Painting plug

General Composites Discussions Composites Talk
#1

I have made a wooden plug that now needs a coat of paint to make it smooth and shiny.
I then plan to make a fibreglass mold of the part. Then I will make a fibreglass test piece to see how it performs before doing a carbon one.

What should I use to paint the plug bearing in mind I don’t have a spray gun. I have used acrylic rattle cans before but the gelcoat seems to melt/stick to it on occasions. Can I brush some 2k paint on and then rub it down? Polyurethane varnish from a rattle can? Any other ideas(apart from duratec as its pricey here in the uk and I don’t have spray facilties due to lack of space etc)

Thanks

Ray

#2

Firstly you cant just paint a wooden plug. It will need to be sealed first or it will just soak up anything you paint it with.

The easiest way to do this would be with polyester spray filler (Upol Reface is ok), and I guess this could be brushed on, but getting it to stage where it was smooth enough to take paint, would take quite a lot longer than with spraying.

As to brush application of 2k paint, I would say it would be best to forget this, as you are going to keep sanding through, and it will end up being a bit of a nightmare.

Best thing might be to try around a few small local spray shops, and ask if they could give your plug a few coats of dark colour 2k, after you have got the spray filler completely flat using a guide coat with 320 wet flatting. Also worth bearing in mind the 2k must be completly dry before you start moulding work.

Finally when your plug is prepared and you are ready to apply gel-coat, apply a coat of clear gel first as this will be more durable than pigmented gel. You can then apply a pigmented gel as a second coat after the clear.

#3

As I feared there is no cheap solution. Is hi-build primer from a rattle can compatible with 2k paint? That way I can get it primered (an spot any imperfections) and then just drop it off for a finish coat at a spray shop.

Thanks

Ray

#4

Wood will soak up any sort of paint from a spray can. I would advise using Upol Reface spray filler (which can be applied with a brush if needs be).

#5

When I say wood I meant MDF. I have used hi build primer on it with no adhesion problems (as long as its scuffed)but wondered if it was compatible with 2k paint.

#6

Another paint you can use is 2 pack polyurethane from a yacht chandlers, readily available and reasonably priced, im sure international paints do this along with others, do a search. Ive used this in the past when i was into boat building. I did try a product i have called Bondaseal Clear which is 1 pack straight out of the tin recently and that worked perfectly. You can get this from http://www.cfsnet.co.uk/

Baz

#7

Most spray can paints are acrylic, as is 2k automotive paint, so shouldnt be any problems at all.

Unless your MDF has a surface which is very nearly perfect though, you will find that spray can paint is not really going to cover any imperfections.

#8

I am a better woodworker than I am a painter…luckily!

Thanks for your help.

#9

I sometimes use wood sealer on bare wood. Deft make it in the US, Freeman (pattern making supplier) also sells one. I don’t know what’s in it but it smells really strong. After about an hour it can be sanded and waxed. It won’t fill large blemishes of course. I often use it for plywood or MDF dams (weirs).

#10

You could also just use a PER coating with surfacing agent in it too.

I have had some luck with spray varnish or in Santa Monica, Calif. is Hastings Plastics which sells a spray cans of mold sealer (which is green and looks like PVA>>>?).

#11

I hope you have a good stock of paint classicbike, I hear they are to stop selling 2k paint soon. What will you use then?

#12

I dont ever buy any 2k paint for doing plugs, so that shouldnt be a problem!

#13

Hahaha, yes that would solve that little problem!

Reason I wrote that was because I was looking for any answers to my problem and came across this…

I have made some plugs recently and find that 2 coats of 2k acrylic primer, wet flatted using 320 when dry, then 2 coats of acrykic top coat, wet flatted with 1000 when dry, then mopped to high shine using medium compound, works absolutely fine, and is probably less costly than using Duratec products

#14

I wonder if you are aware of the cost of Duratec products here in the UK? I think it was something like £75 US gallon last time I checked, so my using scrounged 2K materials from a nearby paint shop really is a bit of a no brainer!

#15

I am aware of duratec costs hence me asking what else I can use. You won’t be scrounging it for much longer when its banned, what worries me is the replacement paint (water based) seems to need a 2k lacquer over the top to make it durable.

As one supplier put it…

‘Government legislation states that anybody spraying with isocyanates should always use a positive pressure air fed full face respiratory breathing system for full protection’.

The same government health and safety advises that trained monkeys should only be used as guard dogs if supervised by ducks with an IQ higher than the average politician.

#16

Seems as if they are going to make the paint even more dangerous and aren’t banning it at all.:eek:

From the HSE site

The introduction of the Paints Directive will mean that MVR bodyshops can only use low-solvent paints after January 2007. Rumours that isocyanate-containing paintswill be banned, are incorrect. In fact, the quantities of isocyanate hardeners required to cure the new generation of high-solids paints is likely to increase. Isocyanates will continue to be used in some primers and base coats as well as in UV-curedcoatings. The standards set out in SIM 03/2006/04 will be applicable

#17

I think they were saying about 5 or 6 years ago that cellulose paints were going to be discontinued. Its pretty easy to get hold of them still, so maybe the ban on 2K material is likely to be just as ridiculous…