1933 Harley-Davidson VL Build: Preparing the Cases

[Peter Cooke]

Thanks gents, that's more useful information to be taken into consideration.

[BoschZEV]

I've also done some research on companies doing Vacuum Impregnating here in Melbourne.

One thing that hasn't been mentioned, that you should carefully consider, is that if you do vacuum impregnate something and then later need to weld it near where the resin filled a crack or surface porosity, you will find it extraordinarily difficult if not impossible. It's not unlike the problem faced by all sorts of people who coated their gas tanks with miracle sealers in the past, and who later found when ethanol fuels were introduced that it attacked the coatings. At the time they coated their tanks it might have seemed like a reasonable alternative to "properly" fixing the crack, but any chemical "fix" (vacuum impregnation, JB weld, duct tape, ...) has a finite life and the risk of future incompatibilities that often can't be foreseen.

If you have a high value vehicle that will see little use so it has small chance of needing to be rebuilt again in the future, vacuum impregnation of the cases might be reasonable to help keep the garage floor clean. However, most motorcycles -- especially ones that are used -- are going to leak from the gasket surfaces and oil seals anyway, so the benefit of stopping the small additional leakage from possible microcracks has to be weighed against the cost of eliminating the possibility of welding in the future.

The bike is yours, so the decision is yours, but make it knowing that there are plusses and minuses to doing this.

[sirhrmechanic]

Peter:

Yes, you need to strip cases completely bare and they need to be really clean as the VI will 'seal' in stains. You will have no problem re-fitting bushes, sleeves, guides, etc. though you may have to do some careful surface cleaning or lapping of tapers, etc. simply to remove any thin surface deposits of acrylic. The stuff does not coat the casting, it's inside the pores. But that doesnt' mean that you can't get some spots on the surface (especially in holes or recesses) where a thin layer remains behind. For example, when we do car crankcases, the bearing saddles generally have to be polished out with Scotchbrite or 600 grit after the VI. And when I put valve guides into heads, I usually do a fine lap to get the 'height' right before knocking them in on their taper.

But anything left in a casting before VI... including studs, guides, bushes, etc... will have to be machined out after VI.

Cheers,

Sirhr

[Peter Cooke]

If that's the case, I apoligize for being part of that discussion and causing that. Next time I'll sit back and just enjoy the ride. Bob Rice #6738

I don't think an apology is necessary Bob. Everyone's allowed an opinion. I actually found it a very useful thread as I'll soon be starting on my 31V and have now decided that blasting of any description will not be used on the crankcase halves. I've also done some research on companies doing Vacuum Impregnating here in Melbourne.
The one I'm looking at provides the following info on there website;
"The process uses ULTRASEAL PC504/66 Methacrylate Sealant, which once set can operate at temperatures between -50 to 200 degrees Celsius".

200 C equates to 392 F. I'm assuming that's more than enough to accommodate the crank case temps??

Also, with VI I believe I'd need to remove all the bronze bushes for the cam and crank. I suspect sealing them is not a good idea??

[sirhrmechanic]

I should have mentioned this before... but back at the "old" shop (before we moved) crankcases, etc. were cleaned by soaking in a witches brew of chemicals offhandedly referred to as "Carb Cleaner" but probably something far more sinister. Or maybe carb cleaner back in the day was made of things that would give you two-headed kids. The container was an old garbage dumpster which had been sealed by welding any kind of fissure, seam, crack or hole. The chemical mix was 'sealed' by a layer of 6" of water floating on it. Every now and then, you poured in some water and it all settled out again. So whatever the actual chemical was had a specific gravity greater than water. Parts were lowered into the tank with an electric chainfall and left for a couple of weeks and they came out clean like you can't believe. We could put whole engines inside (undismantled) and they came out really easy to dismantle.... The tank had been 'filled' probably in the 1980's... and all I know of it was that the toxic waste disposal company that emptied it and took it away when we moved locations charged us about $5K for the disposal. We opted not to deal with refilling it and actually left the tank at the old building. But damn it worked well.

Cheers,

Sirhr

[duffeycycles]

my friend soaked in old time carb cleaner 5 gallon can ,nasty can first, a few days later, less nasty can and then the cleanest can,scrubbing a little each can change..Then he boiled in water..welded many cases in his 40 years at it

[BigLakeBob]

It's still alive over on the riding vintage website. Maybe the 'to blast or not to blast' discussions have put him off updating it here.

http://www.ridingvintage.com/2014/01...vidson-vl.html

If that's the case, I apoligize for being part of that discussion and causing that. Next time I'll sit back and just enjoy the ride. Bob Rice #6738

[BoschZEV]

Maybe the 'to blast or not to blast' discussions have put him off updating it here.

That's too bad. But I see the discussion didn't put him off continuing to blast everything.

[Peter Cooke]

p.s. this thread started out as a build but nothing has been posted for nearly two months. Has it hit a roadblock, or is it still ongoing and the builder too busy to update it?

It's still alive over on the riding vintage website. Maybe the 'to blast or not to blast' discussions have put him off updating it here.

http://www.ridingvintage.com/2014/01/building-1933-harley-davidson-vl.html

[BoschZEV]

As far as the washing your hands comparision, I never washed my hands in 212* boiling water without soap, so its hard for me to agree if my hands would become clean or not.

I'm pretty sure you know the answer to this. Oil doesn't dissolve in water at 212oF any better than it does at the ~125oF of the dishwasher. If it did, you wouldn't have to use detergent in a dishwasher to get the grease off the pots and pans.

If the rear motor mount involved welding a lug that was totally external to the engine, and thus only covered with the usual mud and oil the outside of an engine collects, it's possible straight boiling water might have been good enough in that particular case. But, since you know soapy water removes grease (and dirt) better than straight water, why would you ever choose to use straight water? Even if they only had dirt on them, not many people would choose to wash their hands only with water if they had the choice of also using soap. Or wash their car with straight water, rather than water plus soap. Soap isn't used for purposes like this just out of habit, it's used because it works better than water alone.

[BigLakeBob]

(next time you come in from the garage try washing your hands using only straight tap water). However, if your friend's parts had little or no oil trapped in cracks or pores to begin with, boiling them in straight water could have removed surface dirt (which might well have had oil mixed with it, making the part look oily) and made them cleaner and easier to weld so this would have been the effect he reported to you. But, I suspect if you ask your friend for details he will report back to you that he used soapy water in his turkey fryer.

I'm not sure if he used any soap or not, I need to ask him. As far as the washing your hands comparision, I never washed my hands in 212* boiling water without soap, so its hard for me to agree if my hands would become clean or not. The last item he did was a set of 57 Pan cases that were cracked at the rear motor mount, and as I said he had good welding results. Next time I talk to him I'll ask. Anyway, maybe its a starting method for someone here to elaborate on and hopefully work for their own circumstance. Bob

[wideglide38]

All good points Sirhr & Bob. I am familiar with 1,1,1 Trichlor for degreasing. A know carcinogen we had to abandon in the late '80s on our printed circuit board production line. Unfortunately those chems worked double duty - their intended application and putting one 6 feet under. Safety & caution will be applied moving forward.

[BoschZEV]

I have a friend that has used a turkey fryer several times on cases that needed cleaned before getting welded. He would boil them just like cooking a turkey but used water instead of cooking oil. ...

If you re-read my previous post you'll see that I boiled an aluminum head in soapy water for four hours but, although it looked very clean at that point, there was still a small amount of oil that solvent later released.

Oil does not mix with straight water so, without the soap to emulsify it, boiling in water alone would have left behind nearly all of the oil (next time you come in from the garage try washing your hands using only straight tap water). However, if your friend's parts had little or no oil trapped in cracks or pores to begin with, boiling them in straight water could have removed surface dirt (which might well have had oil mixed with it, making the part look oily) and made them cleaner and easier to weld so this would have been the effect he reported to you. But, I suspect if you ask your friend for details he will report back to you that he used soapy water in his turkey fryer.

p.s. this thread started out as a build but nothing has been posted for nearly two months. Has it hit a roadblock, or is it still ongoing and the builder too busy to update it?

[sirhrmechanic]

All I'll say is that the next three turkeys had a faint flavor of thirty-weight...

Actually, this would be a safe way to go, but not sure how effective straight water boil is. That said, water is an amazing solvent and does separate oil very nicely once the oil starts flowing. The net is that it sure can't hurt.

Several people have commented on the weldability of early cases and castings and this is something our welder always comments on. They love getting our stuff in to weld. IMHO, it has to do in part with the fact that the castings were being made from virgin aluminum. Todays' castings have so many re-casts, impurities, old beer cans, etc. in them that they just aren't the same. Maybe someone with foundry or metallurgical experience can comment?

Supporting this, if I bead blast (down to the white) steel parts from some of the early/prewar cars we work on, I can leave the steel bare and unprotected for weeks before it rust blooms, especially the British prewar vehicles. Postwar British or post-26 American... and the rust blooms start within hours on unprotected metal. Same parts in many cases, same part numbers. Forgings or machinings mostly. It is uncanny. My theory is that the later you got, the less 'virgin' steel went into your parts. And in the U.S., by the mid-1920's recycling, especially in the Auto industry, had really ramped up. There were 10Million Model T's scrapped out by 1930 or so... That's a lot of recycled steel finding its way into mills.

Anyone know for sure or have thoughts in this direction? Again, this is theory on my part. Not fact... but it's very supportable by 'experiment.'

Cheers,

Sirhr

[BigLakeBob]

I have a friend that has used a turkey fryer several times on cases that needed cleaned before getting welded. He would boil them just like cooking a turkey but used water instead of cooking oil. I did not personally see the results, he lives in a different state, but he said they turned out very clean and were easy to weld. Any thoughts or opinions on this, has anyone else tried it? Bob Rice #6738