The Stovebolt Site Forums The Shop Area Paint and Body Shop Powdercoating before or after

I'm doing a ground up resto on my 52' AD. The guy I'm having upgrade my differential from a Patrick's kit wants my torque tube and rear-end complete before sand blasting and powdercoating. After his initial repairs, he'll give me back some pieces with firm instructions of how the powdercoating should be done. My question now is; since the sand blasting and powdercoating will be done on everything connected to the frame (i.e., all suspension, steering etc.) should any and all work be done first to these parts 'before' the blasting and powdercoating?
Thanks ahead of time

In my experience with powdercoating, and I am no expert, but I would do all work and any repairs or modifications before powdercoating.

I have chiped powdercoating in the past and you can't just us a shake and shoot to repair it. I have learned to make sure all work is done before I have my parts powdercoated. I have been real careful about re-assembly as well, can chip with wrench or by hitting parts together.

Good luck.

I would sandblast and powder coat the axle before rebuilding it. The sand will get into the bearings and the heat required to cure it will cook out the grease. Cosmetic work should be done before powdercoating, but mechanical work should be done afterward.

The guy that is doing the diff rebuild has to grind apart the torque tube. This would, I would think, mar the PC finish a bit. So i'm confused as to the process of the rebuild. Any questions I should be asking before the work begins?

I powder coated my torque tube and diff. housing. It must be disassembled BUT there is NO grinding involved if you are doing a standard rebuild.

The torque tube stays attached to the differential carrier that holds the pinion gear and bearings. This is the cast part that bolts to the FRONT of the differential housing.

Good powder coat does not chip easily, at least mine doesn't. Before it is coated they heat it up to about 600 degrees to burn off paint and grease. This temp will destroy any seals or lubricants still in it. After spraying the coating on it is baked again to liquify the powder and bond it to the metal.

I have pictures if you want.

Paul Wisner

Paul,
It appears that the torque tube is hot riveted into the front of the differential. Maybe the rebuilder meant that the rivets were ground away to slide the tuba away from the differential.
So you're say that "4onthefloor" was correct the the PC process will destroy the seals and grease of the rebuild.

Paul,
It appears that the torque tube is hot riveted into the front of the differential. Maybe the rebuilder meant that the rivets were ground away to slide the tube away from the differential.
So you're saying that "4onthefloor" was correct; the the PC process will destroy the seals and grease of the rebuild.

Rattletrap52,

I just finished doing this to my 51. Here's what I did: Stripped the differential out of the housing, pulled the axles and axle seals, pulled the driveshaft from the torque tube, pulled the bushings and seal from the front of the tube. The torque tube was unbolted from the rear axle. I replaced the three bolts that hold the bearing in the torque tube with some different bolts just for this process. I did this so they would not be lost.
I sealed the front end of the tube with metal tape and used the ends of soda cans and more metal tape to seal the ends of the axle housing. I used a 11 inch aluminum pie plate to cover the front of the axle housing. The rear plate was bolted to the housing. (I had to cut the rear plate off with a razor blade when it came back.) The axle housing and torque tube were all cleaned and taken to the coater.
When it came back, I cleaned the tube and axle housing as best I could to get all the sand out of it. You may find a better way to seal it up, but I think no matter what you do, some stuff is going to get in it during the process. Then on to the rebuild. By the way, it looks great!
I hope this helps.

Mark

RT52,

I forgot one thing. I used a second 11 inch pie plate to cover the rear of the torque tube.

Mark

Mark,
Any chance you or anyone else took pictures? I'm one of those visual types.
Thanks,
jeff

RT52,

Sorry, no pictures. Let me know if you get stuck. I'll help all that I can.

Mark

Rattletrap,

You DO NOT have to separate the torque tube from the carrier. If your rebuilder is planning to do this then stop him and take it to someone that knows what they are doing. Separation is not required.

Yes, the heat of cleaning and bonding the powdercoating WILL destroy seals.

If your powdercoater is any good they will know exactly what to tape off (high temp) to avoid getting the coating on any machined surface or thread. If they don't do this then take it to someone that knows what they are doing. The only area you should have to point out to them is the area at the front where the u-joint ball has to slide on the tube. If you let them coat this area you will not get the ball housing to slide properly.

I can post pictures of the housings but can't until Monday or send me an email address and I'll send direct to you.

Paul Wisner

RT,

Paul is correct. You do not have to seperate the torque tube from the carrier. I did it because it was a little easier to move, but given the choice, I would keep it together, too. And, you do NOT have to remove any rivets.
Good luck.

Mark

Paul,
[email protected]
Thanks ahead of time