Cellulose Paint Problem

[richies2.0gl]

I resprayed my Cortina in black cellulose. I used a high build cellulose primer, sanded back with 800 grit, waited 2 weeks and then applied the top coat, flatted back and put the final 2 coats on. I then left the car for a week to let paint properly set. It came out great after compounding back and polishing and I was very happy with the finished job, especially as it was my first go at spraying a car.

Now, after 2 weeks of it being on the road I have noticed the paint has gone very rough, like an orange peel finish. I cannot understand why it has gone like this. The roof is that bad that I have had to 1000 grit it and re-compound. i am very very upset with it and dont know what to do. It only seems to be on the flat surfaces ie. roof, bootlid and bonnet. If I compound back again and bring the finish back will it do it again? And what has caused this?

Thank you, Richard

[domster]

Maybe picking up contamination on the flat surfaces as it hadn't fully cured in that time?

You could most likely machine it back again with a wool pad/compound?

But I'm no paint expert. Just a guess because it is the flat surfaces that have been affected, not all the car itself.

[OldSkoolRS]

I haven't sprayed for a while, but I used to use cellulose myself and found that I needed to leave it a month (or longer if possible) before flatting and compounding. I think it's just down to the solvents slowly coming to the surface of the paint, though someone more experienced might be able to confirm this. I also believe that it's not a good idea to apply polish or rather wax/selant as this will trap the solvents and cause other issues like dulling of the shine.

[s.m.h.]

Problem with cellulose is the thinners in the top coat can re-activate the primer causing sinkage over a period of time. Possibly the high build has sunk, causing the topcoat to do the same. Though the peel finish may be a reaction of some sort. I'm surprised you're still using celly, not used it for a long time....

[richies2.0gl]

Thank you for your assistance with my problem. I think I will have to re-compound the car but will leave it a few weeks to see if any more reaction occurs.

I used cellulose because I didnt like the sound of the side effects from 2K. Its also a very diy friendly way of painting a car (so I was told). It does seem as though there is a very slow reaction taking place, I just hope the problem doesnt persist once the effected panels have been compounded again.

[s.m.h.]

Dont flat it down too much, unless youve ponded it on (which may be the cause of the reaction) you'll soon flat through to the primer!
Are you hand polishing or have you a machine? With it being celly machine with a fine compound will give good results.

[richies2.0gl]

Yea, got myself a variable speed buffer and polisher. It was worth every penny of the £65 I paid for it (even got a free spray gun!!!). Used 3M fine compound, a compound foam (velcro) and lots of water! Came out great again. Lets just hope it lasts!!!

[gary11]

IMO celluose paint is the problem plus hi build primer.

[Type 49]

There might be a reaction to the previous paint unless you have started from bare metal.

As has been said it is best to leave the primer for a good while, (in my case 6 months) for the primer to harden but it dosnt need to beanywher near that long.

The reaction would have been caused by the thinners, the reaction takes a while to take effect.

The solution is to wait and see. If you have put plenty of topcoat on you will be able to flat out the imperfection and buff again.

If it is a reaction either use an isolater or flat back to bare metal and sgtart again, celly is the way to go for home restorers, you can get an excellent finish.