16 replies to this topic

[itguy]

Hi Everyone

I just wondered what pressure you guys seem to spray 2k at to get the best finish you can?

I have been using around 50psi, using a 1.5 gun so far and I tend to find the finish is a bit 'orange peely'.

I am able to flat this mottled finish back using 1200 wet and dry and then machine polish the panel to an acceptable finish, although it still looks like there are very minor pin pricks all over it, and I'd have to cut more paint back to get a true mirror unblemished result.

My sequence is;

dust coat - leave for 15 mins to flash over
medium coat - leave for 15 mins
heavier coat - leave to cure fully

It makes me wonder if I have got the pressure right or if my sequence is wrong... It just seems like I'm having to cut a lot of paint back to get to a shine, and in some cases I end up back at the primer again

Help!

[minim@t]

i find for the final coat thin the paint down with thinners, carefull of runs though,

50psi seems ok, as long as a nice steady flow, not to powerful and not to slow

[Yoda]

50 psi should be fine, i agree that your top coat should be thinner to allow the paint to settle quicker but in my opinion, you cant beat three or four thin clear coats with 2K paint for a deep shine, and it will also protect your colour coats from damage. also light scratches are easy to repair if the colour coat is well protected.

It sounds more like your paint viscosity is the issue rather than the air pressure, as the paint is probably drying out before its settling properly

[itguy]

Thanks everyone - I wondered if it wasn't enough paint going on but Maybe it's just the thinners ratio as you say.

When cleaning my gun out last time I sprayed a spare old number plate that I had lying around and i really walloped the paint on thick - this resulted in quite a decent finish with no 'mottled' effect, but obviously i can't do this on the car as it would easily run/sag.

I'll try a bit more thinners and see how I get on

Thanks for the advice

Might take some photos at each stage this time so you can give more advice if it goes wrong again!

Cheers

[clambert81]

With 2k paint I use about 10% thinners. The orange peel effect sounds like you may have the gun slightly too far from the panel. Also allow about 50% overlap on each pass. for the next coat (when the first coat has gone "Gluey") spray at right angles to the last coat.

[itguy]

Interesting, thanks. I have been using 4:1:0.5 (4 paint, 1 hardner, 0.5 thinners) as my ratio so probably not too far off.

What kind of fan width are you using to get a good finish? i wonder if mine is just a bit too wide and too far away (as you say), maybe just misting the paint on rather than really covering the panel.

Will.

[finch661]

are you using a water trap in your air hoses? my roof has loads of small pricks in it, even though the paint went on fine.

[itguy]

are you using a water trap in your air hoses? my roof has loads of small pricks in it, even though the paint went on fine.

yup

[clambert81]

With 2k paint I use about 10% thinners. The orange peel effect sounds like you may have the gun slightly too far from the panel. Also allow about 50% overlap on each pass. for the next coat (when the first coat has gone "Gluey") spray at right angles to the last coat.

For 2k top coat the ratio is 2 parts paint to 1 part hardener. The 2k primer is 5 parts paint to 1 part hardener. Reduce the air pressure (on the gun) until it stops spraying, then increase it slowly until you get a distinct fan. Set the air fan control control to give a fan about 5" wide about 7" from the body. Have a practice on an old door skin or door card.

[itguy]

With 2k paint I use about 10% thinners. The orange peel effect sounds like you may have the gun slightly too far from the panel. Also allow about 50% overlap on each pass. for the next coat (when the first coat has gone "Gluey") spray at right angles to the last coat.

For 2k top coat the ratio is 2 parts paint to 1 part hardener. The 2k primer is 5 parts paint to 1 part hardener. Reduce the air pressure (on the gun) until it stops spraying, then increase it slowly until you get a distinct fan. Set the air fan control control to give a fan about 5" wide about 7" from the body. Have a practice on an old door skin or door card.

Very interesting - will that be the same for all 2k topcoat paint? I was told the ratio to use by hex, who I bought the paint from.

I must admit that the paint does look a LOT thicker than the 50/50 celly that I have mixed up for my roof.

Need to get out there again at the weekend and give it another go I think.

[PaulF]

mix the paint to what it says on the datasheet. also why not use 2k on the roof instead of celly?

[itguy]

mix the paint to what it says on the datasheet. also why not use 2k on the roof instead of celly?

I found a decent colour and felt more comfortable with celly for a big area like that - it's my first time experimenting with 2k for any substantial jobs

[clambert81]

2K is thicker than cellulose or 1 part acrylic. They both have an increased tendency to run, whereas the 2k can go on heavier. I'm experimenting with single part acrylic and that's mixed 50/50 with thinners. You have to wait for the first coat to dry before putting on the second coat as it blisters and wrinkles, as I've found out.

[itguy]

Well I couldn't help myself so had a bit of a play yesterday with some old 2k paint that is the wrong shade, on an old numberplate!

I did a 2:1:10% mix and then did a dust coat - left it to get tacky and then sprayed the top coat.

After my first couple of sweeps I looked at the finish and it was very similar to the effect I had been getting before, but then I did a couple more sweeps and it was starting to look a bit 'mottled'. I paused for a minute and watched the lights reflection in the paint surface and before my very eyes the paint levelled out and has now dried to a perfect finish.

Very impressed now, just hope that I won't get a run when I try this on the boot lid I have to paint at the weekend!

[clambert81]

And it will be touch dry in about 60 minutes. The good thing about 2k paint is that the hardener uses the moisture in the air to cure. where cellulose blooms if it's a bit cold and damp 2k paint loves it.