Questions about pads, backing plates and RPMs

R

RWT

I’ve been restoring a 1954 Ford F100 as a retirement project. It will be a nice looking driver, not a show truck. Last month I painted the cab with 3 coats each of SPI Dark Red and Universal Clear. As a first timer with body work and painting I have done a ton of research including this forum before each step and have made my share of mistakes. I went with SPI because of the many positive reviews on quality of the products and technical support. They were correct. Barry was awesome in helping me by phone and texts.

I painted the cab in pieces. I’m thinking I will cut and buff most of the panels before assembly mostly because it will be easier to reach and more comfortable working on stands especially the hood and doors.

My paint has many nibs mostly on the panels that were painted in the horizontal position. My homemade booth was a 12 x 20 yard canopy that I lined the walls and floor with poly. The positive pressure filtered forced air caused the polyester roof to flex up. I believe that was the source of most of the contaminates.

I have some varying degrees of orange peel and a few areas of dry spray. My goal is to flatten the nibs, and the worst of the orange peel and dry spray. After reading posts here I have ordered Eagle Abrasives 1000 & 1200 grit yellow film disks, 1500 grit Assilex disks, and 3000 & 8000 Trizact disks. My random orbit DA has a 3/32” orbit. Will it work or do I have to by a 3/16”?

I have questions about compounding and polishing. I will be using a Dewalt DWP849x 7”/9” polisher that I used for stripping paint. I’m planning on ordering the 3D ACA500 compound and ACA520 polish.

1. Lake Country pads are well reviewed here. I’m thinking yellow, orange, white, and black.

2. What diameter? Should I get more than one diameter?

3. Should they all be the flat CCS type? I see they offer a rounded bottom pad. (my old fat fender ford has lots of raised radiused panels)

4. What about wool? I was thinking the 3 coats of clear may not have enough film thickness to include wool?

5. I only have the original Dewalt backing plate. It’s 6.75” OD and the Velcro is 6” OD. Do I need a different backing plate for any of these pads?

6. Can you give me advise on rotary RPMs for each step?

Thank you for your help.
Bob
 
You’ll be better of with some original 6” backing pad from lake country, they have a lower profile and the right amount of flex to help the pad conform to the surface.

Blended wool pads from Lake Country (blue color) work pretty good, using wool at low RPM and clean the pad after every use will speed up the process a lot. What I like to do is spray some water on the pad to soak it a bit then use an air blower while spinning the pad to clean it.

3/16 will save you time, cuts faster. You can probably do it with what you have though.

If you don’t work the 1000-1200 grits too much, just use it enough to clean up the panels from the trash you got in the paint job, leave a little bit of texture behind then jump to the 1500 Assilex, then 3000-8000. You should have enough mils left for UV protection.

When you do enough sanding with the 3K Trizact you’ll start to get some gloss back on the panel, clean it really well and inspect the surface and it will allow you to find any random scratches or pig tails, those I like to sand by hand with 2500 wet sandpaper or with Eagle Abrasive 2500 Buflex, just with my fingertips lightly and it goes away. Sand again with 3K Trizact and you’re ready to try 8000 for final sanding.


RPM start slow around 1400-1500 so you don’t generate too much heat. Once you get comfortable with the pad and compound you may increase it to 1600-1800 on the bigger flat areas, slow down around the edges or protect them with masking tape. 3M Precision masking tape 06526 it’s very thin that the pad won’t lift the edge.
 
I used a combo of pads when doing my truck and I really liked having a wide arsenal at my disposal. Upfront cost is more, but I thought it was worth it.

For backing plates I used a 3 and 5 inch found here. I also bought a 6 inch to work with my wool pad, it was a Lake County found here. Both brands worked equally well.

I used a combo of 3.5 inch and 4 inch pads on my smaller backing plate for tight areas. Then I used 5.5 inch foam pads for the majority of my buffing. If needed, and I usually did need it, I would use a 6.5 inch twisted wool pad from Lake County, I also had a 3.5 inch wool pad from Lake Country for tight areas.

I first purchased the Hexlogic pads from Chemical Guys in 4 and 5.5 inch, link. They are a good pad but during another order with AutoGeek I ordered and tried the Lake County Smart Pads and I kind of like them better, especially in the 3.5 inch size as it fits the smaller backing plate better. Both are good pads though.

To sand I would probably use the 1000 to make a couple passes to break the skin of the clear and then switch to 1200 to do the majority of your sanding. Stop with the 1200 like Jorge mentions above, so just about all the peel is gone. Then refine your scratches, this is where you will make or break your buffing steps, with the Assilex and Trizact. If your not thorough with them and leave scratches behind during a step in grit it will show up when you buff. I personally struggled with a set of steps to get all my sand scratches out and it leads to extra work buffing.

When you get done sanding, start with yellow or orange foam and work a section. Use a light to inspect your work, look for any sand scratches, you may have some swirls from the cutting, but with a quality compound like the ADA they will be fairly minimal. It should have a similar appearance of a just washed car that has been dried with a towel. If you don't get to this appearance after 1 session with your foam you can make a decision from there on what to do next. If you have left over sand scratches that you missed in the sanding steps you could sand more to refine them, continue on with foam for another round on the section, or switch to wool. Whatever you are most comfortable with is the way to go, and its worth saying that its good practice to take the least aggressive approach starting out, even if it might take a bit longer.

Use tape on edges when sanding and buffing. I kind of liked using tape when sanding on occasion just to make sure I didnt have a brain fade and get too close to an edge, extra insurance doesnt hurt.
 
Jorge and Sprint, I appreciate your how to advise and product referrals. Exactly what I need. Looking back I wished I had applied a fourth coat of clear. I'm most concerned about burning through the clear. I'm going to start at the rear of the cab to get my feet wet. Can't be seen when the bed is on. I will get two sizes of backing plates and pads. Do you use the same large buffer with the smaller pads? Do the different types of wool cut the same? Is one more or less aggressive?
I received the trizact disks yesterday. Surprised how they feel as though there is little or no abrasive in it. Bought a box of 15 of the 3000 but only 5 of the 8000 until I see how long they last. They are costly! I will get some sheets of wet 2500 for touch up and a roll of 06526 tape.
Thank again.
Bob
 
I'm putting an order together and see that Lake Country only offers 5.5" and 6.5" CCS pads for DA type polishers. Sprint did you use these DA pads on your rotary? Work OK? I was going to order 3.5", 5.5" and 7.5" with backing plates.
Bob
 
Do you use the same large buffer with the smaller pads

I use the same buffer, same Dewalt you have, it is just heavy compared to buying a smaller buffer.

Do the different types of wool cut the same? Is one more or less aggressive?

Yes there are wide varieties of wool, some cut, some in the middle, some to polish.

Sprint did you use these DA pads on your rotary? Work OK?

Yes I used them, the website and description kind of conflict each other. Which is correct I'm not sure. I haven't used them a ton, but I've liked them so far.

In the description it states the following:

"Smart Pads™ foam is as suitable for high speed rotary polishers as it is for dual action models. That’s because the foam withstands the heat and friction generated by the polisher without transferring it to the paint."
 
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