Sanding grit for epoxy and Featherfill G2

S

sg465

Will be doing an all-over but getting doors ready now. Will be a two-tone with metallic blue and white.
I will be welding a few holes up in doors and then laying down epoxy primer. After epoxy will have some pretty simple filler work and then wanted to use Featherfill G2 to give me plenty to block straight before sealer.
I plan on just scuffing epoxy and then working filler down to 220. Does this sound good and then how smooth do I have to block the featherfill out to before the sealer?
 
I don't have much experience with featherfill, but I think it would be a good idea to put some primer on and block that before you go right to sealer. If you don't want to buy a second product, just use epoxy. This is, if it is warm enough that it will cure in a reasonable period of time. With metallics, most people on here recommend sanding to 600 before sealer.
 
For me its generally epoxy primer (I like black), 2 coats of G2, block with 80 till start seeing epoxy, spray 2 more coats of G2, block with 180 till seeing epoxy, then 3 coats of 2k primer, guide coat, block with 400. From there I use reduced epoxy for sealer. Wetsand with 600 and go to base.
The second round of G2 could be optional if the car is straight, just block with 80 and follow with 180 before going to the 2k.

Interested in seeing what others have to say as well.
 
[QUOTE='68 Coronet R/T;16958]For me its generally epoxy primer (I like black), 2 coats of G2, block with 80 till start seeing epoxy, spray 2 more coats of G2, block with 180 till seeing epoxy, then 3 coats of 2k primer, guide coat, block with 400. From there I use reduced epoxy for sealer. Wetsand with 600 and go to base.
The second round of G2 could be optional if the car is straight, just block with 80 and follow with 180 before going to the 2k.

Interested in seeing what others have to say as well.[/QUOTE]

That sounds like a darn good plan to me. The only thing I might do different is one less coat of 2k. 3 sounds like a lot if you are just using 400, but I'm sure you have a reason...
 
If you are going to spray poly ( featherfill G2) then dont waste the time blocking filler down to 220 before hand.. Its not needed as poly is sprayable filler anyways.. So you would just be wasting time and sandpaper. I like to block poly with 80 first, then switch to either 150 ( thats what I use ) or 180..

From there it becomes personal preference.. Some guys will spray 2k directly over the 180 grit scratch polyester primer.. Some will buzz it with 320 grit on a DA with a soft interface pad 1st and then spray 2k... Some will spray epoxy instead of 2k directly over the 180, while others with again buzz it down first then spray epoxy.. then 2k..

It really depends on what you are going after and how much time you are willing to spend..
 
I will spray 2K over 150-180 grit after rubbing it down real good with a red scotchbrite. Seems to mellow the scratches out a lot.
 
I just block sanded three coats of Featherfill G2 with 320 and it came out very nice, very smooth. But I have a few problem areas (shallow valleys) that need just a tad more filling. Was thinking of just hitting it with a couple coats of 2K primer and reblocking with 320 and then 400. Then seal with reduced Epoxy and paint (or seal, wait a few months, and then scratch and paint). The 2K Primer will adhere to Featherfill sanded with 320, right? Thoughts on this approach?
 
PatG;17342 said:
I just block sanded three coats of Featherfill G2 with 320 and it came out very nice, very smooth. But I have a few problem areas (shallow valleys) that need just a tad more filling. Was thinking of just hitting it with a couple coats of 2K primer and reblocking with 320 and then 400. Then seal with reduced Epoxy and paint (or seal, wait a few months, and then scratch and paint). The 2K Primer will adhere to Featherfill sanded with 320, right? Thoughts on this approach?
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Scuff up the shallow areas and fill them with polyester filler or glaze, block them perfect and then you'll know there won't be any more surprises on the next round of priming and blocking. 2K, then epoxy sealer, then paint.
 
68 coronet my buddy would finish his poly sanding for paint and I have seen a few of these cars and guess what very very poor chip resistance, quite sad. Not sure if Im reading PatG's post right but are you starting your blocking on the G2 with 320grit? If thats the wouldnt you guys think the shallow spots could be from not using a coarse enough grit to level down the G2 evenly?
 
If thats the case I would block down the G2 with some 120grit very minimum and try blocking the panels straight
 
Thanks for all the great replies. I'm not exactly looking for show car finish and would like to reduce cost by using the least amount of products I could. Preferably I want to avoid shooting 2k over the G2.
My plan is to get whole truck ready for sealer. Since I don't have capabilities of shooting sealer and top coat down within window my plan is to have it ready for sealer and then bring it to whoever and have them shoot sealer and then topcoat. So, can I get away with blocking G2 with 80 and then 180, shooting epoxy over it and blocking all the way down to 600? Seams like a big step. Thanks again
 
You can skip the urethane primer and finish it off with epoxy no problem. Shoot two coats of epoxy over the G2 and start blocking with 320 or 400 and see how it goes, then more guidecoat and 600 to remove all the previous grit scratches. Many seal and paint over 320 grit scratches, solid colors definately not a problem.
 
sg465;17486 said:
Thanks for all the great replies. I'm not exactly looking for show car finish and would like to reduce cost by using the least amount of products I could. Preferably I want to avoid shooting 2k over the G2.
My plan is to get whole truck ready for sealer. Since I don't have capabilities of shooting sealer and top coat down within window my plan is to have it ready for sealer and then bring it to whoever and have them shoot sealer and then topcoat. So, can I get away with blocking G2 with 80 and then 180, shooting epoxy over it and blocking all the way down to 600? Seams like a big step. Thanks again
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As I suggested already, you can absolutely use SPI epoxy for blocking (as long as it is fully cured). In the summer time with some sun, I have blocked it within 12 hours. In the winter inside at 70 degrees, it takes about 4 days usually.

My suggestion would be to take the g2 to 180, like you said. Spray a coat or two of epoxy and block it with 220 or 320. Then spray another coat and use 600. SPI epoxy works great as a guidecoat (due to the semi-gloss), and this extra step will quite possibly save you some heartache lalter.
 
This is my own personal opinion, and I am a hack in a garage, but when I us G2 or any other poly primer I only leave on what is needed.

On my current project it went like this:

bare metal:

20120204_150757.jpg


black epoxy - 2 coats 1.8 tip
-24 hour cure-
G2- grey - 2 coats 2.5 tip

*let the car site for 1 week*

blocked with 80 then 150

Results:
20120211_160121.jpg


Then:
Black epoxy - 2 coats - 1.5 tip
-24 hour cure-
2k urethane - 2 coats - 1.8 tip

*let the car sit for one week*

results:
20120212_182023.jpg

20120213_223109.jpg



Blocked with 150 - 320

results:
20120219_171954.jpg

20120219_171802.jpg

20120219_171848.jpg

20120219_171842.jpg


One final pass with:

Grey epoxy - 1 coat 1.5 tip - wet shand with 600 this week (been sitting since last Monday)
20120220_232802.jpg

20120220_233303.jpg


I'm too scared to abuse poly, but love it for initial blocking. I've *heard* way to many stories about brittle paint when its left on too thick. Maybe I sand too much, who cares, they are my shoulders, lol! Sorry for all of the pics, just trying to give you a good example.
 
I did most of my filler work on top of the g2/poly combo. Very minor. most of the dents I was able to hammer and pull out and the g2/poly mix leveled out.

The car has a glass hood and glass decklid. took some work to make then "decent" decklid is very flimsy. Hard to block.
 
orangejuiced86;17506 said:
but when I us G2 or any other poly primer I only leave on what is needed.
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Exactly! There's no sense in leaving build where it isn't needed. There's some people that put polyester primer down but will polyester glaze complete panels-it's the same basic thing. oj'd, nice photos showing the blocking stages-I'm sure those that are new to this appreciate it.
 
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