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Sep 23, 2015, 05:48 AM
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DLG Throwing Peg / Blade - Make your own :-)


Hi,

I have been wanting to try out one of these contoured Throwing Pegs or Blades for a while and saw the Price.

I have no doubt others will mock me or show us all better ways to do the job but Hey, I made it myself and it is just perfect :-) Rigid, strong and customizable for most DLGs.

I thought, "I can make one of those!", and so I have and ended up with four :-)

The material cost is so low I just have to have the right things and off we go.
They are just Carbon Fiber and some Epoxy Resin. Ah, I hear you say, but they are molded :-)

Yes, so I molded my own and here is how. Minimal cost was important so what did I use:-

1. 12K Carbon Tow (not a lot)
2. 10g of molding Epoxy
3. 5 or 6 sheets of A4 paper
4. Some super thin CA
5. A polythene plastic bag
6. A printout - I will post that.
7. A PritStick paper adhesive
8. A piece of old Expanded polystyrene as a worktop
9. A cardboard box that held cakes
10. Some modelling pins
11. some small spring clamps
12. A sharp knife for cutting the paper
13. A Dremel to clean up the finished product (sanding paper will do)
14. A little modelling clay, putty or filler for the bottom of the 3 way junction.

All very simple and readily available stuff to a modeller.

I will post the pictures in stages and tell you what is going on.

It takes 2-3 hours to set up and then the setting time of your epoxy.

The shape comes out exactly as the paper template was set to produce. So if you want a slightly different shape you can draw a changed outline on the template and use the paper strips to follow your own shape.

So here goes this the first stage in pictures and I hope I get the stages down before too many comments come in.

Hope you like it.

Mal :-)
Last edited by Mal Bond; Sep 23, 2015 at 07:56 AM.
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Sep 23, 2015, 05:50 AM
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Getting into the Mold Creation.


Hi :-)

Have you stopped laughing yet :-)

Here is the mold creation.

Just take about 10 strips of the A4 Paper which will bend and contour easily and pin them over the template. Make sure you have a master strip on the molding surface side.

The strips follow the outside edge of the template shape so you get a 2mm gap when they are assembled.

You can pre-bend the sheets but be careful not to crease them.

You can see this being set up for both wings and the tongue below.
The U sections are easiest to practice on so do them first. Then move on to the M shape which has concave curves so more care is needed.

When you have a good alignment of each section you put super thin CA on the top and bottom edges of the strips. The top edge is easy. The bottom edge is on the polythene so take care to get the CA just on the paper and not glue the pins. The super thin CA wicks in nicely. Try not to glue the pins to the molding surface. outside has no issues.

You will find the paper stiffens up and holds the shape.
The CA will fume a lot so take care over that.

When the CA has set you can take off the section created and move on to the next.
if you have any imperfections because of pins or incomplete curves they can be easily rectified now.

That will give you the main 3 sections of the mold which we can use as often as we like.

I put more CA on the molding face and the back of the molding section to make the shape permanent.
be sure not to have runs of CA or glue your fingers.

Next :-)
Last edited by Mal Bond; Sep 23, 2015 at 08:02 AM.
Sep 23, 2015, 05:51 AM
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The mold protection


Hi,

Once you have the basic mold shape you have to set it up for pouring the epoxy resin in.

Each of the 3 sections of the mold can now be faced with a polythene strip.
The lovely thing is you can stick it on with PritStick.
You get a nice smooth surface that will reject the Epoxy Resin later.

Make sure you have 1-1.5cm of spare polythene beyond the edge of the strips.

After that I did a trial clamping to be sure you have got no major misalignment of the mold parts.

You can pin things together with spring clothes pegs that are very cheap :-)

Next :-)
Last edited by Mal Bond; Sep 23, 2015 at 07:41 AM.
Sep 23, 2015, 05:52 AM
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Then you want Carbon Fiber in the mold


Yes putting the Carbon Tow in the mold is so easy once you have marked where it goes.

You will need a 2mm packing strip all round the molding area inside the mold.
I took a thin cardboard box that held cakes.

The cardboard was just 0.5mm thick so I used my PritStick to laminate 4 layers to make my strips from.

I cut that into strips so I could make the gaps in the mold for the cavity.
While the PritStick is not dried I was able to bend and cut the strip to make the mold cavity on one side. Test fit as you go to be sure you don't have any large gaps.

The paper strips with printing have the guide lines though I did not put the end points of the cavity on the print.

Use a marking pen to mark the length of the cavity along each strip and be sure to leave 5-7mm beyond the mold cavity so you can put the Carbon Tow in place easily.

I stuck the cardboard strips into the mold with PritStick again.
It may help to leave some short air gaps in the 2mm top strips of cardboard mold spacers. Just be sure the gap is not where you want to clamp the mold.

Once the cavity is outlined with the cardboard strips you can put the carbon tow in the mold. The ends of the Tow are stuck down on some PritStick pasted in the spare areas next to the end of the mold cavity.

The two U shaped sections are easiest to practice on as the carbon tow goes nicely round the curve. I put 4 strips of 12K Tow over the area to be covered and made sure there were no nasty gaps or misalignment of the tow.

Take care not to get a lot of PritStick on your fingers when handling the Tow as it will burst all over your fingers and make sticking down much harder.

On the wavy strip I also put some PritStick in the concave curves to help align the Tow.

Once everything is in the mold I used a brush and PVA Glue to seal off the cardboard strips on the polythene and at joins.

In retrospect it would have helped to leave air gaps in the top cardboard strip to help let the air out when pouring the epoxy. But it worked any way.

Don't use very fast or thick epoxy. The one I used was runny and set in 4 hours. Not fully rigid for about 8 hours.

Next :-)
Last edited by Mal Bond; Sep 23, 2015 at 08:09 AM.
Sep 23, 2015, 05:52 AM
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Poring in the epoxy


Now you need to be leak proof and pour in the epoxy.

So I used the PVA to seal the joints that were going to come together when I closed the mold and then put some extra outside on the cardboard to ensure a good seal.

I then mated all the components and clamped them being sure the 2mm gapping was set along all the mold cavity top and bottom.

Now there will be a hole at the 3 way junction in the bottom of the mold.
That has to be blocked with a small piece of modelling clay, putty like or filler material and further protected with PVA Glue.

At the top of the 3 way junction will be your pouring hole with polythene edges sticking up.
I took some modelling clay and made sure the epoxy could not flow away along the top of the mold.
A sort of funneling to help pouring.

Only the mold cavity needs the seating, clamping and sealing. The rest is not important.
So be sure the cavity is open for poring and sealed to avoid wasting the epoxy.
Also finally check all alignments to be sure the 2mm gapping is maintained.

Now you can mix your epoxy. I was using 100 to 30 mix molding epoxy resin.
Nice and runny and not too quick to set. I had at least 1 hour when I could have poured the resin in and it did not get too gooey to pour.

Be sure to avoid air bubbles in the mold even though they can be fixed later.
I squeezed the mold cavity a few times while pouring to be sure the mold was filled and the carbon tow got well wetted.

Next :-)
Last edited by Mal Bond; Sep 23, 2015 at 07:10 AM.
Sep 23, 2015, 05:53 AM
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Opening the Mold


Hi :-)

Look what I made :-)

After about 4 or 5 hours I was able to remove the clamping.
It probably helps if you leave it overnight but I wanted to see the result.

The photos show the mold comes apart easily and the main side pieces are re-usable.
The 2mm cardboard strip is disposed off so you need to do them again for another mold.

The result is amazing for a first look.

I took the product from the mold and removed the cardboard strips and it is like magic.

A fully formed throwing peg/blade with edgings of waste material to be sanded off.

The wings and tongue are so smooth and the strength is amazing.

It just needs cutting and finishing to be a perfect 20 (with P&P) Contoured Throwing Peg/Blade.

If you accidentally got an air bubble the area in question can be filled with the same epoxy you molded with so don't fret about that. If the tow in the molded area is not fully wetted when you sand down the waste material, just put some super thin CA on it.

Next :-)
Last edited by Mal Bond; Sep 23, 2015 at 08:16 AM.
Sep 23, 2015, 05:54 AM
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Cleaning up the result


Then we have to clean up the resulting Blade.

Remember the Molds can be used again, even if you strip off the polythene covers and put new ones on.
You do have to make new 2mm cardboard strips to insert when you reload the mold and put in the Carbon Tow.

My first clean up of the molded component gave me a nice 2mm thick epoxy carbon throwing blade at 5.2g . That is the rough cut and I am sure there is at least 2g to come off that as it gets final profiling.

The shape is exactly as the paper template was set to produce. So if you want a slightly different shape you can draw a changed outline on the template and use the paper strips to follow your own shape.

I have included some images of what people do with the pegs and how to customize and fit them.
There is also a commercial one there for you to see what they look like :-) If you can tell which one :-) LOL

I love what I have produced and hope you will too.

All the best.

Mal :-)
Last edited by Mal Bond; Sep 23, 2015 at 08:19 AM.
Sep 23, 2015, 08:10 AM
Oleg Golovidov
olgol's Avatar
I nominate this for the 2nd trophy of the most complicated way to build a simple thing.

Recall that the 1st place went to Gerald for making servo covers using a vacuum cleaner, fiberglass and epoxy.
Sep 23, 2015, 08:24 AM
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Is there another way ?


Quote:
Originally Posted by olgol
I nominate this for the 2nd trophy of the most complicated way to build a simple thing.

Recall that the 1st place went to Gerald for making servo covers using a vacuum cleaner, fiberglass and epoxy.
Thanks Olgol,

I hope you found this amusing as well as practical, cheap and successful.

If anyone can produce such a complicated molded form any more simply or quicker I hope they will post it here and tell everyone, including me, how it should be done.

I certainly have a satisfactory result and it did not cost 20 to get one. Just a rainy afternoon and some stuff I had around :-)

All the best.

Mal :-)

Ps. Are you selling these yourself ? :-) LOL
Sep 23, 2015, 12:46 PM
Aurora Builder
Mal,

Have you flown one yet? I have doubts the layup will hold in pure 12K tow (glass is useless here IMO, just dead weight). That T junction is complex, and has been discussed ad-naseum before; many t-blades have snapped. I recommend wrapping your blade with kevlar thread post wing install.

Oleg,

I too am curious how you would make this part without a mold of some sort? A friend of mine is making contoured throwing blades now but CNC cut a mold to do it. Not a T-blade, a regular blade but contoured to fit your fingers like a glove. Higher drag perhaps than other solutions but worth its weight in gold when needed.
Sep 23, 2015, 01:05 PM
solastagia
kcaldwel's Avatar
The easiest way I have found to make a mould is to cut it out of foam. You can make a long strip of blade material in whatever cross section shape you want.

I just cut the peg cross section shape into a 12" long piece of foam. I use my CNC hot wire, but you could do it easily with templates as well. Cover the foam with packing tape on the mould surfaces, wax a couple of times, and lay-up with 10" wide wet-out carbon uni with a core of carbon cloth at 45 degrees - it takes more layers than you think. For a T-peg, you can put layers on all three pieces of the mould.

You don't have to put spacers in to hold the peg thickness, in fact you will get a lighter and stronger lay-up if the foam is only held apart by the carbon fibre so the excess epoxy is squeezed out to increase the fibre percentage. Throw the whole assembly in a vacuum bag. When cured, cut into 10 or 12mm wide blades. I used a wet cut tile saw with a diamond blade. A jig can make the cutting pretty quick.

These blades are of course only moulded on the inside and outside, and are constant thickness. They have to be shaped to suit.

Kevin
Last edited by kcaldwel; Sep 23, 2015 at 01:17 PM.
Sep 23, 2015, 01:08 PM
Looptastic!
sp00fman's Avatar
It might be easier to hotwire your mold out of XPS foam. I made my curved (non-T) blades that way and it is still holding up in practice. I do think you need more than just lengthwise fibers. a few layers of 0-90 or 45-45 degrees oriented cloth on the outside will hold everything together when stressed.

Personally i dont see a real benefit of the T-style pegs as long as the wingtips are strong enough and you dont mess up with a weak glue job.

Then again, i don't launch to 70 meters yet..
Sep 23, 2015, 01:25 PM
Aurora Builder
Kevin,

That's pretty much what my friends throwing blade mold looks like, just in corian instead of foam. Good reminder that I can cut disposable foam molds very quickly on the CNC
Sep 23, 2015, 01:31 PM
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This is getting interesting :-)


Quote:
Originally Posted by kcaldwel
The easiest way I have found to make a mould is to cut it out of foam. You can make a long strip of blade material in whatever cross section shape you want.

I just cut the peg cross section shape into a 12" long piece of foam. I use my CNC hot wire, but you could do it easily with templates as well. Cover the foam with packing tape on the mould surfaces, wax a couple of times, and lay-up with 10" wide wet-out carbon uni with a core of carbon cloth at 45 degrees - it takes more layers than you think. For a T-peg, you can put layers on all three pieces of the mould.

You don't have to put spacers in to hold the peg thickness, in fact you will get a lighter and stronger lay-up if the foam is only held apart by the carbon fibre so the excess epoxy is squeezed out to increase the fibre percentage. Throw the whole assembly in a vacuum bag. When cured, cut into 10 or 12mm wide blades. I used a wet cut tile saw with a diamond blade. A jig can make the cutting pretty quick.

These blades are of course only moulded on the inside and outside, and are constant thickness. They have to be shaped to suit.

Kevin
Hi Kevin :-)

This is getting interesting :-)

I thought my efforts were easy to do and did not need complex things like Vacuum Bags, CNC Machines or Hot Wire Cutting with templates.

Also we are talking a T shaped peg here so it will be interesting to see how someone made the mold and a photo or diagram would be valuable.

I have tested the ones I made with heavy weights on the end of the tongue and spun it around till I could not hold the weight with my 2 fingers. No breakage there yet.

My design has 2 layers of evenly layered 12K carbon Tow , laid uni directionally in the mold. The epoxy along with that is 2mm thick all the way through except it gets a little thicker at the 3 way junction.

I have seen the ones made from woven carbon cloth and perhaps that is better. I was thinking of buying some carbon cloth and cutting 3 strips to put in the mold.

I bet that would be fabulously strong when wetted in epoxy.

Any how I have 4 pegs now and I am not a gorilla thrower so perhaps it will never be an issue.

I do hope we get some good links, pics and diagrams here of how it should be done on my kitchen table :-) LOL

All the best.

Mal :-)
Sep 23, 2015, 02:10 PM
solastagia
kcaldwel's Avatar
I can't find any of my old T-peg moulds this morning, maybe I chucked them. I've made a crude sketch of what the foam mould would look like.

I don't use anything that weighs more than 1g installed for a peg any more. I made a bunch of T-blades, and I certainly never broke one, but others did. I tested hanging 20lbs off one side, but people still broke them.

A lot of us have hot-wire and vacuum mould equipment around, so anything short of a CNC cut mould seems pretty simple. But there is no reason you couldn't put some wood on each side of the foam and clamp it with C-clamps instead of using a vacuum bag. A little 14" hot-wire can be made easily, and use a train transformer or car battery charger, but if you like gluing paper that's up to you.

Kevin


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