Composites Ramble

(Moved out of another topic.)

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has anyone ever worked with aramid hybrid CF? @glyphiks

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Nope not me

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do you use a vacuum for your enclosures? I’ve only got experience with the FG +epoxy on a mold approach and hella sanding. I’m having trouble visualizing how to get a clean CF look with that approach.

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Nah i don’t use a vacuum. But i would like to start. @rosco or @Scepterr would have better tips than me on how to lay CF neatly

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You need to do it like a skin, and just clear epoxy over the top. Sand and clear coats till smooth.

It’s probably a lot harder than getting a good finish using a mould and vac bag though.

This is the finish on an enclosure from a vac former styrene mould. Straight from the mould.

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yeah @rosco I’ve stalked your threads pretty good on ESN; I’m so close to pulling the trigger on vacuum forming but I just don’t have the space for the set-up atm. I think I’ll order some CF off AE and try laying it manually, and if it’s total garbage I’ll see about setting up a spot to do vacuum forming. I just fell like I’m going to fuck that shit up royally and waste a bunch of spendy CF :rofl:

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Haha. @whaddys - the stalker becomes the stalked. I started by looking at all the Whitepony stuff on .builders, before I decided to build a board and start esk8. Always been part of my plan to make some stuff of my own

The vac pump setup is a bit of a cost but not crazy if you are really keen on diy and making your own stuff. Compare it to the cost of a deck or a build and it’s not much. Once you have it, there’s plenty of other uses (veneer decks, composite decks, degassing stuff). :+1:

The vac former table that I made is pretty ghetto but functional. Will find some sketches and a pic. You don’t need one of them, I just made it to try and make thermoformed plastic enclosures. I the used it to make a mould for my Hummie.

You can always make female moulds with fibreglass, like @glyphiks and many others do - and I think the results are probably actually better that way.

If you make a good mould and do a CF layup in it without a vacuum, it can still look pretty good (bloody good actually). The surface finish of the mould is critical. The vacuum just compresses layers and removes all air bubbles so the part is stronger.

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Ghetto vac former:
Copied from interwebz tutorial somewhere.

Vacuum Box with 5dia holes drilled at about 40mm ctrs. Big enough to fit a whole deck.
Seal all joints.
Made from MDF, 12mm thick top and a small internal volume)
Hole in one end for vacuum cleaner hose
Smaller barb fitting for vacuum pump hose also
Foam seal at perimeter of top

Heater for melty plastic
Big box to cover radiant bar heater
Made from 12mm MDF
Line inside with aluminium foil (spray glue)
Bottom size matches heater
Top size matches plastic
About 1m height from heater to plastic
Make a frame to hold plastic sheet on top
Take safety tip switch out of heater (don’t tell wife)
Heater on under box
Frame on top with plastic clamped in it
Sheet of 40mm EPS foam insulation on top to keep heat in and help foam melt
Leave till melty (20mins?)

Get vac forming
With table on, put melty plastic frame thing onto table and unclamped the 2 stage vacuum pump thingy.

I did a cheap 2 stage pump arrangement:
Vacuum cleaner on for first stage (Remove most air)
Vacuum pump and a 9kg has bottle stored under vacuum with line to vac former table clamped. Unclamp quickly after plastic is on table and stage 1 vacuum has worked. (To remove last bit of air and pull plastic super tight)

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can you elaborate on how the surface finish should be? I have a FG enclosure I was considering laying CF on–will it work if it’s sanded smooth but has that rough sanded texture to it? Or would I need to have a smoot clear coated surface?

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The finish of the part will exactly match the finish if the mould.

I bought a fancy polyester sanding primer for the buck i made and it was finished perfectly smooth.

A good smooth sand with high grit will be good. You will need a release layer (wax) or PVA so that the epoxy doesn’t stick to the mould.

West Systems have some good resources online about mould making etc. and prep which are pretty informative. :+1:

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awesome, thanks man, super appreciate all the detail! Now is it just one layer of CF and epoxy? How crazy would it be to lay CF ontop of the FG as one?

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Nah bro. One layer will be too flimsy, depending on the fabric.

I have used two layers CF and FG layers behind those. Reason is the CF weave can open up and you don’t want to see the white FG through gaps in the weave.

The enclosure (tests) I have made are very thin and probably not strong enough - more like a basic cover. I have done 2 layers 200gsm CF twill and then 2 or 3 layers of FG (maybe 200 or 300gsm?)

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If you make a negative mould, the CF will go down first

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IME most polyester resin sands soooo much easier than epoxy.

I feel like this thread has derailed in the best way possible :rofl:

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lmao I know, I was just thinking how I derailed the shit outta this thread; sorry not sorry :upside_down_face:

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Watercooler bro, anything goes.

Could use a title change to reflect the current situation tho @Movation :rofl:

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Can we change the title?!

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Sure can. I’m not gonna do it, but as long as it remains on point happy for you to :call_me_hand:

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Super nice find Rosco I got my last lot of CF from your link back in the news days.

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