Lets say, hypothetically, a guy has a overlay tank stretch kit that is "almost paint ready". I found lots of information on epoxy primer and the base coat - clear coat painting processes but couldn't find anything on basic fiberglass part prep. 800 grit by hand? Block? How do you know you are smooth enough for primer? Thx
Part painting - basic solid color
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Crazy Beaver
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For something that has a curve like a tank I use a flexable block to get it close then when it is almost there I sand by hand. Then I use a buildable primer with a hardener, depending on how it is mixed it can be used as a thick buildable primer or as thin as a sealer. Once it is primed and sanded a trick to get it perfect is to use a darker color primer in a aerosol can and mist it over the part you do not need full coverage. Then sand again with your flexable block lightly, the dark primer will be removed in the high spots and remain in the low areas. From there you should be very close but if you have any low spots just repeat the sanding and primer. Let me know if you have any more questions.
CHAINSAW
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Basic prep if its in gel coat, just scuff it up with a red scotch brite pad if its "almost paint ready". Now that term can mean a lot of things to different people, so keep that in mind.
Here is what I do to prep fiberglass parts.
1 - clean the surface really good with a degreaser/wax remover. You can get this at any auto parts store, and even walmart. Also, wash your hands and try not to touch a bunch of grease or something. Cleanlyness should be at the top of the list at all times. A good paint job all comes from a clean surface.
2 - scuff with a red scotch brite pad like mentioned above. Do this until the surface is dull all over,.. no shiney parts at all. Corners and edges are important, as thats where the paint will peel first.
3 - As Crazy Beavers said, use a good quality primer. I prefer epoxy based primers, more specific I only use Martin Senour available at any napa stores (that comes from my training, although I have used other brands with success). I use the high build primer because it fills like bondo, and sands easily. DO NOT use cheap rattle can primers, you will regret this. It may be the same paint as whats in the can, but I have never used a rattle can primer thats worth a damn when it comes to sanding and filling.
4 - Again, as crazy beavers said spray a guide coat on. This will show all high and low spots, and any imperfections. Fiberglass is notorious for having small pin holes, ones you normally can't see until something like a guide coat points them out. Sand the part until there is no more guide coat.
Now, step 4 can either be done dry sanding with 400 or 600, or wet sanded with 400 up to 800 depending on how well the surface looks. I normally dry sand a thick coat of primer in step 4 with 220 grit. Then I follow it back up with another thick coat of primer and wet sand it out with 600 then spray my base coat. There are a lot of different methods, and just about every painter you ask will have a different method and pattern to which he follows. Every way gets the job done, so none of them is wrong. Some guys shoot 4-5 coats of primer and block sands each one until they are happy,.. but thats mainly on high end show only cars for high profile clients (think Chip Foose).
Once your happy with your part in primer, your ready for sealer or paint. If your primer job has 100% coverage, most times sealer is not needed. Sealer is mainly used when blending touch up jobs and repairs into complete panels that are already painted.
Youtube has a lot of how to videos on this subject. I suggest finding some that you feel are informative, and asking on here for us to watch that video. I would feel safer with seeing the same video your seeing, and making sure the information is correct. If the video is jimbob in his backyard painting parts on top of cardboard,.. DON'T LISTEN TO HIM!!! Try to stick to videos that are filmed at a Vocational school, or something of that nature.
Here is what I do to prep fiberglass parts.
1 - clean the surface really good with a degreaser/wax remover. You can get this at any auto parts store, and even walmart. Also, wash your hands and try not to touch a bunch of grease or something. Cleanlyness should be at the top of the list at all times. A good paint job all comes from a clean surface.
2 - scuff with a red scotch brite pad like mentioned above. Do this until the surface is dull all over,.. no shiney parts at all. Corners and edges are important, as thats where the paint will peel first.
3 - As Crazy Beavers said, use a good quality primer. I prefer epoxy based primers, more specific I only use Martin Senour available at any napa stores (that comes from my training, although I have used other brands with success). I use the high build primer because it fills like bondo, and sands easily. DO NOT use cheap rattle can primers, you will regret this. It may be the same paint as whats in the can, but I have never used a rattle can primer thats worth a damn when it comes to sanding and filling.
4 - Again, as crazy beavers said spray a guide coat on. This will show all high and low spots, and any imperfections. Fiberglass is notorious for having small pin holes, ones you normally can't see until something like a guide coat points them out. Sand the part until there is no more guide coat.
Now, step 4 can either be done dry sanding with 400 or 600, or wet sanded with 400 up to 800 depending on how well the surface looks. I normally dry sand a thick coat of primer in step 4 with 220 grit. Then I follow it back up with another thick coat of primer and wet sand it out with 600 then spray my base coat. There are a lot of different methods, and just about every painter you ask will have a different method and pattern to which he follows. Every way gets the job done, so none of them is wrong. Some guys shoot 4-5 coats of primer and block sands each one until they are happy,.. but thats mainly on high end show only cars for high profile clients (think Chip Foose).
Once your happy with your part in primer, your ready for sealer or paint. If your primer job has 100% coverage, most times sealer is not needed. Sealer is mainly used when blending touch up jobs and repairs into complete panels that are already painted.
Youtube has a lot of how to videos on this subject. I suggest finding some that you feel are informative, and asking on here for us to watch that video. I would feel safer with seeing the same video your seeing, and making sure the information is correct. If the video is jimbob in his backyard painting parts on top of cardboard,.. DON'T LISTEN TO HIM!!! Try to stick to videos that are filmed at a Vocational school, or something of that nature.
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Sa-weet. This is exactly what I was looking for. Unfortunately, I also know how impatient I can be when it comes to putting a finish on something. I probably won't try a tank as my first painting project since it's... kind'a right there... where everybody can see what a crappy job I did. But it would be nice to paint something like a front fender if decide to go with a different style someday... I'll start practicing on the beer fridge or something.
Thanks for the great information and I'll post some videos I thought were helpful. I figure this would be an interesting topic for a lot of people.
Thanks for the great information and I'll post some videos I thought were helpful. I figure this would be an interesting topic for a lot of people.
CHAINSAW
Site Supporter Until The World Stops Spinning!
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There is just so much info on how to do things, it can be overwelming to a new comer. A lot of times its hard to put into words, and thats why I love youtube. But like I said, there is some bad info out there that will hurt you more then help. The best advice I can give, is you get out what you put in. If you go cheap and use rattle cans and rush it, it will look like it. If you take your time, do it right, it will come out so good you will impress yourself.
dbell66253
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Subscribed, I don't plan to paint my whole bike anytime soon, but may have to touch up a couple of spots, I'll be sure to revisit when I do.
slothy
Balls
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Really wanting to start doing my own. All those steps are definitely overwhelming at this point. My life long body and paint friend (and I) just did my inner fairing with good results, but we didn't do primer or glide coat, only plastic promoter and sealer. In a couple of weeks the fender and bags should be ready to shoot. He rides Harleys and does alot of painting on cars. I know he is interested in quality and I think highly of him and his work. The bags are Top Shop and pre primered so I could do the glide coat at home uh?
My level of patience for body work and paint was validated today. The filler said it would dry in an hour, I gave it two. Went out to sand and it was still soft. This is 2012. I can't be waiting around all afternoon just to prep and paint a frame! Seriously!!!
Crazy Beaver
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Sounds like you might have not put enough hardener in the filler. If it seems like it will not harden after a little longer, you will have to scrape it off and remix your filler and start again.
I'm working on my front wrap fender. My question is; after I hit it with my high build primer do I spray it with guide coat and then sand? Or sand it then spray guide coat and sand it again?
Another question that I have is what grit paper do you recommend to prep a pre-finished surface (say a fairing) before spraying a another base coat. My supplier says 800 but my painter friend is saying 1500-2000. He's been in the business a long time. Not sure how big of an issue it is?
Another question that I have is what grit paper do you recommend to prep a pre-finished surface (say a fairing) before spraying a another base coat. My supplier says 800 but my painter friend is saying 1500-2000. He's been in the business a long time. Not sure how big of an issue it is?
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CHAINSAW
Site Supporter Until The World Stops Spinning!
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You spray you guide coat on before you sand. The guide coat will let you know how far to sand down to reach a level point with no imperfections.
It depends on color when I prep a pre painted part. If its going to be a flat color, I hit it with some 320 or 400 to scuff it up and paint. If its a glossy color, I scuff it with a red scotch brite pad or some 800. I recommend shooting primer sealer on if you have a couple spots where you sanded through the top coat, because those will show up. 1500-2000 would work, but in my opinion would not give enough "tooth" for your paint to stick well. It would work, but with 800 you get the same result, and probably in half the time it took to sand with 2000 grit.
slothy
Balls
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ya sounds like your didnt add enough hardener or mixed it good enought, the stuff my painter uses, hes sanding on it within 10 mins
Actually, the filler I'm using is working perfectly. The problem is I'm a mo-roon and I put it on way too thick in a couple spots. It was like kryptonite this morning.
This forum is great! It's like having Chip Foose on retainer for advice 24/7.
This forum is great! It's like having Chip Foose on retainer for advice 24/7.
Yes, just fixing up the neck rake mess I made. It'll have smooth neck sides with hidden wiring into the fairing. Its good practice to see what the high build primer will fill and what it won't. So far, I've managed to obliterate my VIN number and leave all the sanding gouges perfectly intact. Lol!
coolerman69
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Well another amateur painter is at work. Started last night on side panels and speaker lids. This is my first time painting raw ABS so I hope I'm doing it right!
I had this color custom mixed so I hope its not the same as someone else! Gonna shoot some clear this morning. Im thinkin I need to add some flake!
I had this color custom mixed so I hope its not the same as someone else! Gonna shoot some clear this morning. Im thinkin I need to add some flake!
coolerman69
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Thanks! Will do.
