Clear Over Base ON TOP of Celly?

[SpitfireIV]

Hi guys!

I got great advice some years back when DIY painting my Triumph Spitfire. Some of that advice I did not take at the time to my detriment.

The process I used was as follows:

- Strip back to bare metal.
- 2K epoxy base coat applied, filler applied where necessary and then sealed again with 2k.
- Multiple layers of 1k primer applied, flatted back as necessary.
- Top coat, Celly, applied, approx four coats.

As pointed out at the time, the issues with 1k, namely sinking back and losing luster over time, both of which have happened not helped by the fact the car spent most of the COVID years under a cover outdoors. Multiple attempts to revive the gloss have resulted in some cut throughs on shut lines and the paint just generally looking tired.

I'd like to give it a new lease of life and like the idea of a clear over base with a deep clear gloss. What I'd like to know is is it possible that I can knock back the current celly top coat with P600 (or P800?) and apply the base coat over top of this?

Thanks

 

[ajlelectronics]

Base coat is essentially 1k in terms of its application. Due to its high thinners content, it is highly likely that it will pickle the edges of any blemishes that it finds and ruin an otherwise good job. If you don't want to go back to epoxy, flat off to perfection and then put another couple of epoxy coats over to seal it, then carry on as normal. You could do the same with a 2k primer, but why add potential issues?

 

[Burdekin]

As above.

For the finishing topcoat 2k solid colour would be closer to original and wouldn’t fade as much, or clear over the 2k colour for a deep shine and better UV protection or a mix of 2k colour and clear for your final coat.

 

[SpitfireIV]

Thanks for getting back to me on this guys

So if I were to go down the 2k solid color route is the 1k celly base, once flatted back a suitable base for the 2k solid color?

I'll be repainting in the same tone so it'll just be the external/visible surfaces that'll be painted.

 

[qwakers]

only if you prime it first. no getting around that.

 

[Burdekin]

Thanks for getting back to me on this guys

So if I were to go down the 2k solid color route is the 1k celly base, once flatted back a suitable base for the 2k solid color?

I'll be repainting in the same tone so it'll just be the external/visible surfaces that'll be painted.

Personally I’d at least seal it with epoxy primer/sealer first and check it doesn’t react. You can get epoxy sealers that will lay nice and flat and then you can wet on wet 2k topcoat over.

 

[SpitfireIV]

Ok, I've been giving this lots of thought (and lots of googling) and what I've discovered is: paint/finishing terminology is bloody confusing!

Don't be annoyed but perhaps indulge me for a moment.

What if I were to, *cough*......lash on a fresh batch of cellulose?!

Time and cost are a big factor here. Looking at the price of epoxy primers, 2k direct gloss, base coats and 2k clears etc they're bloody expensive plus I just don't have the necessary equipment for dealing with 2K spraying...

I had a peak at the car today. The paint has been on there a good 6 years now, the main issues being the dullness on upper surfaces as well as the celly having shrank back to expose sanding scratches, not to mention a couple of ghostly primer patches showing through when I tried to cut it back on a previous polishing attempt.

So the current cellouse is surely well set by now and could be flatted back to take out all the shrink back scratches? Can new celly be reapplied then over top of this?

 

[qwakers]

PAINT NEVER HIDES ANYTHING it only makes it more obvious. if you don't have a perfect base, you have to rework it until you do. a high build epoxy primer and nisocoat 2 has the same safety requirements as celly and will have a 10000% better finish.

 

[Burdekin]

It won’t solve you’re 2k issue but this is considerably cheaper than automotive 2k but this will give you a good finish and is tough and will last for a long time. https://www.smlmarinepaints.co.uk/products/hardtop-ax A cheap alternative. I’ve used it to paint two rear quarters to get by until the car had a full respray. It turned out pretty decent.

You can also get 7.5l of Mipa epoxy from Marlow paints on eBay for £105. If you use the fast hardener you won’t need thinners and it lays beautifully.

 

[Dragnet]

I thought the advantages of cellulose were the lack of isocyanates and the ease with which it can be touched up and blended in. The book 'painting classic cars' is a good read. I have seen plenty of threads but have not yet been convinced that for the DIY, time-rich/cash-poor user there's anything better than cellulose. However, like you I've found it's very, very easy to go round and round in circles online, so I guess I'm going to be looking at the links from Burdekin and qwakers as I've got a Triumph to do as well... The Nisocoat 2 says it's available in 'automotive' shades, though whether that means BMC or not is another question.

 

[richie00boy]

Ideally it all wants taking back to epoxy. The 1k primer was a poor choice and was a factor in the shrinkage issues. You should have just applied another couple of coats of epoxy and flatted that back - it would probably have had just as much build as the 1k "high build" primer. You could try a little flat back and reapply cellulose, but I think the issues will be back later down the line as the 1k paints will move again when you spray the new cellulose.

 

[steveo3002]

So the current cellouse is surely well set by now and could be flatted back to take out all the shrink back scratches? Can new celly be reapplied then over top of this?

it never sets /cures....where 2k is a chemical reaction and sets within a few hours celly doesnt , put a wet thinners rag on it and it will come off

i agree with sand it back to the epoxy , anything else will be hard work /chance of more problems

 

[SpitfireIV]

Right, it's settled....

After much flip flopping, to'ing and fro'ing I've settled on a system....

The car is stripped back now and I want to scrub it clean of all waxes, polishes etc before beginning to sand, what's best for this, the ol' fairy liquid and a pink or green Scotchbrite?

Flat the whole car back with 320 to take back to initially epoxy as possible. Dig out a couple a minor rust bubbles, mainly around arch, lash some epoxy primer on them and fill, seal filler with epoxy primer once flatted/sanded back. The whole car then to be given two fresh coats of epoxy primer.

Should I sand up to 400g before applying the epoxy or is 320 sufficient?

Then....

I've sourced an airfed mask so have decided to go with the 2k, it makes the most sense, I know it's that bit more expensive but the long term benefits outweigh these considerably. I'll be spraying in a DIY booth out in the countryside far away from other inhabitants.

So, if I can get the epoxy to lay flat and smooth enough my plan is to leave it flash off and then go in, wet on wet with the 2k direct gloss, approx three coats.

However, if I'm not happy with the layout of the epoxy what grit should I sand it to for the direct gloss application? 600g or 800g even?

I'll be using a turbine sprayer, an Apollo 400 with a 1.3 fluid nozzle and have a compressor to run the mask, it's a small 50L compressor though so it'll have it's work cut for it, but it's only a small car anyway with a removable front section/bonnet so it'll be short runs done in stages

 

[steveo3002]

panel wipe...although dont worry too much if sanding it all off

no reason not to use 180 to it back to primer , will be faster and straighten out any ripples /wobbles , p320/400 should be ok if you need to sand the epoxy before paint ...if using a turbine sprayer id be very surprised if the primer goes on well enough for wet on wet

 

[dave h 2]

Your minor rust bubbles aren't minor, it's rust out from the other side where the water is coming from. It will return.
I once had a 69 Capri with 'shrinkage', it went right down through the original ford primer to the steel.
BTW washing up liquid has salt added as a thickener.

 

[MG David]

Be careful with domestic detergents. Some have silicon in them to help the dishes shine.

 

[ajlelectronics]

Right, it's settled....

After much flip flopping, to'ing and fro'ing I've settled on a system....

The car is stripped back now and I want to scrub it clean of all waxes, polishes etc before beginning to sand, what's best for this, the ol' fairy liquid and a pink or green Scotchbrite?

Clean with soap and water, allow to dry and then use a SLOW panel wipe.

Flat the whole car back with 320 to take back to initially epoxy as possible. Dig out a couple a minor rust bubbles, mainly around arch, lash some epoxy primer on them and fill, seal filler with epoxy primer once flatted/sanded back. The whole car then to be given two fresh coats of epoxy primer.

Cut away and repair the rusty parts. Flat the repair to 120-180 and spot epoxy prime. Fill as required and flat to 320 before applying epoxy coats. Then allow to fully cure and go to at least 400, preferably 500 for solid colour. I doubt that you will be happy with wet on wet, but it will work, you could always flat back the colour coats and reapply.

I'll be using a turbine sprayer, an Apollo 400 with a 1.3 fluid nozzle and have a compressor to run the mask, it's a small 50L compressor though so it'll have it's work cut for it, but it's only a small car anyway with a removable front section/bonnet so it'll be short runs done in stages

I wouldn't even attempt wet on wet with that. At least get a decent spraygun, they don't need to cost the earth.

 

[SpitfireIV]

Ok so I made a start on the process today....

- stripped off some elements of the car that were easily detachable and can be sprayed separately.

- gave the rest of the car a good scrub down, into every nook and cranny with soapy water and a 280 grit scotchpad and then panel wiped.

- sanded a few small spots, individually about the size of a finger nail where surface rust had caused little blisters on the surface, lower edges mostly, possibly caused by stone chips etc.

- sanded rust spots clean doen to 80 grit, panel wiped and applied three coats of epoxy primer by brush to the bare metal areas. Interestingly the epoxy primer I applied didn't react with the 1k top coat, nor the 1k high build but did wrinkle the edges of the exposed old epoxy primer!

- meanwhile I began block flatting the rest of the car with P120 on a long block. For the most part the panels are flat and level, the bonnet, being GRP had a few very minor humps and bumps that were flatted out. Regarding tight curves etc is it ok to use a P120 sanding sponge or scotch pad to rough up these areas and over the rest of the body in general to accept epoxy primer?

Next I plan on roughing up the areas where epoxy was applied today and applying a scrape of filler before this gets sealed in with more epoxy primer when the whole car is done

 

[charlysays]

This is my daily which I painted in nisocoat 2 direct gloss about 3 years ago. Never been polished, always outside in the weather and sun doing up to 20k miles a year. it gets washed about every 3-4 months and had been washed with a water based detergent degreaser before these pics so absolutely no wax or anything. I would say there's no detectable weathering or gloss reduction. Pretty decent performance for an isocyanate free paint! It may be iso free but it's definitely a proper 2k finish.

 

[SpitfireIV]

So things are moving along with this project albeit slowly although today I added some color finally

Last week after addressing some very minor rust bubbles that were sanded back to bare clean metal with 80 grit and epoxy primed the whole car, minus the bonnet was flatted back and 2/3 coats of epoxy applied with no issues or reactions thankfully. It laid on nice and smooth using a 1.3 nozzle Fast Mover LVLP gun...

Have a couple of areas to apply a skim of filler and spot prime before a flatten back to 400/500? to prep for top coat.

In the meantime I had a shot at trying the color with my 1.3 HVLP turbine, very happy with the results as can be seen in the pics. This is the cowling from around the headlights. The one on the left is the original, tired, drab looking celly as removed from the car, the one on the right the freshly sprayed (having been previously epoxy primed and flatted) light cowling straight off the gun!

Now to sort my 'spray booth' and get the bonnet prepped....