How much carbon needs to wrap around the leading edge of mast?

[surfcowboy]

Opie, hang in man. Everyone's first project is rough and you picked a doozie to start on. I'm dead slow as well over here. But it's staying light later so I might start to catch up. I refuse to sand indoors, too much mess in the garage and it's too cluttered to dust easily.

I like the plan of doing like Charlie and the F1 wings. But, that's a pretty advanced construction method.  If you want to do it easier, you could also just shape your wing from 2 pieces of wood glued together to get it thicker. As you've learned, epoxy is heavy. Can't fill much or you have an anchor. If you have a a wood core, you won't need much glass at all. Just a layer to seal it. See the Clearwater videos. Redwood is easy to get and lighter than a lot of other cheap woods as well.

If you need a break, make a handplane for fun and learn a little about glassing foam. That's how I started and it's a lot less to mess up.

It'll come with practice. And I agree, it's awesome that you'll share the mess ups. Kinda like the laps on my first board. Soooo ugly lol.

[opie]

The production line was shut down today so that I could make sure the new CR-10 actually works.  It does.

[surfcowboy]

Niiiice!

[opie]

Okay, I am having second thoughts about doing a t-bar instead of connecting the fuselage after wrapping.  I thought I was making it easier by avoiding one connection and the possibility of not getting it straight, but now I see that wrapping the t-bar is going to be much more difficult.
 I am considering a square fuselage instead of round, it would be so much easier to get it straight.  And to get the wings straight too, for that matter.

Would a square fuselage resist torque well enough?  Or would it be impossible to get the carbon fibers in a good direction?

 I am thinking of splitting a two by four up the middle for the core.

[surfcowboy]

I'm doing a one piece mast and fuselage too. I'm honestly not too worried about it as I plan to just overlap the pieces. If you're doing it all within a decent time table things should combine fine, there's no need for things to be a single piece of carbon or glass if that's what you're concerned about. Just overlap things and they will bond up fine.

If you can't get it all into a bag, that's ok too. Lots of stuff gets made with a traditional layup. I'm really lowering the bar here lol but I think it's important that I just make something, then I can improve and iterate from there so I'm trying to take the heat off myself. But I can see how separate pieces could be easier or lam for sure.

[opie]

  I'm really lowering the bar here lol but I think it's important that I just make something, then I can improve and iterate from there so I'm trying to take the heat off myself.

This is exactly how I am looking at it.   

[opie]

Vacuum system seemed to work.  Pump was smoking quite a bit after 3 hours so I just clipped the hose and turned it off.

I learned that I should have a second surface ready for the vacuuming, I ended up with epoxy all over everything.  Also, I should put a new pair of gloves on after removing the first pair.
 
I learned that acetone cleans epoxy off your tools, vacuum equipment, table and floor surprisingly well, even 18 hours later.

I am pretty sure I used way more epoxy than necessary,  the breather cloth and peel ply looked like I had put a hot coat on it.  I barely got it off with pliers.

Wetting out the strips of biax first made them harder to work with.  I could not longer stretch them to make them thinner or squish them for more thickness.  The next layers I will try just wetting out on the mast.

One last issue was the line tape I bought to help cut straight lines and stop fraying.  It helped with the straight lines but when I peeled it off it frayed the edges significantly.  Maybe I pressed too hard when I stuck it.  Maybe it works better with woven cloth.  I don't know.

Even though its ugly I am happy to have made some progress.  I can see this is going to work. Eventually.

[surfcowboy]

Nice! Glad you're making progress. For bagging and laminating I wear 2 pairs of nitrile gloves and then my big gloves over those. By the end I'm down to the last pair for cleanup.

One critical note. Don't use acetone to clean up epoxy. Over time I t can cause an allergic reaction which will make you unable to use epoxy ever again.

Most folks use vinegar, or alcohol for cleanup. Denatured but I've been using plain isopropyl lately.

For tools, orange hand cleaner does a great job. There are tons of mentions on swaylocks of the acetone thing. I know sometimes you have to break out the heavy stuff but be carful.

My first board I was covered in epoxy and my workspace was as well. Today I went through 3 lamination cycles and didn't have sticky hands for any of them. But man, I remember what I call resin panic when things start to kick lol. A tip from Pono that I use a lot is to not leave your resin in the mixing cup, spread it out fast and it doesn't kick as quickly. I started using heavy paper plates for small batches and it slows me way down since my extra resin doesn't kick faster than what's on my part.

I think you're going to catch me and pass me on the foil. I'd better get off my butt

[jrandy]

Hi Opie-
Glad to hear of your success. Some people vent those pumps outside or devise a stack that allow a reclaim of some of the misty oil from the exhaust.

As far as resin quantity goes, I figure it by weighing the cut cloth and go from there.
On laminations the mix is equal to or more that the cloth, on fill coats it is less.
First lamination over wood I'd match resin (part A) to weight of cloth and add the correct amount of hardener (part B).
This is for 2:1 resin to hardener systems.

Put your gloves on before uncorking the epoxy bottles and clean up right after stuff is in the bag during the time when paper towels, Fast Orange, and Isopropyl alcohol are still effective.  I am not a vinegar guy but I could learn.

-J

[opie]

Thanks for the tips, especially about the acetone and alternatives.

I've already lost a couple batches of epoxy when they kicked in the cup.  A paper plate to spread it out is a good idea.

I guess I'll pick up a cheap Harbor Freight scale to help me know how much epoxy I should be using.  The last three layers on the mast worry me because the carbon looks kind of dry.  Maybe it's just due to the surface the peel ply leaves.
The bleeder cloth was completely soaked by the end of the vacuuming.  Which I took to mean plenty of epoxy was there.

A couple questions.  How do I do the last layer on the mast?  Should I continue to use the peel ply for the last twill layer and then after its dry paintbrush some epoxy on top?  Should I add a layer of fiberglass so that I will not be sanding carbon when I am smoothing it out?

And lastly,  if I stand on my  mast now it bends about a quarter inch,(6mm), good enough?  Or should I be aiming for the stiffness of a rock before the last layers?

Thanks


New fuse, plate and strips of biax ready for epoxy.

[surfcowboy]

Not sure about the stiffness. I'll leave that to the pros.

But for sure use a scale to measure your epoxy. It's the most accurate way to mix too. I got rid of plastic mixing cups long ago. Pour the resin in (33gm is about an ounce) and then add half that amount of hardener and you're spot on every time. And then there's nothing to clean up after, just toss the paper cup you mixed in.

I recently started weighing my glass so that works too. I add about 10% for slop factor.

As to the last layer, I've been trying to put all my layers on at once when I can. Better for bonding if you can do it. I always use a last layer of fiberglass to sand smooth and then you hotcoat with a final brushed on coat of epoxy to finish it out all nice and pretty and sealed up. No glass or carbon weave should be exposed.

I'm about to start my mast and I'm hoping I can laminate it in no more than 2 passes. I'm aiming for one if I can start it at night when temps are low so my resin will kick slow. How crazy is it that you can work wet cloth forever but resin in your cup will go off in no time?

[opie]

Thanks for the info on the hot coat.

I've been using the pumps to measure out the epoxy, and I'm using 60 minute epoxy now so I'll have more time. 
I do need a scale to measure the fabric, though, since I really can't tell if I am even close to the right amounts.
I think I'll add a controller to turn the vacuum on and off, too.

I am going to try to get the plate on straight next.  Then I can bond the plate to the mast with some strips followed by the last couple layers on the mast.  Hopefully all at once for the better bonding.  I will have to get better with epoxy if I am going to start doing things all at once.  From my internet research it seems the plate to mast connection is a common failure point in home builds.

On the fuselage the strips kept falling off when I turned it to do another side.  I think the squared off profile, which I thought would be easier, was not so easy.  Rolling fabric around the corners made it want to come up, so I cut it in strips for each side.  Definitely a learning experience I will not repeat.
I put the fuse and the plate in the vacuum, I'll see what I get.

[surfcowboy]

Keep me posted on the fuselage. I would think that the bag would press it all down on the corners. I might offer the idea of doing the top and sides I one go and then doing layers from the bottom and sides so the sides get double the coverage. That would likely be stiff and then you could sand down any weird or wrinkled parts but you'd still have glass/carbon coverage. . (I know I shouldn't have wrinkles but I'm learning too.)

I'm concerned about the top plate as well. My strategy is to put the strips on that hold it to the mast and then lay my fabric on the mast over those strips and bag layers on the top plate so those strips are held under and reinforced by the longer layers. But yes, many layers on that joint. But take heart, those Clearwater foils are held together with just s little glass. Nothing too strong there and they work (I Guess?)

[opie]

The fuse and the plate both have a spot where they are peeling up from the wood core.  I need better lighting in my garage, and rollers instead of foam paint brushes.  I kept pushing the bias cloth around when I was applying the resin.
I am going to try to fix the dry spots by soaking the last layers of carbon I add in too much epoxy.

On the plus side, the vacuum did pull the sides down tight and the 1.5 inches per side square profile feels very solid.  I am not even sure it needed any carbon at all.

I have no confidence in the straightness of my plate, but I gave it a shot.   I am trying to think of a way I can use the 3d printer to get a straight connection next time.  I'll try making a mold for the mast and one for the plate.  Maybe some kind of wedge like KF box would make it easier to deal with. 

I am watching tutorials on mold making, trying to wrap my head around it.  It seems like no two people do it the same way, or with the same materials.

[surfcowboy]

Mold making is weird, I agree.

The thing I do to get my angles right is to build jigs to hold things in place. I'll post up a shot of the one that holds my mast vertical. It's just a piece of 1x2 wood attached to a shelf that I can clamp to. Anything you can secure as plumb and straight is one less variable to deal with. I got enough variables, right?