Thanks for the info Dave, I had an idea there could be issues with the original paint being top coated by a modern equivalent. Just been out in the garage to try something as you say the finish may or may not be cellulose so I soaked a rag in cellulose thinners and rubbed it on the existing finish and it removed the paint so from that would I be correct in assuming the finish would be an enamel? Again put me right if I am wrong but I would imagine a fully cured cellulose finish (37 years) would be impervious to its own thinner and would require a paint striper or mechanical means to remove it.
Luckily I have decided where the shell will be painted (CARS of Kidderminster, who have an excellent reputation locally) so I will have to confer with them about which way they would wish me to go prior to them having the shell.
Bit of a learning curve understanding all of this as with any question 'Mini' any answer invariably throws up more questions. Thanks for the input midridge all this info is giving me a better understanding of things , so are we saying cellulose can be overcoated with 2K safely and if not it can be as long as there is a compatible barrier coat there?
Dave would this gun fit the bill it doesn't come with both needle assembly's though I would imagine they are interchangeable with that body so it would just be a case of buying the 1.3mm assembly separately https://www.spraygun...h.xRdMqwkJ.dpbs Have found a twin cylinder (50L), not sure if it is two stages though that outputs 11.5cfm the gun in the link requires 8.8cfm.
PS, just been out and had another rub with the cellulose thinner and it would appear my earlier conclusion was or could be wrong all the thinner does is remove any paint oxidation after that thinner has no effect, is there a definitive way of telling whether it is enamel or cellulose based paint?
Yes, celluose can be topcoated safely if sealed. As I mentioned, I would avoid it because cellulose flexes at a different rate than enamels (be they 2K, urethane, polyurethane, or simple acrylic.) But the sealer will prevent any incompatible solvents from reaching the cellulose layer.
I have some DeVilbiss Starting Line guns (but not that model) and they are certainly more than capable of shooting primer and do a solid job with topcoats. If I were myself to take a leap without first-hand testimony for that particular model, I would go ahead. DeVilbiss is a long time manufacturer of repute.
In truth, here's where the expensive guns justify their cost.
1) Atomization for spraying fine metallics consistently (like pearls and custom type finishes - I've used a DeVilbiss and even a cheap China no-name gun to spray silver OEM paint on a Subaru panel,and to paint silver wheels. Wheels are a good way to start learning painting by the way!)
2) Durability - to be able to paint gallons and gallons of paint before needing servicing.
3) When the gun does need parts, you can buy them. Most cheap guns don't have much if any spare parts support. But if you only spray a gallon or two in your lifetime (which is primer and paint for at least 1-2 Minis) then the durability of a high-quality gun might be an unused asset.
Some of the high-end guns are reputed to spray much smoother coats than lesser guns, but the skill and experience of the painter is a much greater factor than the gun itself. I don't think any gun will magically let any novice spray a glass-smooth finish without some practice, IMHO.
If the compressor specs are on the level (it's not uncommon to exaggerate a bit on specs) then it will be enough. The small tank means it will run constantly, but it should be able to keep up with spraying. Just determine what the pressure level the CFM rating is. If it's something like 11.5cfm @40psi or higher, all is well. If it's something like 11.5 cfm@5 psi run for the hills, that's a trick number to fool buyers. If the pressure at that airflow volume isn't given, ask before buying!
I would think that if you can't keep scrubbing off paint color with the cellulose thinner, then probably it is an enamel finish. What you see could be just a decayed, oxidized surface layer being wiped clean. (Cellulose thinner being one of the stronger solvents around for paints.)
Dave
The cellulose thinner will not touch the paint or its underlying primer once as you say the dirt and oxidation has been cleaned off, what it has left behind is a beautiful shiny finish which has been hidden for many years, so it looks like I have an enamel finish.
My reason exactly for going with the Devilbis, quality brand plus spare parts availability, including the option of being able to get the smaller needle/nozzle combination for it, although I will never be able to completely paint a shell which would be next to impossible with the space available to me I like the idea of being able to do smaller projects in the future.
I do have some spray painting experience from another hobby using high end Iwata airbrushes which I know is not on the scale as painting a bodyshell, but it all helps totally different types of paint as well hence most of my questions.
What I will do is go along to the company I want to paint the shell and confirm with them what approach they would prefer me to take, might even take them a small sample of the cured paint just to see if they can identify it. There is also on F/B a page for ex Austin apprentices the admin seems think I would get a response to my question so have posted on there as well.
Dave cannot thank you enough for going to the lengths you have in explaining to me pros and cons of what I am trying to achieve, it is much appreciated.
PS – here’s the compressor https://www.spraygun...h.fnR6TZPG.dpbs they do a single cylinder version of this as well but its only capable of 6.8cfm
Stuart
Just had a response from the Ex Austin Apprentices Association F/B page, and it would appear that the original paint on my Mini is a 1 pack synthetic, which I am assuming is an enamel?
