+x

 

Hanaldo - 10/18/2020 1:05:22 AM

+x

 

ahender - 10/17/2020 11:01:19 AM

+x

 

Chris Rogers - 10/17/2020 3:39:38 AM

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!

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.

+x

 

ahender - 10/18/2020 1:38:43 PM

+x

 

Hanaldo - 10/18/2020 1:05:22 AM

+x

 

ahender - 10/17/2020 11:01:19 AM

+x

 

Chris Rogers - 10/17/2020 3:39:38 AM

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!

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.

Hanaldo, I appreciate you taking the time to assist me. I have ordered a much longer 60" LFT  bagging film from East Composites. I plan to go to the hardware store and get some painters plastic and practice on it with your instructions. I have some old bagging tape which will be adequate for this while I wait for the new bagging film and tape to arrive.

Alan
 

+x

 

Warren (Staff) - 10/21/2020 3:34:34 PM

Start from the corner or one end.  That way as you work your way round you can adjust the pleat size to a) ensure you have enough bag for the detail required, and b) ensure you don't get to the end and have loads of bag over the end or need really big pleats at one end to use it up. 

Beyond that there is no set right or wrong as long as you have enough bagging material to get properly into all the recesses and depth of the mould.