The main body of the car, like a standard Locost, has been paneled in aluminium. The relative simplicity of bodying a Locost with flat sheet is testament to the straightforward overall design of the car. All metal parts, including the rear of a locost, are single plane bends of flat sheet. All the tricky bits, like nose cone and wheel arches, are fibreglass.

In an ideal world, the Valkyrie would have been fully aluminium bodied. In reality, its pretty obvious that to fashion compound curves in aluminium sheet to a perfectly smooth finish needed on a car body, was way beyond what I could attempt! The alternative was fibreglass. Its not by accident that the tricky bits of a locost are fibreglass, and that so much of the kit car and low volume vehicle market use it. It gives the user half a chance of getting a decent result, taking the part from a shape fashioned by the designer over which the 'glass is cast. Notable exceptions  that prefer to use sheet metal are Aston Martin and Morgan themselves - but I am not a time served metal basher!

So, as I'm doing this car with lots of fiddly bits on, its gotta be fibreglass.

Be sure you want to do this!

If you are reading this with a view to making parts for a standard locost that could be bought off the shelf, my advice is DO'NT DO IT!!! BUY THEM!

My experience is that :

1. It takes a fair while to produce the part - as its a 3 stage process of buck / mould / part.

2. It's fairly expensive, as you have to by parts to make the buck, then the fibreglass mould, then the final part. Again, everything is times three.

3. You are only likely to make one set of parts and that does not justify the expense - making your own parts in my view is way more expensive than buying.....cos you are perfoming a 3 stage process.....

4. Its unlikely that your initial parts will look as good as bought ones. If you are going to self-colour the fibreglass parts to avoid spraying them, then your work has to be a really high standard as what comes out the mould is what you are gonna have to live with. You cant sand or smooth the finish down.

5. The process is fairly messy and smelly, with potentially harmful fumes. There is no way you can do this in the house - you will wreck the place and gas everyone! Similarly, hand lay-up of GRP can be pretty 'splashy' and will not be the best thing to do to your garage. You need to cover up things you don't want coated in resin.

Having said all that, its quite rewarding to take a part out of a mould that's all been made by your own hands. If you could have bought it all ready made and you spent time and money doing your own, in my view you are a nutter!

What you need - Tools and Equipment

I bought all my consumables from CFS Fibreglass Supplies. 

http://www.cfsnet.co.uk/

Of the three or so UK suppliers I found, they seemed to be the cheapest and are quite fast in delivery.

The basic essentials, not listing amounts you need (we can work that out later) are :

• 300 gsm fibreglass mat. You buy this in kilos. CFS supplies 900mm wide rolled lengths. GSM means Grams per sq metre. So, 1 kilo is gonna be 3 1/3 square metres. (on a 900 wide roll). Unless you are covering large flat expanses, I wouldn't recommend anything more than 300 gms or it may be hard to shape.
• DONT bother with surfacing tissue.......you are not going to see it! If the self colouring, or gel coat has been applied correctly, or you use white gel, or paint afterwards, there is no point.
• Gel Coat - This is the top smooth layer you see on the outside surface. It can be bought clear, to which can be added colourant if you wish, or white, which I preferred cos its easier to see where applied, and I'm painting over it anyway. 
• Resin - This is the stuff you use to gunge and mould the matt into the shape you want! CFS supply catalyst / hardner for free with it. The resin is  the 'plastic P' part of GRP. Without fibreglass re-enforcement, a piece 6mm or more thick can be snapped in two by hand pressure.
• Mixing Containers - you need something to put the stuff in when working. I recommend the 3 litre (ungraduated from  CFS) and the 1.2 litre (graduated markings) containers.
• Catalyst Dispenser - a neat plastic bottle that you squeeze a measured amount up a tube to put into the resin or gelcoat to make it set. As its only 2% by weight compared to the resin or gel, its hard to guess! If you get it wrong the resin takes ages to set, or will set at lightening speed! (tolerance is 1% - 4%).
• PVA - polyvinyl alcohol - A kind of paint on 'cling film' that stops the part from sticking to the buck or mould. Also known as 'release agent'. Its also possible to use wax - but more of that later.
• Acetone - nasty solvent that's essential for cleaning tools and brushes with. Don't use on skin - it dissolves organics and can cause cancer. Used by ladies to remove nail polish. (perhaps by some guy's too...)
• Consolidating Rollers - metal 'paint rollers' in miniature that press down the layers of resin and fibreglass to create an air bubble free solid mass. Essential - a brush cant do that alone.
• Brushes -  buy a pack of fairly cheap 2 inch brushes - they can last quite a well if you clean them in acetone. CFS sell 10 for less than five pounds.
• Filler - if you are making your own buck, then you need to be able to fashion curves and corners. Small packs of filler from car shops cost a fortune - CFS sell 4 kilo tubs for about 10 quid.
• MDF wood - if making up a buck, then this is one material that can be used, along with hardboard for flat curves, like the sides of wheel arches.
• Disposable latex gloves - GRP work is very messy and if the stuff gets on your hands its really hard to get it off, plus it can sting, and you end up putting it everywhere, like door handles, your hair, etc.

Quantities

You will be surprised how fast you get through resin and gel coat.

Resin is used approx 2.5 times by weight for the glass mat you are pasting down. So, if you buy 10 kilos of resin, this will suffice for four kilos of mat, which at 300 gsm weight, will be approx 13.5 square yards of mat. This does not  sound too bad until you consider that you need to make your mould up from at least 5 fibreglass mat layers thick, then the same for the part itself. So, for our 10 kilos of resin, we actually end up with one finished part of 1.3 metres area, assuming no waste. This is the point at which you should check again the prices of ready made parts! (If you have that option).

I have seen it stated that if you are making a mould, it should be 2 times the thickness of the part you are laying up in it. For low volume use, five layers thick, I find that allowing the first two layers to set overnight, applying three further ones the next day, does not lead to distortion of the parts, at least in my experience.

Gelcoat is a cross between a really gelatinous non drip household gloss, and car body filler. To my mind, the stuff smells a LOT like car body filler. Its hard to say how far a 5 kilo tub goes - you have to paint it on two layers thick (you can supposedly spray it with a special gun, but its pretty thick stuff) - but I went through my first tub after about 15 kilos of resin.

Fibreglass Matt should be considered as being used five layers thick, then if you are also making moulds, this becomes times two. A five layer layup of 300 gsm mat comes out around 5mm thick. I would consider this a minimum for decent strength, anything less than 3 layers looks very fragile. Don't under estimate the amount wasted in off cuts - wastage will depend on the shape of the part being made. Laying the mat in smaller sections may help reduce wastage, rather than one complete single mat per layer.

Mixing Containers last longer than you think! Once the stuff has set in them, you can 'crack out' the brittle residue by flexing the sides of plastic containers, making the stuff flake off. It possible to get several uses of a single container.

Acetone evaporates, so if you can pour some into a covered container for cleaning brushes and consolidating rollers, and put the lid on afterwards, it will last a few cleaning cycles. An open container will evaporate rapidly and you will go through lots of the stuff! DONT CLEAN YOUR HANDS WITH IT!  A compromise (not ideal) method is white spirit or meths followed by soap, then followed by some kind of skin lotion. This works for me, but might be bad for others. You can buy a gallon of Acetone for a tenner, and you will use a fair bit so I would recommend that as a quantity.

PVA is a bit like alcohol mixed in water with  a coloured tint. So, imagine using a sponge to put two layers of water over the parts evenly - two times for mould and buck. Again, a good buy qty is 5 litres for a tenner.

Gloves - I bought mine from http://www.farnell.com/ who have a minimum ten pound buy, and 100 gloves were lest than five pounds. Compared to what a DIY shop charges for five pairs, this is a huge bargain. I think CFS also sell gloves....

Consolidating rollers and brushes will last for the project if you buy a couple of rollers, say 6 ins wide and 2 ins wide, and half a dozen brushes. Their life will depend on how well you clean and soak them with acetone. This is one reason why acetone is a good buy at a five litre quantity.

Making a part

For a part such as a rear wing, this is a three stage process :

1. BUCK - Make up an exact 'solid' model of the object you want to make as a final part (a 'buck')
2. Female Mould - Cast a mould over the buck to get a 'female' mould (you cant use this as a final part as its 'inside out' with the smooth surface on the inside).
3. Final part - Make the part from the female mould to get the finished result.

BUCK 

There are several ways in which to make a 'buck' to form your part - in this example, a rear wing. It could be a wire former, covered in something like fibreglass matting, covered with filler and sanded to the shape needed. It could be made from clay, and / or polystyrene sheet, like production car prototypes. It could be made from an 'egg box' type matrix of slotted together wooden sheets, again draped in some kind of covering material, or filled in with a cheap material, with a plaster / filler skim over the top.

 Or my way.

As the parts I need are generally reasonably simple single radiused edges, sweeping through a curve, and not something more complex like a Cobra replicas 'bulbous' wings, I decided to make the parts from 'terraced' or 'stepped' wooden sheets with filler forming the curved edges.

In the UK, a cheap and crappy (and used extensively on TV home makeover shows) board called MDF can be bought. MDF = Medium Density Fibreboard. Its essentially wood dust glued together, and is a little smoother than chip board. Its cheapest bought in 8ft by 4ft sheets, from a larger DIY store (B and Q Depot) or wood yard, that can saw it for you into smaller sheets. The smaller sheets stocked in some stores are VERY expensive by comparison - get a bigger one cut down.

The wing was usefully just under a third sheet tall, so I kept the 4ft dimension and had the sheet cut into three along the 8ft length. It took six FULL SHEETS to make the buck. That's about 50 pounds.

Once you have the MDF, you need to cut it to suit the shape of the part. In my case, the wing has a three basic large curves -  the outside curve, the inner wheel curve, and the one at the base, just behind the wheel. The 60mm radiused sides of the part are formed by the 'stepping' of the sheets as they are fixed together. I made the small curve at the back of the wheel by drawing around a dinner plate! The main external and wheel aperture curves were made by using a strip of steel. A pivot hole is made at one end, and a series of holes drilled in the other end at different positions to act as a 'compass' to scribe the arcs needed for each stepped wooden layer.

Basic wheel arch former

Each layer is reduced in size by a small amount to create the stepped 'edge curve'. Its easy to do this by drawing out a 60mm radius on paper, then bisecting it with 12mm (the mdf thickness) lines, and measuring how the upper layers reduce in comparison to the base layer.

Stepped sides to create radiused edges

Essentially, I had 6 layers of wood - a base layer frame, on which they all mount, and that the outer curved hardboard flat top surface is fixed, and then the five upper 12mm layers (12 x 5 = 60mm). I used wood screws to hold them together, about 5 per layer, screwed from behind so as to not affect the moulding surface.

The top two layers are not as 'complete' as the lower three - this is to allow the wheel aperture to be formed with a 'return' around the arch rim for strength and appearance.

DONT USE SHARP CORNERS! The fibreglass will not be easy to get in small diameter areas, and may make life harder getting it out of the mould. Another thing thats vital is to consider that the part musrt be designed to be able to be released from a mould! returns and curves in the wrong places may make the buck and female mould inseparable by design!

Assembled basic back shape

Once the basic shape is in place, it needs to have the curves filled in. I used car body filler, bought in fairly big, low priced tubes from CFS. It may also be possible to use water based household wall / crack filler, but I have not tried this.

In order to aid a 'key of the filler to the wood. I drove several nails into the 'stepped' areas, about every six inches, and well elow the final surface.

Mix up the filler, and build up the curve in 3 or so stages, leaving the top layer 'proud' of the rest of the wood. Try and keep the maount of air bubbles to a minimum or they will be at the finished surface, needing extra filler or knifing grade putty. Sand with an electric sander and 80 grade grit paper - or if you are certifiable, do it by hand. I wouldn't recommend it.

Make sure that the curves are within a decent tolerance, so your part does not look dented or rippled when finished. I made up a template a bit like a tri square, with a 60mm radius on the inside - this could be passed over the sanded radiused area to check for accuracy.

Sand any 90 degree edges of panels to give a slight radius. The inner 'return' of the wheel aperture was given a slight radius, and the area where the top two layers met the others was given a radius by a bead of silicone or acrylic bathroom sealer.

Once the buck is complete, give the whole thing a couple coats of water based varnish, sanding between coats with a light grade paper. Use a water based one, in case you melt the body filler! If you dont use sealer, the PVA might not do its job and you will glue the mould onto the buck. Very bad news.

Let the varnish dry. Sit back and admire - stage one is completed!

Female Mould

This is the part of the process that had me cursing most. Decide, at this stage, if you are going to use wax OR PVA. Don't even THINK about using both. My first attempt at a part, the boot (trunk) door, was a disaster of major proportions, as shown in the photo.

Wax repelling PVA into mega-pools!

The PVA goes on great at first, then pools into little puddles, like rain on a freshly polished car. But more of that later!

I did a fair bit of reading up on what was the best kind of release agent (for me) and how to use it.

The professionals avoid PVA and swear by waxing. A special kind of wax (Carunauba) is used to 'condition' the surface of the mould or buck. My understanding is the wax isn't putting a ‘shine' on the surface, rather breaking the potential molecular ‘bonds' from the polished surface to another surface laid on top (the part).

Wax has advantages. The first is it's the best way of creating a smooth part straight out of the mould. Using coloured gelcoat instead of spraying colour means that you can't sand any surface imperfections – what comes out of the mould is what you are gonna get. PVA can never leave a mirror perfect surface. A second advantage is that after the first few uses of the mould, the amount of waxing needed reduces substantially. On the first few uses, I have seen it recommended that between 3 and 20 layers of wax – put on with a cloth, left 2 – 6 hrs between coats, then buffed to be completely polished off, is the requirement. After 4 –5 releases, just  a single coat is needed between releases to take a perfect part every time. The mould conditions with age. If its gonna stick with wax, it will be on first use.

In my project, its only gonna have a first use! Further, I am not using coloured grp –its all being painted, so I can sand and fill any surface imperfections.

DON'T use wax and PVA together,  I have seen the opposite mentioned several times on the net. You get a disaster, like the picture shown! The wax will repel the PVA like nothing on earth. In this case I had to sand off the wax layer, and start again with PVA on its own.  

Applying The PVA

Once the buck has been sealed, and feels smooth to the touch, it can have PVA applied. Keep dust and crap off the surface, cos what's on there after it dries is what will be on the mould surface.

PVA is a water / alcohol / dissolved plastic solution. When applied, its ‘wetter' than water. It runs easily, but does not evaporate that rapidly. So, if you apply too much, it runs off or lays in pools. When those pools or streaks dry, that's what you get on your mould surface. Its important to get as good a finish as you can.

You can spray, brush or sponge.

Originally, I tried to spray with a hand held sprayer from a garden centre. Cost ten pounds, and fell apart in seconds. PVA has quite good solvent properties! Tried a house cleaning spray thingy, but the spray pattern wasn't fine enough. It might be acceptable to use a paint spray gun with compressor, but for me, hiring / borrowing a compressor (I have a gun!) would have been a bit overkill for all my 9 panels and 18 stages of PVA application!

Brushing doesn't work too well. Its quite hard to apply the PVA evenly, and not to get pooling and brush tracks.

What works quite nicely is a small sponge. I used the type that comes with a scourer pad on the back for cleaning dishes. Supermarkets in the UK sell them in a pack of five for about 30 pence.

Pour some PVA in a container, and soak the sponge in it. Squeeze out most of the excess PVA until it is lightly loaded, then coat the buck with the PVA sponge in long sweeping strokes. Keep sponging in the same direction with constant speed. Its not as hard as it sounds but gets better with practice. The important thing after coating the part is to watch it for a few minutes. You will start to see pooling and streaks develop. When these appear, use the sponge to spread the PVA a little more, or remove the excess. You will eventually feel the PVA start to drag – when this happens, its beginning to dry and will be prone to smearing.

One 'cheat' is to use a hair dryer, applied carefully, to accelerate the drying. Be careful - it can 'push' the PVA into pools where it dries them into little PVA 'bumps' or streaks that will show in the gel coat.

Once you have teased the PVA where you want it, go away and let it dry for a few hours. I have heard 1 hr or so is OK, but I would wait three or four hours or overnight. My reasoning is that if you (as you will need to) apply a second coat, if the first isn't dry, you will tend to ‘dissolve' it and move it around with the top coat, creating a single layer again, or a lot of pooling.

Buck after two coats of PVA

The buck shown is evenly coated with PVA - the side section is white hardboard with some of the white sanded away before the varnishing stage to achieve a smooth surface, and the upper curve is the finished, fashioned car body filler.

If you find your first attempt looks bad, its not a problem! PVA comes off with warn soapy water with the greatest of ease. Try again! I got through over a litre of PVA before I came up with something remotely useable.

Apply the second coat with care – try and use a lighter application of the sponge, don't use too much and DON'T  push the PVA around too much – you will loosen and smear the first coat.

If the PVA is a little ‘runny' for your liking, you can try a cheat. Pour the PVA into a container and leave it to evaporate for a while. This may take a couple hours or more, but it will get progressively more viscous – but beware of having something that does not flow and leave marks. PVA IS INFLAMMABLE – so don't do anything silly like heat it up.

Once the second coat ids applied, leave it to dry. If the whole surface is properly covered with an even film, and you are happy with how the surface feels (smooth, no tear drops, grit / dust etc) then you are ready to cast the mould.

Laying Up The Mould  

This is the stage that gets really messy – an creates a lot of fumes. Make sure at this stage that you have a GOOD respirator mask – I paid 25 UK pounds for mine – DON'T use  one of those ‘Micheal Jackson' dust masks. They wont save your lungs at all.  

The first step is to apply gelcoat to the buck surface, you so lovingly covered in PVA. Gelcoat is a MUCH thicker substance than PVA – which can only be a good thing! Its more like treacle, and very like non drip household gloss – the type with a jelly consistency. It very noticeably smells like car filler. Time to wear the breathing mask.

I used gelcoat at a level of approx 400 millilitres for each coat on the rear wheel arch. This is approx 0.7 - 1 square metre in area…..you may find that your coat can go further, or that you use more.

Mix up the quantity of gel coat with hardener by 2% weight. In a normal temperature environment, there is approx 20 - 30 mins life before it sets. (70f, 20c approx). Use a brush, generously loaded, to coat the PVA covered areas of the buck. You are looking for a final surface between 0.5 and 1mm thick. Due to the viscousity of the gelcoat, it tends to leave tracks from the brush, that will tend to even out whilst the gel is still wet. Brush in one direction, and don't overbrush. This will tend to ‘tear' and smear the coverage. Streaks don't matter – it's the coverage that's important. The ‘good' surface is against the PVA which is as good as your PVA – it wont show brush streaks – just valleys in the coating where it was too thin or overbrushed.

On a one time use mould, you might get away with economising on one generous layer of gelcoat. It will need to be evenly distributed. Thin spots might show resin through it, but as long as the mould is smooth, I don't think this is a problem, but is a situation I have not experienced. Always brush on two coats on a final part.

Let the first layer of gelcoat set over night. Depending on the gelcoat used, it will remain tacky or ‘soft' to the touch. I am told that translucent gel always remains tacky – but not so that it comes off on the finger – as it only sets in absence of air. The side against the PVA is absent of air. With the white coloured stuff I used, it isn't that tacky, and feels like one day old household paint.

If you need to apply a second coat, do so now and wait another 6 – 12 hrs for it to ‘go off'.

Now we need to apply the GRP resin / mat laminate itself. The really messy bit.

Work out the area you will be covering with fiberglass mat, and budget for five layers of matt. Its not essential to have complete single coverage with one mat per layer. Its perfectly OK to use separate sections, or to rip the mat to help it around corners. It is important to make sure that any joints don't coincide and create weak spots – go for a decent overlap between ‘patches'. Also, consider adding extra small patches in potentially weaker or greater stressed areas.

Cut up the mat you will be using with decorating / wallpaper scissors. Beware airborne glass particles. Bits always seem to get stuck to your uncovered skin, are invisible, and prickle a fair bit. It's a bit like hair down your neck after a haircut – but worse and typically happens on your arms.

!!!Cover up when using mat and resin!!!!

Work out how much resin to use. DON'T get ambitious! This stuff sets in around 20 mins, and seems to go ‘off' very rapidly in the last minute. It goes from a reasonably runny (like ice cream syrup) consistency, to an unwieldly gelly like gunk in seconds. It generates its own heat whilst in a mixing pot, and the more of it there is, the hotter and faster it sets and the longer its going to take to apply. All a bad combination! Unless you are applying a lot of large areas that are not too tricky, and are fast to apply, don't mix up more than about 2 litres at a time. You will use resin at around 2.5 times the weight of the mats you are applying.

So, if you are applying two layers of mat of 0.75 mtrs area, then at 300 gsm weight, there will be 1.5 metres of mat, which weighs 300 gms per metre, giving 450 gms weight. Multiply by 2.5 gives a resin weight of approx 1.125 litres. In this case I would mix up 1.25 litres – the extra for safety, and for damping in the more stubborn corners.

The clock starts when you add the catalyst / hardener. Get your fiberglass mat, gloves, overalls, consolidating rollers, brush, cleaning materials, eye protection (important!) and breathing mask ready before you mix up!

Apply resin generously to the area you plan to lay up. Only apply to the parts you are going to apply mat to NOW as the stuff will run down and not be wetted at the uppermost vertical areas to a good degree. Make sure your floor and walls are protected as this stuff goes everwhere.

Almost like a Cameron Dias ‘Hey, is that hair gel on your ear' situation.

Use the brush to ‘dab' the mat into place into the resin so that the resin comes through the surface of the fiberglass mat. DON'T use a painting action, the glass strands will be pulled and pushed out of position, it must be a dabbing action. Use the consolidating rollers to squeeze the mat down. I find that on the first layer, its sufficient to use the brush only, then putting the resin over the top of the first ‘glass layer with a brush (dabbed not painted!) then dab the second layer of ‘glass over the top, giving it a good thrashing  with the consolidating roller to press the resin through both layers. The entire surface of the mat should appear a yellowing orange colour, without any sign of white mat areas, and no bubbles or loose areas.

Pay particular attention to the difficult corners and bends. If you don't press the mats close against the gelcoat, the gelcoat wont be properly attached and the surface will  be fragile and come away.

Boot (trunk) door after sanding but before PVA, on mounting board

Boot door after 5 layers of resin and 300gsm mat

At this stage, I walk away and let the first two layers set overnight. Next day you will see your buck covered in an orange / yellow jacket of hard grp. Now start applying the top three layers of fiberglass mat. Once done, walk away and leave it for two days minimum to cure in the mould. If you release it too soon it may distort or disintegrate.

After two days, its fun time! You have to get the GRP jacket off your PVA coated buck. You may find that some edges will pull away by hand, loosening from the mould with a reasonable pull. A good sign, as this shows the PVA is working. Generally, the part needs a bit more encouragement. With the edge of a screwdriver, blunt chisel or thin metal or plastic strip (a small wallpaper scraper works well) , separate the edges of the mould from the buck. Before you do this, it's a good idea to trim off the excess GRP from the mould – the bits where the resin ends and the white mat appears. Use a mask and cover up, and use a grinder with a metal cutting disk to cut away all GRP that's not needed – the closer you can get access to the separation point, the better. Don't go too far, as you need a flange to mould the final part against in some cases, and some ‘over run' to allow for trimming of the final part you will be casting in the mould you have created.

Once the edges are free, prise them away from the edge with a shaft of a screwdriver (don't scratch the gel coat inside!) and pour very hot water into the gap. Allow the water to settle into the gap, then move to another spot and pour in more water. Do this all the way around – you will likely have to do this twice. If you see PVA coloured water running out, this is good! It means the PVA is dissolving and the parts are hopefully going to separate!

Tap around the part with a soft faced hammer – GRP does not shatter that easily, but don't push your luck! Pick a spot around the mould (in a wheel arch, this is at the wheel opening ‘flange'), insert a lever using a hammer, and try and prise the part from the buck. It most likely wont come away easily. If after a while no sign of movement is seen, try inserting a long flat object (I used a steel ruler – but beware – it can mark the gel coat) into the long flat surfaces of the mould / buck. You might hear a ‘crispy' sound of GRP coming away from the PVA. Work the lever around, beware of damaging the gel, and if needed, pour more hot water in. Go back to levering the part at advantage points.

On average, on my two wheel arches, I found it took around an hour to separate the parts. Perhaps with wax, this is all different! Once separation begins, the part will slide off quite rapidly. Once it off the mould it will be covered in the remnants of PVA and sticky PVA coloured water! Wipe the newly released mould down with warm soapy water and a sponge so that it is clean, leaving just a nice smooth internal gelcoat surface.

Buck after mould removal - note peeling PVA

Mould removed from buck, prior to cleaning

You now have a female mould! Its just like the part you always wanted, but inside out!

Now for the final stage of the three.

Making The Final Part 

Once you have got to this stage, you have basically used all the techniques to create the mould from the buck, and need to repeat the process using the new mould as the former for the fiberglass / resin / gelcoat layup process.    

Sponge on two coats of PVA and leave to dry.

Apply two coats of gelcoat and leave to dry 4 – 6 hrs until tacky but no so that your fingers are marked.

Apply two layers of 300 gsm resin and fiberglass mat and allow to dry.

Apply second three layers of resin and mat and allow to dry.

Allow to set in mould for 48 hours.

Release from mould.

Trim off moulding excess.

 Final part, cast in mould.

 Separation of parts.

 Part after initial but not final trimming, awaiting cleaning.

To highlight the time spent / stages, here is a full list of operations and approx times :

1. Make up buck shape (8 hrs)                  1 day

2. Coat with 2 layers PVA (1 hr)                1 day

3. Apply Gelcoat (1 hr)                             1 day

4. Apply 3 layers + resin (1.5 hr)               1 day

5. Apply final 3 layers + resin    (1.5 hr)     1 day

6. Wait 2 days                                        2 days

7. Release from mould + PVA (2 hr)           1 day

8. Apply Gelcoat (1 hr)                             1 day

9. Apply 3 layers + resin (1.5 hr)               1 day

10. Apply final 3 layers + resin    (1.5 hr)     1 day

11. Wait 2 days                                        2 days

12. Release from mould + trim       (1 hr)     1 day

That's a total of up to 14 days start / stop work. At this point, if building a standard car, the idea of actually BUYING GRP panels isn't so bad after all…….  

  Buck, buck after PVA coating, mould and final trimmed part