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Discussion in 'The Garage' started by therivermonster, Sep 22, 2012.
Dabit, your panniers look very nice BTW.
Flat Panel Layup Technique...
I have read that you can also get really nice results by applying mold release to two glass pains, lay down a nice coat of epoxy on one of the pains, lay your fabric, lay down the other glass pain on top of the wet fabric, then apply weight to the top glass pain.
Apparently this yields a nice, smooth panel.
That gives me ideas on some hard panniers.
It is a pigment made to dye polyester, vinylester and epoxy resins. But what is the maximum amount? The datasheet doesn't say much more than 'add as much as is needed'. It is also a very strong pigment; two drops in a batch of 100 grams epoxy yields black paint.
True. But then I would say that it would always suffers from orange peel. Not 9 panels no, 3 panels yes.
I used the bare, clear epoxy to make the flat panels. Later on I used a dyed epoxy to smooth out the 'wavy' surface of the cloth. I dyed it so a scratch in the paint won't immediately reveal the yellow aramid.
G-10 is just like FR-4 printed circuit board laminate, right? I use that every day
Certainly strong, but heavy also.
The side panels consist of 2 layers of glass fabric (0,5mm thickness or so), then a 3mm Depron core, and then a layer of aramid and a layer of aramid/carbon hybrid. Aramid/carbon only because that's what I had on the shelf. Total thickness around 4mm.
The bottom panel, which bears more load, has 2 Depron cores, a layer of carbon/aramid between the cores, and several holes filled with epoxy/glass to tightly interconnect the fabric layers.
The backsidepanel where the mounting resides has a 4mm plywood core instead of Depron. Heavier but far more resistant to concentrated stress around the mounting points and pressure.
The aramid on the outside provides tearing resistance, the very lightweight core increases outside dimensions which provides stiffness. The glass/depron/aramid panels weight almost nothing (45x20cm panel weights somewhat less than 80 grams), but they are pretty stiff and strong. Especially when mounted in the aluminium angle 'frame'.
Truly a composite construction made of glass, aramid, carbon, epoxy, expanded polystyrene, wood, aluminium and steel
Besides the fisheyeing I am pretty happy with the system. Long pot life is a blessing since it usually takes quite some time to lay up and saturate all the fabric for a part, and then the epoxy must still be fluid enough to press out the excess into the absorber mat when pressurizing the laminate. I have a hard time doing that in 40-60 minutes, except for a flat panel or so. The low viscosity saturates fabric quickly without bubbles or air pockets, and makes it hard to use far too much resin to begin with.
BTW: it is easy to thicken the resin, even up to peanut butter consistency. Did that for the 'glue' I used to assemble the panels into a box. It will lose it's transparency and become milky though when adding thickener, so not suitable for bare carbon finishes. But it is what I probably should have done for these panels. Thicken epoxy, apply, sand smooth.
Normally I use water only. The surface is not contaminated anyway since it is freshly cured epoxy which nobody touched with bare fingers. So all I have to deal with is possibly amine blush (which can be removed with water) and a little dust.
But if water doesn't work we all grab whatever chemical is within reach, right?
Will put a full post on them (and the composite luggage carrier) in OC when done.
I used layers of fairly thick polyethylene foil between the panels and sheets of PE on top/bottom. Epoxy doesn't stick well to PE, so no mold release is required.
I did press by stacking the panels and applying weight and C-clamps. But mind you, if you are after maximum strength, you need a LOT of pressure. Even for modest surface areas. This is the beauty of vacuum; 6-10 tons per square meter of pressure. Almost 15 pounds per square inch. And a square inch is not very much. 15 pounds on that little amount of area is, ehm, pretty much.
With this in mind: needless to say that my panel laminate is only around 40% fiber or so. Can't calculate accurately because I did not weigh the Depron in advance. But for this purpose, who cares?
The mini fairing layup popped off the plug with no trouble. Notice the PVA film on the inside of the part...
It looks good. Feels strong...
I can see how laying up in a female mold could give a very nice finish. The inside is much nicer then the outside, but it still has its problmes. Bubbles...
You can see the inside finish a little better here.
Here they are - the plug and the part. I spent a fair amount of time on that plug. Probably too much.:eek1
I trimmed the fairing up a little bit, including a fair amount of the lower part. I like the looks better this way.
I used these cutters in my Dremel from Harbor Freight Tools. They are super cheap and work very well.
Because I layed the fabric on the outside of the plug/mold, the surface finish on the outside of the part is fairly rough with the fabric printing through. Nothing a little sanding won't help.
I didn't forget the beer this time.
I sanded with 60 grit, then 220 grit to get to what you see here. It's much smoother, but doesn't look all that good.
Seeing as this is an experimental piece, I decided to get a little creative with it. Stripes!!!
Sexy. But the cf is still a bit dull.
So I put another thin layer of epoxy down and all is well.
It could look better, but I'm calling it done on this part.
We went from some pieces of foam board, to a plug, to a part. Thats the name of the game, friends!!
Thanks every one for tagging along. Now on with the next project... a muffler shroud for the DR.
I think it looks fantastic!
Can you show us on the bike how it will look?
Project #2: DR 650 Exhaust Shroud
I pulled the exhaust shroud off the DR today to prep it to make a clone out of carbon fiber. I'll make a proper mold for this part.
We'll be making a copy of the shroud pictured here. Notice I have already removed the screws in order to remove the shroud.
I hot glued the shroud to a piece of plywood. The shroud will stay glued to the plywood through the process of creating the mold.
After sanding the aluminum shroud, I shot it with a coat of high build primer.
Then I used some Bondo to fill the small gap between the edge of the part and the plywood.
Then another coat of primer.
That's all I had time for tonight, but I'll post updates as the project progresses.
This is fun stuff!!
Is that a joke, Jim?
The fairing is far to small to work on the bike. It's just a little model. More of a proof of concept really.
The real deal fairing project will come in the future.
No, I didn't catch that it wasn't full size! However, it still looks fantastic!
I can see a couple uses for it right now. A sconce in the den or garage, first comes to mind.
I didn't realize it was not full size either! It really looks great, well done.
I like the sconce idea. It would make for a great office, shop, or man cave light.
I might just give that a shot.
Thanks! It was a really great project to get me started with composites.
I feel a little more comfortable now with what to expect from the fabric and the resin. You'll see on the build for the DR 650 exhaust shroud that I'll be making a mold for that part, so we'll see how that goes. It's all a learning experience.
The CLR-HP is good for up to about 200 deg.F. with a structural load. After 200 deg. it will begin to flex. Watch for yellowing of the epoxy as a sign of heat stress, as you cycle the piece. I think you will be ok....with perhaps a little stress around the mount's ...where the metal screws connects the heat transfer to the pipe. Generally speaking, when I use any parts for muffler I use 1618, as it is good up to 250 deg.F......or in the case of header heat shields.....Max-hte.....
I have no clue how hot the dr's muffler get's.... But just be on the look out when you make parts for exhausts systems....
I have been thinking about this quite a bit, but from the temp readings that I have taken from the shroud, it looks to stay below 110 f.
I'm making a mold of the part, so if we need to go back at make another one again with different epoxy, then that's what we'll do. No worries.
Earling, could you elaborate on your epoxy rub-in process? How do you apply the epoxy, rag, sponge, brush, finger, etc? What steps do you take to apply the epoxy.
If that reading was taken with a IR thermometer, then most likely it is inaccurate, as IR pickups dont work well with shiny metal.... I use a nitrile gloved hand... dip the fingertips in the epoxy.....rub the entire area like your messaging your wife's....uhhhmmmm shoulders....Then wipe the area with a sheet of paper towel...... Do all this under a IR heat lamp,as it will cause the epoxy to thin, and easier will rub in...... I will hang a picture a bit later, of a mould that I had to fix, after it was partially destroyed during a cast.
Thanks for the quick reply, Earling! I needed it.
The mini fairing fish eyed badly, but very small fish eyes this time. Too bad cause it looked cool.
I was hesitant to put more work into this piece, but I decided that it also doubles as a piece of carbon fiber composite that can be used like a chalk board of sorts. Just erase your previous work and continue.
That's exactly what I did. I sanded all the new resin off along with the sexy new paint stripes. Then it was back to where I started after I had finished sanding yesterday. I mixed up a 15 gram batch of epoxy resin and was very surprised at what followed...
This is exactly what I did. I dipped my gloved pointer finger and middle finger just a little bit into the resin. The resin maybe covered up to the top of my fingernails on both fingers. I started to rub this resin into the sanded part and was very surprised how well it was covering. Believe it or not, I had too much resin on my fingers.
After I had rubbed the resin all over the part, I used one of those folded blue shot towles to wipe off the excess which there was plenty of.
If you are going to try any of this composite work, remember that a little resin goes a long way...
Needless to say, the newly finished part looks much better (so far), but without the sexy red stripes. If the resin doesn't fisheye this time, I would like to paint on the stripes again and spray a few coats of UV protectant clear on and call it done.
More to come soon...
Make sure your wife does not see this post as she will now surely indulge upon your fingertips necessity to massage her shoulders.... You are now a certified rubber......
50 Shades of Gray's got nothing on this.
Let me rub some epoxy on that and we'll do a little layin' up in your female mold...