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Author Topic: Project xs750 lowrider  (Read 8872 times)

Offline john83

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Re: Project xs750 lowrider
« Reply #50 on: Apr 10, 2018, 17:37:54 »
Failure is our greatest teacher. Well, that and guys like d9canada who have been there, done that are willing to share info. I would also search this site. There have been several guys who glassed their own tank over the years with some good results.

Offline pacomotorstuff

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Re: Project xs750 lowrider
« Reply #51 on: Apr 10, 2018, 18:30:49 »
Built tanks for a number of years, never had a failure except for a tank that a painter blasted through with his 40 grit sanding disc when he was prepping the part (he did a lot of Corvette parts which were about a quarter of a inch thick), then tried to fix it with bondo and claimed the leakage and dust in the tank were my fault .
Stopped building them due to the "litigatous" society we find ourselves in these days; example - the wife of a customer was looking at 2 really nice tanks I had just built for his racebikes and commented, "Nice tanks and if anything happens, I'll know who to sue" - and then finished up with a lame little laugh.  The customer solved the problem though - he divorced her.
The last tank I built for a friend, used isophthalic polyester resin, veil as the last ply on the build, a good coat of Caswell's tank sealer on the insides, glued it together with Caswells and gave it what we aerospace people call a "slosh coat" of Caswell's after the marry up of top and tunnel, to give additional sealing along the bond lines.
I also have a tank on one of my project bikes, built along the lines of a composite aircraft project I was working on at the time, much the same construction materials as noted above, heavier than I would like but you can stand on it if you wish and nothing is going to break.
I tell customers to drain their tanks if the bike is going to be sitting for any length of time and for a street bike, use gasoline without ethanol.
Up here in Canada, we have a couple of different choices of ethanol free gasoline, usually 94 octane at one of the local stations, kind of a joke when one of my motors is a flathead and could probably run on  80 octane if you could find it these days.
Love your lowrider project, sorry you had a GFU with your first go at making a tank but don't give up.
If it was easy, everybody would do it.
Pat

Offline Markie-V

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Re: Project xs750 lowrider
« Reply #52 on: Apr 10, 2018, 19:21:42 »
Well... I just want to again offer thanks to those who offered encouragement during the last day and a half. I have looked at the bikes that others here have built, and I must say that I am always impressed with the creativity and passion I see here for the love of building bikes and other unique things. What surprised me the most was not all the great advice that was offered (which I must say will be invaluable to me), but it  is just the quiet encouragements from others here... willing to reach out just to offer an encouraging word on the thread as well as some very humbling emails I received here.

Today... with the salve fresh in the wounds of my fiberglass fail... I am going to begin again on tank two. I learned a little bit from carving and shaping the first tank... and I think I can do this one in less time. This tank shape will be different than the first... wider  over the cylinders... longer in the front and a more rounded, sweeping arc from the top of the tank to the seat base.  I'll post step by step pics, hoping that my resident experts like D9Canada, and all will chime in if any of you all see me making a bonehead mistake. I included  a picture of the tank fail. The fiberglass resin I used but ate right through the epoxy paint I applied to the first plug
 It looks like one of those cocoons from the horror film "Alien "


Thanks again guys.!!
« Last Edit: Apr 11, 2018, 01:06:53 by Markie-V »

Offline Markie-V

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Re: Project xs750 lowrider
« Reply #53 on: Apr 10, 2018, 19:38:01 »
D9Canada... I am going to take your advice and build the next tank from a mold of the plug. I'll shape the tank today and tomorrow and try to follow your instructions to a tee.

I think you are right... a mold would be a good thing in case there is a future problem... then I can just break out the mold again. Trying to figure out how to split the molds. Maybe three molds.. left side, right side, and tunnel. My foam block is drying. So I am taking measurement right now. Thinking that I will carve the the foam tank plug... follow your "bondo/fiberglass friendly paint technique, and once the tank is fiberglassed over the plug... cut it into the three sections i need. This would give me the three molds i would need to build the tank with such an extreme backbone cutout.

Thanks again... I'll get back on it. Keep plugging


Offline Brodie

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Re: Project xs750 lowrider
« Reply #54 on: Apr 10, 2018, 21:01:30 »
Glad to see you are back at it. Pity about the first tank.
I'm not sure, but don't ask Brodie.

Way to many build and half done projects to list here.
Sr250, Gs750, Z50A, XV1100, A10, Z160A.

Offline Hurco550

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Re: Project xs750 lowrider
« Reply #55 on: Apr 10, 2018, 21:27:22 »
Had a detour.... needed to do a little work on my skid loader... postponed the low rider for a day.LOL
We have had the same skid loader around the farm since I was a kid. Made for John deere buy owatana I believe? Grandpa replaced the original Wisconsin engine with a Subaru robin lump. It's due for a little hydraulic tlc as well.

Either way, love the bike man, looks like a very well executed project.

Sent from my SM-G920V using Tapatalk

"If you just picked up a drug habbit instead of a kawasaki triple at least you could get high while you waste money"
~ bradj
1988 tw200, the swamp donkey: http://www.dotheton.com/forum/index.php?topic=75455.0
2006 Suzuki DR650 Adventure monowheel trailer build: http://www.dotheton.com/forum/index.php?topic=75033.0
1976 BMW R90/6 farkilitious: http://www.dotheton.com/forum/index.php?topic=74349.msg882477#msg882477
1975 RD350 Road Racer: http://www.dotheton.com/forum/index.php?topic=70652.msg833688#msg833688
1976 GT250 Rebuild: http://www.dotheton.com/forum/index.php?topic=64973.new#new
Full Custom Pit Bike: http://www.dotheton.com/forum/index.php?topic=66954.new#new
1971 Yamaha 90cc twin HS1: http://www.dotheton.com/forum/index.php?topic=70498.0
"much ingenuity with a little money is more profitable and amusing than much money without ingenuity" - Arnold Bennet

Offline d9canada

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  • Just keep pluggin' every day and it'll get done!
Re: Project xs750 lowrider
« Reply #56 on: Apr 10, 2018, 23:07:08 »
Yeah, I never got around to saying "Kudos on the metal work" on your project.  Very nicely done!

As for a mold, yeah that's my comfort zone but it is not a requirement. 

If you go that way, look at the Tracy body mold I made and you'll see that making a part and cutting it up may not be the greatest idea.  If you put a strip of masking tape on one side of the center line, you could do as I did, use hot glue, cardboard and masking tape to make a "fence" that you can use as you build up your first mold section layup, so you get a flange  - so you might put a flange at the bottom all around and one right down the center line.  Make sure you do a pretty solid job of the flanges, not allowing air entrapment at the base of the flange and make the flanges pretty strong so you can wedge them apart to pull the mold apart.  Flanges make mold parts harder to move off a plug because their shape resists twisting and so on.  But it's all "fun".

In this scenario, you'd wax and PVA one "third" so to speak, or half of the body, lay it up and let it set.  Don't move it, just strip the cardboard off the back side of the flange of the first piece then wax and PVA it and the rest of the next section, lay it up, then do repeat the process to get that last part, probably the bottom/tunnel, of the mold made. 

Finally, you have three pieces with perfectly matching flanges, even if they are not perfectly straight.  But it's a lot off work if you're not intending to use it again.  Throw the thing in a bathtub full of warm water with some plastic wedges (like bondo squeegies) stuffed into the flanges to spread them apart a bit to let water in.

You see, this is a fair bit of work when you might otherwise just be getting the tank done.  I'd be inclined to layup the bottom tunnel and maybe make a relief around the bottom edge of the sides about 1/8" deep and extending 1" from the bottom edge, so you lay up the bottom/tunnel and wrap around the bottom onto that relief along the sides.  Let that set and leave it in place then wax and PVA the body of the plug, including that little "flange" along the bottom.  Do your layup.  Then trim/sand carefully along the bottom edge to expose the seam between the body and bottom. 

Get some wedges in there, throw it in a bathtub of warm water and let the snarling begin.  You'll have some wrestling to get water to seep into the thing.  Patience is a virtue on things like this.  So what if it sits there, weighted down to hold it underwater, for three or four hours?  So don't think "Darn, I've been pissing around with this for twenty minutes and it still hasn't budged!"  My Tracy half molds hardly moved for the first couple hours.   :'(

Important - If you know for sure where your filler neck and petcock will go, especially from the filler hole, you can drill in and destroy some of the plug, allowing water to get into the inside.  Even if you don't get to the bondo layer except at the filler hole, removing foam behind the bondo will weaken the plug.  So give that some thought, it may be messy but it could be a real ticket to that magic moment when you see the parts move.   :o

Finally, you should be able to separate the body part from the plug, then the bottom/tunnel off the plug.  And don't be worried about destroying the plug to get the complex shaped bottom/tunnel removed.  So long as the plug was waxed and PVA'd, you may have to chop some foam/bondo to get some movement in there but in the final analysis, you should have a good part.   8)

It's a real toss-up I guess, make a mold or make a finished part.  I know guys who've made custom cars whose bodies were originally intended to be the mold or the plug for a final mold  :D   

Then again, looking at your metal work skills, you might consider getting some 16 gauge steel, make a leather sandbag and get some simple tools and beat one out of steel.  I have to throw that out there.  ;D 

Keep pluggin' - there's no rest for the wicked!
Brian
63 C105T
73 CB350F X2
77 CB400F X2
73 CB500 X2
77 CB550K X3
80 CB650
80 CB650C
Sandcast CB750 #1003245
71, 73 CB750K X5 (help me!)
78 CB750F X2
82 GL500
82 GL500 Interstate
83 CX650 Euro version
81 CB750C
80-82 CB900C X5 one with Motorvation FII sidecar
75 & 77 GL1000
82 CBX
83 Honda 750 Shadow
73 Norton 850 Commando

Online Maritime

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Re: Project xs750 lowrider
« Reply #57 on: Apr 11, 2018, 08:59:43 »
Check out CCriders CB450 build. that tank is gong on 5 or more years and I have seen it in person 3-4 times and it is great looking.  Also Ringo built an amazing CB550(I think) in gulf livery and documented it well too.

CCriders build. unfortunately you need the photobucket fix to see the pics.
http://www.dotheton.com/forum/index.php?topic=9125.0

Ringo's build is the same:
http://www.dotheton.com/forum/index.php?topic=19771.0

If you can make the pics work these are both really good fiberglass tank bikes.
« Last Edit: Apr 11, 2018, 09:09:54 by Maritime »
The GL Rebirth: http://www.dotheton.com/forum/index.php?topic=68337.0
CX500 Low budget Bobber : http://www.dotheton.com/forum/index.php?topic=43617.0
"Beer makes you feel the way you ought to feel without beer" -Henry Lawson
"Beer is proof that God loves us and wants us to be happy." - Thomas Jefferson

Offline jpmobius

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Re: Project xs750 lowrider
« Reply #58 on: Apr 11, 2018, 13:51:29 »
Just throwing this in for a think.  I've done a fair bit of scratch built composite parts, and have settled on mold-less construction as my mostly preferred choice as I seldom intend to make more than one of anything, so maybe some of this will apply to you.  I have done molds, gelcoat, and polyester resins, but for me that is a frightful amount of work compared to simply making what I want straight away.  I haven't ever had the melting foam issue, but that's probably because of aircraft experience and been lucky to have never used incompatible materials by accident.  For what it's worth, I generally use urethane foam - mostly the type sold as building insulation like for freezers.  In fact, I have rather a large supply I got for free from a commercial building I chanced to see being torn down, but it is very affordable bought commercially.  All that I have ever seen is tan in color.  You can also buy it from a specialty supplier for modeling and casting work, but it is much denser and fine grained and very expensive.  At any rate, it is immune to epoxy, which I use exclusively and very highly recommend over polyester resin despite the significantly higher cost.   I use epoxy mainly because I find it much more stable than polyester  (I've done a lot of boat repairs with polyester, but am in no way any sort of expert).  What I mean here by stable is that, whether mold or moldless construction, I have had issues with bodywork retaining its shape perfectly until vast amounts of time (year+) go by.  In other words, dead straight flawless parts are no longer perfect 6 months later.  Granted I am REALLY picky to be sure, but I don't have this issue with epoxies.  I've also used green florists foam with fine results though it is very soft.  I do not attempt to dissolve foam (tried it ONCE!!!).  If the part has to be hollow, like a tank, I make what I want and than simply cut it in half, or whatever, and manually dig out the foam which I find quite easy.  Then simply glass the parts back together.  Epoxies as a rule are vastly more alcohol resistant (and gasoline resistant), and some formulations are in a practical sense actually fuel proof.  At any rate, epoxies are very considerably stronger and are vastly more tenacious than polyester, so for me, on bike parts which are quite small, the extra cost is well worth it especially considering the huge labor (time) involved.  Lastly, for the record, I'd like to suggest that you avoid Kevlar and carbon fiber.  Unless you are swapping your steel chassis for a composite one, there isn't much application for carbon on anything motorcycle (aside from purely aesthetic goals), and Kevlar is much harder to deal with (as well as really having no application).  If you want to improve the strength of your parts, use S-glass.  I almost always use plain 'ol regular fiberglass cloth myself, very light weight woven (finishing cloth) for most parts.  There are some pics of a seat made on green florists foam on page 7 (might be different on your system) in my build thread below if you want to see a result - sorry. it's just the unpainted part, no in process.
Mobius


On a long enough timeline, the survival rate for everyone drops to zero.

1973 RD350 Yamaha build  http://www.dotheton.com/forum/index.php?topic=66498.0

Offline d9canada

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Re: Project xs750 lowrider
« Reply #59 on: Apr 11, 2018, 15:02:19 »
Thanks to JPMobius and others for your thoughts on this.  I didn't want to be the only voice because despite my experiences, like many of you, I am no expert.

I do agree generally, for this project, making a mold is an overkill, certainly, much more expensive.  There's one thing we did not discuss, that being making a female mold instead of a male - just a thought.  And with reference to my suggestion of making a metal tank, a male plug could still serve well to ensure the parts are shaped well before tacking or TIGing begins. 

On the subject of epoxy, something like West Systems or System 3 epoxy is great, very durable and much stronger than polyester resin.  And though those epoxies are more fuel resistant, I would not use such a tank without either Caswells or POR15 coating inside.

But there's stuff about epoxy you need to know (why can't I write a short post??)  There's an expression in boat building about epoxy "It goes on like honey and runs like water."  This is very important.  Epoxy laid on, let's say a cedar strip kayak, will tend to run even though the wood may be wet out first then cloth laid on and more epoxy carefully applied. 

You can't go for a "flood coat" finish all at once or you will get runs.  Even in molds, if you have vertical surfaces, the darned stuff tends to sag badly.  And the really frustrating thing is that the sagging begins to sag at max exotherm (heat generation) which occurs as the stuff begins to get too sticky to brush out!  It's crazy stuff.  You can get catalysts for slow, medium and fast set, and you have to monitor mold and air temps to choose the right one as well as consider what you're going to do and how.

So it's not hard to understand that manufacturers like West System make a variety of filler products which help to bulk up and stabilize epoxy a bit with very little sacrifice in strength.  Lots of times, people just use talcum power - (that's good for patching chips in white appliances too) - but in boat yards, for convenience and also cost reduction, often sawdust is used.  Of course, you can screen it to keep it consistently sized.  But here's a "trick" - commercial fillers are not absorbent, so you can add your filler to the epoxy and then catalyze - however, if you use sawdust or any other absorbent material, you don't want it absorbing uncatalyzed epoxy because it won't set up well.  So you have to catalyze first, then thicken.   In that situation, remember that your pot-life will be reduced as you mess around adding an absorbent filler after catalyzing.   

For a tank, you should be able to mix a small amount of epoxy and wet the mold, (male or female), let that sit until it or the mix can is getting warm (hand held heat gun is great but otherwise check the stir stick in your mix can to see if it's getting sticky).  You can use thickened material if you have hard corners where you expect some "resistance" for the glass materials to lay in well.  (Oh there's another subject, I'll hit with another post.  Groan!) 

You should have your materials already cut.  "No scissors at the wet side!"  Lay your first glass (should be mat especially in a female mold because mat doesn't "print" through), wet that and get a layer of cloth laid in and wet out.  Then stop.

Don't try to "fill up" the mat to a smooth finish, just get that layup wet out.  Let that flash for a few hours and then hit it with another mat/cloth layer, and repeat once more and you should have a very tough shell.  Certainly, when bonding parts together, thicken the epoxy to the consistency of peanut butter.  Again, from boat building, there's "ketchup or peanut butter" consistencies discussed when talking about fillers.

And last of all is a safety warning.  Do some Googling about this and you will cringe.  The sanding dust from epoxy is extremely dangerous.  If you possibly can, use a sander with shop vac connector.  Cover your entire body and immediately take that clothing off and put it in the wash, go shower thoroughly.  People have had to quit working in boat yards and furniture shops because they get "epoxy rash".  Once they get it, just the slightest contact later can cause them to develop horrific rashes.  Working outside is a good idea and try to stay upwind of the work surface.   I'll shut up now  ::)
Brian
63 C105T
73 CB350F X2
77 CB400F X2
73 CB500 X2
77 CB550K X3
80 CB650
80 CB650C
Sandcast CB750 #1003245
71, 73 CB750K X5 (help me!)
78 CB750F X2
82 GL500
82 GL500 Interstate
83 CX650 Euro version
81 CB750C
80-82 CB900C X5 one with Motorvation FII sidecar
75 & 77 GL1000
82 CBX
83 Honda 750 Shadow
73 Norton 850 Commando