Hi guys, Been looking at the resin infusion vids and it looks pretty straight forward. (famous last words) I want to make a 250mm diameter cylinder approx 1000mm length. However I need answers to a few questions please... How likely is it for the resin to reach the the other side and leave corners/edges dry? If its quite likely tips to prevent this? If this happens is the part still salvageable or ruined? Second question, This cylinder needs to be stiff (very very stiff) and upto 15mm thick, it does not matter if its thinner. What sort of layering would you use to achieve the above. Third question, I don't have a mandrill so intending to use a prepared sonotube cylinder, would release from this be difficult? Last question, cutting carbon fiber outside in the garden, would the dust just diffuse in the wind or linger in the garden for a couple of days? Looking forward to get started in this hobby, got loads of little projects planned... thanks, Jan

Hi Jan,

Answers to your questions as follows:

I want to make a 250mm diameter cylinder approx 1000mm length.
How likely is it for the resin to reach the the other side and leave corners/edges dry?

I don't think this will be a problem; it is an unusual shape for infusion and certainly makes the bagging process a little different but I don't think that resin infusing through the full shape should be a problem. I think I would set the tube vertically with a spiral all the way around the top edge, letting the resin flow down through the tube to the vacuum line at the bottom but it would probably work at any other orientation too.

If its quite likely tips to prevent this? If this happens is the part still salvageable or ruined?

It's pretty hard to recover a part in this situation, the only 'recovery' is to sort it as best you can at the time, usually by cycling resin through (into the catch-pot) as long as it takes until the last corners of the infusion are reached. This is very rarely necessary though and I'm sure it will go just fine.

This cylinder needs to be stiff (very very stiff) and upto 15mm thick, it does not matter if its thinner.
What sort of layering would you use to achieve the above.

Well, 15mm really would be an incredibly thick laminate although I suspect it doesn't need to be anywhere near this thick. To give you an idea of how you would achieve different laminate thicknesses, simply add up the thickness of the reinforcement that you plan to use, it really is that simple:

Please note these thicknesses relate to the following reinforcement types laminated under vacuum.
Open layup with the same fabrics would yield a thicker laminate. All thicknesses are approximate.

0.10mm  90g Carbon Fibre Cloth
0.25mm  200g Carbon Cloth
0.25mm  175g Aramid/Kevlar
0.35mm  200g Diolen
0.44mm  300g Aramid/Kevlar
0.60mm  450g Carbon Fibre Cloth
0.80mm  650g Carbon Fibre Cloth

This means that for 10.1mm you could use:
1 layer of 200g cloth as the innermost and outermost layer of fabric (0.5mm total) and then 12 layers of 350g (9.6mm total).

I don't have a mandrill so intending to use a prepared sonotube cylinder, would release from this be difficult?

Using the tube as a mandel or a mould? Either way, releasing will be difficult because without a 'taper' the part will be jammed pretty tightly on wither the inside or the outside of that tube. I think it's likely that you would need to cut the tube to get the part out of it or off it so maybe plan for this in advance by doing a nice job of putting a slit straight down the tube and then sealing it back up with hot melt glue or something similar so that when you're done you can prise the join apart and then contract (or expand) the tube.

Last question, cutting carbon fiber outside in the garden, would the dust just diffuse in the wind or linger in the garden for a couple of days?

This won't really pose any risk to your garden, it might look a bit sooty for a day or so but it will soon dissipate.



Matt Statham
Easy Composites / Carbon Mods - Technical Sales

Thanks for the answers

Oh almost forgot, it will need to be UV protected, both on the inside and outside of the tube.

Is the resin UV stable or would I need to add a protective layer?

thanks,

Jan

It's UV stabilised but that's different to being 'uv proof'. For total UV stability (or as close as you can get to it) you would need to use either our GC50 Epoxy Compatible Polyester Gelcoat on your mould first or, more conventionally, apply a 2 pack polyurethane lacquer (clear coat).

Matt Statham
Easy Composites / Carbon Mods - Technical Sales

I am planning to lay the carbon on the outside of the Sonotube.

So I can easily apply the gel coat before I lay the fibers.

but

After infusion and the process having cured.

Would I be able to just brush the Gel Coat to the outside of the cured part?

Hi Jan,

I've not tested this exactly with the GC50 gelcoat but a couple of things jump out at me suggesting this would not work too well:

Firstly, the GC50 is designed for liquid epoxy to bond well to it, this is different from liquid polyester bonding well to cured epoxy (polyesters in general do not have good bonding strength themselves - GC50 works because it expolits the excellent bonding performance of epoxies).

Secondly, being a gelcoat, the GC50 is not designed to cure fully when in contact with air (i.e. the inside surface when it's been applied to a mould) and so you will have to contend with an unusual surface that would need to be rubbed off before you could start to flat it properly.

By all means give this a go but if it doesn't work (ideally on a test piece) then my suggested route would be to use our Epoxy Coating Resin to build up a few layers on the surface of your tube, then flat and polish that surface (the coating resin is very good used in this way and will stay completely clear even as it is layered over itself) and then finish the tube with a 2k lacquer or clearcoat.

I hope this helps and look forward to seeing the finished part.

Matt Statham
Easy Composites / Carbon Mods - Technical Sales

Thanks for the support, as soon as i'm ready to give this a go I will update the thread.

Any idea when that infusion compatiable spray to hold layers in place will be available.

thanks

Hi Jan,

I'll keep you posted; I don't think it will be long.

--Matt

Matt Statham
Easy Composites / Carbon Mods - Technical Sales