gelcoat or paint question

[griff71]

so i'm fixing up a 1995 kontiki, lots of damp round the lower edge, i'm also repairing the skirt which had several big cracks.
i've sanded back some areas and it looks like a pink primer below the white topcoat, so should i paint it when finished or is this actially a gelcoat, new to all this so sorry for what may be a silly question.

 

[griff71]

actually, forget that question, i used the 3m decal remover and noticed that under decals is gelcoat, most of the skirt has been painted where someone has done a quick bodge job with filler but hadn't used any fibreglass so its all fell apart. i'm going to rub the whole thing down to remove paint, i've already fibred and west system epoxied the worst areas, will give it all a good rubdown and gelcoat/flowcoat it before polishing and waxing, hopefully i can do as good as i've just talked. us brickies aren't known for doing delicate work!

 

[funflair]

To answer the question in the fist post, it have been painted as the pink primer would not be under gel coat, depending how big the area is it can be hard work flow coating and rubbing back to a good finish.

 

[griff71]

its about 4.5 metres long in total, probably about 2m² with all the ins and outs, i've never worked with this stuff before so when i hit the pink i wasn't sure what the deal was but once i pulled off decals i could see gelcoat as the other areas were flush with decals which means painted at a later date.
i'm gonna strengthen up the skirt more from the back and then rub down the whole face, got some filling to do which i will do with west epoxy and micro balloons. get it all good then applying a coat of gelcoat followed by a coat of flocoat.
its gonna be a bit of work but i plan on doing loads of gelcoat repair on the main van so this can be my practice piece to hone my skills and learn from any mistakes before hitting the big job.

 

[funflair]

its about 4.5 metres long in total, probably about 2m² with all the ins and outs, i've never worked with this stuff before so when i hit the pink i wasn't sure what the deal was but once i pulled off decals i could see gelcoat as the other areas were flush with decals which means painted at a later date.
i'm gonna strengthen up the skirt more from the back and then rub down the whole face, got some filling to do which i will do with west epoxy and micro balloons. get it all good then applying a coat of gelcoat followed by a coat of flocoat.
its gonna be a bit of work but i plan on doing loads of gelcoat repair on the main van so this can be my practice piece to hone my skills and learn from any mistakes before hitting the big job.

I trust you are going to use Polyester for the flowcoat, I would repair with Polyester as well to be fair as that would be the original resin used and Epoxy are not always that easy to work with, although you sound like you know what you are doing.

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[griff71]

i've never worked with epoxy or polyester to be honest, i was going to use polyester but i did a bit of research and ended up going for west systems epoxies as it is a tougher material, also they do state that gelcoat will adhere to it. fingers crossed they weren't telling porkies.
I went with west systems for the main damp repair work on the motorhome and so far its pretty good stuff. time will tell if i made a good choice or if i will be leaving a trail of gelcoat down the M4.

 

[sonar]

Gel coat sticks to either as does flow coat .the west system is epoxy you could have used polyester either was o.k.

the difference is in the application epoxy GRP will stick to a few surfaces including wood.
where as a polyester resin will not. Both systems will stick to old GRP. But your not able to mix and match the two systems as the chemical bond will be very weak.

epoxy uses a hardener where as polyester uses a catalyst.

if you intend to use gel coat gel coat is a polester resin again and will require a catalyst as for
your final finish it will require a few drops of wax additive while mixing.
WHY. Because the wax will come to the surface and make the gel coat easier to sand down.

no wax added and it will take a very long time to stop being sticky if ever.

flowcoat is a polyester resin and as stated will require a catalyst .

flowcoat is a runny type of gel coat with wax added and is easier to sand down between coats.
the last and final sanding has to be done in ever decreasing sandpaper / wet and dry
you will find you have small dents at this stage that you can put little blobs of flowcoat on and sand away.
when you have gone down throught the grades to approx 800 grit you can then use some g3 to get the area to really shine.

 

[griff71]

cheers for that info, i have been reading up on gelcoat so i bought gelcoat and flocoat, will do a coat or 2 of gelcoat then top it off with flocoat as that will dry as like you say it has the wax added, i do have styrene with wax but decided to buy the flocoat with wax already added as its one less thing to possibly screw up.
taking the rest of today off so will probably get a bit done tomorrow, i will take the panel into my garage to work on as soon as i can make space, that way i can put heaters in there to ensure epoxy is fully cured before i even consider putting the gelcoat on.
i will post more progress pics as i go on.

 

[sonar]

cheers for that info, i have been reading up on gelcoat so i bought gelcoat and flocoat, will do a coat or 2 of gelcoat then top it off with flocoat as that will dry as like you say it has the wax added, i do have styrene with wax but decided to buy the flocoat with wax already added as its one less thing to possibly screw up.
taking the rest of today off so will probably get a bit done tomorrow, i will take the panel into my garage to work on as soon as i can make space, that way i can put heaters in there to ensure epoxy is fully cured before i even consider putting the gelcoat on.
i will post more progress pics as i go on.

Your right if you give the work a coat of gel coat you will need to apply a very thin coat of flowcoat within 24 hours and then the gel coat will not be sticky any more and then it makes no difference how long it takes between flowcoat Applications.

 

[sonar]

Any update on your progress.

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[griff71]

i've got most of the prep work done, the major repairs are 90% fixed, just got a few dips and small holes to fill, the weather is hampering me a bit as its a bit too cold in the garage for gelcoat, i can heat it ( which i will ) but i would rather the base temp be closer to what i need to start with otherwise anytime i go in the garage the temp will drop way too low.

 

[sonar]

You can fill dips with a std car body fill as there not in water all the time.
so you can fill the dips sand down and then carry on .

flowcoats would be an easier application to apply and sand between coats than Gelcoat.
Gelcoat is very thick and may end up taking a long time to sand back.

Flow coat is just a thinner version of Gelcoat but with wax added and will be thinner more controlled coats like paint.

 

[airwave]

i've never worked with epoxy or polyester

I would strongly advise you NOT to flow coat . This is a very difficult job to complete and certainly not a job for an amateur , worse there's no actual gain . Paint is a perfectly acceptable alternative to gelcoat , and does exactly the same job . Flow coating is more often used in boat construction in areas that are not considered cosmetic . Yes it does seal the fibreglass , but the surface is never flat , so often sanding , and polishing/repainting is needed . As there is no guarantee of the coating thickness , to seal the surface properly , painting will still be required . Epoxy paint , in the main from a marine supplier , is considered to be equally as good as gelcoat . However with a good epoxy coating , ordinary automotive paint will , also do an equally good job .

I would think very carefully !! .

 

[Jamesh]

Don't use epoxy without pigment or paint as UV light will age it quickly.

 

[griff71]

well i've decided to paint the skirt, the temp in my garage is no good for gel/flowcoat. i,ve got a friend out in spain who fixes up yachts and he recommended 2 part polyurethane paint for a good robust finish so i'll go with that instead, the stuff i'm looking at can be used as low as 5° so that means i can crack on with the job rather than waiting for warmer weather, i was thinking of using car spray paint but the previous bodged job was done with that and it didn't look too flash.
i need to get this skirt painted and installed so i can refit doors and hatches to finish this side off before turning my attention to the otherside, which also entails fixing the skirt along with more damp repairs to the joint of wall and floors.
thanks for your advice, between you guys and my mate in spain i could see that i was onto a mission impossible going with gelcoat.

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[airwave]

i was thinking of using car spray paint but the previous bodged job was done with that and it didn't look too flash.

Car paint can be accomplished to a very high standard on plastic , and fibreglass , but the devil , as they say , is in the detail . I used to work in an aircraft paint shop , where radomes and wing tips were painted along with the aircraft themselfs . In some cases , these units was removed for paint , but as with everything , preparation is the key . The majority of people , use the same technique as you you would with steel , and wonder why it fails , yet only in very rare circumstances will this work , often amounting to little more than luck . Now i admit , i'm no expert , but the simple reason in both instances , is because your painting what is basically an oil based product , and by oil based , i mean crude oil ! . They are basically both a by-product of crude oil . Plastic is the easiest to paint , using simple degreasing techniques , but fibreglass more often than not , will require special surface preparation , and the use of an etch primer , specifically formulated for the product .
Flow coating on the other hand , though relatively easy to apply , is not a surface treatment , and was never meant as such . It will smooth a surface , beit unevenly , and is highly dependent on surface temperature as you have already found . It's more usually used to cover and seal the inside of say a lockers , or seal fibreglass inside a water tank . Home builders use a completely different technique to finish the hull of their creations , but that's a very different story . Once dry it can also be incredible tough to sand . Aggressive techniques or power tools are often employed , which due to their very nature , will more often do more damage than good . Honestly mate you were on a hiding to nothing .
Now i will finally add , one further thought . I knew someone who had a Reliant Scimitar resprayed . Now to those unfamiliar with this car , it's a 70's sports car , with a plastic body , yeah okay fibreglass , built by the very same company , famous for the three wheelers . It was a professional company who undertook the work , and he told me , it was been regelcoated . The guy was a bit clueless with fibreglass , but he was adamant it was being sprayed . At the time , personally i thought it was more likely to have been epoxy coated . However products have moved on since i've worked in a paintshop , and i discovered a major problem with my own boat 20 years ago (i finally sold it last year) . So though i do try to keep up with the boating world , it is just possible a new product has emerged since .

 

[cyberyacht]

2 pack polyurethane is quite brittle and will craze on any surface that has any degree of flexibility. The product may have moved on though as I haven't used it for many years.

 

[sonar]

Spray painting you will need a sealer first it’s a flexible system for plastics. Then your able to do your other coats
of paints.

if you had used Gelcoat or flow-coat you would not need anything like this as both are a form of flexible polyester plastic.

 

[sonar]

2 pack polyurethane is quite brittle and will craze on any surface that has any degree of flexibility. The product may have moved on though as I haven't used it for many years.

No your correct it needs a sealer designed for plastic before application.
same as plastic used on cars and any other plastic parts .

 

[griff71]

cheers guys, will look into it

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[Jamesh]

I'd use epoxy paint tbh.

It's what they use for osmosis repair on yachts and will give a stronger less brittle finish.

Just get the mixing ratios right.

 

[griff71]

i've used a 2 part epoxy primer, its called interprotect, on top of that i've put the 1st coat of international perfection undercoat and will finish with perfection topcoat, the side fairing/skirt isn't really flexible since i've reinforced it and when its fixed back on the van it will be even less flexible so hopefully the paint won't crack.
only one way to find out i guess.
the paint i bought goes a long way so i should have plenty to do the other side skirt too which is also pretty badly damaged.

 

[griff71]

just an update of progress, finished painting the first side, took 2 coats of epoxy primer, 2 coats of undercoat and 3 coats of topcoat. it was rolled on using solvent resistant rollers and tpped off with a brush. its deffo not as good as a spray finish but i'm pretty happy with the results for a first attempt at this type of thing.
fingers crossed it still looks like this in a few years.

 

[Jackd]

just an update of progress, finished painting the first side, took 2 coats of epoxy primer, 2 coats of undercoat and 3 coats of topcoat. it was rolled on using solvent resistant rollers and tpped off with a brush. its deffo not as good as a spray finish but i'm pretty happy with the results for a first attempt at this type of thing.
fingers crossed it still looks like this in a few years.

Not bad for an old brickie Well done you!!!

 

[griff71]

thats only the first one done, gotta refit it so i can get door and hatches back on before taking off the other side and fixing the skirt alongside damp repairs, then a total renovation of the interior,

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[sonar]

thats only the first one done, gotta refit it so i can get door and hatches back on before taking off the other side and fixing the skirt alongside damp repairs, then a total renovation of the interior,

Total renovation of the inside just finished mine Thank goodness only took near on three months.
the list just went on and on as one thing was done another was added to the list.
then there were all the bits that did not work the bits that needed upgrading then more bits that had to be fully replaced.
mountains of stuff put in be other owners and partly removed by others.
still it’s quite enjoyable doing it so long as you don’t start counting how much it costs.

 

[griff71]

haha, yeah i've got loads to do, i've repaired the damp on the one side, fixed the skirt, welded the step and painted it, braized one of the hatch frames together. once the skirt goes back on i have the main door and 2 hatches to refit and put new rubbers on, then onto the other side which is much the same, less hatches but window needs to come out to sort a leak. once that side is done i have to reseal all the exterior joints, put a vinyl floor in, build a bed, reupholster the seats, rebuild the kitchen, paint all the interior, install new cooker and fridge, upgrade all the lights and electric sockets tidy up the bathroom. also a stress crack to repair, change rear light clusters, and also give a lick of paint under the chassis.
probably a lot more to do but will concentrate on the above first.
so my 2022 is going to be busy

 

[sonar]

Good luck there will for sure be a lot more to do than you thought.
keeps you busy for a while

 

[Jamesh]

just an update of progress, finished painting the first side, took 2 coats of epoxy primer, 2 coats of undercoat and 3 coats of topcoat. it was rolled on using solvent resistant rollers and tpped off with a brush. its deffo not as good as a spray finish but i'm pretty happy with the results for a first attempt at this type of thing.
fingers crossed it still looks like this in a few years.

I'd be happy with that! Puts many van life paint jobs to shame!

 

[griff71]

i got it back on the van today so can continue the project, the colour is a lot whiter than the van but the van will need a repaint, (next year) as its been painted by previous owner and its pretty shitty. when i peeled off the black tape in the photo to fit the hatch a load of paint came off with the tape, so i'm gonna sand all that back and use same paint as the skirt.

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