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Author Topic: Project xs750 lowrider  (Read 7572 times)

Offline Markie-V

  • Posts: 89
Re: Project xs750 lowrider
« Reply #40 on: Apr 09, 2018, 11:57:16 »
Thanks Maritime. It's my first build, but I always wanted to try to make one after watching all those shows on TV. I am reasonable with an acetylene torch... But everything else I am learning as I go. I guess this is a good way for my obsessive compulsive butt to pass the winter months rather than counting the flowers on the living room wallpaper. LOL! I still haven't gotten to what I will consider the biggest challenge... wiring. If I can't build a harness... I guess I'll have a 495 pound paperweight. On the bright side... I do have a tow rope and can ask my friends to pull me around behind their cars. Ha ha ha !

Online datadavid

  • Posts: 1323
Re: Project xs750 lowrider
« Reply #41 on: Apr 09, 2018, 12:31:32 »
Get a motogadget brain box, wiring is so simple even I can do it!
Only niggle was hooking up the charging circuit, took me about two years to get it right..

Online Maritime

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  • Posts: 9199
Re: Project xs750 lowrider
« Reply #42 on: Apr 09, 2018, 13:14:01 »
Markie-V if the M-gadget is too pricey, which it was for me, Sonrier (Matt) is a member and owns Spark Moto (Sponsor) and has a fuse block FB11 that makes wiring way easier. I have a prototype of it on my GL1000 and I had to rewire it almost completely from scratch after a deer decided to take it and me out a few summers ago. Made the job sooo much easier. He also does full harnesses or you can get him to do a sub harness for your main circuits like charging and use the FB11 to do all the other like lights, ignition, etc.  He also now owns vintage connections so you can get all the connectors you need at the same place.  Also he will help you out with a diagram for it and answer any questions on like "How do I wire up my LED signals and idiot light?" etc

Link:
http://www.dotheton.com/forum/index.php?topic=74475.0
« Last Edit: Apr 09, 2018, 13:15:38 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 Brodie

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  • Posts: 2258
  • Gold Coast, Queensland
Re: Project xs750 lowrider
« Reply #43 on: Apr 09, 2018, 13:15:48 »
Looks good for a first build mate. Very impressive. Don't forget when you are carving the seat shape to allow for a bit of extra room for the seat foam.

Wiring is not so bad. Just break each part down into different sections. Do the charging circuit, then ignition, then indicators ect ect. At least that is how I work it out. Or hit up Sparck moto and have them build you a custom loom with everything you need.
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 Markie-V

  • Posts: 89
Re: Project xs750 lowrider
« Reply #44 on: Apr 09, 2018, 16:44:32 »
Thanks guys! Great advice.... I really appreciate it.  I'm  thinking that the wiring will have to be done on the completed bike because I am running the harness through the inside of the backbone and I have serious doubts that  the harness with all its connectors will fit through the 1 1/2 inch holes in the front and back of the backbone. I'm  not there quite there yet anyway... but it is coming up soon so I am thinking about it a lot right now. Maybe I will be forced to go under and alongside the gas tank.   Right now, I'm estimating 2 3/4 - 3 1/4 gallon tank capacity... every little bit carved from under the tank takes away from fuel capacity
 Hmmm... thinking about this is giving me a headache.  Ha ha ha!
« Last Edit: Apr 09, 2018, 20:03:31 by Markie-V »

Offline Markie-V

  • Posts: 89
Re: Project xs750 lowrider
« Reply #45 on: Apr 09, 2018, 18:48:13 »
45 days in with relatively no problems... then today .... first major FAIL. The spray on material that was suppose to protect the foam mold from the poly fiberglass resin was completely worthless. The foam mold for the gas tank began melting within two minutes of the fiberglass process. No pictures. Just going to quietly lick my wounds.

Offline d9canada

  • Posts: 46
  • Just keep pluggin' every day and it'll get done!
Re: Project xs750 lowrider
« Reply #46 on: Apr 10, 2018, 06:15:44 »
Markie, I've done a lot of fiberglass and epoxy glass, including mold making, mainly marine stuff, but I don't recall ever trying to lay up over raw foam.  We have used the blue foam as reinforcement in epoxy layups and it reacted well and bonded perfectly. 

And I'm not sure,
1 Is your plan is to make a shell on the foam and then dissolve the foam?  I don't recommend this, only because I've never done it, only read about it.  If you know you can get the foam out and leave a clean fiberglass shell that you can epoxy, that's up to you.  Write a book  ;)
2 Or you could make an exterior mold if your "plug" is really nice, so you can then lay up a final part in the mold.
3 Or just make an exterior shell in halves, or top & bottom, remove from the mold and then finish the outside and bond the sections together.  This would allow you to epoxy the interior by hand and use the same epoxy to bond the base/tunnel into the shell, come to think of it, then do a "pour in & roll around" second coat just for safety sake.

So I have to guess a little.  All methods will work.  Making a mold (2) is a bit wasteful for a one-off, but that's my strong suit, and a modification of this process would give you (3) a good shell to work from.

I don't know what spray you used, perhaps Polyvinyl Alcohol (PVA)?  But here's the deal about parting agents - as you may know a lot of "old timers" rely on wax as a parting agent.  But wax is NOT a parting agent really, not even a specific fiberglass molding wax like Part-All green wax.  How do I know?  Because their rep told me after I investigated a disaster at a friend's business. 

Wax only reduces the surface porosity but it is not a chemical barrier.  In fact, the wax can actually melt when the layup goes on because the layup exotherms (produces heat) as it cures.  But if the wax is trapped, it sort of does a job, to some extent of keeping the surface slick, but success in that area depends on a number of factors.  Sorry but you can tell there's more. 

Two things are at work at the barrier, chemistry that can cause crosslinking (causing a fiberglass part to stick to a fiberglass mold) or otherwise attack the mold (as you experienced) and heat which can damage the mold release barrier or even the plug/mold material, which may have initiated the problem you experienced.  So what to do?

I'd suggest you make a new tank plug as you had before except reduce it's exterior dimension about 1/8" to allow for a complete, all-encompassing Bondo coating.  If the part you layup on the plug will be your finished tank, then this Bondo'd plug will allow you to shape and sand so your real tank's interior is smooth.  If you're making a mold from the plug, you'll have a mold that will produce a great exterior and with care, the interior will follow suit. 

After ensuring you've got Bondo all over the plug, paint the thing with any fiberglass friendly paint.  The objective here is to seal the thing.  Throw on several good coats and let it cure well.  If you do have any exposed foam (and I hope you took seriously that I said cover the thing entirely with Bondo), the paint will most likely seal those areas without substantial damage to the foam.  And remember Bondo is somewhat porous.  OK?  So now you've got a slick looking plug, with a paint finish of some sort.  Give it 3 coats of paste wax, Johnsons floor wax, any good quality paste wax, buff each, let it sit 20 minutes and repeat. 
 
NOW, hit it with PVA. As you may know, you don't try to flood coat it like paint.  Just use a touchup gun with about 35 psi and when you spray, the stuff goes on looking like paint sprayed with excessive air pressure - you get a sugar-like appearance.  This is OK.  Do at least 4 coats, giving each one about 15 minutes to flash.  After all this, the darned thing should be just about bullet-proof.

If you need reassurance about PVA, take a scrap of Arborite and spray it as you do the actual plug.  When the last coat is done and dry, take the Arborite and a sharp knife, cut a line along one edge and peel up the green PVA material and you'll have a glossy green film like very thin plastic bag film.  Now take that and put it in warm water and it will dissolve in moments.  But expose it to fiberglass (polyester, vinylester or epoxy resin) and it will be a perfect barrier provided the base it's on is not compromised by pinholes or vulnerable to heat damage.  The cool thing with PVA when used properly, is that it makes a true chemical barrier with one wonderful exception - it's water solubility makes part separation so easy, just add running water or throw small molds in a tub of warm water  :D   

I literally floated my beautiful cedar strip kayak out of the mold I made from it.   :o  And thank God because smearing black tooling gelcoat all over my gleaming woodwork had me nearly vomiting with fear that I might screw up!

You can lay up your part any time after the PVA has dried, even days after - just don't let a lot of dust and crap get on the thing or that will end up stuck to the interior of your part.

In your case, if your layup will be your final part, maybe do the bottom/tunnel first and wrap the edges so they create bonding surfaces to meet the body of the tank.  Then layup the tank body.  So long as you're happy with everything, you could cut into the foam to break some chunks out of it, which you may have to do in order to get the foam out, depending on the tank shape, then let the PVA and water release the remaining foam and you should be OK. 

Epoxy and bond your parts, finish the outside and you're done.  Easy-peasy!  8) 

So Markie, and anyone else tackling fiberglass, I hope this helps.  I apologize for the verbose reply, but it's like writing a guide for "how to change a car tire" when you don't know for sure that the reader knows where to find the spare, the tools, the jack or how to operate those things.  If you assume too much, the reader doesn't understand and if you dwell on everything it comes off sounding pretty condescending which is certainly not my intention.

While I'm at it, I might as well prove I practice what I preach:

Attached, are pics of a mold I made recently of an original 70s vintage Tracy Eliminator body for CB750.  This was a rush job in March with no warm place to work.  I just picked about the only two sunny days with half a$$ed temps and had a shot at it.  I managed with only 55 F air temp because the black plug absorbed heat and I rolled the thing around to keep it in the sun.  A handheld heat sensing gun is indispensable so you can gauge mold and resin temps and adjust catalyst amounts if needed for each successive mix.  For jobs like this, I prefer to use small mixes, catalyze them to gel pretty fast, so you can't have a big pot full or it will be a steaming bubbling mess before you get the layup done.  This also gives the solo DYI guy a chance to grab a coffee, take a break to cut more material, etc.

I used black tooling gelcoat which helps absorb heat from the sun for the while that it's exposed.  I poured off all my resin in small dark colored tin cans, again sat them in the sun to warm them as I worked.  I even laid the glass material in the sun, doing everything I could to get stuff warmed up.  The potato chip box cardboard flange was laid in with hot glue and masking tape to give me something to form a mold flange against.  I just knew eating all those potato chips would pay off!   ;D

The only parting agents used were Part All green wax - 3 coats buffed on the body itself, then 4 coats of PVA on the body and cardboard flanges.  When the first half was done and cured overnight (exotherm kept it warm  :D) then I stripped the cardboard, waxed and PVA'd the other side and did side 2.  Day 3 it rained, no problem, I stuffed a few plastic wedges into the mold flange and clamped the hose there, pouring water into the mold, just through a small gap opened along the top.  And this was cold tap water too.  An hour later, with some begging, pleading, careful wedging on the flanges and maybe some salty talk, the things separated. 

Knowing some folks in business, I tend to be too timid about yanking on things.  With complex shapes, warm water will help because it causes some expansion, enough to allow water to sneak in. But also some deliberate flexing of the part will help get the water in where it's got to go. 

Just think, the part has basically adhered to the mold because there's not a bit of air between them and it's dry as a bone too. That's why some commercial molds have strategically placed air buds, to just force some air in here and there. 

The crude flanges are very useful because they match perfectly together.  They are not perfectly uniform but that's fine because you can certainly tell when they match up.  Otherwise on a real pro job with flanges formed on long plywood backing that's dead straight, you'd put in locating pins or blocks to ensure alignment.  Also on bigger parts, you'd install mounts for stiffening and shape alignment.  In this case I will be making a horseshoe type bridge to keep the sides spaced out appropriately.  for anyone who knows the history of Tracy Fiberglass, Tracy and Friends, and know something about molding, his crew did some very state-of-the-art work back in the 70s. 

In this case I didn't bother with a bottom/tunnel as I intend to make an aluminum tank to go under the f/g body.  Next, I have a genuine Dunstall tank and seat for CB750 to make molds from.  I have no intentions of selling parts at this time, by the way.  I'm 66 with back injuries and too many great bike projects, not enough time  ;D
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

Offline pacomotorstuff

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Re: Project xs750 lowrider
« Reply #47 on: Apr 10, 2018, 09:39:30 »
What D9canada said, right down to the age (66) and the bad back LOL.
Follow the above, you'll get a part.
Regards,
Pat Cowan,
Pacomotorstuff

Offline Markie-V

  • Posts: 89
Re: Project xs750 lowrider
« Reply #48 on: Apr 10, 2018, 09:58:42 »
D9Canada...

Thank you.
Thank you.
Thank you.
Thank you.
Thank you.
Thank you. (Repeating into infinity)

Yesterday... seeing the loss of my firstborn foam gas tank mold... I felt a strange anger, denial, and grief. As I stood there, watching... it seemed as if I was like watching  a cancer spread through my beloved. Startingsmall, then quickly spreading  until all that remained was a wrinkled, pot marked, and shriveled remnant of the once proud gas tank. A single pea inside a gourd of fiberglass as if it were some alien maraca.  It was painful to watch. I am still trying to cope.

I can't begin to tell you how much that I deeply appreciate that you took the time out of your day to share with me, a total stranger, your knowledge and experience in this area. Believe me, I need knowledge and experience in this area

If you don't mind... I'd like to consult with you by email here on this site as I go through  the process again... just a few questions as I go. Would that be okay? Feel free to say no... I won't be offended.  You obviously know your way around this by experience. Your CB 750 bodywork pics look AWESOME.

Thank you again for taking the time to go through this with me step by step. It will be a big help moving forward.

Regards,
Markie


Offline d9canada

  • Posts: 46
  • Just keep pluggin' every day and it'll get done!
Re: Project xs750 lowrider
« Reply #49 on: Apr 10, 2018, 11:11:45 »
By all means, I'm no expert, just experienced, and I'll help if I can.

And don't beat yourself up.  I've seen more than once at boatyards where guys were pounding on molds with rubber hammers and stuffing thin strips of cedar between the part and the mold, trying desperately to get the boat part out of the mold.  This sort of thing has literally sunk some small companies.  It's a humbling thing.  After I witnessed some of this crap, I thought "not me!" and immediately contacted the Part All guys and asked if there wasn't a fairly assured way of getting it right.  So if I can save someone else some grief, I'm happy to help  :D
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