Question about sandblasting a frame
 

Hey there ...

I'm thinking of getting an old frame of mine repainted, and my cheapest / best option at the moment is a powder coat, which suits my purposes just fine. However, I'm wondering if the sandblasting that they will subject the frame to in order to strip the old paint, decals and some surface rust is going to erode the pantographing on the frame. Thoughts? If there is much risk of losing the pantographing I'll just wait until I can afford a proper paint job.

Thanks!

If it's a nice frame don't sand blast....ever. You would want to media blast with walnut shell or soda blast it or something slightly more gentle.

media blasting will strip the frame to bare metal. careful with thin wall frames. talk to the place that is doing it with your concerns

Powder coat is an excellent choice from an utility perspective. The artistic license might be limited, but powdercoat is generally very durable.

Pantographing? Strange use of that word. Engraved lettering?

Sand blasting is a rather aggressive method of paint removal. The damage to the engraving will depend on the depth and width of the engraving, and on how hard the blaster has hit it.
If it's a reliable company you can always ask them to go easy on that area.
A reasonable expectation is a slight blurring of the lettering, as the edges will get somewhat rounded.
Complete obliteration is unlikely, unless the engraving is really shallow already to begin with.
As already pointed out there are milder methods out there.

I wouldn't worry about the integrity of the frame though.
Bike frames tends to do OK despite being thin-walled due to being tubular, as long as they're steel. (Not saying it can't be messed up, only that you have to work on it....)

Ok, thanks everyone! It is a nice frame, and yes, by pantographing I meant engraved lettering and touches on the fork lugs. I will see if the shop (best one in my area) can use a different method other than sand, and if not, I guess I'm saving up for a proper paint job.

Thanks for your input everyone!

Another note on powdercoating. It is pretty common for it to be applied too thick, easily obscuring details like you mentioned. Anyone who does primarily bicycles will tend to do a good job, industrial places will lay it on very thick.

I personally like the too thick look on a mountain bike, it looks odd on a road bike and makes the lugs look horrible.

I would also check out this website: http://groovycycleworks.blogspot.com/

In his older posts on that blog he mentions newer powder coating methods. Only recently they have started using primer base coats when powder coating and very few people do it. Something I would look into.

Sandblasting WILL remove some metal. A good operator with lots of skill at picking the settings and watching what they are doing can minimize this but sand is going to remove some metal regardless. For a really nice road frame where there isn't a lot of material to start with for wall thickness you really want to look at one of the other media. However if I had seen examples of the blaster's work and he had shown that he was masterful enough to do the job right then fine. A good craftsman can do amazing things with minimal damage.

Have you thought about using a paint stripper on your own to prep the frame for powder?

No, I hadn't. Can you suggest something easily obtainable that might do the trick on old paint and decals? Steel wool on the surface rust? This would be a good option I think, as I really would prefer not to mess up the nice touches on this frame.

Check out this aircraft paint stripper. Spray on, wait 10-15 minutes, wipe off with wet rag. Might need to re-apply in some tougher areas. Takes off no metal.

Treat the rusty spots with naval jelly. Wipe off.

Dry and lightly sand with 400-600 grit sandpaper to prep for powdercoating and that's it!

Thanks!

For not much more than the cost of stripper and abrasive paper you can get the frame glass bead blasted or walnut shell blasted by the powdercoaters. Most reputable powdercoaters will have blasting facilities. I've sanded and polished a steel frame as prep for P/C, and I had to coat the frame with WD40 after every sanding session. It depends where you live of course (I live 25k from the sea), but with mine, I noticed rust within an hour if I didn't protect it.