DansYellow66

My Sunfire Yellow lacquer I applied has held up very well until a couple of years ago when I noticed a couple small crazed areas develop. One was over an old repair I redid and the other was over a light touch up I did many years ago to fix a chip from a dropped bolt. They don't seem to be spreading. I have most of a quart of my old lacquer I keep stored in a refrigerator and it seems in good shape so I'm considering grinding these areas down and making spot repairs. They are very visible due to the color and small size but they bother me.

Question - what's the best technique to spot in old lacquer. This was Dupont lacquer that thinned to 125 to 150% I believe. Is it best to over-thin the first coat to burn into the old paint or is that asking for some sort of trouble and should I instead stay with 125 to 150% reduction and a light first coat? Any recommendations on the thinner?

Since lacquer takes quite a few coats to build up - it creates a lot of overspray that spreads out considerably and requires re-sanding and polishing a lot of area. I have better spray equipment than back then but there will still be a lot of overspray. But if I try to mask off several inches back from the repair with a rolled edge of masking tape, I will still get a lot of build up and soft edge and have to do a bunch of careful sanding and compounding to get it all flat again. Any tips for dealing with this? Better to just mask outside the panel and just let it blow over the entire panel and figure on color sanding & polishing the whole panel?

Edit - forgot to ask about primer. Car was gel coated and primed with Dupont lacquer primer. Pretty sure on at least the old repair area I will have to go below the gel coat. The other area may be crazed from applying too many paint coats during a touch up without enough drying time in between. What would be the best primer to spot in the repairs with?
Thanks

TWINRAY

Hey Dan, where exactly are the flaws? Can't break it off somewhere and redo the panel? Good luck

DUB

***** LONG REPLY*****

The good part is that is it lacquer....the bad part is that it is 20 years old and the color could have faded and lost some of the richness of the color.

Is there lacquer clear on the car now????

So if I understand what I read...you gelcoated the car....applied lacquer primer and then painted it. Correct???

Knowing that it is 20 years old and I would have to imagine it is cured out by now. If you go all the way down to the fiberglass. I would do the repair and then apply gelcoat and keep the gelcoat ON the gelcoat that you feathered back and ahve exposed and NOT get any on your lacquer primer. I know this is a pain...but it is what I do when I do repairs and have had much success in keeping my different layers of sprayed products staying on their respective layer (within reason).

The reason do my method the way I do is because of this. When you have numerous layers of applied products on the fiberglass panel. Often times these layers...even though they link up with each pother and can often times chemically bond. They re different in their properties. Some layers require a mechanical bond (sanding) to get them to adhere and stick.

So we know the body is basically solid and will not swell when a solvent is applied to it in some form of gelcoat, primer, sealer.

SO the body has a catalyzed gelcoat that hardens. Then a primer is applied to the gelcoat that is NOT catalyzed. And then paint that is not catalyzed.

So...the gelcoat that is hard and will not soften..and then the lacquer primer and paint that can be softened with lacquer thinner....becasue lacquer paint is NOT a thermoset paint. It is a thermoplastic paint. Knowing that is can be soften with lacquer thinner along with the primer. Applying current type of catalyzed primer on it can work...but if you think about it. When this catalyzed primer is applied on the lacquer primer and paint. The lacquer primer and paint can react slightly differently than that of the gelcoat you previously applied due to they are softened by the solvents

In time....this is when the 'ring-out' effect can show up when the solvents in the catalyzed primer you applied reacted with the lacquer primer and paint differently and when it settles...it shows up the 'ring-outs'. A lot of this has to do with how thick the primer and paint is. YES...I am totally aware of the lacquer paint job in the past from the facotry but they were BAKED and they were very thin and not a lot of product was applied.

SO...I would apply lacquer primer and allow it to cure...even if I have to use my infra-red heaters and bake the heck out if it.

Knowing that the lacquer can be softened with lacquer thinner. I might actually spray some lacquer thinner of a slow drying grade on the area I plan on painting on and blending into. The slower the grade of lacquer thinner..the longer is sits on the panel...and thus it can penetrate the surface and slight soften it so when you go to paint it...your lacquer thinner you use in the paint will melt into the original paint.

If you do this...do not flood the surface with clean lacquer thinner. You are just misting it so you can see that is it going on and stop and let it flash. This is why a slow dry thinner works better. It is about impossible to tell when you have softened it unless you test on an area that is hidden and covered like what you are repairing. Such as behind a door panel.

I would shoot a test panel in the color you have because sometimes this pastel type color can leave a dark ring where you stop the blend. So...playing around with the mixing ratio is something you will have to do. So test it before you spray it on your car.

Hopefully this helps. You can use what you feel comfortable with. But what I explained may make sense and may not. Knowing where these bad spots are located may help in where you can 'break' the paint and stop. Do yourself a big favor and try not to keep the area you mask off to small. The over spray can come back and haunt you if you try to keep the area to restricted. Because when you are done shooting and notice a bit of dry overspray ( hopefully not)....you can blow a light coat of slow lacquer thinner over your blend area and onto the panel further away to melt the overspray in.....OR...while spraying your paint and you notice a dry edge...and a paint gun with slow thinner and dust it on your edge to melt it in between coats.

So many different ways and technioques

DUB

DansYellow66

Thanks Dub - I'm going to have to study your response awhile to fully absorb all of it. Yes, it's straight color Dupont lacquer over lacquer primer over Ecklers Gel Coat - no clear. Wasn't expecting your response to do a spot in with the Gel Coat but I could handle that.

The car has been a mostly garage queen so fading is probably not much of an issue. When I first painted the car I had to spot in a couple minor repairs - a bug crater, a small burn spot on an edge and a chip from a dropped bolt. They all blended in fine and were invisible - but the paint was fresher.

On the spotting in - in the past I tended to spray my first coat small in area right over the repair and then each subsequent coat go a little bigger in area. Now I'm thinking that maybe it would make sense to go large in area for the first coat and narrow the area down of each subsequent coat - centering over the repair. My thinking is that would prevent spraying coats over the top of overspray outside the area of the prior coat. Just thinking.

Thanks again.

DansYellow66

One is on the left, rear deck corner, just above the bond strip for the tail light panel. There had been some damage there and I ground the old repair out a ways and I believe laid some new fiberglass in the area before gel coating. I'm expecting the issue is from the old damage down below the gel coat. On the paint I can cut it off at the fender peak and tail panel edge but will have to fade it into the rear deck area or paint the whole deck. I have a little less than a quart of paint left so at best I have a little more than 2 quarts of reduced paint which with lacquer doesn't go that far and I would like to keep a little in reserve. So I don't think I can do the complete rear deck.

The other is an area on the side of the left, front fender between the fender top and beltline and about 6 inches in front of the door/fender gap. That area was pretty pristine fiberglass underneath and I'm thinking the crazing is in the paint and I may not have to go below the gel coat on it. I think I can cut it off at the fender top and belt line and fade it into the fender blister (I hope).

I also have a stress crack down below a front fender vent I may go ahead and repair while I'm at it. It's down so low I don't think it will pose any issues.

Thanks

TWINRAY

Thanks for the reply, I wanted to lo9k at those areas on my car and see what I might try to do considering the amount of paint you have left. Obviously the rear deck is a tough one and the front sidefender not much better. I just hope the new thinned lacquer won't craze what you have underneath. DUB always gives good advice, I wish you luck knowing the start of these repairs can lead to full strips and resprays.

DUB

IF you plan on laying down a 'wet bed' of lacquer thinner to soften the paint. You can do it in a very large area and go way out past where you know you will stop your blend.

Then blend it in like you have done and wrote in the paragraph above....and then sometimes like I wrote...you blow a light coat of slow thinner to melt in any light overspray at the end of the edges of your blend.

DUB

DansYellow66

Thanks for the replies and advice. Now I just have to work up the courage to dive in. The areas are so small and nearly invisible that I'm not sure I even want to do this right now. Who ever came up with the name Sunfire Yellow - it was spot on. Out in the sun it's dazzling - looking into the paint in sunlight it just has a soft glow to it that makes any minor imperfections virtually invisible.

Thanks.

TWINRAY

My .02 then, I'd look away and not back.

DUB

X2....OR

I would start with the one that would not stick out as a problem if something did not turn out as you want. Because if the method you used worked there..then the other areas should do the same if you follow the same procedure.

DUB

DansYellow66

A good suggestion. I may try the one down below the side vent first. I have some mounting holes in a front wheel well panel to fill where I removed an old CD ignition unit, so I'm going to have to get back in the fiberglass repair anyway.

Mullin Motorsports

Do not over reduce the first coat and allow sufficient time between coats for the thinner to flash. Many times crazing is caused by over reduction or re-coating too soon between coats creating solvent entrapment. That can also cause tiny solvent bubbles to be trapped under the top coat.

When blending lacquer, finish all of your repairs and prime as usual, either with Feather Fill (a gel coat product), followed by original acrylic lacquer primer or modern acrylic urethane primer. Use the same color primer that you used initially, as it can affect the finished color. This is because many colors have some translucent qualities, and sub-straight color can show through the top coat.

After all repairs are complete, meaning you eliminated (sanded down) all cracks and crazed area, and/or repaired the cracks in the fiberglass that caused the cracked paint, then use progressively finer sand paper prior to priming. 400 grit to 600 grit final wet sanding.

On all old paint, I always buffed out the entire panel to be blended with a cutting compound after the final wet sanding was complete, then use a wax and grease remover for final cleaning.

You should also wash it with dish detergent and water. Always a good idea from the start. BTW you should be using wax and grease remover many times from the onset of you repairs to avoid trapping any contaminants.

Then apply your color, (which you mix per label instructions), only to the area that was primed. Keep it confined as small as possible. Be patient and let each coat flash dry to the touch, before re-coating. Don't force dry, unless the shop temp is below 70. Use a clean new tack rag too!

Thinner choice is always determined by the ambient room temperature. Use a good quality thinner. Spend the money for the same brand as the paint you're using if possible. Too slow a thinner will cause crazing. Too fast a thinner will make blending difficult as it will be dry (over spray) around the spot repair. There's a middle ground which you must find, and it's based on your temp and humidity. To fast a thinner and humid conditions will cause a white haze called blush, which is like a chalky appearance. This can be buffed off, but better to avoid, because that means that you trapped moisture in the top coat.

Don't be too concerned if the outside edge of the spot repair is not perfectly smooth at this point. If it's very rough, you can wait till the area flashes enough to wet sand again with 600 to eliminate the dry over spray ring around the spot repair. Do so only with a rubber or sponge backing to avoid finger marks. I don't back mask, rather I keep the fan adjustment very small and keep the color to a minimal area, using a lot of air verses fluid using the fluid control on the gun. This is to get enough color coverage to begin the blend only however.

I hesitate to do any over reduction because it's old paint. I'd probably just feather my last coat without reduction, then add some clear to the mix, and feather coat again, but this time with a slower drying thinner. Again be careful how much material you put on in one coat as it will cause a reaction with the old lacquer and will lead to crazing.

This is the point where you are applying your feather coat paint over the area that you last wet sanded with 600 or 800 paper.

Lastly, you feather your blend into the buffed area. Once you have During the final color blended you can add some lacquer clear to the color for a perfect blend. The entire blended area should be shiny, with little to no orange peel or over spray ring around the spot repair at this point. The clear/color blend should actually bite into the old paint very well at this point.

The addition of clear allows you to buff into the clear/color layer without fear of buffing through and making an unwanted color ring.

Hope this helps,

Dave

DUB

Very well written. It is obvious that there is more than one way to do anything so i am not going to go crazy and comment on everything unless I am asked to do to. BUT..I will comment on those areas of your write-up that need a bit more clarification so those who do not know painting...can 'read into it' in a manner than can mess them up.

SO...these are just my thoughts

And...it all depends on the situation of the repair and air temperature and so on. But often times I will apply a coat of the color or clear with really slow thinner...like PPG's DTL-105 on the panel so it can penetrate and make all of the repair melt together. BUT...if a person were to do this and are heavy handed with the paint gun. Count on giving that area several days to flash off and dry. One again it is all about technique and how many painters have found what works for then...and what works for them can change...depending on what is being repaired.

DUB

Mullin Motorsports

DUB has all very good points. It's almost impossible to cover every bit of the application of paint in a few paragraphs. I gave my best short version that comes from my ages of doing lacquer stacking in the trade, and in my own custom shop. I know that many of us have favorite ways to accomplish the same result. The user must put together all of the advice, and use your best talents to accomplish your best results.

I do over reduce the paint on the last coats of any blend. I used to have very good results adding a bit of clear to the final bit of over reduced top coat color in the cup.

Yes, when using clear, you must be very careful to not change the cast, (or metallic flop,when it's a metallic color), when using clear to blend, but just as modern urethane blending agents on the market today are clear based, we used to add a bit of clear to our final blend coats, especially when not doing a complete panel repaint. A good painter can blend nearly anything to make it look right to the customers eye.

I'm not saying to simply clear coat over the entire blend, just add a tiny bit of clear to the little bit of color left in the bottom of the cup to enhance gloss and reduce the probability of ringing the edge of the blend. The last coats of blend will bite into the old paint as DUB has stated if you're using a good slow drying thinner. He's also correct that if you have a problem with the slow drying thinner checking the old paint, it'll happen right away.

Oh yeah....I forgot, I don't back tape close to the blend, because it's too easy to leave a line that's harder to eliminate with the blend. If you're back taping away from the blend area, then no problem. Just don't be spraying near the back tape area, because you're adding mills of paint, and you don't want to see the line where you back taped. It's all common sense. If you can keep some over spray off the entire panel then certainly protect the blend area by back taping, (rolling a piece of two inch backward, with a piece of masking paper added and rolled backward.)

You are very fortunate to have some of the original paint. If you need to stretch it out, use the clear in the blend. Good old fashion lacquer is hard to find, and expensive.

Again...good advice from DUB

Dave

DUB

Dave,

I commend you taking the time to write what you did. I know for a FACT that if I wrote it...I know someone like yourself could come in a and add more critical information or thoughts because if all possible scenarios were to be considered...and had to be expressed in writing...it would overload/shut down the server for the forum.

We could keep adding to this for days. The main thing is that you DID provide a VERY WELL WRITTEN text on what to do for anyone who does not know anything about it. It is sometimes so hard for painters to write things in microscopic detail because WE knwo what to do out of shear habit... and sometimes our minds know it but our fingers forget to type it. I know for me...I have that problem...my brain is working so fast that my fingers can not keep up with my thoughts.
DUB

DUB

Mullin Motorsports

Right On Brother! In addition, I've forgotten more than I can remember that I forgot, if that makes any sense. LOL!

For guys that have done a lot of painting, fabrication, restoration, etc., doing the work is like falling off a log, but a it's harder to explain how i got there, and why I sat down on the log in the first place.

Being a teacher and expressing the how and why is more difficult especially when writting it out, than actually performing the work itself. All of us that learned the trade had hands on experience and mentors along the way.

I hope that guys such as we, are able to pass a bit of helpful and useful knowledge so that others may enjoy the pride in their workmanship and the artform that we know so well.

Dave

DUB

DUB

cloudshe

enjoyed all your answers! any chance you know someone who would like to touch up and refresh a custom mural(?) lacquer job on my '65 roadster? thanks! cloudshe, grasonville md

DUB

I do not know of anybody in your area...and as for repairing a mural....it all depends on what is wrong with it and the problems that can occur when doing it.

Without specifics.....such as you starting thread on this and posting GOOD photos and descriptions..I am at a loss.

DUB