Here it is boys, something I like to think as the last step in getting a perfect part!

After stepping into the clearcoating/painting business I can tell you, with or without a paint both it is a total PITA. I cant stand clear coating a part after de moulding, then the clearcoat gets wavy or a bug in it. then i san and polish, still not perfect.

I'm starting to learn this real fast; the key to a perfect part, is taking a mould from a perfect part and polishing it there. I plan to make some really perfect molds, then try this.

 



 

The site says you can brush it on, we for my size parts that would be really connivent. Now matter what the surface of the part will be perfect but if your paint strokes on the back are to thick you may see your weave get a little wobbly.

When making parts smaller than ".5 meter" I think my cup gun is a bit much? think an air brush system would work?

 



If Brute Force Isn''''t working your not using enough...

Would be interested to see more results of this gel coat especially brushed on! Also would be good to find out the weight difference of having the gel coat as opposed to not.

Dave.

well you can guess the weight by how much you measure out for your part, then subtract whatever you don't use.

Is there anyone on this forum that has experience using this? especially brushing it on?

If I must spray it on how many coats should I do? any examples or ideas apreciated?

 

Will it stick to pva??



If Brute Force Isn''''t working your not using enough...

I've used the GC50 gelcoat brushed on to the mould at a rate of 300gsm, you need to work quite carefully to avoid voids in the coat - initially you get both thin streaks and large pinholes where the surface tension breaks but get an even coat with very gentle brushing to finish and it works.
I'm sure you could get similar/perfect coverage with less material spraying it on - I will probably try that soon as the gelcoat is the equivalent to another layer of CF at 300gsm.

Hope that helps
Stuart

Hi Guys,

Brushing this gelcoat if fine for smaller parts, you will need approximately 200-300 grams per/sqm for a thin even coat, using a clean brush simply coat it down like you would any standard polyester gel-coat keeping the surface as even as possible. Spraying will require the same quantity for coverage, this should be applied in 1 coat, you will need to build the coat up to a thickness where the gel begins to self level and stop at that point; If the coat is too thin is will appear to have an 'orange-peel' effect if it is too thick it will run.

Brushing the gelcoat it not ideal for larger flatter infused parts (like a bonnet) as no matter how hard you try the gel will not be perfectly level so the brush-strokes will show through, this is not as much of a problem for wet-lay components as the carbon 'floats' a little more and the effect is not as obvious. Small or detailed parts are fine to brush and as long as you make a careful application you should not see the brush-stroke.

This gelcoat will release from any release agent, PVA, wax, Easylease etc. It's also really useful if you want to make an epoxy part from a polyester mould as it will release well from polyester (unlike epoxy)

I look forward to seeing how you get on with it, keep us posted! 

Paul Statham
Easy Composites / Carbon Mods - Technical

[[EDIT - DOUBLE ANSWERED! YOU ARE LUCKY!!]]

Spraying will certainly mean that you can put it on thinner than you will with a brush and, as with gelcoats of every kind, if you have a very slippy mould surface (like chemical release agent or wax) then if you try to apply the gel too thin with a brush then you will see the gel breaking out in fish-eyes. It's particularly important to avoid this with the GC50 because you CAN'T double-gel. If you try to repair a fish-eye with some more gel over the top (once the first layer has tacked off) then the second application won't bond to the first at all. The GC50 simply will not bond to itself, only epoxy will bond to it. 300g/sqm if applied by brush without fish-eying wouldbe very impressive. I think whenever we brush or roller apply polyester gelcoat (which the GC50 effectively is) then the least gel we can put down is more like 500g without fish-eying. By spray-gun you coudl be less than half that.

The clarity of the GC50 is very good and a thicker application by brush or roller won't cause any problems in terms of the clarity of the carbon; the only thing to watch out for, which has already been noted, it the 'ripples' that you can see in the carbon fabric if you have too much texture in the surface of the gel. You won't ever see this if you just 'wet-lay' the carbon onto the gelcoat because the extra resin floating about in a wet-lay lay-up means that the carbon will 'even itself out' and not closely follow the ripples in the gel surface. Under vacuum (resin infusion, pre-preg, vacuum bagging etc.) then the carbon is pressed so hard against the gelcoat that any ripples in the gelcoat will have an efefct on the appearance of the carbon.

Matt Statham
Easy Composites / Carbon Mods - Technical Sales

Will thiss stuff protect from UV, as a Lacquer would?

Hi Alex,

No, epoxy doesn't protect from UV like a polyurethane paint or a polyester gelcoat would. The epoxy would hold up fine but you can't describe it as providing UV protection for what's underneath.

--Matt

Matt Statham
Easy Composites / Carbon Mods - Technical Sales

Thanks guys, Sounds like I will be spraying it on. My question about the pva was not if it would de-mould well but if I spray it on the pva, will it lay right?

 

Guess I need to just wait tell it gets here and give it a shot. I want to have it on thiere thick enough I could do some minor sanding if needed.

 

im at the point were I am cuting back the amount of waxing I do,just 2 times then pva.

 

I can say coming from a noob I was using was to much, so much that the wax was efecting my part surface. NOW I know that just a haze of wax is al you need, otherwise more work later....

 



If Brute Force Isn''''t working your not using enough...

My question about the pva was not if it would de-mould well but if I spray it on the pva, will it lay right?

The gelcoat will go down onto PVA fine. PVA is a much less repellent surface the wax or chemical release agent so, although PVA comes with plenty of its own problems, it does make it easier to put gelcoat down onto it.


Matt Statham
Easy Composites / Carbon Mods - Technical Sales