Spraying Advice - New mk1 project

[SpearMintTom]

Three months ago I picked up a rather sorry looking mk1 golf gti, no mot or tax, basically a bare shell. In my spare time since i've been stripping it down, following advice and opinions online (forums and guides) i've rubbed the car down and prepped her for spraying.

I wanna have ago at spraying the shell myself, i've got a double garage and have extraction fans and sheets, a friend is lending me a 4HP air compressor and air fed mask.

Apparently the paint I have requires thinner to be added to it, but I cannot find anywhere how much thinner to use, how to mix it etc..

does anyone know..

(i figure if the spray goes wrong i'll just rub her down again give it another go.. and if it really goes tits up pay someone to do it!)

[SpearMintTom]

Also could someone explain the difference between the types of guns you can get such as HVLP / suction fed etc

[mrjohnbridge]

ok mate well here is a quick list of the stuff you will need rough guide but all depends how many layers and how big your car is

4 Litres of Surface Primer Filler
3 Litres of Enamel paint(in your chosen colour) chances are you could get away with 2.5 litres for a golf
250ml of Enamel Hardener
4 Litres of Multilac Thinner (thats the size the tin comes in)
2 litres of laquer


a rough guide for the mixture for the set amount above is

mix the 3L of Enamel paint with the whole 250ml tin of Enamel Hardener and put around 300-400ml of Thinner together (just enough thinner so that the paint is sprayable).


HVLP
To qualify under the term HVLP, air flowing through the Aircap must not exceed 10 psi. Generally speaking, HVLP turbine motors produce over 100 CFM (cubic feet per minute) at 3 - 8 psi. (pounds per square inch) depending on the model of motor. Compare this to a typical high pressure set-up where 45 - 60 psi at 8 CFM would be the norm. HVLP turbines supply air at a much lower velocity producing a softer, easier to control spray. This allows you to lay the paint on gently and not blast it on. Benefits of HVLP include less overspray and less paint wastage. Transfer efficiency can be as high as 85%. The quality of finish is identical to the best high pressure spray finishes.



suction fed guns suck the paint up from the bottom into to gun where it is mixed with high pressured air...
a gravity feed gun has the tin on top of the gun and is much prefered in the spraying industry.

Good luck and i hope that helps

[SpearMintTom]

really appreciate that post, forgot to mention i've got about 6 litres of cellulose based blue paint, lovely colour and it was expensive stuff, my mate gave it to me.

With cellulose do I need to add hardener? when do i put this in / on? and the same for laquer..

[mrjohnbridge]

ok well ideally 2k or 2pack is better for spraying but is harder to work with.But.....
as you are using cellulose paint you will not need to add hardener...hardener is only required for enamel (oil based) 2 pack paints

You will still need to add the thinners though at roughly 50/50 mix for the fist couple of layers and primer. then on your final layer thin the coat right down to 30/70 (for your final coats use TOP GLOSS thinners as you will get a better finish, compared to standard alternatives)


You don't need to mix thinner with your lacquer unless your gun/compressor can't spray the lacquer, or if it's too thick. All adding thinner does is slow the curing time of the lacquer.

Sometimes if the lacquer is too thick though, you have no choice and you need to add thinner. There are some advantages to using thinner in your mix, such as getting less orange peel & better flowout. It also enables you to use less PSI, but if your compressor is big enough there shouldnt be a problem. A lot of times, i'll use 50-50 lacquer-thinner (or 1:1) on my final coat to help reduce sanding time.

[sne11y]

why use ennamel i used to work at a bath restoration workshop and know that enammel is stupidly expensive and looks sh!t in any other colors other than white just go for either cellulose or 2 pack so much easyer

steve x