PDA

View Full Version : Fibreglassing



PADDLES
20-04-2011, 08:07 PM
Other than doing a few surfboard repairs i know zip about fibreglassing.

I'm keen on building a custom cutting table/board to go on top of the engine box in our boat and i obviously want it watertight so it can be easily cleaned.

Is it as simple as making up what i want/need out of plywood and getting it sealed at a fibreglass joint, is this the cheapest/easiest option?

How thick is a 'normal' coating of glass/resin over the top of a wood structure?

Has anyone here done something similar who can steer me in the right direction?

Can anyone recommend someone in the Caboolture/Bribie area who does this sort of work.

Thanks.

Horse
20-04-2011, 08:20 PM
The best way is to make a reverse mold of what you want and lay up the cutting board in it. Make sure its smooth then either a releasing agent or a polish with Canuba wax. Thick gelcoat layer then a few lays of heavy cloth andadd some timber where you might be screwing into. Its not hard if yiou think about your design

STUIE63
20-04-2011, 08:45 PM
some tafe colleges run fibreglassing courses from time to time

BM
20-04-2011, 09:14 PM
Paddles,

Building what you want from ply or some other material and glassing over it is the most economical way to make a one off.

In order to make a mould, you must first make the part anyway and the only reason to then make the mould is to make numerous identical parts.

Cheers

oldboot
20-04-2011, 10:43 PM
You can form up a structure from ply or timber and sheath or reinforce with fibreglass...if working with wood you are better working with marine epoxy rather then polyester resin.
marine epoxy is completly impervious when properly laid up, common polyester resin is not.
modern marine epoxies have an incredible afinity for timber, polyester does not.

I've been doing abit of this of late, building a new floor and console for my boat and a few other bits an pieces.

timber, glass and epoxy is a more viable situation if you are only making one.

because the timber is providing quite a lot of the structure you don't need to use as much glass or epoxy.

tape on the seams and joints and one layer of 200GSM will do fine for light work, you will need at least 3 rolled coats of unthickened epoxy to get a fully choked smooth and waterfroof finish, before you start painting.

Two books that may be helpfull is the Warram book of fibreglassing and "the gudgeon brothers on boat building"

but be carefull... if you start with this timber, epoxy and glass construction, you can easily get hooked.

cheers

deckie
21-04-2011, 03:18 AM
Hey Paddles...not far off finished one. Might be useful for you. There are options to glassing. Few things to think about first. 1. Permanant or easily removeable ? 2. Prefer to keep the weight down or no need ? 3. Want it useful for night fishing or not ? 4. Do u want any sort of well built in for bait/storage or even livey's etc? 5. How big ? Too big looks dumb, too small is a waste of time 6. Do u want it to be strong enough for trolling using rod holders on the board, or happy with just rod storage, or maybe no rod holders at all needed. 7. Most important first is where/how to mount it.

This one needed to be kept reasonably light but v strong, set way back over the motor so the weight kept down... which also meant in my case high enough for normal trimming but probably needing to be adjustable for full tilt of the motor, wanted a bait/storage well with a flip lid, LARGE drainage holes and flex tubing to run near straight down over the back, wanted a running water tap plus a cpl of rocker switches at the table, lighting so i wasnt in my own shadow always, wanted it easily removeable when not needed and can dismantle it fast whilst out there, all flat stored into a sidepocket rather than be an awkward pain.

Its not a quick job if u want things to your own liking but dont need to know much about glassing. This one was glassed but working with ply you can get away with multiple layers (maybe 5) of thinned epoxy like everdure then a rough up with coarse paper, a coat of poly resin to prep for a thick poly flowcoat finish, then step thru grades of paper 200, 400, 600, 800, 1200 wet n dry and it'll shine up and look like its part of the boat out the factory. Just depends how much effort u want to put in and if in a hurry.

Oldboot is right about epoxy being a better waterproof than polyester but poly glassing is still pretty bloody good and effectively good enough if glassing. Its far cheaper, and most important easier to use if u havent done much glassing. Ply is fine as long as you are a bit anal about the w/proofing with multiple layers and esp any sawn edges and drilled holes being treated as u go along...then sika any fittings and fasterners in.

Probably easiest tho is to look around for some stuff called king starboard or what my local plastics guy called king board.Totally waterproof, white, as easy to work with as wood, not as heavy as hd polyethylene, easy drilled/cut and sanded plus easy to flowcoat and u may not even want to bother doing that. Track down a baitboard top that suits and attach it to about 12mm king starboard which acts as a really solid mounting base for the uprights/ rod holders etc If you are happy with a simple flat surface then just the king board itself is fine with a polyethelene (kitchen cutting board stuff) cutting surface on top.

Just start at the end..with how and where u intend mounting it and how strong it needs to be...that tells u what u need to do. This one is just an unfinished project still but not too far off. Has a glassed well and will have a handrail out front, no rod holders wanted, will have power to it and water then mounted on adjustable 1 inch 316 uprights. Hope it helps a little.

D river
21-04-2011, 06:12 AM
Try making it out of glass without the ply, You'll need a sheet of glass or something similar to make your fibreglass panels out of and they'll need to be 3 layers thick. just over hang it a little off the glass and when dry you'll be able to break it off and trim it to your desired shape. When you have enough panels and they are cut to shape join them to each other with a single layer of fibreglass. Remember to lightly sand all pannels before joining so they laminate properly and permanently. Also invest in a cheap roller to get all the air out of your panels. It is alot easier than what it sounds and without the wood it'll last longer be lighter and take up less room. You can either put angle bends on it to screw it down or glass it in place. Use a cheap diamond wheel for cutting panels and use a ruber attachment with 36grit sanding disc on the grinder for scratching up and shapinf the panels

deckie
21-04-2011, 06:42 AM
If u really want it light try getting an offcut of 1/2 inch klegicell, glass it with poly resin and some cloth, sand and flowcoat.
Noone wants to sell bits of the stuff but if u get your grannie to go down the local boat builder in her wheelchair all frail and stuff she should return with some nice offcuts on the cheap...hopefully ;D

Now i just gotta find some thin stuff for some boxes.

PADDLES
21-04-2011, 08:40 AM
excellent info guys, thankyou very much. my plan is for it to clamp onto the top of the engine box on our whittley cruiser and then hang over the back of the transom so it can just drain straight onto the swim platform. it needs to be removeable so when we're out camping on the boat and not just fishing, the table can go back onto the engine box and the cutting table goes into the shed.

it doesn't necessarilly need to be pretty or reproduced so i'll probably stick with the plywood structure and seal it with glass/resin. setting a bit of nylon cutting board into it is a top idea, thanks for that.

basically this boat is an awesome cruiser and camping boat but is a krap setup as an offshore fishing rig. the mods i'm thinking of doing to make it more suitable for fishing are:

- adding a bung so i can properly wash out the bilge, at the moment the only way you can get water out of a whittley 660 is with the bilge pumps

- getting rid of the carpet in the rear cockpit area and replacing it with some removeable rubber mesh matting. even when camping we get the carpet wet way too easily and it takes ages to dry.

- making up some covers that drape over the gunwhales and into the inside of the boat to cover up the uphoulstry around the side pockets and the drop down seats. the covers can hopefully use the existing press studs for the camper covers to hold them in place.

hopefully these few little mods will allow me to cheaply convert the 660 cruiser into a more practical offshore boat for whenever i want to head outside for a fish and still retain the boat's comforts for when we want to go away for a few nights on it.

deckie
21-04-2011, 09:43 AM
If its easy mate take a photo of the transom from inside and outside.

Hundreds pf ways to make and mount these things.
Knowing how you want it, now its only a matter of a good way to mount it so thats its useful and removable.

You can make it yourself easy enough if u have the time and inclination, but even if u get it made up it'd be worth having some ideas and what is possible at the ready to talk to them.

One pic can be worth a thousand words.

cormorant
21-04-2011, 09:54 AM
Never a fan of cutting in bung holes into composite or new transoms. It has to be done properly -not many do it properly . Even with a bung hole they have a lip and you never get it totally empty.

For flushing out you can use attachment on gernie that is a venturi pump that will suck out all water and crap rather than run than run long time on the bilge

For the time , work and hassle it may be worth getting a ally fabricator to baitmate to knock up a bait board.

You would want to be very good with timber and have it all at hand to beat the prices of a simple alloy one.

Is there a 50mm ski pole / table pole on that model whitley? I've seen some with the ski pole hole that is the table/ bait board hole?

PADDLES
21-04-2011, 11:19 AM
interesting cormorant, can you get a similar suction pump that runs off compressed air? i'd almost be able to get a plumber to braze something up that'd just take an air blower wouldn't i? alloy is another option but i reckon it's get a bit pricy for what i'm after, and nah this thing's no ski boat, it's got a verandah on the back with a bbq, if the seas were flat or i was up the passage, i'd just sit in a camp chair on the swim platform and fish, but if there's some swell/chop there might be water slopping over it all the time so i'd want to be able to fish from inside.

Chimo
21-04-2011, 11:52 AM
Hey Paddles

I wonder if a little sand pump (mod No 2 is what I have) might work to dry out your bilge?
I bought one to pump sand and the blurb says you can pump out fish tanks etc with them too. I use a spear pump to drive it but reckon the deck wash on the boat would probably work too. Not sure about air as the unit works by concentrating the flow you introduce to it thru a small jet and this causes a suction to be created thru a venturi which lifts the water or water and sand mix up the hose to be moved to where you want it.

Got me intrigued now, I must try it next time the tinny fills up with rainwater but just found the instructions and the blurb says it will do it !

Look at www.slurrpypumps.com/models.htm cause I reckon cutting a hole in your hull would be the last option and really best avoided.

Cheers
Chimo

cormorant
21-04-2011, 11:57 AM
Nah to pump water you need the density of water to get enough suck or really high pressure or volume air.

Here is a hose one for gettng sand out of the pool. There are heaps of examples of ones for emptying pools, fishtanks and so on. Most don't have great suck but have good push and solids don't affect them.

I think Karcher actually make one for their pressure washers


http://epools.com.au/2STDPP%20Standard%20Pool%20Pump-p-2207.html?utm_source=getprice&utm_medium=cpc


After doing lots of little glass items and some big projects unless you have all the gear and are going to do a few items it is pretty expensive for a one off in time and materials. If you have a mate who has used the stuff and has gear use him as the little tricks you learn make all teh difference.

If you are good with wood just make it and epoxy coat it ( a couple of strips of glass in the corners if it needs strength and forget about flowcoating it.

Why not use extra thick pollypropelelne ( chopping board) and use a router to mill what you want and just kake mounts up? Polly cuts and screws , joints similar to wood and no finishing or coating required.

Depends what you skill level on the tools is and the cost of your own time.

Chimo
21-04-2011, 12:03 PM
Corm

Were talking about the same unit and it will empty water out of a container.

Cheers
Chimo

cormorant
21-04-2011, 12:28 PM
Ahhh you were posting while I was 1 finger typing. We use ours to empty the spa and when one of our drain clogs the pit that leads to it. We have high water pressure and volume so it works a treat - well pretty fast and a lot easier than a bucket or siphon.

PADDLES
21-04-2011, 07:26 PM
thanks for the info boys, i've just had a few beers with a mate who i didn't realise (until after a couple of beers) has a hidden talent of knowing how to do fibreglassing. i'll post a piccy of how it all turns out.