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MG Midget and Sprite Technical - An idiots guide to painting
I am getting quite trigger happy on threads at the moment! :-) This is another one following on from similar threads running at the moment.
Is there a deffinative way to paint a bare metal body?
I like to think I can figure out most things myself, but there seem to be so many paints and primers around I'm a little lost.
Do you need an acid etch coat or just chuck primer onto keyed, degreased metal?
What sort of primer? Should it be a zinc primer (for galvanic protection i assume)? Do they all contain zinc? What is red oxide primer?
Top coats... enamal/cellulose/polyurethane/water based? What's the stuff you get in spray cans (enamel?!)? Could you actually paint a car in this or is it too soft? Do you need a clear coat?
Sorry, there is a lot of questions, just sort of thinking out loud, this is all the stuff I'm not really sure about and never really found a straight answer to (maybe I just haven't looked hard enough eh?!)
P.S. About the only thing I do know is that 2 pack will kill you! :-)
|M Le Chevalier|
|I feel your pain, Malcolm! Apparently you can’t get Cellulose paint anymore (something to do with EU directives and other such nonsense) so that removes one item from your list of questions! I think i’ll keep a keen eye on this thread as i too need to know what im doing, especially given the fact that my car is half steel, have fibreglass!|
|Not quite correct Jamie, as you can still get cellulose for "historic vehicles" (ours). So it is still just as complex! |
I could wade in and say what I used but would rather hear from informed experts as well as I still have doubts about what I used. The only lesson I have most definitely learnt is to use metal based fillers, not the talc based ones which absorb water.
|Ah, this is reassuring, it's not just me baffled. How is life up in Rosemount Jamie? :-)|
|M Le Chevalier|
|I can't say if this is correct as I'm not an expert but this is what I've done so far...|
after getting the whole shell back to bare metal...
1. painted a lot of the car in POR15 sealer as everyone says it's a brilliant sealer / rust inhibitor. sprayed POR's own etch primer onto that after first keying the POR15 with a heavy scotchbrite pad.
2. sprayed the whole car in a couple of coats of 2k filler primer.
3. watched in horror as all the primers flaked off the POR despite following the POR guidelines to the letter.
4. took the entire shell back to bare metal
5. used a metal based filler to remove the minor imperfections and cover the welding grinds.
6. sprayed the car with 2 thin coats of etch primer (2K)
7. sprayed the car with 2 coats of filler primer (2k)
8. rubbed the filler primer flat with 240 grit paper - I find it easiest to use velcro backed disks on a hand held flexible block rather than an airtool.
9. filled where needed and sanded flat
10. 2 more coats of filler primer - again rubbed flat
11. stopper paste in the pin holes / scratches
12. 2 more coats of filler primer rubbed flat with 500 grit.
that's where I've left the topside for now as I've got the shell back on it's side and just applied the stonechip.
next jobs will be to prime the underside then paint the basecoat, colour and laquer. Once the underside is done I'll get it righted once again then spray the whole car in the silver base. Next will be to paint the cockpit, enginebay and underside of the bolt on panels in red and laquer before finally putting it all together and finishing the painting.
Note. at no point will I be using any water on the shell - the filler primer sands to a perfectly flat finish dry. I'll only be wet sanding after the clearcoat has hardened to take out any orange peel effect prior to polishing.
another Note. The primer and clearcoats are 2 pack isocyanate. I'm using gerson 2k specific disposable masks (a newish development - saves airfed equipment) and eye protection and I'm making sure I use new filters every time.
|I hereby withdraw my hat from the ring and shall watch this conversation from afar!|
Malcolm - if it helps i've got the number of a guy who's going to paint my midget for "
"at no point will I be using any water on the shell - the filler primer sands to a perfectly flat finish dry"
That is what I thought too. My car was indoors in a ventilated paint spray shop throughout. But in the 12 months since it was finished it is clear that the bits with filler have deteriorated. I think it absorbs moisture from the atmosphere, so unless the car goes into a heated drying booth the moisture is still going to get at it, especially if you have exposed areas of filler left for more than a few hours.
|Not sure how much of the US products will align, but this is a great site to read on prep work and the "why's" of primers, etc.|
|Hi M Le Chevalier,|
If you want to use original the cellulose paint and want and accurate original colours too, then go here.
If you want advice on how to use the paint, then give them a ring. They are very clued up.
These are just one of several companies that supply cellulose paint and can tell you all about it's use. Just google cellulose paint.
|Previous google link missed word suppliers for some reason.|
So just click on suppliers at the bottom of the google search results.
I will be stripping my car back to bare metal next week prior to carrying out a re-spray using cellulose.
I have bought a few books on the topic but nothing compares to the information available on the following website: www.mig-welding.co.uk.
This site has taught me to weld with their excellent tutorials and I will be relying on them to guide me through the painting process with their painting guides.
I have asked many a bone question on their painting forum and they are only to happy to help/advise. A few of the guys who reply are proffesional sprayers.
I just need to grow a pair and get on with it,
|Dave Mckay ('72 RWA)|
|Lawrence - just had a look at that website and im glad to see that cellulose paint is still available. Is all that expensive? A 5 litre tin of paint in the Triumph paint scheme is £124!! That's insane! I've just bought enough 2 pack paint to do my midget for circa £60!!|
|Not wishing to rock boats but must agree with jamie,re expensive cellulose. the web is great for browsing and ideas but ring your local independant he can usually do the same deal or better and you know where he is when you have any problems.|
|So just to satisfy my curiosity, what is the stuff you normally get in spray cans? And if you were slightly insane could you paint a car with it and would it last?|
Anybody have a clue?!
|M Le Chevalier|
|I will second what Dave Mckay has to say about the mig-welding site. Did mine last year and their prep/spraying guide was all I used. The car isn't perfect but good enough for me!|
|With regards to cellulose pricing I bought some for my MGB from a local independant and paid about £25 per litre. Another independant quoted me £36 per litre.|
|I paint all my own cars and it's really quite easy if a little time consuming.|
I use epoxy primer on the bare metal and then do any filling work necessary.
On top of that I use a 2k high build primer and after two heavy coats I flat off using 800 grade wet and dry.
Then I dust the whole car with black paint as a guide coat. This is then sanded off in order to ensure the car is perfectly flat. It's just an easy way of showing any highs and lows on the body.
After that I use base clear system as I find it more forgiving. I lay on two coats of base, let it flash then put on six to eight coats of clear.
When it's all dry I wet sand using 1000 grade down to 1500 and 2000 grade wet and dry then polish back up with compound.
Costs me about $350 to paint a car to what most think is a show standard. There are always a few mistakes that I can see and it's usually the odd fly in the clear coat. I don't have a spray booth or any fancy kit, just an old cow barn and a cheap compressor.
Biggest thing is to keep everything clean. Use only new mixing tubs and filter everything.
I've never tried it at home in the UK and I'm not sure what the environmental laws are like. I didn't try it as my neighbours was a PITA and would certainly complain!!
Here is Canada you can pretty much do as you like. No laws!!
Painting is a bit like welding. If you're not a good welder, you'd better be a good grinder. If you're not a great painter, you'd better be a good wet sander!!!
|All of you speak of spraying.... What is wrong with a paint roller. No mess, no paint in your lungs, easy and one can polish.... Or do I miss something here|
PS I am no great painter, nor welder :-)
|I didn't say Cellulose was cheap, just that it is easy to get.|
128 quid for 5ltrs is WAY more than I paid when I last sprayed my sprite. Luckily I kept what I had over for touch ups. The obsession with all things environmental has forced up the price. On the other hand, 5 ltrs is much more than you need, and if you diy it, then you don't pay for labour and the overall cost is affordable I think. But hey, many things are expensive these days compared to even a few years ago.
There might be another reason that I might prefer cellulose over 2k if (when) I had to repaint my sprite.
Not being one for too much "elf and safety", I am though concerned about what enters my lungs. Cellulose isn't exactly ideal breathing material, but neither is 2K.
There are many references to the following.
"-- Two-Pack is strictly a ‘professional-only’ product. The hardener contains isocyanate, which is extremely toxic if breathed in, and expensive spray-booths and air-fed breathing apparatus must be used. Cellulose of course doesn’t require this; a simple filter mask will do ---- "
So you pays your money and you makes your choice.
a.o. arnold, Netherlands may be right to use a roller. :)
|I didn't realise 2 pack was so dangerous and come to think of it, i'd rather pay £130 for cellulose and not risk breathing in some nasties!|
|danger is relative; 2-pack does not knock you down dead at the first sniff. But the isocyanates are cumulative and the body cannot break them down to dispose of them, so it is v dangerous in the long term for professionals using it everyday. However I once painted a whole Morris Minor in 2-pack with only a decorator's mask - practised my breathing exercises for a few days, then simply did one panel at a time while holding breath, then escaped to the fresh air for a couple of minutes, repeat. That was 16 years ago and no ill-effects. Not recommending - just saying.|
|so, I still don't get it. What's wrong with the roller? When you buy yourself a good polisher I guess you end up with a perfect new skin and a happy lungs. Or.....?|
|2 pack is fine so long as you take suitable precautions. At one time that meant air fed breathing apparatus but recent developments mean that you can get a cartridge based face mask specially developed for the purpose. I use this one from Gerson..|
it's not cheap and neither are replacement cartridges but it's still a heck of a lot cheaper than a second airline etc.
I'm also using a one piece hooded spraysuit and nitryle gloves to minimise any possible contact with the isocyanates - I suffer from Asthma so I'm not taking any unneccessary chances/
Like David Smith, I've used 2 pack in the past - around 26 years ago I resprayed my midget on my dads driveway with no form of protection at all apart from hanging sheets of plastic to make a rudimentary spray booth.
|I thought it was the case that the nasties in 2 pack could pass through the skin, it wasn't enough to just have a mask, you needed a full suit to be protected.|
None of this has answered the original question but very interesting all the same :-)
|M Le Chevalier|
|M Le Chevalier, Grampian|
"Is there a deffinative way to paint a bare metal body?
Do you need an acid etch coat or just chuck primer onto keyed, degreased metal?=="
Years ago I stripped my bonnet and boot back to bare metal. all i did was to make sure it was clean, I sprayed red oxide primer after that a grey primer and then old english white. That was over 15 years ago and no rust or paint lifting.
And all I used was an 240 V electric spray gun bought from Halford. (No compressor).
That was cellulose.
You should be sure to use a good cellulose thinners though, as otherwise you might not get such a good finish, and also I was told (although never checked it out ), that the cheap cellulose thinners has a moisture content that can cause rust problems years later.
|Lawrence, sounds good! Balls to the etch coat it is then! I shall report back in a couple of years if it all goes wrong! ha ha.|
Alternativly in a few years time i will hopefully be heaps richer and will be able to pay for a proper respray! :-)
|M Le Chevalier|
This thread was discussed between 23/08/2011 and 25/08/2011
This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.