Making a nice fibreglass rectangular thingy

No1_Moose

No1_Moose

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I have done a bit of googling for this but I haven't found a lot.

I want to make a 6mm thick 30x15cm rectangular piece of fibreglass with chamfered edges which I will then take to the Peters peeps in Chichester for them to coat it in Fairline off-whiteishgelcoat.

But, how do I go about actually doing the fibreglass work? Where can I get the bits and is there anything I should look out for?

Thanks for any help
 
Fibreglass is normally laid up gelcoat-first. Typically, you'd get a mould surface, paint the gelcoat on to it and then lay the resing-soaked fibres on the back. You can paint gelcoat on afterwards but it's extremely difficult to get a good finish. Why not lay up your bit of fibreglass (with a clear gelcoat) and then take it to someone to paint it a matching colour? Or even lay one up with a white pigmented gelcoat (so that it's close) and then paint it to get an exact match? If so, get an old mirror (lovely flat glass surface), wax it and then lay up on the surface of the glass.
 
Hi,

Has anyone know of any online guides? Iam planing to make a fibreglass box with black gelcoat, any ideas? or books?
 
make a "plug" ( make the shape / box thingie ) in ply or other suitable material,
allow sides to slope say deg to assist in removal from plug.
finish to a high standard with filler then paint. the better the finish the better the completed item will be.
coat in "release agent" then gel coat followed by sufficient glass fibre to be rigid
even add stiffeners as req.
when its all set / cured, prise this mould from the plug
polish the inside of the mould with wax or similar then lay-up with gel coat & fibreglass
 
mm, I didn't know it was gelcoat first. Perhaps I could get the 'local professionals' to do the gelcoating and then I will do the fibreglass.
This is an attempt to save the £250 that they want to charge us to do the whole lot.

It is a 'frame' in the instrument panel so that we can fit a smaller chartplotter in than the one we have just taken out so the final finish has to be excellent.
 
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The big plotter thing second from left is what is coming out and the new one is a long and thin thing.

It really needs to be f/g or the walnut effect stuff but we can't find any of that.

Any suggestions on where I can get it done cheaply? I think from what I've read about its best left to someone who knows what they are doing and can get a good finish. I just assumed that I could lay up some fibreglass, sand the outer face till it was perfect and then get them to gelcoat it, obviously not!
 
Absolutely try doing it your self. As already stated you can colour the gel coat yourself with pigment. Around here the white and beige are common pigment colours the beige for non glare deck colour. You only need a small amount of pigment in plain polyester resin (about 10% should do.) Mix a little of each colour until you are satisfied about 1/4 teaspoon of each should suffice.
If you want a flat piece of f/g then lay it up on glass or even plywood or chip board but put plenty of wax on the surface to give a smooth finish and easy release.
For the size you want you can easily affords to make several until you get it "just so" and you will enjoy doing it and learning.
Get disposable plastic gloves and throw away paint brushes or rollers and do the job indoors in warmth. It does smell a lot though. good luck olewill
 
Have you considered the possibility of using plywood, chamfering the edges and then just brushing epoxy diluted with meths into it until a build of epoxy, fill any dings if necessary, sanding smooth and then taking it for gelcoating? Doesn't have to be marine ply just good clean stuff.

Apart from making the ply resistant to moisture penetration it also stiffens it up alot. If stiffness is very important too, use a piece of ply of as many plies as is easily obtainable, or else epoxy two thin thicknesses of ply together which will give at least 6 ply.

I am not sure of this, but I would expect gelcoat to adhere quite ok to epoxy paint build coats which would provide a better base for getting a smooth finish from sanding, then gel coat on top of that (or good build of linear polyurethane paint sprayed finish) - maybe someone knows.

Have you tried Oldsaltoz for ideas?

John
 
How I'd go about it.

1/2 metre 300g cloth
250g pot of polyester resin and catalyst
body filler
gelcoat

7 1/2" paintbrushes
mixing cups and sticks
putty knife
Sandpaper
electric sander
dust mask
barrier cream for hands
OLD CLOTHES!


The following will work if its a cored area or just plain solid glass.

Remove old plotter.

Chamfer back the edges of the hole at as great an angle as you can. This is not a structural job but getting a good key on the edge is required.

This may be the difficult bit ---- cut a piece of thin plywood - I'd look for, or purchase a piece of 4mm aircraft grade ply from a model shop, they sell little sheets about the right size. The ply should be slightly larger all round than the hole that is left. Varnish 1 side of the sheet. Insert the ply behind the panel and using a bit of epoxy glue it in place with the varnish away from the exposed hole. The ply is going to stay in place hence the varnish.

Do not use any release agent on the ply. Lay up 3 to 5 layers of 300g / sqm glass cloth in the hole. At each layer orient the weave of the cloth at 45 degrees to the last layer.

Mask up the surrounding areas, upholstery, instruments and equipment with ceran wrap, plastic bags and tape.

1 - Cut glass slightly larger than the patch ( remember the 45 degree bit )
2 - mix about 50g resin at a time, you wont need more for each layer.
3 - paint on resin to ply or previous layer.
4 - lay glass cloth on resin.
5 - using a gentle stippling motion 'wet out' the glass cloth using just enough resin to make the glass cloth appear transparent but not so much that it runs. Make sure there are no air bubbles or voids.

Wait for the resin to set but not untill its completely hard - about 3/4 hour at room temperature and repeat the above until the required number of layers are done.

Now the work starts.

Using a grinder or power file trim the edges until you have a reasonable finish.

Fill the patch with body filler, smooth and sand back to about 1/2 mm below the surrounding glass.

Liberally apply gelcoat and wait to dry.

Sand back, check for low areas and reapply gelcoat to them. Repeat as necessary.

Cut new hole and mount new plotter.

It will take you a weekend at the very least.

It will cost about £30.

When next you are in the cockpit and you glance at the plotter you will get a sense of satisfaction unknown to those who blindly just fork out extra cash.

Go and blow £110 ( 1/2 the saving ) on the wife! You are a winner all round.

/forums/images/graemlins/smile.gif

Ian
 
Surf boards are made from the inside out. Most board builders will be quite happy to coat your fibreglass construction with gelcoat and achieve a perfect mirror finish. Try discussing with someone who builds boards before trying the whole thing yourself. Having made a lot of this kind of thing I can advise that it is not easy, especially self-taught. I recently made a Morse control panel for my boat using the old one as a pattern but modifying its depth to take a different design of Morse. It took several days of intermittent working to get a reasonable final product.

Unlike others, I think £250 is a realistic price. Nobody is going to do this kind of work for less than £25 per hour and by the time you make a plug, make a mould, then make the final item I suspect 10 hours would be well used up.
 
Offer to watch it dry for them and see if they'll give you a reduction!

On a more serious note, it's very difficult to match wood grain. If they are willing to tell you what sort of wood veneer they use (unlikely, I agree!) then you could almost certainly get a sheet of that and glue it to a ply backer. In fact, it might just be worth asking them how much they'd want to supply you with a rectangle of varnished veneer of the same sort they use...

If you still want to do the GRP, I think you'll get a pretty good match with anyone's standard white pigment in the gelcoat. (CFS do a good range of online fibreglass stuff but by the time you've bought everything in their minimum order quantity and paid the cariage, it might not be that cheap a way of doing it)!

I'd be a bit wary of trying to bond it seamlessly into the hole left by the other plotter. Fibreglass can sometimes crack along the edges of old joints - especially at right-angled corners. Nothing serious, just a bit unsightly. This can sometimes take a year or two to happen - maybe if that panel flexes slightly when the boat bounces of waves. If it were my boat, I'd think more about trying to put it over (or under) the exsiting holes - which leaves the problem of finishing the edges. A bit of wood might be the best solution in the end. Try searching for kit car websites - they must use wood dashboard veneers from time to time.
 
I had to make an engine cover to match surrounding GRP. I made the cover from plywood and then overcoated with polyester resin. Sanded smooth to ensure no voids, gave it a bit of a key and then overcoated with outdoor gloss from B&Q using colour match. Still looks good after 8 years, and has fooled a lot of people into thinking its GRP.

Alternative approach. get a bit of perspex (dark smoked ) and fix that across existing area including other instruments, then fit all instruments to the perspex - finish looks good, and its easy to achieve.
 
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