Sterling #416 -- Nic's custom build

[farfegnubbin]

Those printed parts look nice, Nic. Very tasteful. That seems like a great way to create trim pieces.

What is the ultimate finish of those pieces? The E-brake handle in your one photo looks almost metallic. Are you planning to paint those or leave them matte gray or what? Did you have to sand or finish any surfaces? My brother and my brother-in-law-ish-type-person plays around with hobby 3D printers a lot and many of their parts have a kind of pixelated surface. Yours look quite smooth.

Again. They look nice. Proud of ya.

 

[Nic]

Hey, thanks for the nice words. The metallic finish is just the lighting I think. It's plain black ABS plastic. It does come off the printer with layer lines (pixelated is a good description). I usually start with 220 sandpaper on a block to get the high points down, then a spray of filler-primer and another sand with 220. Then I hit the low spots with red spot putty, sand again but through the primer this time, and spray again. If it LOOKS good, I'll get some 300-400 paper and give it another sanding. But the process is Sand, Filler-prime, sand, spot fill, etc, etc as needed. I'll get a picture tonight of the base piece this is all sitting on. the trim piece above the shift ring screws into the base and the ring will too. Final color of all this, I havent decided. I picked up a nice medium gray rattle can yesterday and did some test painting. I'll get pictures tonight and post later or tomorrow.

 

[Nic]

The stock Sterling seat doesn't have enough lean to it, unless I tilt everything back, then that also tilt the seat pan, which lifts the knees and then those get in the way of the steering wheel. After an attempt to modify the stock seats, hoping to lengthen the power section, it just wasn't going to work easily. So, I pulled out the large bits of cardboard I'd been saving up and got to work.

Basic measurements and angles.


And the MDF mold/buck I've been working on for the last 2 weeks.








It's mostly done. I'm contemplating adding a cut out like the back or a raised section that mimics the back. I think a raised structure would be nice, right down the center like a leg-separation, and it will add rigidity to the seat pan. It'll also be easier to glass. The edges are all rounded over so I'll be able to round those over for additional rigidity.

 

[Nic]

Added a little leg separation, matches the back, add structure and looks nice. NOW, something I didnt account for... the hip bolsters are too narrow. The tops of my femurs are right against them. So I'm going to remove them and move them to the outer edges of the seat, that'll give me an extra inch and a half. OR... option B is to widen the entire seat bottom by an inch. Make a cut down the center put in a space, 1 to 1.5 inches and then glue it all up again. That honestly might be less of a headache.

 

[farfegnubbin]

You’ll get it dialed in just right. It’ll fit you and the car like a glove.

What are your thoughts on reinforcing behind the headrest? A person’s head isn’t very heavy but I find I put a surprising amount of body weight on my whole seat-back and headrest when getting in and out.

 

[Nic]

Thats a great question! One that I hadn't thought about until right NOW! Once I pull the seat, I think I'll hot glue some half-round foam down the back of the seat and glass over that. I know I'll be sliding up and down the seat getting in and out of the car, so good call.

 

[Nic]

I was wrong about how narrow the front of the drop is. It's nearly 17"

Seat bottom was widened 2 inches last night. I'm going to have to widen the back now, shouldn't be as much of an issue since the center is currently just screwed into place.

 

[Nic]

Happy Monday, All.

Bit of work this weekend. I got the seat fully widened and started filling seams and easing hard angles with wood putty filler. I have to re-make the headrest 'bracket' though now that the seat is wider. More sanding and filling to do. I hope to have something sprayed on to seal it this week; filler primer or maybe another wood sealer.


I printed this up yesterday. It was a design for something else that I edited. I love the texture on the surface. Texture is from the textured bed on the printer. I got the grill design by using Simplify3D app, which has a hex infill pattern (Cura does not). I set infil to 20%, zero top & bottom layers, then something like 55 outer walls to get the outer mounting ring to be solid and the hex pattern on the interior.
This is the part as designed, notice no hex pattern in the center.

Printed part


And placed in the boot. There was already a hole here from previous owner. Since I have the fresh air blower in the boot, it made sense to have this here too. I did have to trim the bottom due to the curvature of this area, but it came out great I think.


That's all for now.

 

[Nic]

Only 1 progress picture from the weekend. The widening and 'features' of the seat are done. I've started filling and radius-ing the seams so I don't have any harsh angles that will be difficult to glass to conform to. Per usual, fill, sand, fil, sand, etc. This is after a few rounds of that. Hopefully this week I'll be done with that and be able to do a final visual check then coat it with a clear urethan, then on to wax and PVA. I haven't decided yet if I'm going to apply gelcoat first or just go with raw fiberglass, and then use the bed liner to finish the back surface of the seat.

The plan is to pull 2 seats from this.

 

[ratrog64]

Nice job, they are going to look killer!!!!

 

[Nic]

I'm getting so close! I picked up some supplies today to make sure I can pull at least 2 seats from this. I've been watching this guys video - https://www.youtube.com/user/WJP004
He seems a little red-neck in his engineering, but the end results are pretty good. From his suggestion in a few videos I picked up Famowood table glaze. It's a 2 part self-leveling epoxy meant for sealing tables. I also picked up neutral gel coat, black pigment, more resin and some release wax.

Maybe this weekend will be the weekend!

 

[Nic]

Happy with this. I think a lite sanding to check for drastic high & low spots, then it's time for epoxy sealer. Wish me luck.

 

[Nic]

Coat of epoxy applied. Even has some free embedded bug carcass'


After this I applied a healthy wax coating and a couple coats of PVA. I bought neutral gelcoat but have tinted it black. MAYBE tomorrow I can get the gelcoat on and a few layers of fiberglass down before it gets too dark.

 

[Nic]

Tuesday night I was able to put down the first layer of gel coat and Thursday the 2nd layer. Friday night the first 2 layers of CSM were applied. Saturday was the first layer of woven roving. Looking back, that was a mistake that I wont make on the 2nd seat. The ends of the WR didn't lay flat and the leg divider hump, I had to pry off and sand down the resin a bit, also didn't stick. So next seat will be all CSM.

You can see the black gel coat under the first 2 layers of CSM

 

[farfegnubbin]

Looking really good. Those are gonna work great for you.

 

[Nic]

Thanks. Finally got some pictures of the first 2 layers of CSM uploaded. These were prior to the WR going down. Hopefully I can get more down tonight over the WR and move on from that disaster.

 

[Nic]

So I pulled the seat a few weeks ago and the mold took a hit and the gelcoat on the seat wasn't great.

So....slow going on the seats. I have the gelcoat gun and paper cups. I cleaned up the back of the seat I pulled and filled in most of the voids. I think this is my plan.

I'm going to use the seat I pull from the mold, as the new mold so I get a nicer finish on the visible part of the seat. After filling the voids, the whole getcoat surface was scuffed and I'm going to spray a thicker layer of gelcoat down. Once it has started to kick I'll spray PVA over it to help it fully cure. Once cured, wash off PVA and wax it well, then PVA again and spray a good layer of gelcoat to start the new seat surface. I'm hesitant to 'pull the trigger' on this as I'm not 100% confident in what I'm doing. So watch this space for updates, eventually.

Second, I modeled hood vents yesterday, they're actually very basic shapes I came to find. 2 circles, one at 2.5 inches and another at 2.25 inches and 2.875 inches apart from dead center of the circles. I'll post exact measurements later with a link to the .STL file I modeled, and the vents in the hood.

EDIT - Link to Thingiverse with pictures and downloadable .STL file - https://www.thingiverse.com/quikniq/designs

 

[vpogv]

You'll get the hang of it soon Nic. After that pulling molds will be easy as you'll learn all the quirks and what works. Keep posting updates!

 

[Nic]

Thanks, Pog.

The seat came out of the mold without a lot of effort, I'm really just thinking about a better quality finish on the part of the seat I'll be sitting on. I don't think the seat will be fully upholstered so parts of the 'raw' seat will be visible.


Here are the hood vents, or one installed, 2nd one finished printing later last night. It's not a 100% perfect fit, but I'd say 95% and the other 5% can be dealt with.

One side in.

Close up in the hood. You can see some slight gaps.

And just the part itself.
The lip at the bottom can be used to fix the vent in place, and the back of it to fix a screen or other grid in place as well.
There is a 45 degree chamfer along the inner edge.

Previous post has the download for the STL file if you're interested.

 

[letterman7]

Seats look really nice Nic! They're almost identical to the Polaris Slingshot...