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Author: Subject: Carbon Fibre - Making It Tidy
bi22le

posted on 1/6/16 at 08:18 PM Reply With Quote
I habe just watched the easycomposite how to guides.

My god that looks like a lot of hard work. The chances of me being able.to make a buck, to make mold to then layup and make a part properly are slim. I would say Im good with practical things but it looks tough.

So, i may give it a go and therefore have some questions!

In the vid they have a dedicated oven with timer and vac line, i assume making one of these will be hard work at home?

Also the pump is specialist as previously discussed on this thread. I bet they are expensive and see non second hand on ebay. What are my options?





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twybrow

posted on 1/6/16 at 11:17 PM Reply With Quote
Smudger - that orange part could be made by any of the processes discussed. Wet lay, wet lay and vacuum, resin infusion or prepreg. If you have the tool, it isn't much work to have a crack at a part, post the results and we can help with any problem areas. The joy of composites is for these sorts of parts, they are very repairable should you make a pigs ear of it.

I agree with Nev that consumables can add up, and infusion uses a little more than just bagging, but when you get your technique sorted, it is a great process to do at home. Vac pumps can be had on ebay for £50 (or make one from an old fridge!). Just remember to wear PPE, and take your time.

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ceebmoj

posted on 1/6/16 at 11:37 PM Reply With Quote
I'm central stockport if you fancy having a look at what I have been up to. Which is a combination of wet lay up and resin infusion carbon bits.
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SmudgerEBT

posted on 2/6/16 at 07:30 AM Reply With Quote
quote:
Originally posted by ceebmoj
I'm central stockport if you fancy having a look at what I have been up to. Which is a combination of wet lay up and resin infusion carbon bits.


Thats a nice offer of which I will take you up on that!

Just up the A6 in Hazel Grove.

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SmudgerEBT

posted on 2/6/16 at 07:33 AM Reply With Quote
quote:
Originally posted by twybrow
Smudger - that orange part could be made by any of the processes discussed. Wet lay, wet lay and vacuum, resin infusion or prepreg. If you have the tool, it isn't much work to have a crack at a part, post the results and we can help with any problem areas. The joy of composites is for these sorts of parts, they are very repairable should you make a pigs ear of it.

I agree with Nev that consumables can add up, and infusion uses a little more than just bagging, but when you get your technique sorted, it is a great process to do at home. Vac pumps can be had on ebay for £50 (or make one from an old fridge!). Just remember to wear PPE, and take your time.


Am thinking vacuum even if it with wet layup (rather than infusion unless I can see it being easier in the long run) which means epoxy?

So when you say vac pumps on ebay for £50, which ones? Have read the the old fridge ones contain oil? Is that right? Also would need a catch can for the excess resin, is it better to buy one of them from easy (for instance) then gamble on an ebay special?

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Neville Jones

posted on 2/6/16 at 09:05 AM Reply With Quote
There's a point which needs to be made, and it's usually taught on the very first day.

In any sort of composite work, from poly resin and csm, to carbon and the latest high spec fibres, and the point is that any corners need as big a radius as possible. Whether the corner is inside or out, the fibres don't like to bend. At least not without a lot of help.

In the clave we get corner radii down to 2mm by using intensifiers, but for anything else, the limit seems to be about 8mm for inside, maybe 5~6mm at a push.

As for resins, we use a lot of vinylester for marine work, and some car stuff. It's a good halfway on costs and strength, and different hardeners can be had to push out gel times, and some that only react with higher temps, making working times a lot more sensible.

And for the man in his garage, resin infusion is not a cheap option. You'll most likely throw away everything that comes into contact with the resin, unless you buy the silicone diffusers and hoses and special fittings, and a lot of mek to clean what is disconnectable after the resin is input, with.

Nev

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twybrow

posted on 2/6/16 at 07:34 PM Reply With Quote
quote:
Originally posted by SmudgerEBT
quote:
Originally posted by twybrow
Smudger - that orange part could be made by any of the processes discussed. Wet lay, wet lay and vacuum, resin infusion or prepreg. If you have the tool, it isn't much work to have a crack at a part, post the results and we can help with any problem areas. The joy of composites is for these sorts of parts, they are very repairable should you make a pigs ear of it.

I agree with Nev that consumables can add up, and infusion uses a little more than just bagging, but when you get your technique sorted, it is a great process to do at home. Vac pumps can be had on ebay for £50 (or make one from an old fridge!). Just remember to wear PPE, and take your time.


Am thinking vacuum even if it with wet layup (rather than infusion unless I can see it being easier in the long run) which means epoxy?

So when you say vac pumps on ebay for £50, which ones? Have read the the old fridge ones contain oil? Is that right? Also would need a catch can for the excess resin, is it better to buy one of them from easy (for instance) then gamble on an ebay special?


Single Stage 2.5CFM 1/4HP Rotary Vane Deep Vacuum Pump 180W 1/4HP

These are the same as easy composites sell. A catch pot can be made very simply with any sort of sealed tub that you can fix pipes in via the lid. A roll of tacky tape to sesl it uo and off you go. The pvc hose costs peanuts as does spiral wrap (and yes, they are consumables) so not really sure why Nev thinks it is all so costly. You could be fully setup for £100 and never have to expose yourself to resins, which is a plus imho.

Nev see my earlier point re the radius - fully agree with your numbers. Better to sort it than bidge a sharp edge.

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SmudgerEBT

posted on 3/6/16 at 08:19 AM Reply With Quote
The hunt is on for cheapness!

Going for release wax rather than pva as well.

Glasplies seem nice and cheap for things.

Moulds: Now thinking tissue, csm, woven and then tissue to keep it tidy?

Or go with the uni-mould kit from Easy?

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Vmax1974

posted on 3/6/16 at 08:29 AM Reply With Quote
quote:
Originally posted by SmudgerEBT
The hunt is on for cheapness!

Going for release wax rather than pva as well.

Glasplies seem nice and cheap for things.

Moulds: Now thinking tissue, csm, woven and then tissue to keep it tidy?

Or go with the uni-mould kit from Easy?


For moulds just keep is simple i use

Tooling gel
6x 450g csm
Braced approapriatly with bits of wool or steel or ally whatever is laying about and will do the job

Leave it to harden for a week
20 coats of wax applied 1 hour apart
Gelcoat
100g csm resin
Pull and bin

The mould will be then ready to use

Never used the unimould system but it looks like an easier alternative






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SmudgerEBT

posted on 3/6/16 at 08:44 AM Reply With Quote
Easier (and I do like green) but more expensive.

Suppose have to look at time/cost ratio.

The less time spent messing with resins and csm the better.

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Neville Jones

posted on 3/6/16 at 12:54 PM Reply With Quote
The reason I see infusion as costly is that you are having to throw away tubes and fittings that get resin in them. If you can disconnect at least the tubes and clean them, then that's a cost saved, but at the added cost of solvents to clean them. Goes in roundabouts. Then there's the exposure to the solvents to deal with, and dispose of.

The proper silicone infusion pads aren't cheap but a one-off setup cost.

As for exposing to resin......the health and safety stuff about epoxies is endless. The epoxy hardeners are among the worst carcinogens known to man. Don't say you weren't warned in twenty years time! So it's big gloves and respirators when mixing the resin. At the local place I mentioned, it's rare for employees being there more than a year and not developing skin conditions, even if they don't go close to the raw materials.

H&S about poly and vinyl esters is a very small number of sheets,(mainly don't drink it or spread it on bare skin!) compared to the volumes about epoxies and phenolics.

I don't want to continue this, those who think infusion is the best thing since a factory bread slicer, will keep arguing the pro's. I know that it is a practice that has been tried around here and promptly dropped. The reason it's not used here is the type of work being done, and demanding standards the work has to be inspected to. I've never seen an infused part pass ultrasonic testing for uniformity of thickness and resin content. Without knowing the infusion points, you can see them plain as dogs danglies on a cat, on the screen, as the sonic head is passed over them, when a large car bonnet is tested. That's enough proof for me.

The same bonnet hand laminated wet then bagged, showed none of the prominent points. The only proviso in all this, is that the wet layup needs to be done by properly experienced workers, who are meticulous. A bad wet layup can be worse than a badly infused part, it comes down to skill and care of the operators involved. Autoclaved prepreg shows up as near to perfect as can be achieved.

Infusion has it's place, as I put a few posts ago, with cheap and quick parts. I wouldn't waste good carbon or expensive fibres on infusion though.

I really don't want to continue this. I've got my opinions, formed from nearly fifty years of messing with fibres and resins or all types, the i'net experts have theirs. And like backsides, mine smells like roses, and yours stink!

Cheers,
Nev.

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twybrow

posted on 3/6/16 at 01:56 PM Reply With Quote
quote:
Originally posted by Neville Jones
The reason I see infusion as costly is that you are having to throw away tubes and fittings that get resin in them. If you can disconnect at least the tubes and clean them, then that's a cost saved, but at the added cost of solvents to clean them. Goes in roundabouts. Then there's the exposure to the solvents to deal with, and dispose of.

The proper silicone infusion pads aren't cheap but a one-off setup cost.

As for exposing to resin......the health and safety stuff about epoxies is endless. The epoxy hardeners are among the worst carcinogens known to man. Don't say you weren't warned in twenty years time! So it's big gloves and respirators when mixing the resin. At the local place I mentioned, it's rare for employees being there more than a year and not developing skin conditions, even if they don't go close to the raw materials.

H&S about poly and vinyl esters is a very small number of sheets,(mainly don't drink it or spread it on bare skin!) compared to the volumes about epoxies and phenolics.

I don't want to continue this, those who think infusion is the best thing since a factory bread slicer, will keep arguing the pro's. I know that it is a practice that has been tried around here and promptly dropped. The reason it's not used here is the type of work being done, and demanding standards the work has to be inspected to. I've never seen an infused part pass ultrasonic testing for uniformity of thickness and resin content. Without knowing the infusion points, you can see them plain as dogs danglies on a cat, on the screen, as the sonic head is passed over them, when a large car bonnet is tested. That's enough proof for me.

The same bonnet hand laminated wet then bagged, showed none of the prominent points. The only proviso in all this, is that the wet layup needs to be done by properly experienced workers, who are meticulous. A bad wet layup can be worse than a badly infused part, it comes down to skill and care of the operators involved. Autoclaved prepreg shows up as near to perfect as can be achieved.

Infusion has it's place, as I put a few posts ago, with cheap and quick parts. I wouldn't waste good carbon or expensive fibres on infusion though.

I really don't want to continue this. I've got my opinions, formed from nearly fifty years of messing with fibres and resins or all types, the i'net experts have theirs. And like backsides, mine smells like roses, and yours stink!

Cheers,
Nev.


So the infused primary structures on aircraft are clearly flying in the face of convention then Nev! I can assure you, it can be made well, and pass NDT. I am not saying it is the only process, far from it, just that it has its place, and can be great at home. There is a chap on here who has made some beautiful parts with infusion. For the applications being discussed, who cares if it has porosity/voidage, these are not structural parts!

If you comment about iNet experts is aimed at me, feel free to do your research first.

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Neville Jones

posted on 3/6/16 at 02:06 PM Reply With Quote
quote:
Originally posted by twybrow
.......
So the infused primary structures on aircraft are clearly flying in the face of convention then Nev! I can assure you, it can be made well, and pass NDT. I am not saying it is the only process, far from it, just that it has its place, and can be great at home. There is a chap on here who has made some beautiful parts with infusion. For the applications being discussed, who cares if it has porosity/voidage, these are not structural parts!

If you comment about iNet experts is aimed at me, feel free to do your research first.


The comment isn't aimed at you, so don't get all in a tizzy, but mainly at the Youtube 'how easy is it..' videos.

I'm intrigued to know what stressed 'primary structures' you refer to???? All that I encounter are prepreg and claved.

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SmudgerEBT

posted on 3/6/16 at 03:49 PM Reply With Quote
A thing for me is I can't do the 2k top coat myself, so would have to farm that out.

Happy to go with wet vacuum, but needs to be uv stable straight from the mould, otherwise its just another cost.

And for me its always informative to read as many points of view as possible, especially from those who are working within the industry and may/will have ways of working.

Hence me asking about ways of making tidy carbon fibre.

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twybrow

posted on 3/6/16 at 10:29 PM Reply With Quote
quote:
Originally posted by Neville Jones
quote:
Originally posted by twybrow
.......
So the infused primary structures on aircraft are clearly flying in the face of convention then Nev! I can assure you, it can be made well, and pass NDT. I am not saying it is the only process, far from it, just that it has its place, and can be great at home. There is a chap on here who has made some beautiful parts with infusion. For the applications being discussed, who cares if it has porosity/voidage, these are not structural parts!

If you comment about iNet experts is aimed at me, feel free to do your research first.


The comment isn't aimed at you, so don't get all in a tizzy, but mainly at the Youtube 'how easy is it..' videos.

I'm intrigued to know what stressed 'primary structures' you refer to???? All that I encounter are prepreg and claved.


Fair enough, I thought it was aimed at me.

The Bombardier C-series has infused wings, and we have just done another large passenger aircraft wings, but it hasn't been publicised yet. Airbus and Boeing are moving this way in a big way - infusion has come a long way! Agrees it isn't easy, but i would say more accessible at home than a lot of people think.

Cheers Nev - I bet we have met at some point, the composites world is still.small enough that most of us know each other!

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Neville Jones

posted on 4/6/16 at 02:41 PM Reply With Quote
Airbus and Boeing? They're having enough problems getting weights down with prepreg. They'll never do it and achieve integrity, using infusion. It's been tried at the locals who make flight surfaces for Boeing and Airbus, without much joy, and for the reasons previously mentioned. The Boeing inspectors are particularly fastidious priks!

I'll avoid Bombardier aircraft in future, thanks for the heads up.

And before someone mentions home build amateur aircraft, I am well aware of how some of the modern machines are built, and also how often they fall out of the sky. Two here in the last six weeks, but no mentions on the news.

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Carbon fibre works

posted on 5/6/16 at 07:16 AM Reply With Quote
quote:
Originally posted by SmudgerEBT
So I need to do some side vents (mid-mounted with rads in the back as no room in the front), I have a basic mould (which I need to reinforce and add layers too) which I will use to make a wet layup part (whilst it would be nice to do vacuum resin infusion its not worth the outlay for a handful of parts) probably using epoxy clear coat.

Now it has 3 lots of right angle, getting the cloth into those corners will be difficult without distorting the cloth and probably the odd void.

So my idea is to run black (or maybe green/orange) gel coat with a width of 5mm around the edges and into the corners, this means the carbon fibre can be cut into a sheet (3 pieces) and as long as time is spent getting it to line up, should be easier.

But will it just look cheap part finished with the gel coat strips and with that in mind is it worth investing into vacuum resin infusion and get that to force the carbon into the edges?

My car is Green, would it be to much to do the parts in Green Carbon?


You could wet lay and vac bag but if you want a high standard of finish you will have some work to do when you de mould, just a note on so called coloured carbon (carbon is black) weave distortion when lay up can be a major issue plus no matter what the fabric looks like dry it can darken considerably when wetted out with resin.
Regards Chris
Carbon fibre works LTD
carbonfibreworks@aol.com

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