Repainting a Dynatech

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mrp0ny
Posts: 7
Joined: 27 Aug 2011, 1:11pm

Repainting a Dynatech

Postby mrp0ny » 11 Aug 2014, 5:25pm

Hello to all

I have a nice Dynatech frame, but sadly the paintjob is too rusted to recover and the holes where the internal cable goes in the top tube are paticularly rusty. But the frame feels pretty solid and is fairly light too.

I was dropping off a couple of other frames for blast and powder coating at Armourtex, and they said they couldnt touch this, due to the heat of their process affecting the bonded tubes.

So now I am looking for a relatively cheap way of cleaning up and repainting a Dynatech frame....

Any help in such matters is greatfully received.....and for the purists out there, I have others which dont require any new paint job....it is a shame to have to paint over such unusual and designs...

Many thanks for any responses and any advice which may be out there!


David

Valbrona
Posts: 2293
Joined: 7 Feb 2011, 4:49pm

Re: Repainting a Dynatech

Postby Valbrona » 11 Aug 2014, 5:46pm

How would you know that you would be handed back of carrier bag full of tubes/lugs unless you try?

This reminds me a little of a friend I once had who installed milking equipment on farms. He said that on his first ever job he set up the machines wrong so that they all sucked much too strongly. He went back into the milking shed and found these black and white (they were Fresians) pods.
I should coco.

Brucey
Posts: 39495
Joined: 4 Jan 2012, 6:25pm

Re: Repainting a Dynatech

Postby Brucey » 11 Aug 2014, 6:03pm

they did the right thing and you dodged a bullet there; powder coating uses a cure temperature of about 170C and this is well above the temperature at which the kinds of adhesive that are used in bike frames will turn to mush.

In fairness there are some adhesives which may not be permanently ruined by such a thermal cycle (they go hard again when they cool down) but most will be degraded.

I would suggest normal painting techniques could be used quite happily. Lots of means of removing and treating rust out there and you can get a decent finish with rattle cans if you know what you are doing. But for a first-class finish go talk to a good bicycle refinishers (they don't use powdercoat on top quality steel frames). Or, go talk to a car bodyshop with a decent paint booth. If they can use the surplus paint from another job to blow in your frame at the same time, it shouldn't cost too much. You will probably have to do the prep work and the priming though.

cheers
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mrp0ny
Posts: 7
Joined: 27 Aug 2011, 1:11pm

Re: Repainting a Dynatech

Postby mrp0ny » 11 Aug 2014, 6:29pm

Thanks for the replies so far...

So can I use nitromoors or similar to remove the paint without affecting the bonded lugs?

Or maybe there are people out there with different ways of removing paint/rust etc other than blasting at 170 degrees....

Brucey
Posts: 39495
Joined: 4 Jan 2012, 6:25pm

Re: Repainting a Dynatech

Postby Brucey » 11 Aug 2014, 6:41pm

No, don't use nitromors either, this will also attack some adhesives.

Simply use mechanical means to remove the paint and rust wherever it is needed, and leave the sound old paint everywhere else.

Chemically treat the corroded areas with a rust remedy type product, then repaint in the normal way.

Heat and chemicals are bad for your adhesive bonds, and removing sound paint is very simply a waste of time.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Valbrona
Posts: 2293
Joined: 7 Feb 2011, 4:49pm

Re: Repainting a Dynatech

Postby Valbrona » 12 Aug 2014, 1:42am

mrp0ny wrote:Or maybe there are people out there with different ways of removing paint/rust etc other than blasting at 170 degrees....


I thought they blasted it with sand or soda or something else depending on the particular method, but did not use heat. I thought only the powder coating process involved heat. And there is this stuff called wire wool ...
I should coco.

BigFoz
Posts: 491
Joined: 2 Jun 2011, 12:33pm

Re: Repainting a Dynatech

Postby BigFoz » 14 Aug 2014, 4:39pm

The guy I spoke to up here about painting a 753 frame said because tubes are so thin, he prefers his "man" to blast with walnut shells so as not to damage the tubes. That should do the trick? Can't imagine that damaging bonds. Then proper paint rather than powder coat should bring it back to life.

Ank@eel
Posts: 56
Joined: 8 Mar 2007, 4:50pm

Re: Repainting a Dynatech

Postby Ank@eel » 15 Aug 2014, 3:30pm

Rolls Royce used to (may still) tumble "Sprit of Ecstacy" radiator mascots in walnut shells to remove the casting nibs. But quite how you would blast something with the shells is a mystery.

Brucey
Posts: 39495
Joined: 4 Jan 2012, 6:25pm

Re: Repainting a Dynatech

Postby Brucey » 15 Aug 2014, 4:15pm

you can buy crushed and graded walnut shells in bulk quantities. This kind of media can be used in both pressure and syphon type blasting systems, provided the nozzles and flowrates can be adjusted accordingly.

cheers
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