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Assembly after powder coating pieces
#1
Can anyone give me some help on this? I had dis-assembled my bike in order to have a powder coater paint it and now the person who said they could re-assemble for me says that the painter painted parts that shouldn't have been painted. Should I grind off the powder coating or is my "friend" not accurate? I need to get this bike re-assembled but unsure to proceed if there will be problems down the line with parts not going together correctly. Can you give me some input? Thanks for your help.
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#2
Some photos of the painted parts would be helpful. Otherwise, there isn't any way for us to know what was painted.
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#3
Pictures please Smile
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#4
The parts that shouldn't have been painted or need clearing =

Bottom bracket threads.
Internal of the headset for headset bearings.
Rear dérailleur mounting hole thread.
Other minor threads - bottle cage threads. mudguard eyes.
Maybe seat-tube internal for seatpost?

If doing the BB thread then this is a very fine thread and care will be needed. Scrape the "paint" away, with a sharp knife blade, and it might be a good idea to have your LBS run a tap through after.
The faces of the BB and headset may need cleaning as well.

When I had a frame done I fitted an old style metal BB and screws in the threads. I didn't bother with the seat tube or headset as they are fairly easy to clean out after.
[font=Trebuchet MS]Ride hard or ride home alone![/font]
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#5
ive used a small stainless wire brush (and lots of patience!) for paint in the bb threads, but i doubt it would work for powder coat.
Get on your bad pedalscooter and ride!
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#6
[attachment=1782][attachment=1780][attachment=1781][attachment=1783][attachment=1784]
(12-26-2010, 09:11 PM)kkelton8356 Wrote:  Can anyone give me some help on this? I had dis-assembled my bike in order to have a powder coater paint it and now the person who said they could re-assemble for me says that the painter painted parts that shouldn't have been painted. Should I grind off the powder coating or is my "friend" not accurate? I need to get this bike re-assembled but unsure to proceed if there will be problems down the line with parts not going together correctly. Can you give me some input? Thanks for your help.
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#7
The main problem I see is the paint inside of the bottom bracket. It covers up the threads. Also the holes on the tabs towards the rear of the bike and on the fork should have threads in them I believe.
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#8
(12-28-2010, 04:56 AM)nameused Wrote:  The main problem I see is the paint inside of the bottom bracket. It covers up the threads. Also the holes on the tabs towards the rear of the bike and on the fork should have threads in them I believe.

Thanks for the input. In other words, prevention is always better; but I guess I will know next time.
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#9
It appears the headset cone and cup have been left in.
The choice is to meticulously clean the bearing surfaces or fit new ones.
The fork also has the lower bearing cone and the bearing surface needs cleaning. (or new one?)

I'm not sure about the bottom bracket - have you left the cups in there as well?
If so then again the bearing surface needs cleaning or new ones fitting.

The smaller holes (mudguard eyes etc) may or may-not be threaded. If threaded than need cleaning out (retapping?) or, if not threaded, then just leave. (nut and bolt.)

You might have to clean out some of the cable guide holes to allow the cable to pass or cable ends to fit.

Looks like a nice job on the coating.
I'm not sure if it was my imagination, but my frame coating seemed soft at first and then hardened up with time.? So initially try not too scratch it.
[font=Trebuchet MS]Ride hard or ride home alone![/font]
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#10
Nice paint job!! Smile What kind of bike is this frame? As far as the Bottom Bracket bearing cups they are simple to replace! If you want to match the color of new ones just get a model brush with red paint and touch them up staying away from where the bearings go inside by masking taping it off. Clean off the fork crown race where the bearings lie. Headset bearing races needs paint removed, also I am in deep thought as to how the bottom headset bearing race connects to the one one the fork?

At any rate very nice paint job Smile
Good maintenance to your Bike, can make it like the wheels are, true and smooth!
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#11
Yes, that is a nice paint job. Powder coating lasts a long time and turns out very smooth and glossy. Almost looks like plastic. Maybe because it is actually. Smile I think you can buy a fairly nice gun for less than $50 at Harbor Freight. But the problem with doing bicycle frames is that you will need an oven big enough to fit the frame. The powder is baked (and literally melted) on the metal. Normally, most home powder coaters just use an old electric oven but that's not big enough for a bike frame.

And the problem with taping off areas on a bike frame again is dealing with an oven at 450 degrees (F). If you use paper tape they might catch fire or scorch. Plastic will melt and so on. But an experienced bicycle frame powder coat painter probably has those issues figured out.

Steve
Junkyard Tools rescued from the junkyard!
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#12
what he should have done was tape off the areas that were not suppose to be powdercoated. Then after spraying the bike you unmask and take off the tape before you bake. If you bake with the tape on it will be next to impossible to remove and will leave a hard edge on the powerdercoat.
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#13
Yikes 10-4 to what CyclerUK said. Your powder coater should have known better that to coat threaded surfaces. Those you need to clean off . The headset races IMO should be replaced. Unless they can be removed coating dissolved in a liquid media and than whipped clean. Scraping will damage them. Same for bottom bracket.

Ask the coater if there is a liquid stripper for it. The races should have been removed and threads covered prior to coating.
Never Give Up!!!
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#14
(02-25-2011, 12:16 AM)GeorgeET Wrote:  . . . Ask the coater if there is a liquid stripper for it. The races should have been removed and threads covered prior to coating.

No stripper that works on plastic that I can think of. The powder melts into a hard plastic-like coating. It isn't really paint. I think they call it a polymer or something like that.

Steve
Junkyard Tools rescued from the junkyard!
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#15
Well, hopefully the bike is back together ??
Perhaps we can see a photo and get a report on overcoming any problems.
[font=Trebuchet MS]Ride hard or ride home alone![/font]
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#16
all your bearing surfaces have been coated, these should have been removed before coating, but they can either be replaced with new ( the bb is a one piece and is not threaded, bearing sets for these should not cost more than £10 and similar for the headset) just knock the old ones out, clean up the seating area and install.
Or clean them up, they are hardened so don't be afraid to use abrasives such as emery cloth, you wont damage them.
I see he hasn't coated the fork thread, so thats ok, and the drop outs are ok as they are.
Then it should go back together better than new.
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#17
Just to throw this idea out there I wander if a dremel with the right bit would remove the paint?
Good maintenance to your Bike, can make it like the wheels are, true and smooth!
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#18
Powder coat is impervious to every chemical most people can get legally. It maybe easier - and cheaper - to get a replacement frame, and start over.

At a previous company, we had to rework some products that were powder coated, and the screws held in place with red Loctite 721. We used plumber's torches on the screws to get the Loctite to weaken enough to take apart. Several minutes direct blast of the torch had no affect on the powder coat.

It appears to be a Schwinn Varsity based on kick stand and joints.
Nigel
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#19
wikipedia
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#20
Clean threads (micro torch?), assembly bearings w/o cleaning paint. Balls will strip paint, take apart, clean, grease.
Just send me your frame, I'll pay for shipping.Smile
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