A small "how-to" on chip repair/wetsanding + spring cleaning (black G35) (56k = owie)

Over at vwvortex someone asked me to go through how I do the above but with a spray can. I apologize for any spelling errors or exclusions, I did write it quickly, been a busy week. Speaking of which, gotta go! Cheers.



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Alright, so the "spray-can" how-to. This is similar to the one above except that it's 1) tougher to do, 2) requires more patience, 3) has a much higher chance of being done wrong, 4) is *much* faster when done right, and 5) looks better.



I apologize in advance for how quickly I go through this, I've been extremely busy this week. I won't be attaching many pics, but will try to explain the best I can.



- Why do we want to use spray instead of touchup?



It's faster and when done right it looks better. Often times touchup can't tackle larger jobs like bumper chips. example:



montage4.jpg




On the left is where the bumper was hit by another car. The paint chipped off and continued to peel until this spot was created. It was about 4 inches by 8 inches, touchup brush paint would have taken days to fill it in and would have looked like a big ugly mess. Here is how I spray touchup:



What you'll need:



All the stuff from above



A spray can with the appropriate color. I like duplicolor a lot, their colors are good matches, their paint dries fast and won't shrink, it's cheap, it's available everywhere, and the sprayer is half decent. You will also need a sprayer with clear in it if you have a clear coated paint job. If you're doing a bumper make sure to get the bumper version, as it has a flex agent in it.



primer



A lot of painters tape. I like the 1 inch variety for this.



A pencil and some paper (for real)



a stiff peice of cardboard or plastic that you can throw away later, it helps if it's 6x6 or larger.



an exacto knide



If the chipped area is deep (1mm or more) the paint will not fill it alone, you will need to fill it using some automotive putty. I like 3M super red putty (yes thats the name), it's highly manipulatable, dries quickly, doesn't shrink, sands down really well, and isn't expensive. It is only for small areas though (filling maybe 1/2 inch or less tops). For more you might consider bondo or another putty.



If you're using putty - a small plastic trowel thats flexible.



So time to start.



Clean the area well and then sand it edges down with some 1500 or 200 grit. You don't want it to peel any more than it has. This might open the chip up considerably, so plan for this. The one above started about 4x8 but went up to maybe 6x10 after sanding. Make sure to sand down spots inside the chip well (so if there is some paint that didn't flake off inside the maint area of the chip, try to get rid of it).



If your putty requires a base coat of any kind do it now. 3m super red doesnt, so lets fill the chip with it. This part sounds hard but it isn't. Spread the putty in the chip started from the middle, just like repairing drywall. Use the plastic trowel to manipulate it into place. Don't worry about high spots, just make sure there are no low spots - this is important. Also, dont worry about going over the edges of the chip, you'll sand it down later. The most important part is to be at or above the level of the existing paint.



Wait overnight.



Sand the area down using 1500 or 2000 grit, make sure its very smooth and get all excess that went over the edges. If you have any low spots re-fill then and wait another day to sand. You do not want low spots.



When it's sanded the fun begins!



Get your pencil and paper and put the paper over the area and trace a rough area that you'll be painting. Try to be as precise as possible as this will determine how well it blends later. mark the center of the chip with a pen on the paper.



Cover the area with painters take, all of it and make sure you go at least 4-6 inches over the area you'll be painting (so now the painters tape is over the filled area, and 4 inches on any side). Mark the center of the chip with a pen.



Hold the paper you drew on over the area and line up the dots you marked. Now use an excacto to cut out the diagram in the paper while simultaneously cutting the painters tape (lightly, dont go all the way through).



When you're done peel the tape away over the chip. How well you did this will determine how nice the area comes out.



Prime the area using a spray on primer. I use the cardboard/plastic to follow the spray can do no overspray gets on the car. Spray lightly (really, really lightly) and keep to the directions (if the can says stay 4 inches away, do it), a run is a bad thing.



If this works wait till it dries. If you get a rud wait till it dries, sand the run and re-prime.



Get your colored spray and spray. Same deal, follow instructions and spray lightly. You'll be doing at least 2 coats, maybe 3. SPRAY LIGHTLY, if you spray too much you'll have a ridge when you pullt he tape off and it'll look like ***.



wait till it dries, remember between coats you want to wait till it dries, but not all the way, you want ti spray again when its tacky.



clear the area using the same technique. if i didnt get it through to you before, SPRAY LIGHTLY!!!!!!!!! too much = too much gloss = everyone who looks at it going "hm, what happened there?" = :mad:



I do two clear coats unless it's too glossy after one.



When it's dry remove the tape and access. 9/10 times if done right you will not be able to see the touchup, however even so I like to do the following just to blend it all in.



wetsand per the above instructions (first post)



compound per above instructions



Now, in cases where the surrounding paint is in good shape this should leave you with a 100% perfect match. In cases like the bumper above the rear bumper was kind of chipped, so it was visible if you looked for it just by virtue of it having no chips. Over time it will fade to look more like the surrounding area.



Questions? Let me know. I went through this quick so I may have missed something obvious.
 
I am thinking of doing this soon on a couple chips I have on my fender. My question is, where can I buy a bottle/can of clear coat? And is there a specific brand/type I should be looking for? Thanks.
 
Wow this thread brings back memories. :)



You can get clear coat paint at just about any automotive store, pep boys, autozone, canadian tire, etc. I usually buy duplicolor paints. Another place you can get it (I usee you have a G35) is an Infiniti dealership. The paint pen they give you will have two sides, one with color and one with clear paint. :)
 
Excellent job. But the great results on a black are much easier to achieve than compared to a metallic color, where touch up paint color comes out almost never the same as the original paint.
 
Bioman said:
Pen? I stopped by and they gave me a small bottle of touch-up. They sell such a pen at the dealership?



Oh weird, I haven't seen Infiniti give out a bottle in years. It's always felt tipped pens here. Well, either way hit up an auto store and grab a small jar of duplicolor clear. FWIW, you don't actually need the clear, it just helps blend the touchup.



noooorb said:
Excellent job. But the great results on a black are much easier to achieve than compared to a metallic color, where touch up paint color comes out almost never the same as the original paint.



Very true. I just used black in this example because at the time my car was black (and so was my sisters); I didn't want to do a "how to" with a customer car. :)



Incidentally both cars have been sold since I posted this thread 8 months ago.
 
newbie question ahead...



should you apply the paint, then clearcoat, then sand? Will this remove the clearcoat? OR do you apply the clearcoat after you sand and sand again? HELP!!
 
sorry for my dumbed down questions...but does this compromise the paints strength at all? or perhaps make that part of the paint exposed without clearcoat protection?
 
No, and no. I've never seen a chip repair that I did oxidize or pop out after it was sanded and polished. They sometimes pop out during sanding, which is why I like to wait 48 hours.



If I was doing a large scratch I might add some clear as the last layer of paint before sanding. I generally find when adding clear it's actually harder to get the paint to match perfectly.
 
Amazing write up!! Thank you so much!



My question is: When doing a car and waiting the two days for the paint to cure, can the car be driven?
 
Thank you for this awesome information!!! One more thing...does the sand paper brand matter? I should have put these in 1 post! Will attempt soon and post b/a pics...High 5IVE!!
 
Excellent write up. Someone slammed their door into mine and took out a chunk of paint. After reading this im no longer nervous about painting it up, and sanding it out. Going to give it a shot soon.
 
5IVE said:
Thank you for this awesome information!!! One more thing...does the sand paper brand matter? I should have put these in 1 post! Will attempt soon and post b/a pics...High 5IVE!!



Well the brand doesn't matter so much but I highly recommend unigrit paper. I find it's much, much easier to get out sandpaper marring when using 2k-3k unigrit as opposed to regular 2-3k grit.
 
Great write-up and great work, thanks for taking the time to share. Hope you're getting less snow than we are in Calgary right now.



Edit - Question:



If you're adding clear at the end and before sanding, isn't there a danger if you build up the basecoat too deep that you will sand all the clearcoat off while levelling the scratch?



Also, is it worth masking off an inch out from around the whole scratch to reduce how much area you're sanding?
 
Picus, I got a scrape on the underside of my front bumper (the lip). Its below the actual face of the bumper so from standing outside you can't see it. Would you approach a scrape (with quite a few spots down to the black plastic) the same way? If not, what would you reccomend? Thanks.
 
Reflections said:
Great write-up and great work, thanks for taking the time to share. Hope you're getting less snow than we are in Calgary right now.



Edit - Question:



If you're adding clear at the end and before sanding, isn't there a danger if you build up the basecoat too deep that you will sand all the clearcoat off while levelling the scratch?



Also, is it worth masking off an inch out from around the whole scratch to reduce how much area you're sanding?



Heya - when I layer the paint the layers are really, really thin, so it not a lot of sanding is required. I suppose it is possible all the clear is sanded off, but as I mentioned above that doesn't really matter anyway. The clear is more to make the touchup match than for protection.



Masking might work, I don't do it because the whole process is almost like blending paint, so making might leave funny marks. It is worth a shot though, maybe I will try it on my next one. :)



BMW335i said:
Picus, I got a scrape on the underside of my front bumper (the lip). Its below the actual face of the bumper so from standing outside you can't see it. Would you approach a scrape (with quite a few spots down to the black plastic) the same way? If not, what would you reccomend? Thanks.



I know those scrapes! :) The problem with bumpers is that the paint is often thicker on them, so it's harder to reach the level of the existing paint. Otherwise I would approach it in exactly the same manner.
 
Great write and nice paint. I'm thinking of fixing a few little chips and scratches by doing basically what you did. I'm looking at purchasing some unigrit paper. Should I just get a couple sheets if all I'm going to do doing is what you did? How many sheets per problem? Thanks for you help.
 
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