Painting over paint

[Burton]

I am repainting a bike for someone who has decided they are not a raiders fan and wants to change the flame color from silver to a pearl red. I just got done painting this set no more then 2 months ago. I used all Hok material over the original paint which is new the bike is a 2002. The front fender and rear fender are both plastic. Should I shave it all the way back down to the primer/first coast and use sealer or should I just scuff up the clear coat and go at it? I don’t know if this will help but here is a picture of the tank.

 

[DenB.]

tho it means extra work i'd say take it all the way down to bare metal . if you put too much paint on any job you'd risk checking and cracking dowm the road.

 

[rex]

How you been Burton?I hate to say it but that's pretty thick to go over.Sanding back down to original or so would be great but you don't really want to do it.I just carefully chemical strip what I can and bead blast and sand the rest off and start from scratch.It's not enjoyable either but it's a nicer job and peace of mind.I feel for you,I'm redoing my tank now.Throw some 80 grit scratches in it and the stripper should work fast since it's a fresh job.Just stay away fron the tank mount tabs and petcock bung,it's he!! neuralizing stripper when it seeps into joints.

 

[TWISTED]

Im trying to find an easy way to strip the plastic myself. A shop in town here has a blaster that uses baking soda and water instead of sand or beads. I was going to see if that might work.At least to get the bulk of the paint off then hand sand the rest smooth.
Also I have had adhesion problems with sport bike fenders in spots where the plastic has been exposed. Any one got a quick fix for that?

 

[Burton]

Hey Rex,
I’m doing great!

How about yourself? I really don’t want to chance any type of bead blasting just because it’s not my bike and the guy that owns it is fairly large!

I’ve also never tried chemical stripping before is that safe for plastic? Also what the prescribed way of doing it? I’ve seen the paste or gel type stuff that sits on the surface and then you scrape it off, same stuff? Is there any brand I should use or stay away from? I know you didn’t suggest sanding but other then the time is there any other reason not to take it down by hand?

Twisted,
Have you tried the adhesion promoter form PPG or HoK? I’ve use the PPG and it works pretty well. The adhereto (HoK) can even be used on paint for between coats so you don’t have to worry about sanding all the paint off the surface. I think PPG is the same but I’ve only used it on bare surfaces like plastic front bumpers and the plastic fender flairs.

 

[TWISTED]

I dont get a lot of plastic work. Most of what I do get is a helmet here and there that is a solid color and just scuff it and paint.
I know that most strippers will melt the plastic. If you think about it urethane and acrylic paints are pretty much plastic.
I started sanding down the plastic side bags and fiberglass trunk bag for the bike I'm painting. lots of work. I think I'll try the adhesion promoter on the trailer that goes with the bike.

 

[Austin]

There is a paint stripper made for car bumpers, but even with that you have to test it a a small spot to make sure it doesn't react. SEM makes it, it comes in a spray can. I can get the part # from work if you like.
Austin

 

[Burton]

Austin,
If you have a chance, get me that part #

Thanks!

 

[FastCat]

I'm in a similar situation, and from the input I've seen so far, it's going to mean alot of elbow grease. I'm stripping/repainting an '85 bike. Tank, and a few pieces of plastic fairings. So far the best way I've found to strip it down to plastic, is with the help of a mechanical stripper. I was browsing through ACE Hardware and came across the following:
San Buf Flap Wheel...basically it's a plastic wheel with short sandpaper strips attached to it, that when attached to a hand drill spins the sandpaper to help strip, it comes in several grades, from Coarse to Fine. As a trial I picked the Medium, and so far has cut down on the amount of sanding hours to a minimum. I will have to sand the plastic with some very fine paper to get the smoothness back, but it cuts through the three old layers of paint and the decals, with little problem, since the sandpaper strips are plyable, it conforms to the plastic and pressure applied. this has worked well for me so far. I couldn't pass trying it for the $5 or so I spent on it, compared to other alternatives. My time is worth more than that.

I would appreciate any other tips on restoring plastic pieces.

I'm also going to be stripping and painting the tank, so far this is my plan of action:

1. Chemical stripper: to remove the three coats of paint including the factory coat, and the decals that have been painted over.

2. Wetsand in progression down to bare metal. Bondo the few small imperfections on the tank, dents and such.

3. Prime the entire tank.

4. Basecoat of dark gray or so, wetsand in between coats to remove imperfections, runs or anything I don't like in the paint and recoat.

5. Clearcoat, Wetsand and Recoat.

The trick is I have no paint gun, can't afford a PRO paint job, and don't want to buy expensive paint guns for this one time. This bike needs alot of TLC in other areas, like engine and mechanical care, and that is where I'd prefer to spend the majority of my time and money, if any.

Any recommendations as far as DIY paintcanning the parts? Any particular brand of canned paint that is better? Any tips for paintcanning a project like this?

TIA.

 

[Burton]

Fastcat,

Thanks for the tips. I don’t know much about rattle can paint but I believe there have been a few posts on the subject. Do a search you might come up with something. What I would do is spend the extra money and buy a detail gun. If you have a harbor freight around take a look at the central pneumatic detail gun or even eBay. It’s about around 60.00 with the regulator. You can do the whole job with that, it may take a couple more coats of primer but it will get you there. Also check out one of those places that sells the paint per once. It’s normally HoK but in the quantities your buying it will still save you money. The two I know of is coastairbrush.com and innate.com.

 

[popo]

FastCat,
most paint jobbers will put your choice of paint in airasol form for you.

 

[FastCat]

Thanks for the tips all. I'll do a few more searches to see what I can find about this method. In the meantime, I'm going to look around my local area in hopes of finding a hobbyist or someone with the tools, who wouldn't mind getting some 'practice' on my pieces if I provide for cost of paint and abit for time.