making fibreglass moulds

[mattij2005]

Hi all just wondering, i want to do some mods to the dash of the pongrass, when you want to fibreglass a new section do you just make a wooden mould polish the wood with heaps of polish and then lay the fibreglass over the top or is there another way?

[Noelm]

well up to a point that is what you can do, but you need other products to make sure the glass does not stick to the wooden mold (release wax/agent) and you also have to make sure you can remove the item you made, that is, the new item can actually be removed from the mould and some funny shape will not get stuck. Most (for a one off) just make it out of timber, then glass it all over and flow coat and finish as you would a spray painted item, and that involves sanding and polishing.

[mattij2005]

i'm gunna spray the whole boat anyway Noelm so can i just spray it when i spray the boat or is it best the flowcoat it first? i was thinking of making the piece then cutting out the dash slighly smaller than the new piece, then grind away the paint that is on the dash already, then glass the new piece to the old dash. would that be the way to do it or is there another way that is heaps easier. Oh and i'm going to considerably modify the dash just not enough room on the one i have for fluch mount radios gps etc so it's gunna be a bit bigger.

[gavsgonefishing]

Another way of doing it is to premake your glass peice then cut and shape it in the dash.

buy a peice of melimine (spelling) then wax the piece up with wax release agent, about 5 coatsbuff off between. Put a hot coat of resin on with a roller then lay up your glass (3 x 600 chop will be heaps) spend time rolling the excess resin and air out. You can successfully lay up a 600 x 1200 piece in one go.

Let dry for 24hour then mark out the dash bits. Pop off the board and cut. I use hot glue to hold the pieces in place sand then glass on inside. you can use car bog or a qcell/tlc mix for bogging before hand to round off the corners etc.

The other way os what Noel said. Cut your ply out to shape 9- 12mm is heaps, prefit, precut the holes etc and have a play around so it fits in the area (this will include cutting your own dash up). Once you are happy sand the ply back, glue the pieces together or put temp screws in to hold the shape, one coat of resin on one side, let it tack off then put 2x 450 chop. Next day trim and take the temp screw out and do the other side

Hope this helps

Gav

[mattij2005]

I'm not quite sure i understand what you mean in the second part there gav, I'll tell you what i'm gunna do then tell me if i'm right if thats cool.

From the attached picture i'm gunna cut the piece out with the yellow lines. Then extend it with a piece of glass down to the red area with that general shape.

I can just glue in a piece of ply for the extra section cant i then glass over it, then glass the whole thing back to the dash. I'm also goin to lift it up so that the top of the yellow line is in line with the top of the lip for the windsreen. then i'm going to paint the whole boat so i'll paint the new glass at the same time.
http://i176.photobucket.com/albums/w190/mattij2005/dash_mod.jpg.

Sorry i tried to import the picture direct but don't know how.

[cormorant]

make up what you want out of some cardboard and then work out if it will actually be useful to mount stuff in.

A dash on many older boats is a point of strength and if you are thinking of cutting out the existing part teh nre one has to bond well and be of similar strength.

After modifying the cardboard cut out youcan use it as a template to cut up some melamite, plastacine internal corners using a 10 cent piece as a guide , wax it, pvc it and away you go.

The other way is to go to the $2 shop,bunnings , storage shop and look for any plastic crate about the right size. Trinm it up and then you have a perfect mould ( a glue gun and a bit of ply reenforcing on teh outside) to lay up glass on. They are great as they all came from a mould so generally have good corners that will mould well.

Best time you can spend is thinking about it before you cut anything.

Not to stuff you up or anything but I like stuff mounted low with a sun guard so it can be seen in sunlight and is more protected but every boat and owner is different. Pretty easy to look lower abd can be seen from back of boat with rod in hand.

[gavsgonefishing]

the red bit you have drawn in is hanging lower than the rest of the dash. Without support it will vibrate and generally be a pain in the ass. Did you plan to brace it back into the dash proper?

Those holes can easily be filled with ply then glassed either side. Or glass the ply up. Then cut the glassed ply to size and epoxy in.

I am not reel sure what gain you are going to get with the top dash section. That top section will probably be glass with stiffener in the middle. It amy be a pain to mate up with the rest of the dash.

Cormorants idea with the cardboard is excelent. It will tell you weather its going towork or not. Dont start cutting anything until you are very clear about what you want to achieve.

So you if the top section is glass, stick with that, the facing section is definately glassed ply, and easy to repair. the proposed section you are adding on can be either, but it will have to be braced back to the dash proper.

Hope this is not getting more confusing

[mattij2005]

Nah yourright gav not gettin confused at all. Was thinking exactly what you pointed out last night about having to brace it. I think I'll continue it all the way to the floor and make it sort of like a console arrangement with cup holders room for both radios and an am fm radio and a little bit of storage. I only went for that short piece in that picture because of limited leg room. But I reckon the console thing is the go