Making a Fiberglass Mold and Duplicating

[dcmspikes]

Oldog.  that was a great write up.
 i have some decent experience with resin.  i live in ca  so apparently i have to surf and therefor having been fixing my boards for years.
 i think the most important parts for getting your results is using the correct resins and plenty of mold release.  the tooling gel will make things heaps easier for making the mold and the gel coat with make the surface on your finish piece very smooth.  also taking care to get out air bubbles when you apply the first layers of thin fiberglass cloth will give you much better results and less finish work.  this goes for making the mold and making your final piece(s).  when the resin starts to kick off(gel) you can cut the bubbles open and pour resin in them.  the thicker fiberglass matt and/or cloth is difficult to get into tight corners so start with the thinner stuff.  also, you should be able to add your next layers as soon as your previous layers start to harden.  remember that ultimately you want the fiberglass saturated with resin, but no extra resin on top of your fiberglass or underneath it.  just enough to thoroughly wet the fiberglass.  extra resin will not make it stronger only heavier.  if you can find a rubber squegee tool for resin, those help to get extra resin out of the weave of the fiberglass. 

well your mold and final piece  look really nice.  like i said, ive worked with resin quite a bit and i hope i can get results like that.
but im thinking aluminum for my seat/cowl

[oldog]

Oldog.  that was a great write up.
 i have some decent experience with resin.  i live in ca  so apparently i have to surf and therefor having been fixing my boards for years.

dcmspikes..
 Thanks for the thumbs up. My Mother used to live in Napa and I was able to visit from time to time. Compared to where I live (SW Ontario), Napa CA is Gods country for sure! Breathtaking mountainous country roads. Coastal cliffs etc...all within a days ride.

 

[dcmspikes]

yeah its nice up there.  unfortunately im in southern california.  where people get excited about 4 miles of canyons and crowded beaches with millions of parking meters.  could be worse though.  could be covered in snow.  just kidding.  you guys will be out soon enough.

[IagainstI]

hey oldog,i'd like to buy a seat,how much?

[oldog]

hey oldog,i'd like to buy a seat,how much?

PM sent

[NPHLYT]

PM sent

Oooh, oooh, me too, me too!

I would also like some info on that exhaust, if you made a build thread, point me in the right direction, please.

[oldog]

Thanks for the comp!
I do have a build thread here> http://dotheton.com/index.php?topic=1470.0

[NPHLYT]

Thanks for the comp!
I do have a build thread here> http://dotheton.com/index.php?topic=1470.0

How much for one of those seats?

[rockwell500k]

i LOVE how you incorporated the stock taillight.

keeps it still looking like a honda, which i like.

would that seat fit any other bike? perhaps a 71 cb500?

any info on your rear sets as well? i like that mounting plate...

[JRK5892]

PM me i would also like a seat!

[papa wheelie]

hey olddog, bike looks amazing! 

could you give me some pricing for the seat as well?  thanks

[oldog]

Hey...
 Thank you for all the great feedback for this seat project. I've had numerous pm's on price requests. Without going into details, I have chosen not to reproduce this seat for resale...sorry.

[Heironymous Josch]

bump

[Heironymous Josch]

I've been making seats for a few years now,and it's nice to see how it's done the profesional way! and a very nice mould!(and seat) I have basically cheated by dulplicating existing seats,and the process is easy!Borrow the seat, acquire pva release liquid ($20.00) cover it a couple times with a fine brush,let it dry.Then apply your glass and resin over the seat,let it cure a couple days and now the fun part! slowly pull your mould away from the seat,sometimes gently prying with a paint stir stick.Gel Coat is the way to go for nice finish,but you don't have to use it. Now inspect the mould for flaws(air bubbles most common)correct by filling or sanding. apply the release agent to your mould and start laying in the glass and resin   There are some nice custom seats being built on this forum,with the use of metal,wood??etc.take it to the next step and use your seat as a mould,just make sure that contours are always decreasing or it won't release from the mould. If you have any flaws, simply fill and sand.....OLDDOG,,start selling seats!!!!!!!!!!!!!!!!!  To date I have constructed 4 moulds( sixties cb race seat, ducati hailwood seat,norvil commando seat,and a 18" front fender) I would like to know a little more about building plugs??? anyone?

I've learned a hell of a lot about building plugs in my quest to master the craft of fiberglass parts fabrication.  It all started with an ill-conceived plan to build a seat pan / rear cowl on the frame with blue masking tape, aluminum tape, spray foam, wax from a commode seal (had one laying around) and bondo - all to form the "plug" for a fiberglass seat.  Needless to say, it turned out like shit.  It would have worked but I'm too much of a perfectionist.  So I moved on to forming a positive mold, core or "plug."  Polystyrene foam, like pink foam sheathing, is easy to come by and relatively easy to work with.  It has a tendency to "chunk out" when you cut it; I solved that problem by building my own hot wire cutter.  (anyone interested in a 30" professional-quality cutter that can be built for around $40, let me know and I'll post a build thread).  The biggest problem with polystyrene -- It's non-compatible with polyester resins, which means that a plug constructed of this material cannot be sealed with resin and even bondo reacts with it slightly as it's a polyester-based product.  Properly sealing a plug allows you to tool out any imperfections before you create your mold, tooling inside of a mold sucks.  Also, I think tooling bondo sucks, so I prefer plugs that require no bondo.  Pink foam has it's purposes - sheathing the exterior of your home before your siding goes up and building plugs for projects were an epoxy resin or primer is used.  I personally prefer working with polyester resins to epoxy any day of the week.  There are two types of high quality and kinda pricey foam that can be purchased from your composite store that are compatible with poly resins -- PolyIso and Polyurethane.  The Polyurethane can come in a solid or a mix and pour, the latter is similar to the spray foam lots of guys use.  I never cared one bit for the spray foam in a can.  It was too light weight, had poor expansion characteristics and rarely cured all the way from surface to center.  No one wants to be sanding a project only to pop open a pocket of yellow gooey crap.  The mix and pour works well, comes in several weights but must be poured into some sort of cast (which can easily be constructed from plywood, cardboard or whatever you have lying around).  The mix and pour will also minimize the likelihood of large air bubbles, is easy to shape and can be sealed with a poly resin.  The only real downside to this sort of foam is that it adds yet another curing phase to the project.  PolyIso is by far the best product for plug manufacturing but it is also by far the most expensive.  I prefer working with solid foams and don't like the price of PolyIso, so I use the super soft light green foam used for artificial plants.  This is a polyurethane based foam and is compatible with poly resins.  This stuff is easy to shape, almost too easy, you have to be really cautious not to go too deep into your material.  I build my plugs with these blocks, shape it out and seal it with 2-3 coats of poly resin.  The resin goes on super smooth, almost like glass and is easy to tool to perfection.  After graduated sanding up to 400 wet, you now have a mirror surface to wax and pva for your mold.  I'm building a custom seat for my buddy and I built the plug tonight in about 2 hours.  I have a perfect plug that needs to cure for a full day before I mold over it.  Cost of supplies for the plug - $15.

[Heironymous Josch]

Great write up olddog. I've only ever made one off pieces and so never bothered to do it this way, but have always wanted to do it. This way saves a lot of time and effort having to smooth out the finished product with body filler.

Also, do you mind me asking you what colour that is on your bike, I love it.

Deacon,

The biggest benefit to this process, even for one-off pieces is that a perfect mold and a gel coat sprayed into it gives you a near perfect finished product with no bondo and tooling.  When the finished product is built over a positive center, the irregularities in the fiber and resin have to be worked out.