GailT

This is the Davidson Impulse I picked up in Denver several weeks ago - I tried to do a careful inspection when I bought it, but when cleaning and waxing the frame, I found a small crack where the left seat stay meets the seat post lug. Pictures from the front and back are below. Seems to be a bit of staining, maybe some rust? I like the bike and hope to keep riding it, so my questions are: is it safe to ride as is? If not, I assume my next step would be to sand off the paint to get a better look at the crack. I have a newer road bike that I ride most of the time - wanted this bike to get a feel for how different bikes ride, the Davidson works well for pedalling out of the saddle, so I hoping to use this for shorter rides on hills.

delicious

The paint is strange looking in the first picture - touchup applied to the area in the past?

Chombi1 

It should be fixed as it will just get worse and why limit your riding experience on such a nice bike. Cannot tell exactly what color the bike is from the pics, but if it is white (except for pearl or some metallic whites), it will help make it easier to blend in the paint after re-brazing the stay on to the seat lug.

GailT

So, just got the frame back after having the crack in the seat stay repaired. The original brazing material had not fully penetrated the lug on the side with the crack. The frame was cold set to 130 mm, so that I can build it up with 11 speed Ultegra. This is my first try at building a bike so it's likely to be a slow process with help from youtube. First, I need to repaint the repair area, my plan is to sand and steel wool the repair area, spray on a rustoleum primer coat, and then either spray or brush on a white enamel. Will post more pictures as I make progress.

Chombi1 

I'd say, spray on the new paint so you can blend/feather it in with the old paint.
even with the white paint, it will be critical to match up the paint as close as you can get it.
An option will be is to strip the paint to the next lug seam so you will have the new paint on the whole seat tube and the whole top tube. A slight mismatch at the head tube top lug and the BB will then not be as noticable. At least you will not have to mess around with the downtube decals.....

Chombi1 

I'd say, spray on the new paint so you can blend/feather it in with the old paint.
even with the white paint, it will be critical to match up the paint as close as you can get it.
An option will be is to strip the paint to the next lug seams so you will have the new paint on the whole seat tube and the whole top tube and the seatstays. A slight mismatch at the head tube top lug, the BB and the rear dropouts will then not be as noticable. At least you will not have to mess around with the downtube decals..... maybe you can still get the "Impulse" decals from Bill Davidson for the seat tube?.....

SurferRosa

That seat cluster is so h o t.

Chombi1 

The short point lugs designed by Bill Davidson is, from all angles, so well proportioned and finished. It is a very good counterpoint to long point lugs that had always been preferred by most on steel bikes. Makes a lot of long point lugs look a bit excessive......

obrentharris 

Some very good tips from @Chombi1.
Regarding paint match; there are several companies offering matching spray paint for any recent model of cars, and there are lots of white cars. Years ago, when I wanted to match the paint on a white Colnago Super, I carried the frame with me on a driving tour of the local parking lots, holding the frame up against every white car I saw until I found a good match, then ordered the appropriate paint. Take a photo of the car so that, with a little internet searching, you can figure out the year of the car.
Brent

due ruote 

RiddleOfSteel

Gorgeous Impulse! And I say that having an exact clone of yours, color, decals, and size. Your decals are in better shape than some of mine but no worries. Your comment on the bike feeling really good when out of the saddle is something I completely agree with you on! Such a phenomenal bike. 11-speed Ultegra should look So. Hawt. on that!

This is mine, in 10-speed 7800-era Dura-Ace adornment, if only for camaraderie and encouragement!

Chombi1 

Check out the lug and fork crown design drawings in this Davidson site:
https://www.davidsonbicycles.com/historical/
He supposedly provided his lugs or his lug designs to other builders too....

GailT

Thanks for the comments and tips on the paint. I should mention that Mark Nobilette did the repair and cold set. Mark is a super nice guy, and it was fun seeing his shop. There's a group photo on the wall of Mark, Bill and several other great frame builders from the early 1980s.

gugie 

I met Mark at the last Velocult Velo Cirque in Portland. Despite his pedigree in the iindustry, he's a very unassuming guy.

Another way to match the paint is to take the frame into an automotive paint store. Most of them can mix spray color on the spot. For under $20 they can go through thousands of paint chips to find the closest match, or if you want an exact one, you can leave your frame off and for around $50 they'll iterate to a perfect match. That's been my experience.

GailT

Thanks for the tip on auto paints - I took the frame into NAPA auto parts, and they were very helpful - it is a tricolour paint job, base white coat, top coat, and clear coat. The guy looked at sample tabs of 20 different versions of white and then mixed the paint and filled two spray cans, the base white coat and the top coat. He also gave me the two cans that he used for mixing the base coat and top coat which still had a little paint left in the bottom, that I can use for spot touch up. Cost was about $44 plus another $8 for spray can of acrylic clear coat.

The inset lettering on the seat stay is a silver colour, so I'll need to cover that when I spray. I'm thinking I could press some play dough type material into the insets, and that would be better than trying to tape inside the insets. Any other good options for covering the inset lettering? It has been way too cold to do any painting, so I'm waiting for a warmer day. I'm planning to apply a base layer of Rustoleum spray primer, dry for 24 hours, use steel wool to smooth if needed, and then base coat. The NAPA guy recommended waiting 30 minutes for the base coat to get tacky before spraying on the top coat. I assume I'll need to wait several days for this to dry before spraying on the clear coat, still need to research that.

Mr. 66

TiHabanero

Why attempt to feather it in? A spray can will not match the color of the original. Mask the tubes off and put a stripe around each tube where the old and new meet.

due ruote 

bulgie 

Thanks! I designed that lug, with a lot of input from Bill Davidson of course. I made the steel masters that we set to Takahashi to have them reproduce by investment casting.

It's the seat lug from the "oversized" set originally designed for the Stiletto frame. Stiletto also got a slightly OS DT (30 mm), and the seat tube (which is normal at the top) flared to oversize and ovalized at the BB shell. After we got the OS lugs, we started using the two TT lugs on the larger frame sizes of Impulse. Impulse never used the OS DT, ST or chainstays though -- it stayed with trad diameters everywhere else, OS (9/8") only for the TT and only on big frames.

If you ever see a Stiletto, don't blame me for the BB shell -- they LOST the master I made, that took like 40 hours to make. Bill told them to just "wing it", as in do as they saw fit. It came out a little clunky-looking IMHO and with some errors that we had to fix on each and every shell -- more work overall than just making a new master would have been.

Other than that one time though, Takahashi was very good to us. The BB shell on the Impulse, no OS all trad tube diameters, is one of the nicest BB shells ever made. Look on the bottom of the shell to see a little raised hallmark cast-in, it means Hitachi, who did the actual casting.

-Mark Bulgier, Seattle

bulgie 

Not quite a clone, because yours has a 1" top tube, where the TT on the OP's frame is 9/8" (slightly oversized compared to traditional diameters). The two TT lugs are different too of course to fit the TT diameter. I can't tell you what year the change happened, early '90s tho. Earlier frames all had 1" TT, and later ones got the OS TT only on, I think, the 3 largest sizes. Smaller frames remained at 1" TT.

I did not design the 1" TT lugs. The Impulse lugs were designed by Bill Davidson before my time there. I started in '84 and the first boxes of lugs arrived shortly after I got there, so no Davidson of '83 or earlier vintage has those Impulse lugs.

-Mark Bulgier, Seattle

SurferRosa

Wo! Now that's ^ some great stuff (a primary source of info) here on BF.

Thanks for that, Mark.

GailT

Mark - thanks for posting, it's fun to hear more details on the history of these bikes! Do you know when they stopped making the Impulse? Here are some pictures of the BB.






and the top tube lug

markwesti

I really like the color white on your Davidson , I have heard the name but didn't know anything about it . looking over their website was very cool , especially the historical and fab section . and they even made a track bike !
Davidson | Handbuilt Bicycles since 1973

RiddleOfSteel

@bulgie thank you for correcting me and enlightening the rest of us with regard to GailT's Impulse! Looking again the the TTs between both framesets, and there is a definite difference. I actually just went over into another room and picked up my Impulse to look at the BB shell. It is indeed very beautiful. The rest of the bike is beautiful as well--my frame has plenty of marks from use prior to my ownership, which bums me out from a I-like-pretty-things standpoint, but it still shows well, and of course is a superb rider, accelerator, and climber--my top road bike, and bought as a frame, fork, and headset on a rainy February night. I was elated to finally have a Davidson frameset!

I wish there was some serializing of the frames--unless I am blind as a bat and didn't see anything on, say a steerer because I never took the headset apart--so as to date mine, especially as there were no original parts on it prior to my ownership. The headset is actually a Record unit from the 10-speed era as the prior owner had it built up with 10-speed Chorus. I've just assumed, using the scattered few Davidson catalogs available on the web, that it is most likely a late '80s. Your 9/8" tube comment puts a nice bracket/bookend on how new it could be (well, that and the 126mm rear spacing).

GailT

As you can in the close-up pictures, my paint is also in rough shape, lots of chips and scratches and poorly applied touch-up paint. I liked the idea of restoring it to as new condition, but that doesn't seem to be an option with original decals no longer available, and in any case, I'm just happy to have the crack repaired and looking forward to riding it again.

I can verify that there are no identifying labels on the steerer tube. So I suppose the lack of ID is just part of the Davidson mystique.