Baby Jet

[Vumad]

We are about to embark on an amazing adventure to waste an absurd amount of time and money to introduce a little lady into a sport she can't even yet comprehend...

Initial measurements and sketches were taken from her walker onto PEG board. The wheels for this were salvaged from a jogging stroller.

 

[Blaine Mac]

Dad of the year!

 

[Vumad]

My first round of drawings were not on PAR with what I was hoping for so I redrew them.








The PEG board was then cut on my BladeRunner to be used as a stencil to cut the foam (also on the blade runner) that would become the plug.







After the pieces were cut, they were glued together with Gripper and some pressure.








Additional pieces were roughed out for what would be the hood and nose.

 

[Vumad]

Some height testing, a few pictures of our little rider omitted.








Time to start shaping. I widened the tray area some from my original plan.








Once the foam is roughed out it's time to get a little more detailed. I do this work using drywall mud.

Also considered a rocker since the nose looked so big. It's so big to accommodate the huge 11.5" wheel and the swivel hardware from the stroller. The wheels are large so this will roll on any surface, namely grass.

The rocker will be removed to go back to the original design. The rocker shape adds a lot of extra work to both symmetry and making the mold flange.

 

[IS0LD0UT]

Congrats. Looking forward to the updates.

 

[Vumad]

Symmetry challenge...

Contour gauge on a part of the plug I liked...






Then cut on the blade runner...








Shaped on the drill press with a drum...






On the hull...






Started shaping with the tool...

 

[Vumad]

Lots of shaping. Getting close.

 

[Blaine Mac]

Looks great, so much sanding!!

 

[Vumad]

Pretty much there. Also lengthened the handle pole. The shorter version might have been good for a real ski but was probably too close for a push toy. The hull won't have the arched leg cut out like the lion walker did. Hope its the right length now.

 

[SXIPro]

Awesomeness!

 

[Mdavies_02]

Great work. Excited to see what the finished project looks like

 

[2HIGH4U]

Needs rocker awesome job ,can't wait to see how it turns out

 

[Vumad]

So now that I have the attention of many of you with a picture heavy start, lets go ahead and do a little recap.

The 1st picture in this thread is the very start of this project. It was taken 10/3/16. At the time, our little rider was just beginning to walk with her lion and could not yet walk on her own but a few steps. My goal was to make a walker that resembled my Superjet. It would share similar ergonomics to the walker but would be substantially larger for cosmetic and functional reasons. The tires salvaged from the stroller are 11.5 inches. Although these would impact the design significantly, it would gain the ability to roll through grass and ease the burden of how replica of a Superjet the project would end.

This project started simply enough during nap time. It has ballooned over the last week into a massive project of incredible effort and cost. The goal has expanded this week from a simple project I never intended really intended to finish into a near-production-quality endeavor. The driving factor is Daytona. In the last 2 weeks (December 20th is when I sprayed the tooling gelcoat), this has gone from a plug to a nearly completed assembly.

So, if you are wondering how this turns out, doubting as many build threads do, let me admit that you wont have to read along thinking that this is a tire turner with no direction. I'm only dragging this thread out to Daytona for suspense and our enjoyment.

I intend for her to receive this gift in a functional capacity at Daytona, although it may still be short some cosmetic work which will be mentioned upcoming.

 

[Vumad]

Lets recap the process to get to this point in the project...

First sketch to pictures in this post, 6 weeks of nap time.

- Salvaged the wheels from a jogging stroller, 11.5", 3 wheel, front swivel
- Drew out the plan on a piece of PEG board
- Cut the PEG board into a stencil
- Used the stencil to cut out numerous layers of 0.75" EPS foam
- Glued the foam together with gripper
- Roughed out foam higher than the gunnels, hood / nose
- Roughed out a rocker
- Roughed out a handle pole shape
- Began using 5 minute drywall mud to detail the shape
- Made a sanding block to help shape the hood area
- Removed the rocker
- Lengthened the pole to better facilitate pushing
- Finalized the shape

Side note... Gripper works well, grabs quick, but leaves a gap. Epoxy resin would accomplish the task with more consistency between layers at the cost of extending dry times and possible slippage.

Everything else are my typical methods.

Of course you want some sort of picture after 2 posts, so here you go...

I attached the plug to a piece of EPS that would become the mold flange. I attached it with drywall screws. I also used EPS attached with drywall screws to add back the bond rail I had omitted. An edge was added to make the mold flange more rigid, but in hind sight, it would have been much less work to make a 2d flange of more layers. I wont make a flange like this again.








And of course, more drywall mud for the details...

 

[Blaine Mac]

looks amazing and very quick work!! I wish my actual size super jet was going that fast.... stupid house reno....

 

[Vumad]

looks amazing and very quick work!! I wish my actual size super jet was going that fast.... stupid house reno....

This is why I use drywall mud and foam. They work very quickly. Have to be a little more careful not to punch through when going for a showroom finish but it can be done.

Also, not sure if you read the timeline there. I've posted this over 5 days but you have viewed 6 weeks worth of work.

 

[Blaine Mac]

Yeah I did somehow miss the time line ,either way still impressive I have two small children and believe me I understand shop time is precious! I also have a superjet made out of foam right now and going though the sameish process,

 

[Vumad]

So the thing about using drywall mud and EPS foam is that drywall mud is porous and EPS is made of polystyrene. This means that the drywall cant be waxed and the EPS will melt when using high build primer, bondo, glazing putty, gelcoat or poly resin. This is addressed by sealing the plug in epoxy. Sand off the shine before applying anything but be sure not to sand through the epoxy exposing any foam.







After a few coats of epoxy, I sprayed feather fill high build primer from a TCP global gun 2.0 tip @Nate_D recommended, although he uses a different primer. This was my first time using a primer like this on a plug and I have to say it's pretty great stuff.








I then used a fair amount of sand paper and glazing putty to get to where I wanted to be.









Then I sprayed my primer again. In total, I used half a quart of primer.

 

[MADMAT]

Mind=blown!

 

[Vumad]

Bought some spring clamps from harbor freight and some tarps to turn my car port into a paint booth. Wish i would have thought of it sooner.







Wax and PVA. Side note. The glazing putty is somewhat porous and not sealing it isn't a very good idea. I was on a timeline and making a children's toy so I felt a few imperfections were not worth the effort. Really the putty didn't affect the mold much, more-so the pull.









So this was my second time spraying Gelcoat. It was my intention to put down a quart. I put it down, but mostly on the ground. I have a G100 dump gun but the gelcoat wouldn't come out. It started to set up in the gun which would have been an expensive mistake. I then dropped the cup on the ground. It was going all sorts of bad for me. I found out when I was done that the first time I used the gun that the tiny vent on the cap got clogged and I didn't realize it. Now I know to check it every use.







The mold is 1 layer of 3/4 chop, 2 layers of 1-1/2 chop and 1 layers of 1208 hand laid open molding. I hate working with chop.







While the layup came out very nice, the gelcoat did not. My incident with the G100 resulted in inadequate gelcoat thickness and resulted in a bunch of allegation. I was pretty disappointed to have to make so much repair, but I walked away learning something so it's all good.