You always see videos of guy's block sanding doors or hoods and so on but never see anything on sanding edges or lines!! I noticed you can and will break through real fast!! Do even bother trying to block sand or smooth the edges?
Block Sanding Question
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I put three coats of poly on this and I'm blocking with 400 which I'm not really sure this is correct? I just watched a video that a guy was using 220 and then wet sanding with 400. Someone get me straight here?? LOL
Haven't got along far enough yet that I can't change my direction.
Haven't got along far enough yet that I can't change my direction.
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Spray poly takes the place of applying regular polyester puddy with a plastic spreader, which is usually the last step after doing bodywork with regular body fillers, (bondo).
But when it's sprayed on, the obvious benefits are no spreader marks, and a nice even application. Applying the spray poly is to fill the deeper scratches, 36, 40, and 80 grit, that are in the body filler. It's also to fill pin holes, and to straighten all the body work with a long board. I usually start with 100 grit to cut down the initial roughness, and then move to 150, or straight to 180.
Then, you can apply a urethane primer over everything, and once it is cured, "that" is what's wet sanded with 400, 500, 600, or 800,...depending on your paint brands recommendations.
Yes, have guide coat and it's dusting up some but balling some I think due to cheap brand of paper. I sanded the car with 180 before spraying the polyester primer and started blocking with 400. 99% of body work is done so far I've found one low spot in a quarter that will need some icing to get correct.
I was thinking the polyester was my final step before putting down a sealer and then paint? Shit
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Frank is correct. The object is to achieve the result you want with the least amount of material left on the car. You only want enough filler to level the surface . Then only enough glaze to fill the deep scratches and pinholes. Most of it will get sanded off. Then the primer surfacer to fill the scratches from the 150. At the same time you should be improving the straightness of the panel with each step. That's the best way I can describe it. It's very labor intensive to do right.
I don't question Frank at!! I'm sure glad I ask the question. So urethane primer over poly primer is okay? At !st I bought Eastwood's poly and did not like it so I went with EverCoat's poly which I like much better. After getting this info I still have a shit load of work a head of me!! LOL. Well I sure do thank you all for the info because I was about to fucker up!! lol. The car was pretty straight to start with other than the quarter I replaced. It's okay to put urethane primer over polyester..
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Yes, urethane is fine over the sanded poly. Try your best not to sand through the poly. That poly is great at holding everything down. Breaking through ruins its effectiveness.
I experimented with it on my 442 hood. Should of been stripped, but I was too lazy. Hit the checks and scratches with poly and 6 years later still looks perfect.
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you won't get your polyester cut nice and flat starting with 400,I usually do like Frank and start with 120 and finish with 180 to 220 and reprime with urethane but have finished out Slicksand to 400 and sealed with either epoxy or urethane sealer and didn't have any issues,was always leary about doing it but have on a couple blow to go's and seamed alright
The bad news! I broke thru and hit bare metal in a few spots. Will I have to go back and hit those spots with epoxy again? I did pick up a gal of urethane primer today and I'm guessing it's not to be used on bare metal? The epoxy say's you must wait a couple of day's to sand which I don't have that kind of time but it also say's it's ready for top coat in an hour so could I hit those bare spots and in a hour go straight to the primer? I'm running out of time getting it in paint before winter sets in. Work anywhere between 12/15 hours a day don't leave a man much time to work on it!
Thanks Bill
Thanks Bill
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Bill, I would start over the bare spots with epoxy and then the poly. Not sure what the other pros will say. That is me. Anything else will be cutting corners, and as hard as you have worked on this thing, I wouldn't recommend it. You want a solid unbroken coat of poly for the best longevity.
Sorry man!
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iif you just have some small breakthroughs and the panel is straight I don't see why you couldn't epoxy those spots or the entire panel for that matter,let flash and then urethane it,if you breaking it trying to get it straight and it needs additional filler work then I would say re-poly the entire panel and block again,
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Confused about the epoxy?? Will I need this to sit a day or two or can I shoot right over it. I'm thinking of the rough texture it leaves. Can it be sanded after a hour or so before going to the other primer or do I shoot right over the epoxy with out sanding? Sorry about all the rookie question!!!
Thanks Bill
Thanks Bill
Thanks, I'm thinking about just shooting the whole shell in epoxy and then going straight to the 2k urethane.
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A good job does take time. Most people think the body
man is crazy when he asks the kind of money he does, to do a quality job. And no one knows just how time consuming and labor intensive it is until they try it themselves.
It may have taken you a bit longer than someone who does it everyday, but that is to be expected.
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If you just have a few small spots of bare metal showing here and there, you can just spot prime those areas with epoxy, using light pressure to reduce overspray,....and when it flashes, (drys dull), you can prime the whole thing with your urethane primer.
No need to epoxy the whole car, that's a waste of time, material, and money,...and more chance of runs, dirt, and other surface defects to deal with.
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