East coast fibreglass supplies I found to be very reasonable. I bought 2.5l as it was cost effective but you could start with just 1L.
Flowcoat is just gel coat but with wax added. You could buy gel coat and add the wax (just like adding the catalyst) which is very cheap. This way you have gel coat in case you need it as well.
You can get it cheaper in black or you can get it mixed to a RAL colour close to your final colour.
I buy 25 disposable 2" brushes from Ebay for under £10 and just chuck them. 4 pint milk bottles are ideal for mixing, I cut them so that the handle is still attached which makes a convenient place to hold it and you get to know how much resin/catalyst you need without having to be too exact. There is a picture somewhere on my build thread showing the milk bottle cut down.
I just put a thick coat on, as thick as you can without runs (easier said than done), you can go back and brush out any runs before it goes off. I changed my colour halfway through so had to put a second coat on, because of the wax which floats to the top to allow it to cure I washed the old flowcoat very thoroughly with meths to remove the wax.
You don't need to do under the rear clam but if any of it can be seen it looks much neater, if it is in an area that will get dirty it will make it much easier to clean if it has been flowcoated, personally for the small cost involved, I would flowcoat everything.
because of the wax which floats to the top to allow it to cure I washed the old flowcoat very thoroughly with meths to remove the wax.
Do you know if it's important to have the top surface at the top (if you get my drift?) ie if flowcoating the underside of the bonnet, does the bonnet need to be upside-down (compared to when fitted) so that the wax floats to the TOP, or does the wax go to the surface whichever way up the part is? If it relies on gravity, then the wax could go to the fibre surface and the flowcoat remain sticky?
I would advise the OP waits until the ambient temp increases unless in a heated workshop! This cold weather isn't great for GRP work!
First foray into a kit build starts next week or so. I will have questions I'm sure
First one is with regard to flow coat. I'm doing the underside of the bonnet of a Kobra. I assume it would be good practice to do under the rear clam?
Bonnet gets painted in body colour I assume though.
Any tips on the amount of flow coat I need. Best makes and where I can purchase them and method of application ( rush or roller?). How many coats?
As background I am intending to go a dark silver body. The donor is black so I a, planning black or grey flow coat.
Any help is appreciated
I would endorse Jaguartvr’s recommendation of eastcoast fibreglass as suppliers (they have the added advantage of being close enough for me to pop in when I need something).
I’m building a Dino at the moment and have covered the inner raw fibreglass on the panels and interior with gel coat.
I buy clear gel coat and add the required pigment to give me the colour I need.
I have tried flow coat but was not happy with the finish I got, it’s dull and without removing the wax coat with copious amount of meths you can’t paint it or put another coat on.
I now just use normal gel coat, it’s curing is supposed to be air inhibited and so after I have applied it I wait until it’s hard but still tacky, then cover it with an acetate based film such as cling film or pallet wrap to exclude the air. After a day or so it’s fully cured and I just pull off the film.
To be honest though I have noticed (from drips of gel coat on my garage floor) that it only takes a few days to cure properly anyway without being covered.
I apply it with a brush if I’m working upside down (this does get messy and I go through quite a few pairs of latex gloves!) or on a vertical surface. For horizontal surfaces I just pour it on and use a spreader to get an even coat.
I used about 500ml of gel coat for the inside of the my Dino bonnet.
When working at this time of the year I would advise heating the gel coat before you add the catalyst, I have an old microwave oven I use, a quick blast of about 10 seconds per 100ml of gel coat gets it nicely warmed up. An infra red heater is also useful to warm the panel up before you gel coat it.
I find that acetone is the best cleaner to use for brushes and any gel coat spills or splashes that you need to clean up afterwards.
Following on from Neil's good advice re using gelcoat and acetate........ It is indeed sometimes useful to be able to apply additional gelcoat, and as Neil states the wax can be a problem. So if using gelcoat and it remains sticky, another way (works in the same way to exclude air) is to spray the sticky surface with spray release wax!
Gelcoat and spray with PVA. Its water soluble. Easily removed.
Good thinking Batman!
I've never found PVA mould release to work - In fact I spent many an hour extracting a (thankfully) destructible plug from a mould that I couldn't get out. For me, PVA seems to act as a glue! (and yes, I am using the mould release and not PVA glue
Now I have a use for the bottle full in my garage!
I've used matt black cellulose brushed straight on the underside of a GRP bonnet for 9 years and it's lasted ok. It depends if you want a 'coating' or a 'cosmetic coating'. A useful thing (for underwing areas likely to get stone hits) is the super-elastic not bitumen coatings for waterproofing flat roofs. I can't remember offhand the brand name, but it's about £30 a can (2l?)
Heres the link to a picture of the underside of my front end after it had been flow coated, probably less than 1L used. The only prep was to give it a blow over from the airline and then brush painted upside down before painting. Any overspray can be rubbed off with meths due to the wax or if very bad just another coat of flow coat. Really transforms the finish and general appearance. http://www.madabout-kitcars.com/foru...t=5892&page=16