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Block sanding question

Started by 1BAD68, February 20, 2012, 09:35:41 AM

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1BAD68

5 1/2 hours later...
I set up a box fan with a furnace filter in the service door, the fan was pulling in filtered air which helped a lot and the garage door was open about 6 inches so there was also an opening on top of the garage door.



Spraying the base coat went ok, started out too heavy which caused blotching but quickly adjusted. It took 5 light coats and looks even to me but it ended kind of bumpy, not orange peel but just weird.



I figured oh well, nothing I can do about it now so after an hour I started mixing the clear. Spraying clear is a whole new ball game at least with this gun. This stuff creates a huge cloud and hangs in the air awhile (thanks for talking me into setting up a fan)
The first couple coats I sprayed light, not intentionally but it just happened that way. It was not looking anything like what I've seen pictures and video of but more like that bumpy, orange peely texture.
I kept playing with the air pressure's but it wasn't changing things too much. Then I figured it out, I knew that being a LVLP gun meant that it was slow but I didn't realize how slow it was.
After REALLY slowing down it was spraying good unfortunately by that time I was running low on clear



I got a lot of wet sanding to do, I'm thinking I should just order another gallon and spray it again.

elitecustombody

No to throw salt on wounds.It does look pretty rough.But as long as your metallics laid down good ,you're in good shape,just get more clear and possibly borrow or buy HVLP gun.Play with it and adjust it so you can lay the clear smooth 


AMD-Auto Metal Direct  Distributor, email me for all your shetmetal needs

Stefan

b5blue

Harbor Freight has one on sale for 15.99 right now online. I'm using it for epoxy primer and it's working good, it's got a 1.4 tip. I love that color, it's sharp!  :2thumbs:

1BAD68

Should I wet sand it 1500 then 2000 like the sheet say's before spraying again?


elitecustombody

Use 600 and red scuff pad on edges and corners.Maybe even use 320 or 400 to knock down some of the heavy orangepeel,it will save you a lot of time. Have you checked your door jambs? They probably got some heavy overspray by now, maybe get them prepped and painted?


AMD-Auto Metal Direct  Distributor, email me for all your shetmetal needs

Stefan

Patronus

What happened??!? Your base coat looks great! The clear... well... you'll get it. You can get a nice finish with some elbow grease.
'73 Cuda 340 5spd RMS
'69 Charger 383 "Luci"
'08 CRF 450r
'12.5 450SX FE

Wicked72

good luck!! not sure if ill spray mine in the garage or pay someone yet.  :popcrn:
M-Massively O-Over P-Powered A-And R-Respected

jaak

If it (the clear) is thick as it appears, I would sand the whole car with 600 grit and re-clear it. It would take you forever to sand with 1500/2000, and that's too fine for re-clearing anyways. Although I haven't ever done it, I have heard of guys doing that even if the orange peel isn't that bad, its called flow-coating. After the clear has dried, they sand the car with 800 grit paper and clear it again, suppose to make the finish really slick, but I have heard it makes it easier to get runs in the clear.

Jason

1BAD68

Took a look at it this morning and it's like it flattened out overnight.
Still has orange peel but it seems only half as bad as it was yesterday.
Definitely hoping it can be saved, I sprayed a full gallon (4 coats) so that should help.
Maybe I should wait another day or so before working on it?

left picture from yesterday, today on the right.


elitecustombody

It probably just died back,so it shows less orangepeel. Roll it out in the sun for a day or two before sanding. 


AMD-Auto Metal Direct  Distributor, email me for all your shetmetal needs

Stefan

1BAD68

I decided to try and "bake" it
Don't really have equipment to bake it but I turned the thermostat up to 90 in the garage before I left. Came back for lunch and could definitely smell fumes again (couldn't smell any this morning).
As of lunch time there was significant improvement so I'm leaving it "bake" until later tonight.

This is the roof as it sits now, much better than last night...


and the rear as of now...


1BAD68

a better picture taken with my Canon w/flash instead of my camera phone...



b5blue

Hey it's looking better already!   :2thumbs:

1BAD68

8 hours at around 100 degree's and I can see a huge improvement, a smooth finish would have been nice but at least I think it can be saved.



Patronus

I'd go at it with 1200 and see if you can get it flat, use a bunch of water. Do you have a buffer? What product are you going to use?
'73 Cuda 340 5spd RMS
'69 Charger 383 "Luci"
'08 CRF 450r
'12.5 450SX FE

1BAD68

I was thinking 1000-1500-2000.
On the front valance I only sprayed 2 coats of clear and tried sanding an area with 1000.
I was able to get through the orange peel without going through the clear so with 4 coats on the body, I should have no problem smoothing it out.

Patronus

'73 Cuda 340 5spd RMS
'69 Charger 383 "Luci"
'08 CRF 450r
'12.5 450SX FE

69 OUR/TEA

If it were mine,I'd be letting it sit outside in the sun for awhile to try and get most of that trapped solvent out of it,re-block/wet sand starting with 320,400,600,re-buy the paint,get better spray equipment,rent a booth and do it again.But if you feel the need to try and save it  I'd wet sand w/3M thin rubber squeegy block 500,800,1000,then 1,200 da,1,500 da.(3/32 orbit da).Each time you cut it,leave it open for a day or two before going onto the next grit,and after your 1,500 da leave open a day before you start buffing.From what I see anything 1,000 or above is truly never going to get that peel out of it,way to rough!!!
Me personally,from what I see,you try and save it and buff it,may look decent at first and you'd be excited,but a month or so down the road give or take,it will be having die  back and looking hazed out,and by then the cars all put back together and your stuck with it.Maybe it sounds like I'm being alittle harsh,just don't know what level of quality you were looking for.

1BAD68

Well I feel pretty good about this now. I'm going to pick up some wet sanding paper and start on it later tonight, it's going to be a lot of work but at least I don't have to spray anymore.
This is pretty much the texture it has as of today, some areas are a little worse and some better but pretty much like this...


1BAD68

what's "die back" and what causes it?

EDIT: I just googled "gloss die back" and this actually might be a problem that could happen here.
I sprayed 4 light coats of color waiting for the flash times followed by 4 coats of clear. So I have a lot of film build.  :brickwall:
So far the gloss hasn't changed at all, I'd rather wait it out than to block sand and respray again. Any tips on what to look for any signs of "die back"?
How long until I can be sure that this paint is fully cured?

elitecustombody

Heavy coats without proper flash time trapping solvents. Don't waste your time sanding and buffing.I agree with 69 OUR/TEA. To get rid of this heavy texture, it must be cut with 320 and by the time you are up to 2000,there won't be much material left and if by some miracle there are no busted through areas,you will have major die-back . You can sand it,but you have to allow the solvents to come out. Sand with 320,finish with 600 ,let it breathe for a week and then re-clear it, you will be much happier.But obviously it depends on what kind of quality you are content with.

BTW, what clear are you using? Is it high-solids? 


AMD-Auto Metal Direct  Distributor, email me for all your shetmetal needs

Stefan

69 OUR/TEA

Honestly,it looks like it already has died back on you.Hard to tell,but in one of your pics of the roof it looks like I can see solvent pop,microscopic little"dots".Thats the trapped solvent trying to get out of a surface that has "skinned over",hence my air movement comment being important.Trapped solvent basically pushes so hard trying to get out makes little explosions to release itself.
But after having this happen,you sand and bufff this,like I said may look nice at first,then however long after starts to look dead again,dying back,looking hazy and not crisp, shiny and clear anymore.Your 4 coats of basecoat being so dry may cause alittle damage to it to as it starts curing and settling.
But as I said,don't know what you were after for end result.If you were looking for driver quality,then take it for what its worth.

1BAD68

well it looks like your right there appears to be solvent pop. Little bumps that look like tiny bubbles weren't there yesterday dammit!



elitecustombody

You can not sand and buff out solvent pop. Because its throughout the thickness of clearcoat and no matter how much you sand or buff ,you will have little craters and under certain lighting conditions will appear like dust specs


AMD-Auto Metal Direct  Distributor, email me for all your shetmetal needs

Stefan

1BAD68

How do I know if it's solvent from the base or from the coats of clear?
I can re spray the clear but shooting a bc/cc again is out of the question. Besides, I don't baby my Charger in fact I'm sure the first time out I'll lay some rubber and have a bunch of stone chips in the quarters.
So as long as it's a 10 footer, I can live with it awhile. Would have been nice to have a really nice paint job especially after all the hours of block sanding but it is what it is.

"BTW, what clear are you using? Is it high-solids?"
yes it was Kirker EC300 Ultra H/S clear