Infusing magnetic strips.

General Composites Discussions Composites Talk
#1

I have a Project i will be starting in the next week. But my question is has any one infused magnetic strips into there layup.

The rason i want to use magnetic strips is because it reqires a few panels that need to be changed quicky. And are constantly being changed.

My layup shedule will probably 2 layers of twill 2x2 carbon then twill woven glass my magnetic strips (possibly 4 strips 100 -150mm apart). Then another layer of glass then carbon on the rear.

Im just abit worried it will restrict my flow of epoxy? ? Any other ideas would be great but i would want magnets in the layup tho.

#2

How big are the strips? If they’re not too wide I doubt you’ll have any problems with epoxy flow underneath. I did some extremely informal tests a year ago and I found with my 700 cps resin, a bidirectional weave I was using and a 27in hg vacuum I could put down ~1 inch strips of cardboard and with no flow issues. Bigger than that and the bottom side would be dry. Test with some small samples to get an idea of how your infusions will go

#3

Its not so much wide its more like length. As they will be hopefully no more than 10mm wide but depending the width of the part i design ther might be nearly the full width of composite panel for ease of use in a short period of time. I guess only test panels and a bit of R&D is only way to go.

Did u sandwich the the cardboard ?? Did it act like a rib and was there any kind of print through?

#4

I sandwiched the cardboard with two layers of thin fiberglass. The roughly one inch direction was directly perpendicular to the flow.

#5

Lets say my pane will be a rectangle, with longest sides verticle it my help if i lay my resin lines along the top and a quarter of the way down ?

#6

My advice is to skip the strips - the magnetic strength vs weight is very poor, and you’ve got the added penalty of a continuous void of “foreign matter” - a pocket that resin won’t likely bond to or permeate.

For panel attachment/alignment, I’d suggest small neodymium button magnets - you can get them very thin and small, and one on each end of the edge will achieve alignment as well as a strip of the other stuff.

It may simplify matters to embed the magnets after the part has been produced, so you can very precisely tune your panel alignment.

#7

you can infuse any foreign object succesfully regardless of charge but magnetic strips may lose charge. i would glue on some afterwords or bolt on.

#8

I don’t see how any part of the infusion process would interact with magnetic fields…is there something I’m unaware of??

#9

Not knowing what the panel is, or what KIND of magnet you are using, make sure the magnets are clean, and roughened. Sand them down to give a rough surface. I see no problem of infusing around them at all. However, the magnet field MIGHT repel the resin around them, so there is a large air bubble.

Well, if you are using ferrous resin :wink:

#10

Ferrous resin? Although I’m initially doubtful one exists with the composites industry you never know what secret projects are going on :tongue:

#11

bead blasting them would give them an excellent surface to adhear to, although I dont know if that would effect the magnetic field of the magnets, I wouldnt think so, but you never know untill you try.

Have you thought about wrapping the magnets in a thin layer of fibre glass around them before the carbon to reduce any risk of corrosion?

#12

How about some Bighead fasteners, which allow you to click the panel in place, or even velcro? Most panelling in luxury yachts are velcro-ed in place.

#13

Dzus fasteners are what race teams use sometimes.
I can’t see a problem with infusing with magnets though.

Take a sample magnet and poor resin on it and see what happens?

#14

actually i have been working on a project that involves making composite parts that carry a charge… fyi. it is possible and very easily feasible to make magnetic composites without affecting strength or not so much the wieght characteristics. per se.

and when i mean easy… i mean uber super easy. oh and… no magnets in the sense involved. pme me for more information as i am in the process of applying for a patent for this as well as using it in many different industrial applications.

#15

it has been tested and proven that ferrite increases the strength characteristics of composite laminates as a simple additive. it is also being developed to being a source additive to remove the micro bubbles that propogate inside the composite itself by using an electromagnetic alternating wave that vibrates the ferrite mixed resin in a manner that brings the bubble to the surface of the organic matrix so that it can be removed from the layup… thats really as much as i care to say but im sure you can draw your own ideas from the little bit ive devulged… your welcome.

#16

of course they wont lose charge in the infusion process. I meant if the magnets after time lose charge, you wont be able to get them out. I should have explained myself better :slight_smile:

#17

Tell you what. Take some magnetic ferrite and mix it in some resin. Saturate some glass with it an lay it on a piece of released plexiglass. Then lay another piece of plexiglas glass over that and smash it. You Made a test strip. Now take a magnet and lay it on the plexiglass. Let it cure and see what happens. :slight_smile: chances are you just poled that spot and when you remove the plexiglass your magnet will always go to that spot on the strip. Getting the whole panel to be magnetic is a bit more tricky. This will get you the alignment feature like you had asked for. Neodymium powder works as well but can be tricky to work with.

You need to try this.

There are tons of materials to experiment with like this. There is not need to laminate a magnet into your layup that’s the point of my stories.

Wanna know how to make carbon fiber glow in the dark!

Oh and most magnets can be recharged with a few different methods

#18

All depends on what ferrite you are using. flakes, powder, add in some CoY/Z in there… Also have to worry about filtering the additive through the fibers. We have had that problem in the past. Also, another issue is the weight added to the composite. Adding metal to the resin will make it bloody heavy. I think adding simple magnets in the laminate would be fine for now, without a major research grant :slight_smile: I can agree that sometimes adding an active layer in a composite improves strength. I just found a 2x higher tension loading just by adding ONE iron layer (not saying what of course)…even flatwise showed higher loadings…Ah research.

#19

add glow in the dark pigments? I don’t believe I didn’t save the company info that I just requested samples from. I wanted to try to make glow in the dark panels :wink:

#20

Adding your magnetic strip or any other material to your layup should not be a big deal; if you are worried about resin flow you can drill holes through the strip to increase reined flow. This also helps bond it in. You need to have a layer of glass between your carbon and the magnet or you will get galvanic corrosion. We bond in metal reinforcements, plates for radio reception etc. all the time. Anything bigger the 2 square inches will need to have holes drilled in it, bigger pieces require groves cut in them in increase flow.

As pointed out Velcro works great for panel placement.

Glow in the dark panels. Check out ALSA Corp. on the web