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Building a Baum

Anthony Little |

Here’s a little glimpse of our Baum Corretto being built.  Note that we left many of the steps of the process out as the post would simply be too long to post!  I wish we had a few pictures of the frame itself being built, but we’ll leave that for another time.  Enjoy the photo’s and as always, let us know of any questions you may have.  Next post is coming soon, and even more relevant to most, how the bike went together and how it rides!  Stay tuned…

Here are 7 of the 8 tubes.  The head tube is internally butted while the other 7 are externally butted.  Here David weighs the tubes and marks them where they will be butted.  The sheet at the bottom gives him all the information he’ll need for the butting.  The chain stays have already been butted, formed and notched and are ready to have the scallops welded in.

The stems and seat posts that will be painted along with the frames.  One set is for the Corretto and the other for our Ristretto.  As you can see, we used Deda stems and 3T Ltd. Posts, but the standard for the frames now are 3T Team stems and Enve Posts.

All the tubes have been butted and mitered and are now in the jig waiting for Darren to do the welding.

The posts and stems have been sanded down and prepped and are ready for priming and painting.

The Enve fork also gets the same treatment as the stem and post.

The Corretto is now in the sandblaster having only the section that will be exposed titanium getting its surface treated.  This is a two stage process, first step is with Gamet and then the glass bead.  With the Gamet Jared doesn’t need to work the tubes as aggressively to get rid of all the heat discoloration caused by welding.  If you were to skip this process and go straight to glass bead you would need to work the tube more and run the risk of flattening the welds.

Once the glass bead has been done Jared hand brushes the tubes to put Baums signature finish on them.

Hand brushing the frame.

From there they apply the back masking is put on anywhere there will be graphics on the titanium and then blasted with Gamet.

Then the frame goes back into the sandblasting machine to have the last of its surface treatment done.

The grade of gamet Baum uses works perfectly with the primer Jared will use for the paint.  Get these steps right and you can basically eliminate any chance of the paint d-laminating (easier said than done).

After all the back masking is taken off he inspects for any blowouts from the sandblasting.

From here the frame goes into a detergent tank to remove any grease residue that is left over from the fabrication process.  It’s also another great chance to get any leftover deposits out from inside the tubes.  Once scrubbed and repeatedly dunked it goes into a water tank for rinsing.  It is then blow dried with an air compressor and then put into the paint oven for 2-3 hours to completely dry.

Once the frame has completely dried and cooled Jared wipes all the painted sections with a spirit wipe.  This removes any last possible bit of grease/glue etc. that will give him grief in the painting stage.

Then he uses a tack rag/cloth to remove the little fragments of paper cloth that was used for the spirit wipe.  On this picture you can also see that the frame is back masked where he wants the titanium left.  On the top of the seat tube he has masked out where the seat clamp will sit.  The mask he uses perfectly fits the inner diameter of the clamp they use and avoids the paint getting crunched when the seat collar gets tightened and loosened repeatedly.

Now the fun part, painting!  As you can see here all the frames have had their first round of priming and are about to receive a dose of 60 degree C heat for 3 hours.  Once they have been cured they come out and cool down for 2 hours and then their surfacing treatment begins.

Two of our bikes in the oven…

Cooling on the rack…

Once the first round of primer is fully cured and the frame has cooled down he proceeds to surface finish the tubes.  This entails rubbing the entire frame with a medium grade wet/dry rub paper to take off any surface imperfections.

Then he re-primers the frame and lets it sit for 30 minutes at room temperature and then proceeds to de-nib it with the red abrasion pad seen above.  This gets rid of any remaining (don’t see how that’s possible after all the above!) contaminants before color goes down.  Then the frame gets sprayed black.  Black is always used first as it shows up any areas of the frame that may have been missed.  Any part of the frames surface he is unhappy with gets attention now before he goes any further.  Ignore this step and it will bite you in the ass later especially when using pearls and metallic paint.  Once this is done he applies another coat of black paint to ensure full coverage on the frame.  Frame/fork, stem and post are now ready to have the graphic masks applied.

The techniques used for painting are propriety but I know that it is just as detailed or even more so than anything that has happened up to now.  Come into the shop and check one of these frames out in person to see what I’m talking about.

More masking and getting closer…

The Fork, stem and post have gone through much of the same processes as the frame has, also the same amount of attention to detail.

I think this is right before the final clear.

Masking coming off revealing a first glimpse of the end product…

The two new Above Category bikes side by side.  On the left, the Ristretto and on the right, the Corretto.

From the other side…

Frame, fork, stem and seatpost all finished.  Even the King titanium bottle cages have been custom finished to match the bare titanium on the stays.

I hope you’ve enjoyed reading this post.  I know that maybe sanding and painting a bike may not be the most exciting part of the process for everybody but what I’m hoping is that it gives a good impression of what’s involved in finishing a Baum frame.  This is a 20+ hour process of hands on work and you can tell when looking at the finish in person.