phtomita

Hello,
I am thinking on doing some minor repair on a Tange 1 frame (by bike shop) and maybe get a new fresh paint on it.
I was reading the internet about sandblasting frame for powder coat = will remove some steel from frame and question is:
How safe is sandblasting the frame with such thin frame material? Did someone here do it before?
Thanks in advance!

Andy_K 

It's fairly standard practice for the powder coaters I've worked with to sandblast frames. I haven't had a problem with it.

For frames I painted myself I've used chemical stripper followed by sanding. The sanding will also take some small bit of material off. The amount it removes is unmeasurable. I think in either case you'd have to be fairly reckless to remove enough steel to cause problems.

noobinsf 

You might ask around your local places about the media they would use. I found a place here in the Bay Area that uses glass beads, which are supposedly gentler on steel frames. Very happy with the results — you can see them in my Eisentraut thread.

gugie 

This comes up from time to time by newer members, it's "well ploughed" territory. I've had dozens of frames powder coated over the last few years. Media blasting is always done, as it removes rust and roughens the frame for good adhesion. I've used 5 different powder coaters, all of them had experience working on bicycle frames. Note that wet painted frames get the exact same pre-treatment, it's no different.

I started a thread awhile back to track powder coaters that forumites have used successfully and can vouch for the quality of their work. You'll see three of them in driving distance from you.

mprince

Most painters refer to this as media blast, not sand blast. It will remove previous paint and surface rust from the frame. If the frame is in good shape to begin with, I would not worry about this process affecting the integrity of the frame.

gugie 

I've used 5 different powder coaters in the last few years. I've been satisfied with all of them, had to change when one went out of business, another moved, others were shipped out.

They each used a different media. I believe it's much more important to control the pressure and angle than the media itself.

easyupbug 

As gugie said the blasting media should not be a concern with an experienced coater and you want someone experienced with lugged frames as I have seen them too heavy with a loss of detail and have one that is too thin with the frame color through showing through the yellow at the lugs.

delbiker1 

I finished putting what I thought would be the final coat of paint on my Fuji Ace frameset yesterday. However, I do have to go back and do another spray on a couple of areas where the coverage is not quite enough. Yes, it is a rattle can spray job. This is, I believe, the third time I have actually stripped it to bare metal. I also partially sanded it down a couple of times to "fix" some areas of a couple of bad coats I had done. My "fixes" just made it worse. A couple of areas around the head tube and seat tubing cluster, mostly the lug lines, had some surface rust the first time I stripped it, and those areas did lose a bit of definition. I do not notice it now without really looking closely. Also, the serial number on the underside of the bb is a bit hard to see now. Other than that, all good.

It is kind of crazy for me to do it this many times, but I had never painted a bike before and I really messed it up a couple of times. I think I got it right this time. I had a couple of bikes powder coated a couple of years ago, and that is likely what I would do again if I have a next frameset to refinish. I was not going to do the Fuji again, but I am sometimes hard headed, and I needed a project. I think I finally got it right. Now to just let it sit for a couple of weeks before I rebuild.


Now I just need to decide whether or not to purchase and install new decals. Fuji Ace set is about $35, just plain Fuji decals can be found for around $10 with choice of color. If I decide to go with decals, it will likely be the Ace set. It is not going to be anywhere near original, but I like the Ace decals.

Drillium Dude 

Not a problem if the frame is in reasonably good shape and not rotting from within (or without, for that matter).

Some details from a media-blasted frame done by a Portland area outfit follow.

Half the original chrome was gone, so the remainder was blasted off; the pitting was present before the blast:



Extremely clean results on the rear dropouts:



DD

phtomita

Thank you, this is very helpful

phtomita

Thank you all, now is what color to choose
Seattle Powder Coat is the one I was looking and is along the Burke Gilman trail I rode many times.

xiaoman1 

A comment about media blasting......I prefer glass beads or walnut shells....the later must be cleaned with acetone or something that will clean the oil from the frame. Sometime the "sand" has too much teeth and can really cause problems with the fine detailing on the frame. JMO,
Might be a members bike so please take no offense.
Best, Ben

Looks rough and will require a lot of clean-up work or heavy paint to make right. Imagine what it would be like on a bike with fine lug work.

Fredo76

Well, if you take it to some joint that sandblasts construction equipment, you might end up with a coarse blast like above, but any frame finisher would not accept that quality, as it would mean far too much afterwork for them. Frames have been sand-blasted for generations, and media-blasted for decades, so it is nothing to worry about structurally. Here's a shot of mine, after blasting and before powder-coating:


Fredo before powder-coating

delbiker1 

I have had 2 bikes powder coated, but I stripped and sanded the framesets myself. The last step before cleaning was wet sanding with 800 grit paper. The cleaning was Dawn detergent and a blue scotch-brite, rinse well and let dry, finally wiping it all off with acetone. The fellow that did the coating said the job I did was excellent, but I never asked him if it still had to be blasted or prepped in any other way, and if not, does that make the cost lower to me. I never thought about either until getting more learning more about the process. I guess if I have him do another at any time, I will ask those questions. The stripping and sanding is not that hard, but it is time consuming and tiring.

repechage

that side clover cutout still visible after powdercoating?

Fredo76

powder-coating fine detail

Sure is! The guy who did it also builds steel frames. https://olearypowdercoating.com