I think it's time for me to use Trizact sanding discs, opinions needed

L

LilJayV10

New member
I'm in the process of doing a full correction on a black 93' Camaro Z28. The passenger side door is, well, I can't find words for it so here's a pic. It is HEAVILY scratched up and oxidized. IMO it's not clear coat failure and the steps I have taken so far show the clear will come back to a high gloss but I can't get the defects out.

DSC01886.jpg


door.jpg






I started out with PC and Meg's 5inch MF pads and M105. Didn't touch it. You couldn't tell I had done anything at all. After talking to Jeff@Immaculant this afternoon he said the next step would be to try a rotary w/ a wool pad. That did very little. It brought the gloss back up but didn't touch the scratches/swirls. Then it was time for wet sanding with 2000 grit. I did this by hand using a semi flexible foam block. I had to do quite a bit of sanding to see any results. Whatever this clear is its super super hard. It would probably take at least two hours to hand sand it w/ 2000 to see a vast improvement. I firmly believe the least aggressive approach is the best however it comes to a point when you have to step it up some.



The hood has been repainted and has severe orange peel. It needs to be leveled in the worst way.

hood-1.jpg






I have read several threads about the Trizact sanding discs and after what I went through tonight with the door I think that's what I need. What I don't know is what grit I should go with.



I'm not a newb at paint correction, wet sanding, etc. I know the dangers of a rotary and wet sanding and how fast you can see primer. I wanted to say that so everyone didn't think this was the first car I have done. This is however the first car that I've done that is THIS bad. The owner is a close friend of mine and came to me about repainting the car about six months ago. I told him that a full correction would be much cheaper and the car will still look really good. He said if I can't get the hood and door looking like the rest of the car to go ahead and respray it. Hopefully it won't come to that. The entire car is in bad shape but it's fixable. I did a test panel last night, MF pads/M105, LC white pad/M205, and then LC black pad w/ Menz 85RD.



fenderbefore.jpg


fenderafter.jpg


menz.jpg




My camera isn't good enough, but in the after the fender is like a reflection and you can see the lights in great detail. They get washed out in the pic.



Thanks for the help guys. I love learning how to do something new that I can add to my arsenal of ways to correct paint.



Jason
 
I think the same guy painted the hood on the car I'm working on! I appreciate you reply Charles. I always look forward to your posts. I had also thought about the Unicut sanding discs from Megs. I have a PC7427xp but not one of those fancy hand sanders. Not yet anyway.
 
LilJayV10 said:
I think the same guy painted the hood on the car I'm working on! I appreciate you reply Charles. I always look forward to your posts. I had also thought about the Unicut sanding discs from Megs. I have a PC7427xp but not one of those fancy hand sanders. Not yet anyway.
Click to expand...



Thanks Jay; to be honest I don't think there's too much difference between the Unigrit discs and the Trizact, or at least the 5000 grit discs I just got are constructed very similarly to the Meg's 1000/1500/3000 grit finishing discs I've been using. Ultimately it's a matter of preference and which is easier and cheaper to get your hands on. I know ADS sells the Meg's discs individually (as does Kevin Brown/BuffDaddy) if you don't want to pay for a full box of them at first. Kevin might suggest a Mirka disc also/instead for your project, though I haven't used theirs so I can't comment on them.



No worries about not having one of the fancy pneumatic DAs -- I did all the sanding work on that door with my G110v2 and older G100 (PC 7424), and usually they are what I use for other similar projects. Your PCXP will serve you just fine for this job as long as you pair it with the proper backing plate and interface pad.
 
There is a Meg's dealer that comes to our dealership. If he has the unigrit stuff I will probably get them just because I need to get going on the car. If I ordered something online I don't know if I could get it by this weekend or not. One thing I do want to know is, i want to make sure I word this correctly, is there a difference between damp sanding w/ a machine compared to doing it by hand with the same grit. What I mean is if you are using 3000 grit by hand will it finish out the same or different than with the machine. I understand that the machine will speed the whole process up.



As bad as that hood I am working on is I figure I'm going to have to start out with something halfway agressive, 800-1000 if I was doing it by hand. Would that be the same for the machine sanding? Sorry if I repeated myself I just want to make sure I conveyed my thoughts correctly.
 
LilJayV10 said:
There is a Meg's dealer that comes to our dealership. If he has the unigrit stuff I will probably get them just because I need to get going on the car. If I ordered something online I don't know if I could get it by this weekend or not. One thing I do want to know is, i want to make sure I word this correctly, is there a difference between damp sanding w/ a machine compared to doing it by hand with the same grit. What I mean is if you are using 3000 grit by hand will it finish out the same or different than with the machine. I understand that the machine will speed the whole process up.



As bad as that hood I am working on is I figure I'm going to have to start out with something halfway agressive, 800-1000 if I was doing it by hand. Would that be the same for the machine sanding? Sorry if I repeated myself I just want to make sure I conveyed my thoughts correctly.
Click to expand...



There is definitely a difference, but there are a LOT of factors that will go into determining how aggressive a given grade of disc is going to be, such as whether you're using an interface pad or not, if you're using a finishing (foam backed) or sanding (film backed) disc, machine speed/rotation, backing plate flexibility (or lack thereof), how much water you use, etc...



Interface pads, as well as foam backed finishing discs, tend to reduce the effective cut of a given disc by a fair margin in a lot of cases, but the advantage is you gain surface conformity and consistency, which is good especially for curved panels like the doors, fenders, and quarters of that Z28. The hood, on the other hand, being an LT1 4th-gen you can probably tackle the bulk of it without the interface pad if you prefer and need more cut since there are several fairly flat areas to work with in and around the style lines and scoops.



Depending on how the finish responds, however, I wouldn't necessarily bank on needing 800 grit for most of what you're doing. Note that the paint in the thread I linked you to was rock hard, and I only used 800 grit on areas that had severe trash and nibs (a couple very long hairs, probably 18" long were stuck in the clear). The rest was done with a 1500 grit finishing disc and 3000 grit finishing disc, and ALL of the sanding was done with an interface pad between the backing plate and the disc. So honestly, that's what I'd try first -- and even then there are intermediate steps such as stepping up from a 1500 finishing disc to a 1500 sanding disc, removing the interface pad, or switching to 3" discs so you also have the option of a 1000 grit finishing disc or 800 grit sanding disc as needed. No different than buffing, start with the least aggressive and work up only as needed unless there are areas you *know* going in are full of trash right at the surface.



The real advantage of DA sanding over hand sanding, at least in my mind, is that it's MUCH easier to obtain uniformity in the finish when compared to hand sanding, which can mean a DA sanded panel is easier to buff out when you are done. Just for giggles, here's some supplemental reading from Kevin Brown and Mike Phillips on the subject -- probably some of the most technically detailed information you'll find at this point:



Interface Pad Facts



Unigrit Sanding System



All About Meguiar's Unigrit



Jason Rose Interview- About the Unigrit System



Dampsanding Tools, Tips and Techniques by Mike Phillips - Auto Geek Online Auto Detailing Forum



Oh, and it probably goes without saying, but if you have a PTG (I hope you do!), definitely use it! I'll be interested to hear how it goes, especially on that door since it does kinda look like it may be failing clear.
 
Thanks for the links. I need to do some reading on the topic. I don't know the difference between the sanding pads and the finishing pads. Is it just the grit?



I must have been half asleep last night when I would start out on the hood with 800 grit. I think 1000 would be safer. Yeah the 800 will be faster but then you have to deal with getting the 800 scratches out. I think I should change the name of the thread to "I think it's time for me to damp sand" instead of the trizact pads.
 
LilJayV10 said:
Thanks for the links. I need to do some reading on the topic. I don't know the difference between the sanding pads and the finishing pads. Is it just the grit?
Click to expand...



It's the backing material... read through the links and there's a far better explanation of the difference. ;)



I must have been half asleep last night when I would start out on the hood with 800 grit. I think 1000 would be safer. Yeah the 800 will be faster but then you have to deal with getting the 800 scratches out. I think I should change the name of the thread to "I think it's time for me to damp sand" instead of the trizact pads.
Click to expand...



Getting 800 grit scratches out is no big deal, but it's more than likely overkill for your project. DA sanding is a very different animal as compared to hand sanding, and requires a somewhat different mentality.
 
You must log in or register to reply here.
Back
Top