Novice builder questions

[jabcb]

Am looking at powder coating a GT250 frame & later on a GT550 frame.
What do you guys do to prep a frame for powder coating?

[RING_DING]

The powder coater I use will just take the frame and sandblast it first, so no prep on my part. Make sure they plug any threaded holes prior to applying the powdercoat.

[sbaugz]

yep, what he said. Any good powder coater isn't going to trust your sandblasting and prep work, so don't bother doing it yourself. any dirt or residue left over will cause the powder to not adhere properly so most reputable powder guys insist on doing their own prep work right before they spray.

[joolstacho]

Also, watch out for high temperatures in the powder curing.
After they apply the powder coat, it is then cured in an oven at very high temperatures.
Any plastic, rubber, or fibre parts are at risk of melting or distorting. (Bear this in mind when masking off).

I recently did a frame which has fibre swing arm bushes, I couldn't remove them before powdercoating without destroying them.
So I left them in situ, and sure enough after powdercoating the bushes were ruined (At least they had shrunk so they were easy to get out!)

[sbaugz]

I recently did a frame which has fibre swing arm bushes, I couldn't remove them before powdercoating without destroying them.
So I left them in situ, and sure enough after powdercoating the bushes were ruined (At least they had shrunk so they were easy to get out!)

It is possible to leave those bushings in place but you have to tell the powder coater about them. They can bake longer at a lower temperature to try and save them.

[joolstacho]

But if they lower the curing temp the powder may not flow out properly. Extra time won't help it.
The high temp is so the powder melts and flows out nicely to give a good smooth finish.
They don't like risking the 'orange-peel' finish that comes with lower temp cure.
Also you'll quite possibly pay extra to have your part cured separately from their other workflow.
Just remove the vulnerable parts. Easy!

[sbaugz]

Just remove the vulnerable parts. Easy!

Easier said than done. I've rebuilt a lot of bikes and those swingarm bushings don't like to come out! Also, there are some bikes where you either cannot get new ones or they cost $30 each.

[joolstacho]

In that case, don't powder coat, paint with 2K. Again... simple really!

[jabcb]

Recently ordered new swing arm bushings for both bikes.

We will detab the frames.
Then the frames will go to a welder for some mounts for cafe seat (both bikes) & oil tank (GT250 only).

The GT250 frame doesn’t have any rubber bushings but the GT550 frame has rubber bushings at the exhaust mounts.
Do I need to remove the GT550 exhaust bushings?

There are just a few threaded holes, so its no big deal to provide the frame with throw-away bolts installed.
I’ll make sure to tell them to plug the steering+swing arm holes.

[sbaugz]

Recently ordered new swing arm bushings for both bikes.

We will detab the frames.
Then the frames will go to a welder for some mounts for cafe seat (both bikes) & oil tank (GT250 only).

The GT250 frame doesn’t have any rubber bushings but the GT550 frame has rubber bushings at the exhaust mounts.
Do I need to remove the GT550 exhaust bushings?

There are just a few threaded holes, so its no big deal to provide the frame with throw-away bolts installed.
I’ll make sure to tell them to plug the steering+swing arm holes.

all good powder coaters will properly plug all threaded holes and places where bushings press into. They should also mask off the inside of the steering stem. Nothing is worse than getting freshly coated parts back, only to find out that you have to scrape away powder from inside steering head so that your bearings will fit inside.

[Alan H]

Recently ordered new swing arm bushings for both bikes.

We will detab the frames.
Then the frames will go to a welder for some mounts for cafe seat (both bikes) & oil tank (GT250 only).

Always good to fit new swing arm bushes during a rebuild anyway. You can get the silencer hanger bushes out with a couple of tubes and a bolt.
Leave them in and they will be destroyed.

You can now get cafe type seats that fit the original mounts and lock, so swing up for easy access of battery etc. Now available in the US.
This is the one I got http://www.ebay.co.uk/itm/Custom-cafe-s ... xySFJSHg-o" onclick="window.open(this.href);return false;
Or http://www.ebay.co.uk/itm/1972-1978-Suz ... Sw4HVWEoCx" onclick="window.open(this.href);return false;

[jabcb]

We should have the GT250 frame back from the powder coaters in about a week.

We are using Hotwing Glass seats.
Recently got the GT250 seat + other parts back fro the painter — they turned out quite nicely.

Thanks for the tip on the GT550 hanger bushes.