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Wet sanding

#1
I'm wet sanding my cab and have a question. I have been sticking to 1500 except for where I have runs. So like on my roof for example only 1500 as no runs and just some trash. The question I have deals with trash in the clear, dirt/dust. I have everything pretty flat but where the trash is I have kind of a ring still. What I have been doing is using some 1500 on a small block on these areas to take care of it. But my question is if there is a better way? It seems like no matter how hard I look for them I miss one. I'll work on a 2x2 area, think it's done and then do a walk around and find a faint one i missed.

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#3
I've had those dimples be a slight recess where dust/junk landed. The only way to build it up to the level of the other clear is to dab a drop of clear in, then it can be blocked down.

If you just have a high ring with no low center, you would be ok to just block.

As far as a faster way, use coarser paper. Just make sure you block back up to your 1500. Maybe circle the areas you used coarser paper so you don't miss them...?
 

EddieF

Top Banana
#4
I too get junk in paint cause i chose doors open more over cloud.
Hard pvc block i use dry for final run leveling can get highspots but i've learned good chance that dirt will scratch. Be gentle, keep checking it. Block has pink tolecut full sheet cut in half stuck to it. It's self lube dry. Pricey too but lasts.
Pvc i slightly rounded edges.
Roof looks good from here other then your spot. run3.jpg
 
#5
Thanks everyone.

I think starting with coarser paper would get more of them leaving me with less to try and pick up on, I tried some 1200 on my dash and it did seem a little easier as not so many were left over. Its not really an issue getting them out once I see them but seeing them is. Even with the panel dried and blown off they are tough to pick up in the reflections.
 
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#6
You may laugh at this but I know there are some that actually guide coat clear before sanding.
I too, think dry sanding is much more revealing. I used to always wet sand, but lately
dry seems quicker and easier to me.
 
#8
I ordered some eagle yellow, tolax and buffex last night. Going to give that a try on my next pieces, the yellow is dry so that might be nice for the first step.
 
#9
I like the Eagle yellow, it's what I use mostly. I find it works great on my electric random orbital
sander I normally use for woodworking.
The secret to it working so well is to turn the speed down to about half of normal high.
 
#11
I was working a little on my cab this weekend and really had a bad time. I tried buffing a 2x2 area of my roof and it came out nice and flat but a bunch of scratches I figured were leftover 1500 I didnt get out, resanded with 2000, 2500 and 3000 and not much improvement, in fact then I started putting in deeper scratches from debris I assume. Tried sanding those out and put in more, seems like no matter what I do I end up putting deep scratches in. I use a spray bottle, and try to keep everything clean but keep getting deep scratches. This was all with 3m wet/dry by hand on a soft block, and 3000 trizact, all used wet.

Moved to next adjacent area and the same thing, even seemed like my compound wasnt taking out scratches that it should be taking out. I used the same steps on my firewall and had good luck, a few odd scratches here and there but easy to live with. The roof has turned into a nightmare all the sudden.

I had to give up and quit for the day. Its so frustrating to see everything come out nice only to have a bunch of scratches in it.

I think I will give everything a good cleaning, maybe flush my spray bottle out, and try my new eagle paper when it comes. Not sure what else to do, the whole deal really left me at a loss.
 
#12
1500 aren't very deep, did you have loud music on? Have to listen & feel as you block.
Maybe scratches were in previous layer? Post a photo. Sorry you had trouble.
Dirt in clear can get you. Got me before. Dip block in water, not just spray bottle. And change water.

I did my runny mess door today, 600 800 1000 1500 2000 3000, no buff yet to see.
I put many heavy coats, only way to use course grits.
 
#13
Sprint, sounds like you're have the same problem I've had in the past. After wet sanding up to 2500 using a spray bottle for water then buffing, saw sub 5oo grit scratches all over. I think the sanded off clear coat (wet sludge) is chunking (for lack of a better term) up between your paper and clear coat surface. This chunked up clear then acts as a coarse grit which scratches the clearcoat. My theory anyway.
Try using a constant stream of clean water to wash off the surface as you are wet sanding. Or better yet, use Jim C's dry method with yellow thin film discs, then green and black bufflex discs on a DA.
 
#14
Sprint, sounds like you're have the same problem I've had in the past. After wet sanding up to 2500 using a spray bottle for water then buffing, saw sub 5oo grit scratches all over. I think the sanded off clear coat (wet sludge) is chunking (for lack of a better term) up between your paper and clear coat surface. This chunked up clear then acts as a coarse grit which scratches the clearcoat. My theory anyway.
Try using a constant stream of clean water to wash off the surface as you are wet sanding. Or better yet, use Jim C's dry method with yellow thin film discs, then green and black bufflex discs on a DA.
Its funny that you say that as I was reading over a post of yours earlier and it seemed very similar to my problems. I have no other explanation for my troubles other than what you have suggested. I didn't feel or hear anything, really about the only time I have was down on my cab corner, and that was obvious. I wouldn't mind using a constant stream of water but as of right now I have no way of doing so, no water in the shop and its down around 0 outside.

Ive read over some of Jim's comments on the eagle stuff which is why I ordered it. I ordered 1200 yellow, tolex, and green buflex.

What methods and grits did you use with the dry system?

And how did you go about getting the scratches out in your photos here? They look like a mirror image of mine.

http://www.spiuserforum.com/index.php?threads/the-screech-when-wet-sanding.5108/
 
#15
You often don't hear the scratch being created. I had 6 full wet coats of clear on the door in that link and must have wet sanded some parts with 600 at least 3 times. The solution was to eliminate the water and go all dry. The green and black buflex didn't last very long for me. Most of its cutting power was gone after ~3-4 square feet, but then I would wipe off the dead clear dust frequently after that and keep using. I think Jim uses them wet and gets much more area done than I, so I'll try them wet next time. I used a 3M DA.
I had a sample pack of yellow film (600 800 1000 1200) then bought a box of 1000 and 1200, so I used these depending how bad the scratches were. The last car I started with 1000 or 1200.