Slicksand blocking steps and grits.....

Jorge M.

Member
I did some searching here but I couldn't find the exact answer that I'm looking for.

For you guys that have lots of experience with Slicksand, what blocking steps (grits) do you usually use and what's the next step?

I sprayed two wet coats over 2 day old SPI epoxy, about 6 hrs later I started blocking with 120, guide coated the panels again and went over the 120 with 180. Took all the guide coat off and then some, it looks as if I removed all the 120 scratches, but I know there will be some left behind, panels feel flat, blocked my arms off, specially at the edges so I don't have a lot of primer build up.

Now my question is, what's the best way to proceed from here?

Spray 2K Regular, block 220.
Spray 2K Regular, block 400.

Seal with epoxy 1:1:1 or maybe 2K sealer 4:1:2 just before paint.

Will be a solid color btw.

Thanks in advance.
 
If the poly blocked out straight and you've finished with 180 shoot your 2K and block it with 400, give it a rubdown with a doubled up scotchbrite to mellow out any blocking defects, seal it with epoxy, and apply your paint. Using guidecoat is the key to knowing when all the scratches from the previous grit have been removed. I don't see any need to start the 2K sanding with 220 unless the primer goes on bad.
 
Thanks Bob, I like your suggestion. No need for another two rounds of blocking.

Ill shoot the 2K as evenly as I can and block it just one more time.
 
Make sure your blocks are flat, your surface will only be as flat as the blocks you sand it with. Any warpage or irregularities in the block surface will transfer inconsistant sanding pressure on the surface of the primer. Some people spend years trying to make stuff straight and never get the results they are after because they don't realize the tools are the problem.
 
Bob,
That is an excellent point. I chased my tail and wasted a lot of primer until it hit me my sanding block wasn't flat. Bought some with the wooden handles and aluminum bases and viola things came together much quicker. Most of the durablocks I bought just sit in the cabinet now. Still use the round and teardrop though.
 
Bob Hollinshead;16681 said:
Make sure your blocks are flat, your surface will only be as flat as the blocks you sand it with. Any warpage or irregularities in the block surface will transfer inconsistant sanding pressure on the surface of the primer. Some people spend years trying to make stuff straight and never get the results they are after because they don't realize the tools are the problem.

For this car I checked my durablocks, and sure enough they weren't up to snuff. I had to true my blocks over a glass table, few minutes with them and they are flat now.

I'm doing a vw thing, talk about a shoe box with wheels, it does have a lot of flat panels.

Then Im also working on a 73 Bettle, I think I got the hang of it with flexible blocks, I have so much to learn still, but its coming out nice. An experienced body man is checking my work lol.

Thanks for the advice Bob and 68 Coronet.
 
68 Coronet, can you be specific about the wooden handled blocks? (as in brand, length, etc)

Thanks
 
I use this type for getting larger panels straight. I also have a 9" version of this. The durablocks have their place and I am sure there are newer versions of the wooden handled blocks I have and use.
16InchSandingBlock.jpg


I am by no means the resident expert on block sanding but after messing around with the larger durablocks while working on the 68 Coronet quarters I finally realized I was just wasting build primer by spraying it on and then sanding it off.
Yes, I would get the guide coat off but the block was flexing some and reaching the guide coat that the straight firm blocks would not have touched thus leaving a low spot or "dish" shaped area. Another tip to block sanding is not to press real hard on the block. Let the paper do the cutting and when it quits change it. You will feel like you are wasting paper if you do it right.
 
Good to see you finally posting here Jason.
For those of you who don't know, Jason is a production painter who does very good work, and has extensive knowledge on all things paint related.
 
Thanks for the kind words but I'm just a regular Joe.I also spent many years doing combo work,heavy collision/metal work and restos.I used to post on the old board many years ago.
 
Jayson M;17218 said:
I like the 3m stickit 17inch yellow board for flat panels http://www.jamestowndistributors.co...id=13752&familyName=3M+Hookit+Hand+File+Board
This one also looks good for very large panels http://www.jamestowndistributors.co...Longboards+4-1/2+inches+wide+x+30+inches+long
I also use some RH blocks and the k-blocks look good too.http://www.tcpglobal.com/autobodydepot/randh.aspx

The links show the 3M Hook-it boards do they also make a Stick-it for PSA roll paper?
 
have any of you guys tried Car systems poly surfacer, blocks way nicer then slicksand IMO
 
Never tried it, never heard of it, post up a link if you can.
 
I see this in the tech sheet: To prevent the formation of blisters, particularly under humid conditions, all surfaces
must be given an isolating coat of min. 35 my of acrylic primer (two component), an
epoxy based filler or equivalent (not allowed to be sanded) before the top coat is
applied.

They want you to apply a layer of 2K or epoxy primer before topcoating so it must be quite porus? I've always felt a poly primer should be sealed at a minumum before topcoating, I wonder what thickness 35 my is? I seen a sample sprayout of some standox polyester once at the CarCraft Summer Nationals, very interesting stuff, amber in color, and fairly flexible. Always wanted to try it buy unfortunately no suppliers in this area.
 
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