prepping a tank for paint

[jed.only]

ok all, ive searched for my answer and havent seen my question even remotely mentioned.

i want to paint my tank, but i dont want any badges, i see guys who have removed the suzuki badges from their tanks, and there is the little strip laying in the side of the tank that the badge attaches to. how do i get rid of that? can i pry it out? fill it with mud or lead prior to prepping? i dont want to goof up this tank by going out on my own to figure it out if someone has already done the legwork for me.

thanks in advance.

[chef1366]

There are small mounts under the Badges. Fill with bondo if you don't want no stinkin badges.

[jed.only]

im assuming they just pry out then, right?

[chef1366]

Pry away but I think they're tack welded in there.

[jed.only]

Pry away but I think they're tack welded in there.

oh, then mud over them i guess.

[po-boy]

The plates which the badges attach to, are in fact, welded to the tank. I would not pry on them unless you want to create more work for yourself. Just use a good filler and apply thin coat to the area then sand, prime, paint... If the tank has seen some severe outdoor conditions, rust may have developed between the tank surface and the plates, slightly raising them, which will require some filing to get them back to a level plane w/ the tank itself. If you do this take your time, filing only a small amount at a time, as you can severely weaken the corners where the tank was pressed to accomodate the plates. Sorry for the long winded answer, just my experiences. Good luck and post up some pics when yur done.

[PAULYBOY]

One more piece of advice. The high end painters I've read about all advise against wet sanding bondo on bikes until you have a good film of sealer and/or primer on top of it. Bondo tends to retain water, and will ultimately release it on a really hot day and maybe cause a failure of your paint film in the form of blisters. Yeah, I found that out last summer on a practice tank I got from ebay.

[nastyjones]

I'm doing the Tremclad job and my tank had the badges too. All I did was gently tap the welded strips till they were slightly lower than the rest of the tank. Then bondo away, sand and paint.

Paul

[bucketsofgs1000]

I bondoed mine too. I was doing an overlay with carbon fiber after all the tank work, so I wasn't worried about the bondo rattling loose. If I were just painting it, I would have used straight epoxy, rather than body filler. The area is not very large and bondo is just epoxy with filler (making it weaker or more hydophilic). Good luck.

-Zack

[jed.only]

I bondoed mine too. I was doing an overlay with carbon fiber after all the tank work, so I wasn't worried about the bondo rattling loose. If I were just painting it, I would have used straight epoxy, rather than body filler. The area is not very large and bondo is just epoxy with filler (making it weaker or more hydophilic). Good luck.

-Zack

i thought about epoxy, and honestly will probably go that route due to price and ease over bondo.

[motoCYCHO]

STOP!

Do not do anything until you at least read what I am about to tell you. I am in no way an expert or claim to have all the answers but I have done this several times and I can tell you what works and what does not, and what will absolutely lead to more work. Then, proceed as you see fit.

Ironically, I just received the replacement tank for my GS1100ET Tuesday by way of a good eBay deal. Last night, yes, Christmas eve, I started in on this exact project... removal of the tacky, circa 1970's/80's, badges, smooth tank indentations, etc.

Proposed Method 1) tap down below level surface, if necessary, and simply fill with polyester filler, a.k.a. Bondo, Rage, etc.

I have done this once. Although it will look fine for 1 or 2 seasons, eventually it will crack or separate or both from the metal badge bracket/tab. The thermal expansion/contraction rates of the tank metal and of the polyester filler is different. Over time, the tiny pockets of air underneath the bracket and the Bondo will allow separation. It will! One day you will look down at it and see a perfectly traced outline of the tab showing through the paint or the paint itself will also be cracked in this pattern. It will ruin your day, pi$$ you off, make you wish you would have read the rest of this post. I had this day once... OK, more than once.

Proposed Method 2) use epoxy the same way as method 1.

Although I think this would be stronger and last for longer, It will eventually suffer from the same fate, depending on the type of epoxy used of course. However, the main reason to avoid this method is that you won't be able to shape the epoxy with a sanding board or by hand sanding very easily. One of the characteristics of polyester fillers the way they are cut away by sand paper and ability to be sanded at a rate comparable to the paint and primer surfaces you are working with. Epoxy is just not a good substitute. Besides, Bondo has a catalyst type reaction when mixed properly, and provides you a material you can shape into the curve of the surrounding area perfectly. For the record, I have had this day as well.

Proposed Method 3) Break away the tab via prying or lifting tabs off.

This WILL leave holes in the tank where the spot welds were. I have done this, bad idea, tears the metal right open and you now have holes in what was a sealed tank. BAD! Now you get to weld closed a gas tank. (not actually as bad as it sounds, but a pain in the ass none the less)

Proposed Method 4) Approved and known to work. Grind away at the spot welds, remove tabs gently, trying very hard not to tear away the metal and leave holes in tank, remove the rust that is going to be under the tabs in most cases and then fill with polyester filler of your choice. Which, with no rust and air pockets will properly adhere to the metal and if done correctly, last as long as the paint job you put over it.

This is where I am now on this very project.

Note the rust I still need to remove. I got the easy to reach rust already but the deeper indentations have to be cleaned out with smaller sand paper pieces which I have not done yet.

Now the bad news. Even grinding carefully can burn through the spot welds. The hole I made shown here, now gets to be welded. I will get pics and write that up when I do that too. It's not as hard or dangerous as people make it out to be. I have welded on 3 motorcycle fuel tanks and all had gasoline in them just hours before the welding took place. Just have to clean them out a bit first. I will post more on that when I do it. Plus the rest of this process if you guys want to see it that is?

[jed.only]

if im going to go thru all of that, i mind as well just mig the slots and then ill have metal there instead of epoxy/bondo. repainting after 2-3 years doesnt sound too bad. likely, ill want a color change of the tins by that time anyway.

[posplayr]

Bondo 123's

As I did my restore/refurb on my ED this year, I was struck by the assortment of new materials that exist to do retore/repairs. In particular the various Por-15 products, PPG paints and modern epoxies (1min, 5 min and 10 min). As with all things Bondo has also come a long way from the red stuff I used in high school.

Item #1 below is basically a NON-waterproof filler for improving a surface to be painted or filling some small holes. It is easily sanded but it has VERY LIMITED STRUCTURAL PROPERTIES. It is very pliable and will flex considerably with whatever it is applied to. It will even stick to glass. It doesn't do good in sheer. It is best used to skim coat areas that have homogeneous mechanical properties where it is to be applied.

The badge area on the Suzuki gas tank is apparently not homogeneous because there is a relatively thick tab spot welded to a thin metal skin. Simple red bondo is not good here. I'm assuming that this is the stuff motoCYCHO using in Approach #1

Numbers 2.) and 3.) below are also made by different vendors and while they seem similar to the red stuff in #1 they now have fiberglass fiber in them, and they are in fact waterproof after the the material has hardened. The short fiber stuff 2.) is closer to a puddy for easier spreading to conform to a flat surface. The long fiber stuff 3.) has longer fibers and more difficult to spread. The plus side is that #3 is stronger than #2; both are waterproof. The only down side to using these two products instead of the red bondo is that they are somewhat harder to sand and so you have to be sure that you form the fiberglass filled stuff to minimize sanding after hardening. By an large I just don't use the 1.) stuff anymore. This includes doing wooden window repair where dry rot has damaged wood. #2 and #3 are about as easy as wood to sand and are about as strong depending upon the wood.

I don't think that motoCYCHO described either of these products. If either is sufficiently thick (i.e. greater than 1/8-1/4") either will resist significant sheer stresses and still be flexible. The tap depth is nearly flush with the surface of the tank so you would need to create a pocket to achieve the 1/8-1/4" thickness. Dent in the tank around the tabs and fill with #3 long strand filler. Sand smooth If you need to finish off any irregularities the #2 short strand stuff is closer to a puddy.

As an aside, I have used the long stand #3 stuff to improve the strength of with side and tail covers. I just spread #3 on the inside of the cover after I had plastic welded or epoxied any splits or cracks. It kind of looks like I chopper gun sprayed the inside but that is OK you don't see it and it makes the covers much more substantial even if it adds a few ounces of weight.

Finally if you really need something strong not something that is trying to resist expansion forces (like build a seat pan) then you use the stuff listed in 4a and 4b. There are fiberglass resins. 4a has more fumes, is cheaper and a little less strong. 4b is more expensive less fumes , is stronger and has a longer working time. For making seat pan either is fine.


Some general recommendations for any Bondo type product 1,2, or 3 sand the surface down to bare metal. Use a 40 grit sand paper to cross hatch the metal so the bondo can bite. To reduce the amount of sanding you can do two things:
1.) while the mixture is still fluid but has been applied, use masking tape to tape over the surface to insure that the bondo conforms to the surface.

2.) One the material has hardened partially, pull back the tape and use a safety razor blade to trim back any excess that you don't want to have to sand.

3.) If you do the two steps above there is very little sanding to do other than final feathering. If the surface is still irregular skim coat it with the #2 short strand stuff for a final feather sanding.

motoCYCHO Also mentioned using Expoy to fill around the area. While I dont know exactly what kind, if it was some two part repair expoy then this stuff tends to be very hard and may break because it doesn't flex as much as say the fiberglass filled fillers. On the other hand if the tank were dented in a "plastic weld" type epoxy should be strong enough in this type of application. The primary downside of this type of product is that it is more expensive, harder to sand. There are many different types so I hate to generalize too much. Marine-Tex for example is a "heavy duty structural epoxy" that does get hard but is very strong. Ulitmately this might be the best solution if you dent the tank in so that you can put enough material into the dents so it will have some strength.

Marine-Tex, the legendary high-strength repair compound designed for filling, bonding and rebuilding wood, fiberglass, ceramic, glass, metal, masonry and many plastics.

http://www.marinetex.com/marinetexepoxyputty.html

Comments Welcome; Happy holidays.
Pos


1.) Bondo Body Filler, 1 Pt

Shapes in minutes and is formulated to be a non-shrinking, non-reactive and permanently durable material for repairing metal, wood, steel and plastic. Repairs dents, patches holes and leaks and restores chips quickly and easily. Complete autobody projects the same day started. Includes cream hardener. This Bondo Body Filler is one of many top quality items in our Auto Body Fillers department.

http://automotive.hardwarestore.com/90-549-auto-body-fillers/bondo-body-filler-604941.aspx

2.) Short Strand Fiberglass Body Filler

For metal and fiberglass repairs. Easy sanding and easy working formula is perfect for the do-it-yourselfer. This Short Strand Fiberglass Body Filler is one of many top quality items in our Auto Body Fillers department.

http://automotive.hardwarestore.com/90-549-auto-body-fillers/short-strand-fiberglass-body-filler-172445.aspx

3.) Long Strand Body Filler

Body filler handles tough repair jobs better than ordinary plastic body fillers. Easy mixing and sanding properties make quality repairs easier to do at home. In addition body filler is rustproof and waterproof to ensure durable repairs. This Long Strand Body Filler is one of many top quality items in our Auto Body Fillers department

http://automotive.hardwarestore.com/90-549-auto-body-fillers/long-strand-body-filler-172437.aspx

4.a) Polyester resin to used to wet Fiberglass cloth

http://automotive.hardwarestore.com/90-549-auto-body-fillers/bondo-fiberglass-resin-611752.aspx

5.) 2 part epoxy resin to be used to wet Fiberglass cloth

http://automotive.hardwarestore.com/90-549-auto-body-fillers/elmer''s-fiberglass-repair-656668.aspx

[jed.only]

this doesnt need to be Barrett-Jackson nice, its a beater bike. maybe i failed to mention that. its not a restored piece of history, its a daily commuter turned modern cafe. cross-branded pieces and hand made parts. id like it to look nice, but it will still be a hack. i rescued it from a barn and the PO abused/stripped/threw together this bike. it runs, and now im trying to make it look decent.

[posplayr]

Sorry If I made it more complicated that nessesary

The simple point is in the old days body work was done by using metal (i.e. lead) to fill in body damage. Then came polyester bondo to change the paradigm. Today there is a large selection of epoxy and polyester options you just need to understand some of the strength issues of the material being used.

Considering it is a beater, and you don't want side patches just:

1.) hammer in the sides so you have about 3/16" depression
2.) Clean, sand, scratch the bonding surface
3.) spreads some long/short hair waterproof filler in the hole
4.) cover with masking tape to minimize sanding
5.) Final skim coat and final sand

Proceed with your favorite paint approach.

Unless you develop rust under the filler, it should be strong enough to resist any sheer (around the tabs) but still flex with the tank.

Pos