Plus 2 paint preparation

PostPost by: Grizzly » Wed May 14, 2014 10:06 am

bdthompson wrote:Gents,

I hope I am speaking on behalf of a few of us but please keep this going A layman's terms best way to paint a fibre glass shell is important to a lot of us......

I think there are 3 generic questions here too,

1) what is the best way to paint a fibre glass shell with regards trying to keep a vehicle as original as possible.
2) what is the best way to paint a fibre glass shell with regards trying to get the best and long lasting finish as possible.
3) With the advances in paint tech you would think that new ways are the best, but how much ??? will it upset any resale prices of the car as and when and if "you" want/have to sell it on?

I know this expands the discussion point a bit, but if people in the know could comment I KNOW I would find it very useful especially as I am on the road to completing a full body off resto.

Thanks guys.............

TBH with you, i have Painted cars with Cellulose as original before now and imho it is not ideal to use on GRP (it has allot of Solvents which attack the GRP it also is old tech so does not stick to GRP well at all) the labour of putting three coats on denibbing increase the Thinner and three more coats etc etc takes an age, so for me i would not entertain refinishing as Lotus.

That said you could use Modern Primers that Do stick very well then Refinish with Cellulose again being careful that the large amount of Solvent doesn't lift any edges which will give you a Original looking car BUT!! as every one knows Cellulose requires allot of Maintenance (Sun fades badly and need t-cutting every six months or so)

As for 2k colour, there are two ways of going, First is Direct Gloss (this is only Solid colours i.e. non Metallics) the 2k Direct gloss has some traits of Cellulose, it tends to have a Milky shine to it and still oxidises in the sun alltough much slower than Cellulose) its put on in usually two wet coats and it lends its self well to the diy'r as you don't have to worry so much about marks and nibs as its a colour coat. Then you have Base and Clear this is the Modern way of top coating, you have a Colour coat which is very Solvent (mixed 1-1 with thinners in allot of cases) you build this up in nice even coats and let it dry to a matt finish, the 1 major issue with Base and Clear that means its a PITA for DIY'rs is that once the Base is on you can't touch it as any mark or bit of dirt is held in animation by the clear coat which is obviously ..... Well Clear and has to go over the base to seal it and give the gloss and UV protection, so instead of the Direct gloss covering marks every time you re-coat the Clear picks up marks and dirt with every coat so if you plan on more then two coats on it could end up looking like some thing from Jurassic park with bits of flys and all sorts in it, But get it right and the Base and Clear doesn't Oxidise, Doesn't need t-cutting to get a shine on it, takes a lot more to chip etc just more modern and harder wearing.

That is all Solvent based paints and i could go onto Water base paints but tbh it would look really wrong on an Old car, Water even though its allot Easier to apply (you put it on and it drys almost instantly with a hot air gun) its not for the DIY'r, its Three times more expensive than Solvent, the Colour is Much cleaner and Metallics brighter as the Water Base acts like a Barrier coat so the solvent don't make the Clear go Milky. TBH it just looks wrong on an Old car as there is Too much gloss and because water Base is much rougher the clear has to be thicker which gives you a better shine but just looks wrong.

As for Price, well i have never worked in the US and here in the UK i get my paint at trade so might be a bit off so i added a bit so you get an idea what to pay if you walked into a Paint shop, i usually pay about ?10 a lt for Cellulose colour, ?6 a lt for Cellulose Primer, and i would expect a small car to use 3 lt of Primer and 4-6 lt of Colour depending how deep i wanted the gloss. 2k Direct gloss is usually ?20 a lt and Primer about the same, on the same small car i'd expect to use 2lt of Primer and 2lt of Colour. Base coat can be as much as ?10 a lt to ?2000 a lt depending what you buy but for a Solid colour (nothing mad) i'd expect ?15 a Lt and the Clear again depending on Make and Model i use RM Diamond clear which is ?200 for 5lt and for the same small car i'd expect 1lt-1 1/2 lt of Base and 2lt of Clear. Thats just a basic idea of the Costs, you have Hardeners,Colour Thinners, Gun Thinners, Flatting paper, Fillers etc etc to add on that. but i often put a ?500 budget on a paint job for Materials and often have change. The other thing with paint is don't think your getting a deal buying cheap, its cheap for a reason, most paints are Pigment suspended in Binders so as the Binder is cheap they just reduce the Pigment meaning you need to put more paint on the get the same Pigment coverage, the other Knock on effect of More Binder is that is sinks / shrinks more as its drying and because you tend to over apply it often traps solvents so you get popping etc as well.

The Epoxy Primer i use on GRP to seal it and make anything going over it stick well is about ?40 a Lt and because i use it more as a base to build off i don't use more than a lt on a small car and i put two medium coats on and leave it upto a week to cure so its rock hard.
Chris
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