flyingbrick Posted September 21, 2018 Share Posted September 21, 2018 Carbon fiber does conduct electricity. It is not as good of a conductor as most metals, but if you build a structure with it, you will find that its electrical conduction can easily contribute to galvanic corrosion, by electrically connecting dissimilar metals. 1 Quote Link to comment Share on other sites More sharing options...
Popular Post Roman Posted September 25, 2018 Author Popular Post Share Posted September 25, 2018 Made a 3 piece mould so i could get a full bellmouth lip going on. Turned out ok but I will buy some more carbon sleeve in the next size up so the bell can be made from the sleeve too. Will be much nicer as well as easier to make! Getting a little better though as this is the fiddliest / smallest complex shape ive made so far and turned out not too bad. I used a 0.8mm gap between mould halves but will try 0.5 next as there were still some areas with too much epoxy. 11 Quote Link to comment Share on other sites More sharing options...
kyteler Posted September 25, 2018 Share Posted September 25, 2018 So what's the plan there? Make them all up then slice the sides to fit them together, then enclosure or open? Quote Link to comment Share on other sites More sharing options...
Roman Posted September 25, 2018 Author Share Posted September 25, 2018 Yeah make a jig so i can trim each side accurately. Will be enclosed in an airbox eventually. Gonna make a flowbench so i can test a few different schemes. 2 Quote Link to comment Share on other sites More sharing options...
flyingbrick Posted September 25, 2018 Share Posted September 25, 2018 That looks amazing man.. super professional. Big units too! Could sell them to honda guys for putting into their bumpers for cold air lol Quote Link to comment Share on other sites More sharing options...
Roman Posted September 25, 2018 Author Share Posted September 25, 2018 The bellmouth I made previously for a 3" inlet pipe with same geometry is bloody huge hahaha. Cant wait to get flowbench setup and do some nerding with it. Quote Link to comment Share on other sites More sharing options...
Popular Post mjrstar Posted November 30, 2018 Popular Post Share Posted November 30, 2018 This thread has inspired me to dip my toe into the world of composites.. (please don't use any of the below as advise just observations from a noob) First attempt on a headlight mould to make more headlightly type things for my pos racecar.. no idea if I'm doing it right.. or if it will release properly.. if it does the next step will be to use the mould to produce a headlight blank. If it doesn't I'll need to figure out why and try again. . Made an edge barrier out of junk, cleaned sanded, cleaned etc.. Laid down 7 coats of wax -/ mould release. 2 coats of PVA. 1 coat of moulding Gel coat, next time I will use a bit less than 2% catalyst as even on a small thing like this I ended up in a hurry. 2 layers of 200g cloth. 2 layers of 225 chopped strand 1 layer 450g chopped strand. (No idea if that will be strong enough) What I noted is that working the cloth required scissors to get it to shape nicely whereas the chopped strand behaved better when pulled apart.. When the mat wasn't behaving more resin seemed to help. The little roller thing I purchased isn't much good dabbing with a brush was the successful method. Be prepared to go through a fair few brushes and mixing cups etc and set up a covered area on your workbench. And use disposable gloves etc... It's hard to tell if you are pushing the first layer of mat through the gel coat- I reckon the inside may have signs of this if I get to split the part open. If it turns to shit I will delete this post and deny having done any fibreglass work.. 9 1 Quote Link to comment Share on other sites More sharing options...
Roman Posted November 30, 2018 Author Share Posted November 30, 2018 Awesome look forward to seeing results! Inspiring me to do some more stuff too have been lazy. Man one of the best things I've bought is a super sharp set of sewing scissors. Good snips makes a huge difference. Quote Link to comment Share on other sites More sharing options...
mjrstar Posted November 30, 2018 Share Posted November 30, 2018 Impatient much.. anyway I decided to get in to it because I wanted a bit of flex to the the light out before the resin had 100% cured, but moreso so i can sleep tonight, lack of draft angle and semi keyed in angle in a couple of places meant it could have been touch and go. surface finish has some light lines from brushing on the pva and a small bubble at the point of the light which is covered by the bumper so no problem. Released easily... I'm calling that a win for a first attempt, hopefully I can now make a usable part! Will have a think about how much of the edge to trim up. 9 Quote Link to comment Share on other sites More sharing options...
Roman Posted December 2, 2018 Author Share Posted December 2, 2018 Yeah i find not a nice finish with pva. Well its ok but not shiny straight out of mould like you might get from super polished + wax. But thats risky. Awesome result! Quote Link to comment Share on other sites More sharing options...
flyingbrick Posted December 2, 2018 Share Posted December 2, 2018 I have seen people getting a good finish with PVA. Unsure if they are maybe thinning it somehow before spraying? I find it always dries to a satin finish no matter what I try. You cant wax too much. Quote Link to comment Share on other sites More sharing options...
sentra Posted December 3, 2018 Share Posted December 3, 2018 Pva belongs in the rubbish bin 4 Quote Link to comment Share on other sites More sharing options...
mjrstar Posted December 4, 2018 Share Posted December 4, 2018 22 hours ago, sentra said: Pva belongs in the rubbish bin Please tell me there is something in a spray can I should be using instead of PVA. 1 Quote Link to comment Share on other sites More sharing options...
flyingbrick Posted December 4, 2018 Share Posted December 4, 2018 There are spray on waxes and release agents. I saw one on the shelf at the fiberglass shop in hamilton. Pretty sure they are wax. Quote Link to comment Share on other sites More sharing options...
mjrstar Posted December 7, 2018 Share Posted December 7, 2018 Had to fight for over an hour to get the second light out of the l/h mould. I was willing to sacrifice my $20 light to save the mould. Below is the remains of the light. Also my aliexpress carbor fibre turned up today, man you have to be careful not to open up the weave! Will find out if I have managed to make a thing or if I have wasted a bunch of time and have zero to show for it. this is just 2 layers of cf and budget polyester resin. It went off a bit too quick for my liking probably because it was pretty hot in my shed this afternoon.. I'm pretty confident it won't be great on the finished side but may be salvageable. 6 Quote Link to comment Share on other sites More sharing options...
mjrstar Posted December 7, 2018 Share Posted December 7, 2018 Certainly not perfect, a couple of bubbles on the surface, and spots at the edge where the resin didn't fill right out, but the weave underneath looks better than I anticipated. 8 Quote Link to comment Share on other sites More sharing options...
flyingbrick Posted December 7, 2018 Share Posted December 7, 2018 That is extremely impressive. Just drip some resin into those voids, sand smooth then give the whole lot a coat in straight resin. If its anything like my epoxy it will level out and go crystal clear and smooth as glass Quote Link to comment Share on other sites More sharing options...
chasinthemirage Posted December 7, 2018 Share Posted December 7, 2018 Hey dudes, I've had a read through this thread but am still a bit unclear on the best way for me to go about what I am trying to do. I'm in the process of shaping a comb raiser for the stock of my rifle to bring my line of sight up to where the new optic is mounted. I am currently using high density foam to shape a template, once this is finished what would you guys recommend as the next step? Do I need to go to the trouble of making a female mold from the template and then fibreglassing this or will a couple of coats of reinforced filler/bog over the foam be sufficient? It needs to be fairly sturdy as at some point its likely to get dropped but weight isn't too much of an issue and neither is the ability to make another as this is likely to be the only rifle of this type I build for awhile. Quote Link to comment Share on other sites More sharing options...
Popular Post mjrstar Posted December 8, 2018 Popular Post Share Posted December 8, 2018 Sanded and polished, finish is a little better but not amazing, the voids are flat now but did leave a visible bubble under the surface for some reason. I think could in part be the difference between cheap polyester resin which is not doing a great job of self levelling when compared to proper epoxy, and leaves a slightly dull finish. Did at least get rid of the pva streaks. Went from 600 wet sanding to polish because I didn't have any 1200. If it turns to crap down the track I will spray on some 2 pot clear. 10 Quote Link to comment Share on other sites More sharing options...
flyingbrick Posted December 8, 2018 Share Posted December 8, 2018 22 hours ago, chasinthemirage said: Hey dudes, I've had a read through this thread but am still a bit unclear on the best way for me to go about what I am trying to do. I'm in the process of shaping a comb raiser for the stock of my rifle to bring my line of sight up to where the new optic is mounted. I am currently using high density foam to shape a template, once this is finished what would you guys recommend as the next step? Do I need to go to the trouble of making a female mold from the template and then fibreglassing this or will a couple of coats of reinforced filler/bog over the foam be sufficient? It needs to be fairly sturdy as at some point its likely to get dropped but weight isn't too much of an issue and neither is the ability to make another as this is likely to be the only rifle of this type I build for awhile. I know a guy that makes very cheap adjustable cheek rests. I have one here i could get photos of if ya want. Quote Link to comment Share on other sites More sharing options...
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