CAPTAIN FANTASTIC
Well-Known Member
I would like to buy a thick 10mm to 25mm (1/4in to 1in ) by 300 by 700mm (or similar dimensions) board/panel made of GRP. Where do I get a GRP panel from?
GRP thick board/panel; where from?
- Thread starter CAPTAIN FANTASTIC
- Start date
macd
Well-Known Member
Roofing suppliers often sell GRP sheet, but nothing like that thickness. I'd suggest you make your own but one inch thickness is enormous for solid GRP (and heavy: something over 50kg for the area you have in mind). What on earth is it for?
nimbusgb
Well-Known Member
10 mm is considerably thicker than 1/4"
Unlikely you will find anything that thickness off the shelf. How big do you need it?
1 inch is a really solid piece of glass.
May be better and cheaper and faster to lay up glass over 18mm ply core.
Unlikely you will find anything that thickness off the shelf. How big do you need it?
1 inch is a really solid piece of glass.
May be better and cheaper and faster to lay up glass over 18mm ply core.
penfold
Well-Known Member
What you describe is not available off the shelf; you can buy foam or plywood sandwiched with GRP on the outside. What's it for?
Croak
Well-Known Member
where from?
CAPTAIN FANTASTIC
Well-Known Member
The bottom sacrificial grp skin of my twin encapsulated keels is wearing off; It is common to Macwesters. I have a few options; I can make stainless steel "shoes" and dress the bottom 3 inches of the keels; build up the thickness with glass cloth and grp in situ; or get a thick grp sheet and cut it out to shape and stick in place with grp and cloth.
Doing it in situ, layer by layer, it will be difficult because I will be working up side down and there will be very little working space between keel and ground. Fabricating stainless steel shoes requires much more specialism. So, if I could get a thick grp sheet it will be much easier to do the job. If I can not get it ready made, I would have to make up the right size and thickness at home and then stick it well with epoxy on each keel.
Doing it in situ, layer by layer, it will be difficult because I will be working up side down and there will be very little working space between keel and ground. Fabricating stainless steel shoes requires much more specialism. So, if I could get a thick grp sheet it will be much easier to do the job. If I can not get it ready made, I would have to make up the right size and thickness at home and then stick it well with epoxy on each keel.
Croak
Well-Known Member
Why not use a strip of hardwood, that's what mine has.
CAPTAIN FANTASTIC
Well-Known Member
Yes, but the trouble with wood it is difficult to "stick" on and make a good bond on the existing grp bottom of the keel.
PCUK
Well-Known Member
I think you need an expert to tell you what you need cos' your ideas are daft! Sorry to be blunt!
West Coast
Well-Known Member
What you describe is pultruded GRP plate, I can possibly get you some 12.7 mm plate off cuts from my company workshops. You mentioned a size of 300 x 700, but what sizes had you planned to cut these to? However, by definition, it is flat and straight, really not easy to cut and shape to suit a shaped keel. Suggest better to mould something.
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lw395
Well-Known Member
Make a simple mould, to make the plate roughly the right shape and slightly over size. Then laminate it nice and thick, before bonding it in place with a mix of resin and chopped glass.
If you want a narrow strip, GRP sail batten is fairly cheap.
You could fix some wooden or metal rubbing strakes to the plate before bonding it on?
If you want a narrow strip, GRP sail batten is fairly cheap.
You could fix some wooden or metal rubbing strakes to the plate before bonding it on?
CAPTAIN FANTASTIC
Well-Known Member
Sorry to disappoint you, but these are the options you have for repairing 1970's encapsulated bilge keels such as the Macwester; and this is how numerous other Macwesters have been repaired; obviously you are not the right person to respond to the question.
Croak
Well-Known Member
How were you going to stick Stainless Steel shoes on?
CAPTAIN FANTASTIC
Well-Known Member
I may end up having to make a mould (this is what a few Macwester owners have done) but I would need to raise the boat high enough to be able to work comfortably. Many thanks for the offer to provide me with plate of cuts, if I get stuck, I'll get back to you.
CAPTAIN FANTASTIC
Well-Known Member
In the case of stainless steel shoes, a 3 inch strip is shaped round the keel and then is welded to a flat stainless plate which forms the bottom; the whole thing is like a "shoe" which fits tight on to the existing keel and bonded with epoxy; almost impossible to get it out again.
Tranona
Well-Known Member
Make a mould and then construct a GRP shoe which you can stick on with Sikaflex. You only need one male mould which replicates the bottom of the keel going about 75mm up the side, and then laminate GRP over it. The mould can be made of softwood, painted and coated with release agent. Finish the outside with epoxy and antifoul.
penfold
Well-Known Member
There are loads of makers; here's a couple that appeared on the first page when I googled. Smyth composites and Normanton laminating.
Avocet
Well-Known Member
Sorry for the thread hijack, but I have a similar problem, in that I'm looking for some cheap (if possible) and stiff fibreglass sandwich-type panel to replace the drop sides on my trailer. They're currently 18mm ply, skinned on each side with GRP. They weigh a ton and the ply inside has rotted in quite a few places. There must be a better way!
oldsaltoz
Well-Known Member
My advice would be to avoid putting any timber under water, no matter what treatment you apply to prevent it self destructing.
Have you considered a simple plate of Stainless steel with two 'U' shaped brackets that are through bolted on the keel.
The process of drilling and filling the holes is simple and quick.
Say you want to use 12 mm through bolts, simply drill a 25 mm hole, fill it with a mix of Micro-fibres and epoxy resin, let is cure then re drill the hole to take your 12 mm bolts.
After the "U" shaped brackets are fitted you can smooth out the whole area with Micro balloons or micro spheres (made of glass rather than resin) and anti foul as normal.
This method eliminates the need to fibreglass any areas.
This will be easy to replace if needed a some in the future if need be without hacking the keel.
I used this system on the mini keels of a Catamaran many years ago and they are still there and no problems at all.
Good luck and fair winds.
V
Have you considered a simple plate of Stainless steel with two 'U' shaped brackets that are through bolted on the keel.
The process of drilling and filling the holes is simple and quick.
Say you want to use 12 mm through bolts, simply drill a 25 mm hole, fill it with a mix of Micro-fibres and epoxy resin, let is cure then re drill the hole to take your 12 mm bolts.
After the "U" shaped brackets are fitted you can smooth out the whole area with Micro balloons or micro spheres (made of glass rather than resin) and anti foul as normal.
This method eliminates the need to fibreglass any areas.
This will be easy to replace if needed a some in the future if need be without hacking the keel.
I used this system on the mini keels of a Catamaran many years ago and they are still there and no problems at all.
Good luck and fair winds.
V
Bobobolinsky
Well-Known Member
I can't see what is wrong with sacrificial strips in iroko, bonded with thickened epoxy. Bond on at half thickness and then screw and sika a second half thickness, thay makes it easy to replace if it is "sacrificed" I have a similar arrangement on my dinghy with softwood on the outer lamination.
