# Steel frame sand blasting



## JasonByers (Nov 13, 2010)

I'm thinking of getting my bike frame refinished and had a question for you guys. I want a clear over raw steel finish and I have a powder coater nearby that will do it. I ask him if I could get a dull light grey finish. This was his reply: " Usually when the frame is blasted it comes out a very light sparkly finish.We would just need to see what yours looks like after blsting to see. I think the clear will darken it up some and be close to what you are looking for." Do any of you guys have a pic of a frame that has been sand blasted that I could get an idea of what he's talking about? I'm a little scared of the sparkly part. Thanks guys for any help.


----------



## Yogii (Jun 5, 2008)

Clear over raw will not last as long as clear over powder. Clean metal is shiny. Sounds like you want a brushed or raw titanium finish. How about dull light grey powder, then clear? or go gun kote.


----------



## uncle_bob (Jul 26, 2010)

Found this pic, hope it helps. Although, in my experience with power coating, I would definitely go colour then clear. After a few hits or rock strikes the clear will chip and the underlying steel will quickly rust. Whereas, with the colour added, you get an extra layer to give more strength to the coating. You can actually get a powder coating colour that nearly matches raw blasted steel. Give it a thought.


----------



## JasonByers (Nov 13, 2010)

Thanks guys. I'll give this a little more thought but I have a question about the powder coat process. I was thinking that clear powder coat would be the same as any color powder coat in durability. Is this not true? Also I thought powder coat was a one coat process and that you had to have bare metal for the powder to stick to. So is the clear over powder a clear coat paint?

I'm looking for a finish that's maybe a little darker than titanium but with a glossy topcoat. I still want to tell that's it's bare steel under the clear and I don't know if just a dull grey powder coat will look the same. I see this finish on a lot of frames on mtbr and I actually got the idea from searching "raw finish". Thanks again for the help. I might send in a fork and get this guy to try it first on it.


----------



## uncle_bob (Jul 26, 2010)

Powder coating is a one coat process, this is where the problem is. With a raw, clear coated frame, if it chips it rusts. If its coloured then cleared you have double protection. I'm not a fan of powder coating bikes. I have a little saying for powder coating: If it moves paint it, if it is stationary powder coat. Good luck which ever way you go.


----------



## cdn-dave (Jan 6, 2007)

There's also chemical dipping as an alternative to sand blasting. I had a couple frames dipped for I think just a couple bucks a pound! Just have to remember to coat the insides of the tubes for rest prevention...


----------



## JasonByers (Nov 13, 2010)

I appreciate it guys. I'm honestly not too terribly worried about the durability of the finish. I'll likely change the finish again in a year so if it last that long I'll be happy. I get bored with appearance easily. I just didn't want to spend money on a finish I didn't like. I have talked to the powder coater and he has a frame he can do samples on with different blasting and clear options that he will show me when I drop off my frame. Thanks again guys for the help.


----------



## Jinxy (Aug 1, 2010)

Blast & clear coat is a medium gray & limited sparkle. Brazing will show as seen in the above photos. I've done it and instead chose to paint my last couple frames (acrylic laquer). Check out your coaters silver samples and you'll find some look great. Paint is fine too and easy to touch up. Either way put a clear coat top on it.


----------



## JasonByers (Nov 13, 2010)

When you guys are talking about a clear coat top are you talking about clear coat paint? Thanks.


----------



## RCP FAB (Jun 15, 2011)

I get some of my frames done in clear powder coat, it is just as durable as regular powder coat.

I even scraped a test piece against a brick and soaked it in a cup of water for a week, no rust at all.


----------



## uncle_bob (Jul 26, 2010)

JasonByers said:


> When you guys are talking about a clear coat top are you talking about clear coat paint? Thanks.


Sorry, I meant clear powder coat when I said "clear coat'. If you were to powder coat in colour you would powder coat clear. And there are different types of clear powder coat, so ask about those too.


----------



## Yogii (Jun 5, 2008)

If you are going to change it in a year or less. Just rattle can it with a good Polyurathane clear coat. Wipe with solvent first.


----------



## dbohemian (Mar 25, 2007)

Yogii said:


> If you are going to change it in a year or less. Just rattle can it with a good Polyurathane clear coat. Wipe with solvent first.


I think we had this discussion as it pertained to trying and get a raw finish just a short time ago. The consensus and it is my opinion too that the only way to get this finish that is durable is to clear powder coat it. Clear powder is no less durable than colored powders.

I just want to clarify the chemistry of this whole thing. There is not really a "poly-urethane" that comes in a rattle can. It may be a simple urethane, but a "poly" urethane or many urethane molecules cross-linked together is only accomplished by having a catalyst and that means spray equipment and chemicals that can be hazardous etc.

Any time you create a longer chain molecule you make for a tougher coating so you can only expect so much from a one part air dry rattle can. In fact, he may be better off just coating the frame with a good car wax. Watching it for any rust and just tending to it with a little scotchbrite and more wax.

Personally the whole raw thing and the whole flat thing super industrial BS is really driving me up the wall and is about as cliche as it gets right now. Like people are trying too hard to be "core"


----------



## jay_ntwr (Feb 15, 2008)

dbohemian said:


> Personally the whole raw thing and the whole flat thing super industrial BS is really driving me up the wall and is about as cliche as it gets right now. Like people are trying too hard to be "core"


Dave, I was at the Mercedes-Benz dealer the other day and saw a flat black SL63 AMG for just under a couple hundred thousand bucks. That takes balls to ante up to and really did look cool. Generally, I'm with you--not a fan of the raw look and less of a fan of the raw but clear coated so that it looks raw but isn't really raw look. And just look at my avatar. That road frame is still rusty or "patina'd" as the current buzz word in frame-building is I suppose. It's starting to drive me nuts. I really wanted to get another road frame built and just replace this one with the new one but I haven't gotten to that yet--I'd hate to throw money at this one just because I'm tired of looking at a rusty frame but I'm almost there. It is fun when folks say "nice bike" in their team kits with a sarcastic tone. I just say "thanks" as if I took it as a true compliment.

To the OP, I'd coat it as cheaply as possible. It's fun for a while, but you'll get bored with it and want to change it later. The rattle can is a good idea 'cause you're out a few bucks and it'll be mostly protected. Even under clear powder, it's going to start rusting and look bad so you'll end up doing something else in a year or two tops I'd bet.


----------



## CHUM (Aug 30, 2004)

the guy who built my frame (Rick Hunter) warned me that a clear powder over raw steel looks really cool...for a while.

then you'll start to get 'spiderweb' rust (which according to Todd from Black Cat) happens under all powdercoat...and it starts to not look so good.

then Schmitty (an experienced forum member here) has had positive luck with clear over raw steel - but takes a fair amount of prep and to use Drylac powder...

in the end i went with 'black chrome' powder with clearcoat paint....which really looks like pewter.









i am very happy....


----------



## TgMN (Aug 22, 2006)

dbohemian said:


> I just want to clarify the chemistry of this whole thing. There is not really a "poly-urethane" that comes in a rattle can. It may be a simple urethane, but a "poly" urethane or many urethane molecules cross-linked together is only accomplished by having a catalyst and that means spray equipment and chemicals that can be hazardous etc.


Don't want to disagree with any of the general recommendations given in this thread but as a point of clarification: Moisture cure polyurethane coatings are very common. The single component coating of urethane monomers, oligimers & initiators are applied and then atmospheric moisture drives the cross link reaction. If you really want to geek out, here is some additional info on the chemistry around this stuff.

http://www.bayermaterialsciencenafta.com/businesses/cas/moisture_curing_1K_coatings.html

It doesn't really change anything. A moisture cure system is not a great choice for coating over ferrous metal.

Chemical engineering pays the bills at my house. Framebuilding would not support me in the manner to which I've become accoustom


----------



## Yogii (Jun 5, 2008)

Maybe he should just move to the desert and leave it alone.


----------



## dbohemian (Mar 25, 2007)

TgMN said:


> Chemical engineering pays the bills at my house. Framebuilding would not support me in the manner to which I've become accoustom


Thank you for the clarification TgMN! Good to know you know where the dough comes from


----------



## JasonByers (Nov 13, 2010)

dbohemian said:


> Personally the whole raw thing and the whole flat thing super industrial BS is really driving me up the wall and is about as cliche as it gets right now. Like people are trying too hard to be "core"


I'm not doing it to be hardcore at all. I just want something that I don't see every day on the trails.

CHUM the powder coater actually showed me a frame he did in black chrome and it was pretty cool looking. I nearly went with that. I decided on him chemically removing the paint and bead blasting for the smooth texture then a flat clear.

The frame is going to look awesome...to me and that's all I care about. Yes I'm sure I'll change the color in a year or so. It's not expensive at $100 and that's part of the fun for me. Thanks everyone for the help and advice, if you care I'll post a pic when it's put back together.


----------



## Yogii (Jun 5, 2008)

Hope you like it!


----------

