Current paint option

[Ian Williams]

I have painted a lot of cars over the years, Cellulose, Acrylic, Enamel, and 2k, my first choice today is 2k for several reasons; It is tough, it won't sink as it dries which is a major issue with the others, you don't get anything like the same degree of dry overspray as the other systems, once chemically cured it is hard unlike the others which although touch dry can take weeks to fully cure. Concerns about 2k being too glossy are unfounded, but you do need to add flatting base to take the shine back a notch I use 10% to 25% depending on degree of shine I require, I also go over any paint job with 2000 grit paper then polish this gives you a finish with thousands of minute swirl marks as an old paint job would have, light is refracted differently from this surface than from a perfect gun finish which can look plasticy. I would warn against applying a lot of high build primer, it is a common mistake made by many paint shops on old cars, high build primers help hide blemishes but they also loose details and round off edges which again makes a car look plasticy and is in my opinion wholly inappropriate on a 90 year old car. It is far better to spend more time on your preparation and apply primer sparingly, body shops are all about quick turn around so use the one shot high build's to speed up the preparation process. As for concerns about 2k and health they are real, but the comment about paint drying in your lungs applies to any paint system! You do need to use a respirator designed for spraying, cover your body and hair with a painters overall, wear gloves and ear plugs, but that is all good practice with any paint system, for one off jobs with sensible precautions an air fed mask is not necessary.

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I have just read Andrews post which appeared as I was typing, yes overspray remains wet in the air so sticks to anything it lands on, but if you are getting a lot of overspray perhaps the gun pressure is to high. Personally I don't find 2k runs any more easily than anything else, in fact in my experience probably less. Curing is by chemical reaction but the speed of reaction is temperature related, so if you are painting without a booth in winter it will take a long time to dry. I only use it in summer and find it will be completely dry in very short time, in fact I sometimes have to use a retardant to slow down the cure time.

[Stuart Giles]

Like Ian, I use 2K paint for any bigger spraying job now. The paint finish is both hard and tough. It has much more filling ability than cellulose so is a lot less likely than cellulose to reveal fine sanding marks in the finished job when the paint  hardens. It can be flatted and compounded in exactly the same way as cellulose once it's hardened; so even if you do put the odd sag or orange peel area in the paint job, it's not difficult to correct it afterwards. The so-called fast hardener is the one to use outside a spray booth; it delivers air drying in any reasonable ambient temperature. Using either a fast or slow acting 2K thinner is the best way to ensure the paint finish settles out in a reasonable time according to the ambient temperature on the day.  

But...Using 2K paint means that you do need to wear the proper protection while you're using it. I have an air fed mask, and I use a separate oil-free compressor to feed it -the oil free compressor is kept  well away from where I'm working so it's not sucking in contaminated air. Neither of these items is particularly expensive, and properly used will ensure that you don't suffer the hideous effects of breathing in the Isocyanates that are present in the air while you're spraying with this paint. There's some more information on safety here.
https://www.hse.gov.uk/mvr/bodyshop/isocyanates.htm

[Derek Sheldon]

Thanks everyone for your input, several questions answered.Still don’t know which way to jump. As I am super allergic to both filler and paint applications it’s down to somebody else to fill and spray. My previous  three spray jobs were done by my pal on site. 2pack primer (home made breathing apparatus on separate compressor fitted with the appropriate inline filters) followed by cellulose top coat. Unfortunately he can’t do it this time.

[Adam Brown]

Speaking as a paint supplier.

If you are going to a professional set up it is unlikely to be your choice. They all tend to use 2k paints and are measured on their emissions so cannot use Cellulose in most cases even if they want to. A backstreet garage may be a different affair....

Stick to one system throughout, whilst primers are usually compatible with most things either keep it 2k or cell. If it goes wrong and you've mixed and matched you'll have an expensive mess.

My usual advise is as follows. If working at home and you have the facilities you can either spray Cellulose or Synthetic (Coach Enamel). Cellulose can be sprayed multiple coats in a day, buffed and polished. Synthetics are generally a maximum of a coat a day and should be left 6-8 weeks to fully cure before cutting back and polishing but will give excellent results, and can also be brushed in most circumstances with similarly excellent results. If farming it out listen to the person putting it on - they will always get the best results with what they want to use.

In my opinion a good brush job knocks spots off any spray job you'll ever see. Depth of colour, shine etc.

Also remember paintwork takes a while to 'settle' when new. People complain about 'unatural shine', 'sharp colour' etc. After a year or so the newness leaves and colour settles a bit. This cannot be rushed or forced!