which shortent the gel time considerably, all of that under vacuum left for 8 to 12 hours, I lost vacuum on one after 3 hours and the tension of the laminate in diffucult places sepereated it from the core in some places, hence now I gel it at 30C to avoid that After that post cure for 8 hours as described in EC-TDS-IN2-Infusion-Resin.pdf2hrs at 40°C 2hrs at 50°C 2hrs at 60°C 2hrs at 70°C First time I did that I was really suprised about how strong the epoxy got that way, 30% is not far off Thank you. I am close to finishing the layup. I will infuse in the morning. Next time around, I will use Easy's infusion resin.
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ahender
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+xFor my canoes I use epoxy infusion resin and infuse the part at 25C and a 30/70 mix of fast and slow hardener, once infusion is complete the temp of the mould is raised to 30C which shortent the gel time considerably, all of that under vacuum left for 8 to 12 hours, I lost vacuum on one after 3 hours and the tension of the laminate in diffucult places sepereated it from the core in some places, hence now I gel it at 30C to avoid that After that post cure for 8 hours as described in EC-TDS-IN2-Infusion-Resin.pdf2hrs at 40°C 2hrs at 50°C 2hrs at 60°C 2hrs at 70°C First time I did that I was really suprised about how strong the epoxy got that way, 30% is not far off Torsen. I want to get your opinion on bagging an irregular object like a canoe. My attempt yesterday failed. I understand the concept of pleats. I watched a Gougeon Brothers video on this. It was a short video so every detail was not mentioned. In this demonstration, a pleat was made every few inches. It was also recommended the vacuum bag be 20% larger than the mold. A few questions I hope you can answer. Where do your start when adding pleats? Should the bow and stern be done first or last? My bag will be 120" wide and several feet longer than the linear feet of the inside of the mold. How do I determine where to start on the bag? I thought yesterday just pushing the excess bag into the boat would work but I still had bridging problems on the ends. Thank you. Alan
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Hanaldo
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20% isn't really enough for anything but quite flat moulds. I would go atleast 50% to 100% larger than the size of your moulds footprint (including the flanges). 100% bigger will be big, so I generally only do that for very deep moulds or quite complex ones. A canoe is a fairly simple shape, but has quite a deep draft - I would recommend somewhere in the vicinity of 50%-65% bigger. Remember that there is no harm in going larger other than wasting material, but going smaller is a big problem, so 'err' on the larger side.
As for pleats, this is always difficult to describe in words, but my best advice is to start at a known location. If your flanges are rectangular and have corners, start at a corner. If it doesn't have corners and is more like the 'oval' shape of your canoe, this will be a bit harder because you will really have to cut your bag to suit the shape otherwise the overhang may confuse you and you'll end up with messy pleats. But in this case, start in the middle and work your way towards on end of the mould. It is important to start in a known location, because if you just start anywhere then you can lose track of how much bag you have left and can make the bag too small in one area.
For pleat sizes, again there is no harm in going bigger other than wasting bagging tape. If you aren't confident of how big they should be, just make them quite long, like 4-5" each. You can always fold them over onto themselves more if you find you only need short pleats, but you need your pleats to be long enough to take up all of the extra bagging film you have. Placement wise, I tend to place them every 4-5" as well as at every change in geometry of the mould, ie. long straight sections can get away with less pleats, lots of geometry requires more pleats. That isn't too critical, as you work your way along the flange you can decide whether you need more pleats and just add some more.
Realistically, the size and placement of your pleats is mainly determined by the size of your bag. So start with making a larger bag, and the pleats shouldn't be too much of a worry.
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Chris Rogers
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I'm still a little concerned with your resin viscosity and I have never used that brand so no experience. If it flows, it flows! On the vacuum bagging, I did an article on this a while back - too long and poorly edited still but it has some embedded videos. Might help: https://explorecomposites.com/articles/lamination/basics-vacuum-bagging/And technically there doesn't need to be vacuum after the resin gels but with epoxy it is a good idea... because the gel process takes some time and things can still warp or get messed up if you slack off the bag before the epoxy is fully cured. I'd also suggest post-curing under vacuum too if you're going to do that. Hanaldo is right about bags needing to be be much bigger than you think! And a canoe is not a super obvious thing to bag... Good luck!
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ahender
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+xI'm still a little concerned with your resin viscosity and I have never used that brand so no experience. If it flows, it flows! On the vacuum bagging, I did an article on this a while back - too long and poorly edited still but it has some embedded videos. Might help: https://explorecomposites.com/articles/lamination/basics-vacuum-bagging/And technically there doesn't need to be vacuum after the resin gels but with epoxy it is a good idea... because the gel process takes some time and things can still warp or get messed up if you slack off the bag before the epoxy is fully cured. I'd also suggest post-curing under vacuum too if you're going to do that. Hanaldo is right about bags needing to be be much bigger than you think! And a canoe is not a super obvious thing to bag... Good luck! Hanaldo and Chris. Thank you both for replying. Chris, I did read your post while researching pleats. As for my resin choice, I'm hoping a little warming will make it sufficient. I also plan to warm the mold some. This will help thin it. Hanaldo, see if what I state is correct. I will cut my bag much larger than the mold interior surface. The bag starting width is 120". The length will have plenty of excess. I will then lay bunched up blankets inside the mold to conform the bag to all mold contours. This will help me determine the size needed when I start adding pleats. Adding pleats will primarily draw in the length of bag from bow to stern and much less from side-to-side. What I am concerned with is having far too much bag width when I start. Once the blankets are pressed in place, I assume I should cut the bag width some and start attaching the bag to the mold at the bag's edges? Once I reach the bow and stern, I will trim the bag length. Are my assumptions correct? Alan
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Hanaldo
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+x+xI'm still a little concerned with your resin viscosity and I have never used that brand so no experience. If it flows, it flows! On the vacuum bagging, I did an article on this a while back - too long and poorly edited still but it has some embedded videos. Might help: https://explorecomposites.com/articles/lamination/basics-vacuum-bagging/And technically there doesn't need to be vacuum after the resin gels but with epoxy it is a good idea... because the gel process takes some time and things can still warp or get messed up if you slack off the bag before the epoxy is fully cured. I'd also suggest post-curing under vacuum too if you're going to do that. Hanaldo is right about bags needing to be be much bigger than you think! And a canoe is not a super obvious thing to bag... Good luck! Hanaldo and Chris. Thank you both for replying. Chris, I did read your post while researching pleats. As for my resin choice, I'm hoping a little warming will make it sufficient. I also plan to warm the mold some. This will help thin it. Hanaldo, see if what I state is correct. I will cut my bag much larger than the mold interior surface. The bag starting width is 120". The length will have plenty of excess. I will then lay bunched up blankets inside the mold to conform the bag to all mold contours. This will help me determine the size needed when I start adding pleats. Adding pleats will primarily draw in the length of bag from bow to stern and much less from side-to-side. What I am concerned with is having far too much bag width when I start. Once the blankets are pressed in place, I assume I should cut the bag width some and start attaching the bag to the mold at the bag's edges? Once I reach the bow and stern, I will trim the bag length. Are my assumptions correct? Alan Are you able to post a photo of your mould? It is difficult to give advice without knowing what the mould looks like. I'm not sure where you are going with the bunched up blankets, this is unnecessary. Your pleat sizes are not hugely critical - they need to be big enough and there needs to be enough of them to take up the extra bag and fit it to the mould. Chris' inch-worm analogy is a good one. It does not make a massive difference whether you have less large pleats or more small pleats, as long as the bag is big enough and there are enough pleats to make use of that bag. It is sometimes less time consuming to do larger pleats and less of them, while it is sometimes easier to manage the bag if the pleats are small but frequent. If I knew what your mould looks like I could offer more specific advice, but I feel you are overthinking it a bit. Keep it simple. Use a flexible measuring tape to measure the widest distance between the bow and stern INCLUDING the flanges. So start at one edge of the flange, measure down into the deepest part of the canoe, across the bottom, up the other side and to the opposite edge of the flange. Then do the same across the widest distance of the short dimension. This will give you the L x W footprint of your mould. Multiply this by 1.65, and make your bag that big. This ensures that your bag is big enough for the widest parts of the mould. From here if you need to tailor it to suit the shape of your mould then you can do that - much much easier to tailor the bag before you start sticking it down. Once you start pleating it it is going to crease and you may inadvertently cut it too short.
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