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How to remove powder coating from bolt holes etc?

Posted: Tue Jun 26, 2012 3:06 pm
by Anders F. R.
Hello again!

I have a frame that previous owner has had powder coated. Powder coating would not be my first choice for a frame, but since the job is done I will probably live with that. However, there are two things that I must attend to, before I can assemble the bike: .-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-

1. The powder coating is a little "too complete", i.e. most bolt holes and especially the large holes for the rear plunger springing "inner tubes" are also filled with the stuff and consequently too small. I have foun that it is rather hard work removing this...... How to do it as good as possible, without damaging the coating outside the holes (or damaging the holes themselves)? .-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-

2. Fortunately the seats for the steering bearings are not powder coated. However, here the coating is flaking off a little on the edge outside the bearings. How do I repair this? Hot air gun to "weld" the coating in place again? Superglue under the loose edges of the coating? .-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-

3. Or should I get the whole frame stripped and properly repainted with "real paint", primer etc. etc., like it most likely was done at the factory "anno dazumal" in 1938?

Thankful for all good advice or thoughts about this!

Regards, Anders F. R.

How to remove powder coating from bolt holes etc?

Posted: Wed Jun 27, 2012 10:39 pm
by Yorkie

Hi Anders FR,
If you decide to strip the frame completly FROST RESTORERS have a product to do this job.www.frost.co.uk-01706-658619.

Hope this helps

Yorkie

How to remove powder coating from bolt holes etc?

Posted: Thu Jun 28, 2012 5:43 am
by simon
I like you would probably live with the powder coating as in large part it is probably ok. I'd re drill the holes with the appropriate sized bit or use a chainsaw file to clean them out. I'd probably touch up with a vinyl etch primer we have a product called PA10 over here that is brilliant for touching up and also for securing flakey edges. It's a one pot quick dry paint that washes out (but doesn't thin) with meths.
S:)

How to remove powder coating from bolt holes etc?

Posted: Thu Jun 28, 2012 7:58 am
by Anders F. R.
Thank you, both Yorkie and Simon!

Thinking of it, it is too bad to do it all over again as long as most of the powder coating seems very good. So I go for the "clean-up-the-holes-and-fix-the-few-blemishes" solution. .-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-

I have started out with a round file, but the four large holes for the rear plunger spring system, two each side at the rear end, are approx. 25 mm in diameter and 20 mm deep, so it takes some work to tidy them up properly. The same presicion is needed here as where fitting the front fork legs in the fork yokes, so I must not remove any of the steel. Anyone who has seen a rear plunger sprung frame probably understand what I mean. .-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-

I guess I just have to buy a bucket of good old elbow grease and have a go. The long term weather forecast for the summer holiday isn't too good anyway. .-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-

Regards, Anders F. R.

How to remove powder coating from bolt holes etc?

Posted: Thu Jun 28, 2012 9:37 am
by MadMike
Anders, the easiest way to clean out holes that have powder coating or paint in them is with a small flap wheel in a drill. Altermatively make a mandrel, cut a slit in one end and use a narrow strip of coarse emery clothe to remove the powder and a fine one to finally clean the hole. Check the fit with a bolt frequently. HTH.

How to remove powder coating from bolt holes etc?

Posted: Fri Jun 29, 2012 5:13 pm
by m1ks
If you're talking plain holes for bolts passing through then a mandrel and paper or a flap wheel as said.
If a threaded hole then run a tap through