Fibreglass fabrication - a few questions
after having a garage clear out I have a lot of free space and no project - so am going to make a new marlin board - yay
it will be approx. 195cm wide and 800mm deep (well that's not approx. but exact) and am thinking of a few large recesses across the board so I can inlay with my hoard of teak
I have done a bit of fibreglass repair before but not something this big - have started making a mould using melamine covered chipboard - looking for ideas to take the 90 degree edges/corners to 1/4 round
Was going to lay up a few coats of gelcoat/flowcoat first - then a few layers of cloth then drop in the marine ply for strength - glass the ply in with a few more layers of cloth
To those who have done a bit of glass work before
1)Would you use epoxy or glass resin?
2)gelcoat or flowcoat? (I am leaning towards coloured flowcoat - white yellows)
3)what matting/cloth thickness and type? - matting is strong but I am not good at getting it to go around bends! - have had some success by applying resin and as it is setting applying some wet matt - but its not easy - (much respect for those who have mastered!)
4)what release agent? - have seen an aersol spray but I think it is for epoxy only?
Was thinking of doing a thread on it from start to finish - wont post until its finished - just incase it comes out cr@p! haha
cheers
dodgy
Posts: 4577
Date Joined: 01/02/10
Do you do much backing up on
Do you do much backing up on fish? Solid Marlin boards can be a fantastic way of scooping lots of water into your cockpit.
Does anyone know where the love of god goes, when the waves turn the minutes to hours?
pelagicyachts
Posts: 1322
Date Joined: 23/02/11
not much mate - but that's
not much mate - but that's more a reflection of the luck of the skipper than the intent!
this is going on a 23 footer - and will be used for boarding (getting on) really
z00m
Posts: 1086
Date Joined: 10/05/14
Corners
In your mold add some fillets using bondo or epoxy based putty and once they are set sand them to the required shape. Once covered in release agent and wax nothing will stick to them.
Make sure the board is strong enough to withstand the pounding it will take when at anchor. Leave some air vent space in your design to let the water come up through it instead of trying to lift the whole transom.
If you have loads of nice teak would it not be nicer to have a stainless frame and then recess and bolt the teak to it? You could still claim the project part as you would be cutting and attaching the slats
pelagicyachts
Posts: 1322
Date Joined: 23/02/11
thanks mate - have used
thanks mate - have used plasticine before but that was for a small overhead console and was wondering how it would go! - just to clarify do you need to wax the mould and then coat in release agent (its cheap so not a big deal) or is the wax enough?
The vents will be where the teak slats are - and yeah without these -even if the board is strong enough it will end up stressing the glass where it joins the transom
I do have a stash of teak - sometimes i cut a bit just to smell it - but now I digress..... ! - yeah thought about that but with the existing pod it would be difficult and I live in perth so $$$$$$$$$$$!
z00m
Posts: 1086
Date Joined: 10/05/14
Mould prep
Yes, you wax and buff 2 to 3 times and then apply your release agent in 2 directions. All the glass and resin in the world can't make up for a piece stuck in the mould.
pelagicyachts
Posts: 1322
Date Joined: 23/02/11
nice one - I made an overhead
nice one - I made an overhead centre console and a couple of baitboards over the years, I have used carnuba wax(car) previously (no release agent) the first baitboard came out great the second .... still in the mould I think!!! :-(
Lesson learnt!
eziliving
Posts: 875
Date Joined: 30/12/09
I personally would use gel
It's been along time since I've done fibreglassing but I personally would use gel coat, glass and resin. If you are applying the gel coat first you can just lay up the glass behind it. If the gel coat is going on last you will need to add wax and styrene to it to take away the tacky ness. As for the corners you can use plasticine or car bog (slow mix) and use a marble or something give it shape then lightly sand to take out the edges. We use to use a filler called q cells which you just added to the resin. Flow coat is usually used just for smoothing a surface over or at least it was when I was fibreglassing.
You should wax the mould quite few times and use release agent if you can get it to ensure that it will release. depending how big it is going to be you could drill a couple of holes in the mould to use compress air to help release it from the mould. Just use the white round stickers from the news agencies to cover the holes.
When laying up the glass precut the glass to size with little over hang that way you should create less air bubbles with the over hang leaning over. If need be cut them into manageable pieces as once you start laying up the glass the last thing you want is to be fumbling with sheets of glass with sticky fingers. Also it pays to have a couple of different size rollers especially a small one for the corners
i can't remember the grades of chop strand and woven rovins but your supplier should be able to help you there.
Get busy living, or get busy dying!
Rob H
Posts: 5796
Date Joined: 18/01/12
Flow coat and gelcoat are
Flow coat and gelcoat are for 2 different purposes, is my understanding
Flowcoat to paint on outside, with wax and is thinner
Gelcoat thicker and no wax to paint in mold before laminating. If it had wax in laminate wouldn't stick.
Give a man a mask, and he'll show you his true face...
The older you get the more you realize that no one has a f++king clue what they're doing.
Everyone's just winging it.
z00m
Posts: 1086
Date Joined: 10/05/14
Flowcoat
Flowcoat is just Gelcoat with wax added so it cures completely. Gelcoat won't cure past that tacky stage unless is it sheilded from air.