fibreglassing - uni project
Discussion
hi guys,
probably not in the right section so any mod's please move wherever's best!
I'm doing a BA in Product Design, and for my major project I've gotta make a scuba helmet.
the helmet is made in 2 parts, a neoprene hood covering the whole head, and a plastic part which doesnt cover the top of ones head.
I've got to make a life size working prototype and am thinking fibreglassing is my best bet for making the plastic part.
The problem is, none of the workshop technicians are experienced using fibreglass. (I've never used it either)
I'm going to make a mould out of wood, and lay the fibreglass over it?
Do i need to seal the wood? I only want the part 2mm thick, so how many layers of fibreglass would i need?
the other thing is, i need the part to be smooth all over, how hard is it going to be to sand it to get it completly smooth? can one acheive a perfectly smooth finish?
Thanks in advance!
probably not in the right section so any mod's please move wherever's best!
I'm doing a BA in Product Design, and for my major project I've gotta make a scuba helmet.
the helmet is made in 2 parts, a neoprene hood covering the whole head, and a plastic part which doesnt cover the top of ones head.
I've got to make a life size working prototype and am thinking fibreglassing is my best bet for making the plastic part.
The problem is, none of the workshop technicians are experienced using fibreglass. (I've never used it either)
I'm going to make a mould out of wood, and lay the fibreglass over it?
Do i need to seal the wood? I only want the part 2mm thick, so how many layers of fibreglass would i need?
the other thing is, i need the part to be smooth all over, how hard is it going to be to sand it to get it completly smooth? can one acheive a perfectly smooth finish?
Thanks in advance!
Your best posting this in the TVR forum 
Luckily, as a TVR owner, I am well versed in fibreglass usage.
It's very simple to work with, if not slightly messy. Basically imagine it as paper machie and your halfway there.
Mix up your resin with the hardener, you don't need much hardener, but the more you use the quicker it set's, so rather too little than too much.
Cut the matting into 4 by 2 cm strips. Place it on the area your fibre glassing and basically paint the resin on top. You shouldn't need to prepare the wood but I've never had to fibreglass wood. Then just keep putting strips on and painting on more resin. The matting is what gives it the structural strength so don't be modest with it. The matting will absorb the resin so make sure to paint loads on.
It takes about 12 to 24 hours to fully cure, then just attack it with sandpaper, starting with 80 grade and working up.
HTH
Luckily, as a TVR owner, I am well versed in fibreglass usage.
It's very simple to work with, if not slightly messy. Basically imagine it as paper machie and your halfway there.
Mix up your resin with the hardener, you don't need much hardener, but the more you use the quicker it set's, so rather too little than too much.
Cut the matting into 4 by 2 cm strips. Place it on the area your fibre glassing and basically paint the resin on top. You shouldn't need to prepare the wood but I've never had to fibreglass wood. Then just keep putting strips on and painting on more resin. The matting is what gives it the structural strength so don't be modest with it. The matting will absorb the resin so make sure to paint loads on.
It takes about 12 to 24 hours to fully cure, then just attack it with sandpaper, starting with 80 grade and working up.
HTH
This all depends how much of a good job you want to do...
What you would do if you were doing a proper job is to make a full size model of what you want the finished thing to look like...
Polish it up, add on a release agent and gell coat and lay choppedstrand matting on top with resin... once its set peel it off your plug (model)... you now have a mold from which to cast your finished part...
Polish up the mold and layup the fibreglass in it...
IMHO.. your local library should have some good books on the subject, and youtube has some good tutorial videos...
I suggest you use Polyester resin and medium weight chopped strand mat...
cfsnet sells good quality stuff.. DO NOT be tempted to use the tat from halfords..its a nightmare to work with!
What you would do if you were doing a proper job is to make a full size model of what you want the finished thing to look like...
Polish it up, add on a release agent and gell coat and lay choppedstrand matting on top with resin... once its set peel it off your plug (model)... you now have a mold from which to cast your finished part...
Polish up the mold and layup the fibreglass in it...
IMHO.. your local library should have some good books on the subject, and youtube has some good tutorial videos...
I suggest you use Polyester resin and medium weight chopped strand mat...
cfsnet sells good quality stuff.. DO NOT be tempted to use the tat from halfords..its a nightmare to work with!
tegwin said:
This all depends how much of a good job you want to do...
What you would do if you were doing a proper job is to make a full size model of what you want the finished thing to look like...
Polish it up, add on a release agent and gell coat and lay choppedstrand matting on top with resin... once its set peel it off your plug (model)... you now have a mold from which to cast your finished part...
Polish up the mold and layup the fibreglass in it...
IMHO.. your local library should have some good books on the subject, and youtube has some good tutorial videos...
I suggest you use Polyester resin and medium weight chopped strand mat...
cfsnet sells good quality stuff.. DO NOT be tempted to use the tat from halfords..its a nightmare to work with!
What he said.What you would do if you were doing a proper job is to make a full size model of what you want the finished thing to look like...
Polish it up, add on a release agent and gell coat and lay choppedstrand matting on top with resin... once its set peel it off your plug (model)... you now have a mold from which to cast your finished part...
Polish up the mold and layup the fibreglass in it...
IMHO.. your local library should have some good books on the subject, and youtube has some good tutorial videos...
I suggest you use Polyester resin and medium weight chopped strand mat...
cfsnet sells good quality stuff.. DO NOT be tempted to use the tat from halfords..its a nightmare to work with!
tegwin said:
This all depends how much of a good job you want to do...
What you would do if you were doing a proper job is to make a full size model of what you want the finished thing to look like...
Polish it up, add on a release agent and gell coat and lay choppedstrand matting on top with resin... once its set peel it off your plug (model)... you now have a mold from which to cast your finished part...
Polish up the mold and layup the fibreglass in it...
IMHO.. your local library should have some good books on the subject, and youtube has some good tutorial videos...
I suggest you use Polyester resin and medium weight chopped strand mat...
cfsnet sells good quality stuff.. DO NOT be tempted to use the tat from halfords..its a nightmare to work with!
What you would do if you were doing a proper job is to make a full size model of what you want the finished thing to look like...
Polish it up, add on a release agent and gell coat and lay choppedstrand matting on top with resin... once its set peel it off your plug (model)... you now have a mold from which to cast your finished part...
Polish up the mold and layup the fibreglass in it...
IMHO.. your local library should have some good books on the subject, and youtube has some good tutorial videos...
I suggest you use Polyester resin and medium weight chopped strand mat...
cfsnet sells good quality stuff.. DO NOT be tempted to use the tat from halfords..its a nightmare to work with!
I need to make the thing look real, so it needs to be a damn good job!
thanks mate, so i make a wooden plug, polish it etc, then fibreglass over that, polish that fibreglassed "mould" and then lay fibre glass into that to make the final part?
is it possible just to skip the middle step and make the finished part straight from my wooden "plug" (sorry if im getting the jargon mixed up)
is it possible to acheive a perfectly smooth finish on both sides? i understand that the side against the "plug" comes out smoothest, but the other side pretty rough?
just looked on cfsnet, thanks for that recomendation mate!
thanks again guys!
rhys27 said:
tegwin said:
This all depends how much of a good job you want to do...
What you would do if you were doing a proper job is to make a full size model of what you want the finished thing to look like...
Polish it up, add on a release agent and gell coat and lay choppedstrand matting on top with resin... once its set peel it off your plug (model)... you now have a mold from which to cast your finished part...
Polish up the mold and layup the fibreglass in it...
IMHO.. your local library should have some good books on the subject, and youtube has some good tutorial videos...
I suggest you use Polyester resin and medium weight chopped strand mat...
cfsnet sells good quality stuff.. DO NOT be tempted to use the tat from halfords..its a nightmare to work with!
What you would do if you were doing a proper job is to make a full size model of what you want the finished thing to look like...
Polish it up, add on a release agent and gell coat and lay choppedstrand matting on top with resin... once its set peel it off your plug (model)... you now have a mold from which to cast your finished part...
Polish up the mold and layup the fibreglass in it...
IMHO.. your local library should have some good books on the subject, and youtube has some good tutorial videos...
I suggest you use Polyester resin and medium weight chopped strand mat...
cfsnet sells good quality stuff.. DO NOT be tempted to use the tat from halfords..its a nightmare to work with!
I need to make the thing look real, so it needs to be a damn good job!
thanks mate, so i make a wooden plug, polish it etc, then fibreglass over that, polish that fibreglassed "mould" and then lay fibre glass into that to make the final part?
is it possible just to skip the middle step and make the finished part straight from my wooden "plug" (sorry if im getting the jargon mixed up)
is it possible to acheive a perfectly smooth finish on both sides? i understand that the side against the "plug" comes out smoothest, but the other side pretty rough?
just looked on cfsnet, thanks for that recomendation mate!
thanks again guys!
I wouldn't try skipping steps - the time taken to make another moulding (or mould, then moulding from mould) is insignificant compared to the time taken to make the initial shape. As you can see my mould was made from foam and plaster, which was then coated in reface and polished to give a good finish.
The reverse side of my fibreglass parts were filled with car body filler and sanded with an orbital sander. It didn't take as long as I expected to get a good finish.
awesome, cheers guys, well im planning on adding a flexible additive to the resin, and the design of it will allow me to take it off the plug.
The thing im confused with is why does one make a plug, then make a fibreglass mould from that, and then make the real thing from the fibreglass mould?
surely it would be simpler to make the real thing straight off the orginial wooden plug? am i missing something?
love the speakers mate! top job!
The thing im confused with is why does one make a plug, then make a fibreglass mould from that, and then make the real thing from the fibreglass mould?
surely it would be simpler to make the real thing straight off the orginial wooden plug? am i missing something?
love the speakers mate! top job!
rhys27 said:
awesome, cheers guys, well im planning on adding a flexible additive to the resin, and the design of it will allow me to take it off the plug.
The thing im confused with is why does one make a plug, then make a fibreglass mould from that, and then make the real thing from the fibreglass mould?
surely it would be simpler to make the real thing straight off the orginial wooden plug? am i missing something?
love the speakers mate! top job!
Depending on what you are making you'll end up with the smoothest surface on the inside. Lay up straight off the buck but that would have to be the reverse of your final product. It's generally easier to create an accurate buck, take a moulding off that (which will be correct reverse image) and use that to create your final piece. That way you know that if your original piece is correct then your final one should have the same dimensions. The thing im confused with is why does one make a plug, then make a fibreglass mould from that, and then make the real thing from the fibreglass mould?
surely it would be simpler to make the real thing straight off the orginial wooden plug? am i missing something?
love the speakers mate! top job!
It's a bit tricky without some drawings, if you could post some up that would help. If I were you I would steer well clear of CSM (chopped strand mat) as it's the devil's spawn. Use some weave instead, and if you need it to go round corners use twill weave, not plain weave, you'll be amazed what it will go round. Of course, if you are using twill weave glass, you could actually be using twill weave carbon, and it's quite easy to get a "porn star" carbon finish on that with the use of some colloidal silica on a last very thin coat of epoxy, some careful wet/dry sanding and some 2 pack varnish.
Also consider vac bagging, basically you put your finished still wet item in a plastic bag covered with some other goodies like peel ply, bread wrap and bleed cloth, and connect it to a vacuum pump. The vacuum compresses your layup onto your mould or whatever it is and means you have to do very little finishing and fairing afterwards.
Some useful resources to Google are the tech pages on the West System website, and a good source of supplies is Wiz at Matrix Mouldings (now MCMC I think).
Also, I assume that this helmet is for protection...as well as avoiding CSM avoid polyester resins. A well consolidated (ie no voids, cloth properly "wet out") layup using epoxy on glass or carbon weave will be much, much stronger than polyester on CSM, and also a shed load lighter.
Also consider vac bagging, basically you put your finished still wet item in a plastic bag covered with some other goodies like peel ply, bread wrap and bleed cloth, and connect it to a vacuum pump. The vacuum compresses your layup onto your mould or whatever it is and means you have to do very little finishing and fairing afterwards.
Some useful resources to Google are the tech pages on the West System website, and a good source of supplies is Wiz at Matrix Mouldings (now MCMC I think).
Also, I assume that this helmet is for protection...as well as avoiding CSM avoid polyester resins. A well consolidated (ie no voids, cloth properly "wet out") layup using epoxy on glass or carbon weave will be much, much stronger than polyester on CSM, and also a shed load lighter.
thanks for that mate,
oh right, well its primarily for display purposes but i would like to be able to test it!
thats the bit i want to make, Carbon Fibre finish would look pretty imense, but i was after a bright colour finish, to increase the visability of the diver when surfaced. I have access to an industrial oven, will find out re vacuum bags.
whats wrong with Chopped strand matting? Thanks again guys
oh right, well its primarily for display purposes but i would like to be able to test it!
thats the bit i want to make, Carbon Fibre finish would look pretty imense, but i was after a bright colour finish, to increase the visability of the diver when surfaced. I have access to an industrial oven, will find out re vacuum bags.
whats wrong with Chopped strand matting? Thanks again guys
Edited by rhys27 on Thursday 30th April 20:31
Edited by rhys27 on Thursday 30th April 20:31
OK, I get it. With some careful designing you should be able to get that off a female mould, or make a male mould in pieces that come apart.
CSM is just coarse and rough. Look at the non-visible side of a bath, bits poking out everywhere. It absorbs loads of resin so it's heavy, and as the fibres are only ever an inch or so long and lying in all directions, it's never very strong. When you try and lay it up around a curve, the short fibres will be pinging up in the air and you'll struggle to get them to lay down properly, although this is less of an issue with a display, rather than a functional piece.
This is a picture of a dinghy mast I built/modified. The main tube was a commercial item (albeit scrap and salvaged from a lake bed!) but the pokey out bits (spreaders) were made by me with layers of carbon fibre laid up over a balsa wood core, and then glued to the main mast section, and held in place with layers of twill carbon cloth. The fibres all run the same way (0 degrees, 90 degrees) and add strength, and there's just no way that CSM would have stayed put whilst epoxy went off (this mast was not vac bagged)
Don't worry about an oven, you don't need it, only if you are using pre-pregs as per the F1/aerospace industry. Just use it as if it were glassfibre at room temp!
Bottom plate is just a few layers of coarse weave CF laminated together under pressure of some G cramps.
CSM is just coarse and rough. Look at the non-visible side of a bath, bits poking out everywhere. It absorbs loads of resin so it's heavy, and as the fibres are only ever an inch or so long and lying in all directions, it's never very strong. When you try and lay it up around a curve, the short fibres will be pinging up in the air and you'll struggle to get them to lay down properly, although this is less of an issue with a display, rather than a functional piece.
This is a picture of a dinghy mast I built/modified. The main tube was a commercial item (albeit scrap and salvaged from a lake bed!) but the pokey out bits (spreaders) were made by me with layers of carbon fibre laid up over a balsa wood core, and then glued to the main mast section, and held in place with layers of twill carbon cloth. The fibres all run the same way (0 degrees, 90 degrees) and add strength, and there's just no way that CSM would have stayed put whilst epoxy went off (this mast was not vac bagged)
Don't worry about an oven, you don't need it, only if you are using pre-pregs as per the F1/aerospace industry. Just use it as if it were glassfibre at room temp!
Bottom plate is just a few layers of coarse weave CF laminated together under pressure of some G cramps.
Edited by Hard-Drive on Friday 1st May 00:17
An alternative suggestion that might be a lot easier to use.
And its actually "Plastic"
I've used it a few times and it does what it says on the tub.
http://www.maplin.co.uk/Module.aspx?ModuleNo=35511
And its actually "Plastic"
I've used it a few times and it does what it says on the tub.
http://www.maplin.co.uk/Module.aspx?ModuleNo=35511
Ah right, awesome,
so if I use a twill weave carbon.f or f.glass will the side thats not against the mould come out pretty smooth?
What sort of finishing does it need? would one lay it in sections or just try to "wrap" the whole shape of the mould with a single sheet?
Is it possible to then paint over that? (as much as i'd love a pure C.F finish, the helmet needs to be highly visable) Im also guessing laying up carbonfibre uses the exact same methods as fibreglassing then?
Thanks mate, really valuable stuff there, imense help!
so if I use a twill weave carbon.f or f.glass will the side thats not against the mould come out pretty smooth?
What sort of finishing does it need? would one lay it in sections or just try to "wrap" the whole shape of the mould with a single sheet?
Is it possible to then paint over that? (as much as i'd love a pure C.F finish, the helmet needs to be highly visable) Im also guessing laying up carbonfibre uses the exact same methods as fibreglassing then?
Thanks mate, really valuable stuff there, imense help!
TBH if it's display rather than functional and going to be painted use glass, it's cheaper. If it's made over a male mould, some filling and fairing will be needed, but not much. Inside a female mould, in theory none needed, depending how good your mould it.
You'll need to do it in pieces as the weave distorts when you go round corners, but you'll probably need a few layers anyway or it will be very flimsy indeed.
You'll need to do it in pieces as the weave distorts when you go round corners, but you'll probably need a few layers anyway or it will be very flimsy indeed.
rhys27 said:
thanks mate, some really helpfull info you've given me! I've just contacted a GRP specialist boat repair shop, hopefully get a visit to their workshop and see up close how its done.
Thanks again, really appreciate your time!
Which one? If it's big boats expect to see CSM and polyester resin! Your best bet is a dinghy one.Thanks again, really appreciate your time!
Sewing neoprene...have a look at the Gul/Gill/Magic Marine website or a diving specific one, you'll need to do a blind stitch otherwise it will probably leak. I'd be tempted to glue it instead...it is a complex machine jobbie anyway.
No worries on the help, I look forward to getting some exam marks!!!
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