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-   -   Sand blast and powder coat a 753 frame? (https://www.bikeforums.net/classic-vintage/1168604-sand-blast-powder-coat-753-frame.html)

JimboMartin 03-18-19 05:48 PM

Sand blast and powder coat a 753 frame?
 
Hello All:
I just picked up a 1991 Waterford Paramount with OS 753. I'd like to have it refinished locally by a powder coater who does a great job at a very fair price (~$110 plus powder). But, I'm just a little nervous about having his sandblaster remove the existing paint along with some of the steel. Maybe take the frame to a soda blaster first?
Those of you who have experience refinishing 753 frames, should I be concerned about this or am I being silly?
Specialty bike refinishers charge a LOT more but maybe its worth it?
Thanks,
Jim

rhenning 03-18-19 06:02 PM

Sand blasting will not remove any stable steel. Rust yes but good metal no. Roger

malcala622 03-18-19 06:05 PM

How bad is the paint on the frame that it needs a repaint

Chombi1 03-18-19 06:06 PM

Most C&Vers frown on powdercoating' because of the wa it goes on so thick that it "blurrs" out the detail on lig edges' points and pantographing. Also, when the powdercoated does not prep the frame properly the PC gets into the threads and holes on the frame which makes it difficult to install comppnents.
I did notice though that more and more people are ok with powdercoating newer frames because they are usually TIG welded/lugless, and do not have as much pantographing like frames from the 80's. As for blasting off paint, not sure, as I have never done it. I heard that soda blasting might be kinder to steel and maybe walnut shells. Anyway, I think most blasting different from sand and glass bead sound to he less abrasive.

noobinsf 03-18-19 06:19 PM

Well, this thread shows that Waterford has specific advice about chroming an 853 frame, so it may be worth contacting them directly with your specific question.

https://www.bikeforums.net/classic-v...lds-853-a.html

SurferRosa 03-18-19 06:25 PM

I've an old Lygie I can't sell due to bad paint. I'm thinking about investing in my own powder coat job with a $30 can from this site: https://us.spray.bike

Been a while since I painted a bike. I vowed never to do it again, it's so labor intensive. But that site claims only one coat is needed. And their instructions look fairly simple.

Bandera 03-18-19 06:32 PM


Originally Posted by JimboMartin (Post 20843937)
Specialty bike refinishers charge a LOT more

And well they should.
753 Frame-sets with their thin walled heat treated tubing are quite delicate to handle/prep/blast/finish to avoid dents/damage,.
I would only trust a re-finisher with considerable experience in handling high end classic bike frames to touch one regardless of finish type to be applied.

As always, suit yourself.

-Bandera

noobinsf 03-18-19 06:55 PM

Also look at Groody Brothers, which specializes in bike powder coating. It looks like $150 + shipping, and they will know whether you should proceed.

https://groodybros.com

wschruba 03-18-19 07:17 PM

"sand" might be a misnomer for most, now. Many use wanlmut shells as a medium.

mstateglfr 03-18-19 07:46 PM


Originally Posted by SurferRosa (Post 20843994)
I've an old Lygie I can't sell due to bad paint. I'm thinking about investing in my own powder coat job with a $30 can from this site: https://us.spray.bike

Been a while since I painted a bike. I vowed never to do it again, it's so labor intensive. But that site claims only one coat is needed. And their instructions look fairly simple.

I've done 2 frames now and can attest to both the ease of use and durability(so far). One frame was done close to a year and a half ago and looks the same as it did when first sprayed. It isnt a heavy use bike, but so far so good for $43 total.

notes
-fluorescent colors arent smooth due to the material.
- colors are flat and the clear coats give gloss.
- more frame prep means better application.

repechage 03-18-19 08:20 PM

I will continue to go on record as being against powdercoat for a lugged frame. Sharp edges are areas where the powder will always taper out in the baking process. Multi stage PC jobs do help, immediate spraying after media blasting can and does help. It is cheap, you get what you pay for.
on a 753 frame... if you wish to kill its value, go forward.

Strong opinion? Yes. I have four bikes that when if bought them were powder coated, really ugly rust worms upon chemical removal.

verktyg 03-18-19 08:25 PM

Bewere of gorillas
 

Originally Posted by Bandera (Post 20844003)
And well they should.
753 Frame-sets with their thin walled heat treated tubing are quite delicate to handle/prep/blast/finish to avoid dents/damage,.
I would only trust a re-finisher with considerable experience in handling high end classic bike frames to touch one regardless of finish type to be applied.

As always, suit yourself.

-Bandera

:thumb: Bandera, you saved me from typing the same response. Many sand blasters are used to doing industrial type work and have little if any experience with light weight bike frames. What would you do if the frame got dinged from rough handling?

The wall thickness of the thin sections of 753 main tubes is only .5mm thick and can be easily dented by an unskilled worker.

If you ever want to sell the frame or want to recoat or repaint it, getting the PC off can be a problem.

I've seen real butcher jobs done by platers. A friend had a classic Cinelli steel stem replated. Between stripping the old chrome off and over polishing they just about wiped out the stamped in Cinelli logo. Guys who are used to replating car bumpers shouldn't be let near a bike frame!

As far as powder coating a 753 frame, they were so rare and held in such high esteem that to me it would be like rattle can spraying a Ferrari...

:thumb: @repechage "on a 753 frame... if you wish to kill its value, go forward."

verktyg retrogrouch :50:

SurferRosa 03-18-19 09:52 PM


Originally Posted by mstateglfr (Post 20844123)
I've done 2 frames now and can attest to both the ease of use and durability(so far). One frame was done close to a year and a half ago and looks the same as it did when first sprayed. It isnt a heavy use bike, but so far so good for $43 total.

notes
-fluorescent colors arent smooth due to the material.
- colors are flat and the clear coats give gloss.
- more frame prep means better application.

Great info. Thanks. :thumb:

Johno59 03-19-19 05:00 AM

Repairing PC 753 frame
 
The problem with PC is that any breach in the coat - at a lug, stone chip whatever will lead to a capillary action by moisture from the breach . On a stovepipe frame this isn't a biggie as there's plenty of steel for the rust to eat. On a 753 frame the steel is very thin. I have redone stovepipe and 853 steel.
You can't see the rust as the PC masks the problem until it is severe . You tap the PC and listen for a ding or a tock. Normally the worst is at the BB owing to the large flexing.
The 853 was a write off, the cheap stovepipe I managed to save - but only just. The amount of unsightrd deep rust really put me off PC for good.
You can paint over PC. Check the Web for some great videos
​​​​​

easyupbug 03-19-19 08:47 AM

My 753R frame was blasted by an industrial shop that had done other bicycle frames, so no doubt 531. When we discussed the foreman assured my painter they do thin metal projects from time to time. Further from my very long ago "strength of materials" classes as 753 has a ~50% improvement in tensile strength over 531, which is the capacity to withstand loads tending to elongate, I did not see a danger in the blasting denting my frame. No worries.
Sorry can not help with PC.

trainman999 03-19-19 09:24 AM

JimboMartin unless that Paramount is a 93 build it is TrueTemper OS , Reynolds 753OS doesn’t begin till mid 93 according to the Waterford website.

Serial is on the BB and reads like this 570CWJ86048 570 57 cm frame, C fork size, W?, J September , 86 1986 048 48 frame built that month

mstateglfr 03-19-19 10:38 AM

why not just chemically strip it and emory cloth off any remnants?

Sandblasting hasnt removed any appreciable amount of material in my experience(limited to a handful of hours of sandblasting .8/.5/.8 tubing), but if there is concern someone will damage the frame- just strip the paint yourself.

Johno59 03-20-19 01:30 AM


Originally Posted by mstateglfr (Post 20845070)
why not just chemically strip it and emory cloth off any remnants?

Sandblasting hasnt removed any appreciable amount of material in my experience(limited to a handful of hours of sandblasting .8/.5/.8 tubing), but if there is concern someone will damage the frame- just strip the paint yourself.

In my experience removing PC is unbelievably difficult. If that stuff is still adhered to the metal surface nothing seems to move it. Paint stripper softens the surface but doesn't penetrate like it does paint. When you scrape or wire brush the soft surface there is just more underneath but now it is all over the place and is just as hard as the original surface.
Sandblasting is definitely far more effective and cost saving - but is risky with 753,853 gauge tubing.

mstateglfr 03-20-19 05:10 AM


Originally Posted by Johno59 (Post 20846233)
In my experience removing PC is unbelievably difficult. If that stuff is still adhered to the metal surface nothing seems to move it. Paint stripper softens the surface but doesn't penetrate like it does paint. When you scrape or wire brush the soft surface there is just more underneath but now it is all over the place and is just as hard as the original surface.
Sandblasting is definitely far more effective and cost saving - but is risky with 753,853 gauge tubing.

sure, this makes sense for a frame that is already powdercoated, but the frame in question has the original paint. That could be easily chem stripped. A couple rounds of a stripping spray, 15min with some empty strips, and it'll be bare metal.

Chr0m0ly 03-20-19 10:06 AM


Just wondering what you use to refinish a lugged frame instead of PC? Auto paint? Something like that?

I always thought PC was the “best” covering, but sounds like “no”.

Ive never refinished a frame, but I will be at some point I’m sure, I’d love to get some knowledge dropped on me. :thumb:


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