Topic: Can this tank be saved?

[Kickstart]

OK.. I know it's not a four... but it is a Honda (and a classic - CL77), and I figure there might be someone here with a similar question.

I recently bought this bike (non-running, and a handful of a project), it had a "bump" of flaking bondo in the front left corner of the tank.  I figured someone just used a bunch of bondo to fill in a large dent.  I was thinking I'd strip off the old bondo, maybe try my hand at a stud welder, and fix her back up the right way....

But, I found a much larger patch as I started stripping, and I'm kind of puzzled what a PO was doing here... trying to fill in the dents with solder?  Or did they try using a stud welder and couldn't pull the dents out?

Any suggestions on how to proceed?

Thanks,
Chris

[thelowmax]

Looks like somebody "fixed" it with a drill and a dent puller. A good body shop could repair it but I bet that would cost more than you'ld want to spend.  I could be wrong but I think you might just be better off redoing the bondo. Good luck.

[Kickstart]

The more I look at the cleaned-up picture, I think that the tank actually tore open.

That would explain how there are a few creases/dimples in the tank... you can see an upside-down "L" shape to it.

Yeah, I hate to re-do the bush-league bondo-repair... but these CL77 tanks are hard to find and if that really is a repair seam then I don't think there's much more I can pull out with a stud welder.

Any recommendations on a type of "bondo" to use?

[Kickstart]

Thanks for the advice!

The tank does hold fluid without leaking - I had evapo-rust sitting in it all day (although it could start leaking after I get all the rust cleaned-up) - so yes, definitely going to coat this.  I'm also going to strip the whole thing.

I'm a novice to body repair... when you say "fully push all the air out from behind the filler at the first layers"... is there there a specific technique, or is it as simple as applying a lot of pressure/kneading when putting the bondo on?

Also, "horse hair bondo" - I assume this mean a bondo with fiberglass, correct? Like this stuff:
http://www.eastwood.com/usc-pro-glas-body-filler-qt.html

Eastwood seems to have a lot of bondo options... these bondos with aluminum also caught my eye:
http://www.eastwood.com/usc-all-metal-2-1-lb.html
or
http://www.eastwood.com/ew-contour-alum-repair-compound-25-3-oz.html
Not sure if they're any better than the fiber-reinforced bondo.

Thanks!
Chris

[Kickstart]

I really appreciate the help!

I'll post pictures on my progress.

Thanks,
Chris

[dave500]

heres some inspiration for you,i had this done a while ago, I #$%* once I had all the filler of,it had a pin hole leak under it and was lifting.

[Kickstart]

Wow... it's been a while!

In my defense, I've been focusing on road racing.  I've converted my street bike back to road racing (no lights, signals, etc.) and I've been pretty busy with that.  I was able to race at two AHRMA events this year (Grattan, and New Jersey Motorsports park), and plan to go to Barber in October.

But I have made a little progress on the tank.

I decided to completely strip/stand the tank to see if there were any other issues.
Looked pretty good so I did a quick coat with some primer to prevent any new rust while I tackle the bondo job.

I think the "Zinc Rich" primer may be a scam... standard 12oz spray can, but doesn't feel any heavier than a regular spray can... hmmm  

[Kickstart]

But now some bad news...

I decided to do another treatment with Evapo-rust since the inside still looked pretty rusty.
However, this time I topped off the tank with water (I only have two gallons of the stuff - expensive!), and I realized I do have a leak.

Where the PO had the tank welded/brazed, there are two small holes!

I could actually pour water out of the holes (about 1/8th inch sized holes that I just didn't notice before.)
I know that sounds crazy that I didn't notice them before... I guess they were sealed over with rust from the inside and opened up after I filled the tank with Evapo-rust.

( cleaned it up a little and applied some JB weld to the holes.  I'll let this cure and then line the tank for good measure.

[dave500]

jb weld?unless that's temporary do it properly man!

[Kickstart]

I was thinking it would work as a permanent fix.

I figure the JB weld is just acting as a backer for the tank liner, and backer for the bondo on the other side.  It won't come into contact with gas because I'll be lining the tank (using Casewell liner), and there is plenty of metal around the holes (it appears they missed these spots when it was welded.) 

I was actually thinking this was good fix... what am I missing?

Thanks,
Chris

[Lostboy Steve]

lead fill? or weld. Then line the tank. Thats what I would do.

[Vinhead1957]

If it had already been brazed, it will not weld easy. Braze it solid then fill. Looks like they used too heavy of a grinding wheel on it too. Makes the metal thin in spots

[Kickstart]

I was thinking about lead fill (while flipping through an Eastwood catalog)... but... is the JB weld a problem?

I would really like to make some progress this weekend, rather than waiting for some more stuff to come in the  mail.

What's the downside of the JB Weld?

I think I'm the one who used too heavy of a grinding wheel
I hit it with the dremel tool to rough it up so the JB weld (and soon for the bondo) to have a better grip.  I tried to only hit the high spots.

[Vinhead1957]

I don't know the longevity of jb weld.  It is just an epoxy.   You can braze with stuff available at Home Depot and a mapp torch

[martin99]

I've used JB Weld to seal up pinholes before, as a temporary measure. But I stress temporary and pinholes. An 1/8" hole is hardly a pinhole. It's going to allow fuel to piss out when that liner fails, the first you'll know about it is when you look out your window after a good run and see your bike on fire. Filler (or Bondo) turns to mush when in contact with petrol. Take the advice of these guys and do it properly. Worth the time to save your bike, and possibly your ass.

[Kickstart]

I do appreciate the candid advice.... and I wasn't ignoring it.  I slapped some JB weld on those holes before I got the advice not to do it.

Well, I guess you could say I'm ignoring the advice to redo it... but I'm really not that concerned about the JB weld.  Maybe I'll pay the price later for my lack of concern now. 

Please don't take offense, I just feel the repair is solid the way it is.

I've got two coats of Caswell epoxy tank sealer in there now.  The stuff is pretty thick... you can feel the weight added to the tank.  I really think I'm good. 

On to the bondo.

[Kickstart]

OK... I understand if many of you loose interest in this thread due to my bush-league JB Weld job, but hopefully the following posts may at least be useful to others to tackling a large bondo repair job themselves.

First picture - prep:
I cleaned up the area to be bondo (bondoed?)  - using some dremel wire wheel attachment to get in the knocks and crannies, and some 120 grit to clean up everything.. and some really large grit (30?) to scuff it up some for a better grip.

Next picture - after the first layer dried - and just started sanding:
Using the Bondo Fiber product, I ended up gopping it on... which wasn't my intention.  The stuff was trickier to work with than I had anticipated.   I started just applying it to the low spots but soon it was smeared all over everything.  I pushed it into all the crevices as best as possible... hopefully I didn't trap many air bubbles. I figure I would just sand most of it away... next step:

Last picture - sanded/filed down the first layer:
After waiting about an hour, I used a small orbital sander to clean-up the excess - and then some more 120 grit to get it ready for the next layer.

I did apply another layer right after this (no picture)... I'm letting that dry for a day or two before I file/sand it down.  I'm thinking maybe one more layer of the Bondo Fiber before moving on tho the regular bondo.

[Kickstart]

OK... I've got three layers of Bondo Fiber on now... I think I'm ready to move on to the regular bondo.

First Picture - Second coat from the previous night

Second Picture - Second coat sanded down.  I don't have a picture of it, but I scuffed it up pretty good with some 30(ish) grit before I put the third coat on.

Third Picture - Third coat

Forth Picture - Third coat sanded down. - It was getting late, so I brought the tank inside to take the picture