Let's build a girl's bike: a 1967 Sportster XLH

[chuckthebeatertruck]

The pamphlet also says the metal work was called electric induction brazing. Technically, I guess its a different process than welding because the bikes were all considered lightweights with the heaviest listed at around 280 and the Warrior TT close to 300 lbs. Frames were chrome molybdenum. I think the pamphlet also says something about 'silver induction brazing,' perhaps the process was not completely abandoned.
-JR

There's a lot of info packed in here. First, yes, induction brazing is very different from welding. Induction uses magnetic flow to heat a metal object. This is much more efficient than a furnace. The metals are neatly joined. If you search google or this forum you can find pictures of furnace brazing on frames, which is similar but involves, well, a furnace and flames at station.

The why is in the material. At the time, welding 4130/4140 chromoly steel required real skill. It is a persnickety metal, especially if you weld in anything but annealed state. Normalized state is great for tough tubes, etc, but is a mofo to work. Brazing solves this issue and, if the joint was well designed, is more than strong enough. Brazing frames was the primary construction method clean into the 1960s. Induction just speeds it up. Today, tig brazing remains popular with bicycle builders.

Silver solder is the preferred braze for mild steels and many tool steels. It is easily worked, flows beautifully and can be repaired in several ways easily. Induction hard soldering has been around a long time and is super efficient. hence, the fuel tanks were silver brazed.

if given a choice, most choose silver for fuel tank repairs. I do sometimes, but it's usually the cost that gets me. Silver is pricey.

[JTR249]

That's very interesting. I never learned how to weld or braze. Still learning other aspects of the parts and mechanics. Brazing sounds safer than welding. Is that true? No tanks of gas or spark?
-JR

[T. Cotten]

That's very interesting. I never learned how to weld or braze. Still learning other aspects of the parts and mechanics. Brazing sounds safer than welding. Is that true? No tanks of gas or spark?
-JR

The terms are often misused and confused, JR!

It comes down to the temperature each 'filler' requires, whether steel to another steel, brass to steel or whatever, silver-solders to whatever, or even lead/tin alloys, each is progressively lower, and therefore safer. Higher temps for steels and cast iron actually melt the metals together for a true 'weld'. Non-steels risk 'admixture' into ferrous metals at those temperatures, destroying the properties of both. 'Soldering', at the other end of the temperature spectrum, adheres metals without "penetration".

So when previous brass or silver-solder repairs are encountered, it it safest to repair those with a filler of a lower melting temperature, and then touch those up with the next lower temp filler available.

The higher the temp, the more warpage is likely. Beyond that, I'm still an amateur....

....Cotten

[chuckthebeatertruck]

That's very interesting. I never learned how to weld or braze. Still learning other aspects of the parts and mechanics. Brazing sounds safer than welding. Is that true? No tanks of gas or spark?
-JR

Induction brazing isn't possible at home. So, the amateur enthusiast is stuck with open flame and bottles of gas.

Brazing is no easier than welding and has mucho challenges to a truly neat repair. Buying an oxy/act rig is as expensive as a mid priced welder, whether MIG or tig. And, currently, industrial gas is not inexpensive. Replacement bottles are pricey and getting to your local praxair or farm and fleet may not be convenient.

As for learning, many community colleges and career centers offer welding classes for $250-400 a semester. I do want to learn tig and plan to take one myself as soon as time presents. We are never too old to learn new things.

that said, in most cases it is safer to send irreplaceable or expensive parts to experienced hands than to try a repair for the first time and make it worse. Best to practice on twenty buck cast offs. When searching for a repair, it isn't always a shop, but also can be a well experienced club member. There's a wealth of skill tied up in the brains of amca members and many do not share online. I've watched people gas weld aluminum alloys as neat as a tig. . .and that is a serious skill.

[chuckthebeatertruck]

That said, silver soldering IS within the grasp of almost anyone and relatively easy to learn. Strong, neat joins. But, it is expensive at present.

[T. Cotten]

That said, silver soldering IS within the grasp of almost anyone and relatively easy to learn. Strong, neat joins. But, it is expensive at present.

I found a five-pound tube of Stay-Silv 15 in the dumpster, Chuck!

Aught to cash it in, I guess?

....Cotten

[chuckthebeatertruck]

I found a five-pound tube of Stay-Silv 15 in the dumpster, Chuck!

Aught to cash it in, I guess?

....Cotten

A quick glance suggests the current price on 15 is $120 per pound!

So, yeah, a 5lb tube is worth a wee bit at present . . . and will likely go up considerably in the coming months.

Lead, copper, cadmium, zinc, and silver -- along with all ferrous metals -- are shooting through the roof in ways not seen since the early 1970s.

Sadly, few people will know what to do with 5 lbs of silver ;-)

[T. Cotten]

A quick glance suggests the current price on 15 is $120 per pound!

So, yeah, a 5lb tube is worth a wee bit at present . . . and will likely go up considerably in the coming months.

Lead, copper, cadmium, zinc, and silver -- along with all ferrous metals -- are shooting through the roof in ways not seen since the early 1970s.

Sadly, few people will know what to do with 5 lbs of silver ;-)

Me neither, Chuck!

That's why I still have it since 2008 or so (when the dumpsters dried up,,,)

Its too high of copper for anything pretty.

I've had better luck with cheap guitar frets.

....Cotten
PS: Remember when the Hunt Brothers cornered the Ag market? Those were good times.

[chuckthebeatertruck]

Over the past week, I prepped the two fuel tanks to get lined with Red Kote. The primary reason liners fail is because people "think" they've done the prep work "to the t" as described in the instructions. In reality, many people leave garbage in the tank, especially rust, and expect the liner to "seal" it in. Liners don't do that. They work if they are applied to clean, rough, steel. Otherwise, you're totally wasting your time.

There are many ways to get a tank spotless inside. The easiest is to have it "boiled out" in a hot tank at a radiator shop. This is basically a big tank filled with a caustic soda solution. You can create something similar at home with TSP and boiling water . . .but it is messy. Second easiest is something like vinegar. Yes, you can use chelate stuff like evapo rust or metal rescue -- but it's much more difficult to get that stuff rinsed out than most folks imagine. If it isn't completely gone -- the liner will delaminate from the tank wall. Because it's most likely to puddle in corners and seams -- you can see the issue.

So, you've got to take the time to really clean the tank interior. I do this in three or four steps:
1) Fill the tank with vinegar and let it sit for a week. This gets rid of the majority of the rust and will often loosen or remove a fair amount of failed liner.
2) Do your lead work -- often the heat from a torch will burn off old liners and cause rust to "flake out"
3) Fill the tank with tumbler media and/or sharp, fresh drywall screws and tumble the tank. If you don't have a tumbler -- wait till the other half leaves the house and use the clothes dryer on the air fluff setting.
4) Wash the interior of the tank with TSP and HOT water, followed by a double rinse with a pint of acetone.

Inspect the tank and repeat as needed to remove every single bit of garbage inside the tank.


About now, someone says: "sure, you use the dryer -- I've heard that BS all the time."

Well, I'm even worse. First, I "borrow" the dog's shop bed.
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Then I fill the tank with media and cap it

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I then wrap the dog bed around the tank and secure it with a luggage strap

IMG_2309.JPG I then wrap that burrito in some moving blankets and using a few foam pillows get it positioned in the clothes dryer

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That done -- it's just a matter of how long it takes the tumbler media to get all the crap out of the tank.

In the case of the "good" turtle tank -- two, 30 minute cycles had it rust free and looking very nice. I then washed it again and dried with acetone.

Mrs. Chuck's tank, however, had a DOUBLE liner. Some wonderfully clueless person first poured a type of urethane epoxy in the tank to seal the bottom seams. They then coated over that whole mess with a KREEME type product. We got the KREEME and 85% of the epoxy out on the first tumble. In the "old" days, I would have filled the tank with 1/2 gallon of methylene chloride paint stripper and the epoxy would have been gone in 2 hours. Sadly, methyl chloride has been totally off market since autumn 2019 and out of consumer market place since 2014. Don't be tempted to use old stuff -- it doesn't work as well. And, it's deadly anyways.

So, one has to resort to MEK/Acetone or the like when dealing with crap epoxy. The idea is not to dissolve the epoxy but rather to reduce it's bond to the base metal by "wetting" the metal and hoping it flakes right off the rust. With that in mind; I filled the tank with 1/2 gallon of acetone and let it sit for 36 hours. This softened the epoxy well, but not fully. After 4 hour of tumbling, we were up to 90-95% removed. About 4 more hours will have it spotless.

Right there -- it means I'll have about 10 hours in tumbling and 2 hours in cleaning for this tank.

But, so far I've spent almost no money to save a $400-500 fuel tank from the scrap heap. It just takes time and a lot of patience -- but it isn't hard. Just remember if you compromise or rush when lining a tank -- it will fail and be even more difficult to deal with.


Oh, and don't forget to give the dog back their shop bed. They tend to get unruly when you take "their" spot in the shop.

[chuckthebeatertruck]

Last week, the weather was nearly perfect in the morning for coating tanks. BUT, I remained unhappy with a couple of tiny spots on Mrs. Chuck's tank. There were a few pieces of old epoxy still hanging on and, believe it or not, just a little bit of rust trapped deep in the seam pockets. One think I learned a long time ago is to NEVER coat over garbage. If there is anything in the tank but clean metal you're in trouble.

So, I went full stop on this one and filled the tank with a quart of 34% HCL (aka muriatic acid). In 30 minutes the epoxy was separate from the rust and the rust was gone. Now I was in a battle against time to stop flash rust from the HCL. I flushed the tank with a garden hose for 15 minutes, drained, and filled with a quart of acetone -- twice.

With all that done; the two turtle tanks each got 16 ounces of Red Kote poured in and sloshed around. The next day, I had one tiny spot I didn't care for on the tank. One of the nice things about Red Kote is that it sticks very, very well to itself provided the tank hasn't been put into service. So, about an ounce went into the tank and the crappy spot taken care of. With that done, the tanks and the other body work was treated to a coat of body filler and is now awaiting sanding.

While I was waiting on the body filler, I tossed the engine cases back in the oven in preparation for installing the main bearing race in the left case the cam bearings in the right case.

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I also had previously put the main race in the freezer. After a few days -- it was nice and cold. With the cases brought up to 300 degrees, the main race more or less fell into place and needed very slight pressure to seat against it's retaining ring. Same was also true of the four cam bearings.

So, as the cases were heating in the over, I prepped the crank. The crank came from a previously running bike, but it wasn't running true after some "use" and abuse. Straight out of the wrapper it ran almost dead even on the sprocket side, but was out .002 and change on the pinion side. I loosened the pinion nut and retorqued to 80 pounds. Then, using my favorite 2 pound lead hammer -- had at the high spot. About a half dozen solid thumps got it to run dead even. As I drew the nuts to full torque (175 ft/lbs in this case) the wheels did splay a bit 180 degrees opposite the pin. I nipped them in vice and got both sides down to .0007. I prefer .0005 a side; but can live with this one.

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That done, it was time to install the crank in the cases. To make life easy, I heat the timkens in a pan of oil to about 300 degrees. It makes them slip right over the shaft with almost no fuss.

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For the outer bearing, I have a short sleeve I use to "press" it the final bit home using either the crank nut or the compensating extension (as in this case). Works a charm.


BUT, I did have one minor issue to deal with. When I did the cases, I decided to break protocol and glyptal the entire right side case. HD normally did not do the upper half of the right case. It's a fully machined surface. Turns out that a coat of glyptal can "just" barely touch the rim. It took me a minute to figure that one out. Off came the case half and I scraped back the glyptal where there were scratches. Problem solved and lesson learned. Won't be getting creative with the coatings in the future.

IMG_6000.JPG The little grey "boogers" are the flecks of yamabond I pulled off the case halves. I should have cleaned up before taking this picture.

[chuckthebeatertruck]

In between two weeks out West riding old motorbikes and Wauseon – I had a chance to get down to working on Mrs. Chuck’s bodywork.

Let’s stop for a moment and talk about all this mess. Earlier, I shared how I lead filled the panels/tanks as needed. You CAN make lead your final stage and finish it very well. However, the tins on Mrs. Chuck’s bike were so wavy that a skim coat of filler was going to be needed or a lot of hammer time.

Because I have so many different layers of materials going on, I prefer to use full professional grade body fillers. In essence, all body fillers are modified, catalyzed polyester of some sort. The reason they sand so well is talcum. Yep, talc and pinch of gypsum – just like baby powder. Cheaper fillers like consumer grade Bondo (real bondo, not the generic name) is 70 year old technology. It has a very high amount of talc. This means it holds solvents – and that is why so many “bondo” jobs delaminate overtime. They either absorb water from the backside of panels (super common on automobile repairs and motorbike fenders with holes) or solvent gets trapped and bubbles later.

Higher quality fillers and almost all professional fillers reduce the talc and instead rely on the poly itself to be “closed pore” and easily sanded. This makes for a more stable filler and you get more out of the filler as it actually fills with fewer pinholes.

As much as possible, I try to use evercoat. I’ve found it to be the best value vs ease of use and long term adhesion. I like to use Rage or Rage Gold for base filler and Metal Glaze for spot putty. Please, do not use traditional spot putty for filling pin holes. If it isn’t two part – it means it is thick lacquer and talcum. This means it will swell/shrink. So, don’t use it just because it is at the auto body store or parts store. Buy premium stuff for a few dollars more and NEVER think about it again.

With all that done, it was time to get down to body filler. If you want your filler to last – do three things: 1) Sand ALL your body work with 40 to 60 grit paper. I mean SAND it. You want deep scratches.
2) Clean the hell out of the metal
3) BUILD the filler in 1/32 layers. First layer is called a press coat. You should make it thin and shove it as hard into the metal as you can. We don’t care about build, we care about adhesion with this first coat.

Once you have a press coat in place, all the other layers will bond handily to one another if you use the same family of products. So, let the press coat dry – scuff it hard with 60 grit and then start your filler process.


Sand back with 40-60 grit, spot fill, and repeat.





You can see we had some filling to do for low spots, etc.


As a tip; hold a flash light at an angle to filler. All the pinholes and low spots will become pretty darn apparent. Circle them and fill. Also, use your fingers to fell for low spots – fill. Sand it all back and don’t try too hard. It’s easier to go slow and do multiple layers than to have crusty, thick filler. Filler also sands much easier if you let it sit for 12-24 hours. Finally, high humidity makes filler harder to sand and slower to dry. A nice, dry shop is very convenient for drying and sanding.






Once you’ve gotten everything pretty well blocked out – you can move onto priming. Wipe down your bodywork with your solvent of choice – but make sure to let it fully evaporate from the filler or you risk solvent pops later on. Then, just before you shoot your primer – wipe everything with a good, silicone/wax free tack rag.


In terms of primer, for a rider I prefer to use two part epoxy. There are several types of epoxies, some of which are sandable (ie have talc in them) and those which do not. Some people like to prime with full epoxy (non sandable) and then spray a layer of sandable over that. I find that works best for automobiles exposed to a lot of weather. For our motorbikes; I go right to sandable epoxy. I prefer to use House of Kolor 3000 series. It seems to change names every 10 years, and most recently was called DTS3000 and now KD3000. It’s a direct to substrate (hence DTS) primer and adheres like crazy. It also builds very well.


So, that done, I shot four double coats on everything. Took a full quart of primer (40 ounces sprayable) to have enough build. As long as you let the coats fully flash it’s possible to build about 8 mils of thickness without splitting or gatoring with the HOK primer. Do not try to go thicker without sanding back – and don’t try to rush thick films.


Then, even though you can sand the primer in a few hours, wait at least a few days. In theory, epoxy primers don’t shrink. In reality – they do shrink just a bit as they off gas. Letting the primer sit for a few days allows all the heavy solvents to escape. This helps to both harden the primer (easier sanding) as well as prevent solvent pops when we get to base/clear. Not all gatoring is caused by lac over enamel – if you shoot too hot (ie too much solvent) you’ll create the same mess with just about any type of paint system. So, take your time. Let the body work sit – then block it for color. We’re hobbyists – we have the time.


Final set of tips – yes, you can paint outdoors. It’s not a big deal and not tough. Only clear coats present a bit of challenge. Everything else is a mix of common sense, experience, and DRY air. Really, it is the dry air supply. If you have any moisture – you’re screwed. A crappy filter won’t cut it. On my own system, I have three progressive tanks with auto drains to store air at 150psi, these are coupled to 120 feet of ½” pipe with three, six foot drip legs interconnected by double filters and the final filter is a desiccant filter. There is ZERO moisture in my air system by the time it reaches the desiccant filter. I then run 75 feet of 3/8^th vinyl hose with a desiccant snake and four in-line filters before we get to the gun. The end result is a copious supply of very dry air.


Another tip – we always have big holes to tape up before painting, especially tanks. The easiest way I’ve found to do it is to tape over the whole thing with abandon – and then take an x-acto knife to it. That way, you can make a perfectly round taped up hole without fighting yourself.




I do two crosses at 90 degrees on the tape because that is the "shallow" spot and we don't want paint under the tape.


And, you can see in the photos all of the white painters rags after I hung parts on my DIY racks. I basically use a ton of acetone and as many clean paper rags as it takes to have NOTHING appear on the rag. Don’t be cheap or fast here – the primer will only adhere as well as you prep the surface.

[joe fxs fxr]

Thank you for all this good advice. It came at a perfect time as I will be painting my 82 FXR soon. I've done cars and bikes before, but it's been over ten years, so I appreciate the reminders and tips that will help me do a better job.

[chuckthebeatertruck]

Once the primer had dried for a week; I lightly sprayed some cheap black enamel over it in a mist to create a "guide coat" In essence, we use the guide coat to spot low areas.

It was then just a matter of sanding with 220/320/400 wet/dry paper to achieve a flat, smooth surface.

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With that done; it was time to get down to painting.

Mrs. Chuck chose a tangerine candy; which is pretty much a translucent top coat. To get the consistent punch of the color -- we first based in white; then gold; then taped out our graphics; then tangerine; untape; and clear everything. While I was at it; I did a gold/white turtle tank for my 1964 XLCH. I grew tired very rapidly of running out of fuel after 50-60 miles. The 4.4 gallon tank will solve that in a heart beat.

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After a few more days of dry time; I'll color sand and buff the parts. I normally wet sand from 800-1000-1500 to 2000 and then 3m cutting compounds until final polish.

[chuckthebeatertruck]

With the paint dry and buffed, it was time to start putting a bike back together.

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[joe fxs fxr]

Looks very nice, but you cheated and painted the front fender struts. I was hoping to learn how to rivet them back together.