Hon30 25’ boxcar

[Chris333]

Sell "Ice Cube Tray" to ChiTuBox.

[Erock482]

Can you take a screen shot of just the ice cube tray in your CAD Software?

[timwatson]

Can you take a screen shot of just the ice cube tray in your CAD Software?

Sure thing @Erock482

Some bad news, after I removed the supports the shell did start to bow out at the bottom. I put some clamps on it and it’s now in paint. I will see if it stays put after paint.

Here is a few images of the ice tray supports. These extend about 6-7 mm beyond the bottom of the shell.
They’re currently too thick where they attach (.5mm) so I’m going to knock that down to .35mm where it attaches to the side of the model.

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[Erock482]

Interesting, very similar to the bulkheads I print in my cars, but I leave them in to hold the sides from bowing and don't have a continuous bar to hold them all together. Maybe Try making the lower portion removable to a point you can insert the floor, but the rest of the bulkhead remains in the car.

[timwatson]

Interesting, very similar to the bulkheads I print in my cars, but I leave them in to hold the sides from bowing and don't have a continuous bar to hold them all together. Maybe Try making the lower portion removable to a point you can insert the floor, but the rest of the bulkhead remains in the car.

Then the car can’t be hollow! That’s part of the goal. Hollow car open doors.

[Erock482]

In that case, I agree and would make the ice cube tray easily removable so it may be removed after curing, that way the car is more likely to set in the rectangular disposition

[Chris333]

Did you remove the ice tray before you cured it?  I do stuff like leave braces in for curing and several days after before I cut them out.

[johnb]

Um, how about making a bulkhead near the door that looks like crates?  2 birds, 1 stone?

[timwatson]

Did you remove the ice tray before you cured it?  I do stuff like leave braces in for curing and several days after before I cut them out.

I did cure it first but I think the interior wasn’t fully cured. I need to make sure to do that next time. I’m trying to incorporate the ice tray into some roof support that also break away.

It’s good to know you let it sit for a few days Chris. That’s a good idea to try next.

[AlwaysSolutions]

If your ice-cube tray supports are too difficult to remove, I can offer a suggestion on the lattice type support structure that caused the waves.  If you randomize the contact points on that lattice you should be able to eliminate the ripples.  It's a technique I use on my shells.  I usually break the lattice into vertical components that span the width of the shell, with the sprues reaching out to the wall.  I have three unique vertical components that each have different contact point locations so when you line them side-by-side up in series, there is no pattern or visible row of contact points.  I hope that's making sense - I can post a picture later when I get home if you need.  Then I copy those three repeated to fill the length of the shell.  So every three the pattern does repeat but by then you're far enough away from the first as to not cause the ripple.

To keep the bottom from bowing out after you remove supports, cure the heck out of it.  Even that may not help so you could create some alignment pins on your floor that slip into receiving loops inside the walls to pull the walls back in if they bow out.  It's a pain but sometimes you gotta do what you gotta do.  Another technique I've tried is to cure the shell with the walls bowed inward slightly so when you slip the floor in, the walls hug the floor part while the floor pushes the walls out to the proper shape.

I hope that's helpful or provides some ideas.

-Mike

[timwatson]

If your ice-cube tray supports are too difficult to remove, I can offer a suggestion on the lattice type support structure that caused the waves.  If you randomize the contact points on that lattice you should be able to eliminate the ripples.  It's a technique I use on my shells.  I usually break the lattice into vertical components that span the width of the shell, with the sprues reaching out to the wall.  I have three unique vertical components that each have different contact point locations so when you line them side-by-side up in series, there is no pattern or visible row of contact points.  I hope that's making sense - I can post a picture later when I get home if you need.  Then I copy those three repeated to fill the length of the shell.  So every three the pattern does repeat but by then you're far enough away from the first as to not cause the ripple.

To keep the bottom from bowing out after you remove supports, cure the heck out of it.  Even that may not help so you could create some alignment pins on your floor that slip into receiving loops inside the walls to pull the walls back in if they bow out.  It's a pain but sometimes you gotta do what you gotta do.  Another technique I've tried is to cure the shell with the walls bowed inward slightly so when you slip the floor in, the walls hug the floor part while the floor pushes the walls out to the proper shape.

I hope that's helpful or provides some ideas.

-Mike

That's very helpful Mike thank you.

I know you offered but I would love to have an image to look at to help us visualize what you're talking about with the alternating lattice idea?
I love the receiver pins idea for the flooring and walls.

To keep the bottom from bowing out after you remove supports, cure the heck out of it.  Even that may not help so you could create some alignment pins on your floor that slip into receiving loops inside the walls to pull the walls back in if they bow out.  It's a pain but sometimes you gotta do what you gotta do.  Another technique I've tried is to cure the shell with the walls bowed inward slightly so when you slip the floor in, the walls hug the floor part while the floor pushes the walls out to the proper shape.

It's funny I am doing that very thing right now to the shell.

[AlwaysSolutions]

...I know you offered but I would love to have an image to look at to help us visualize what you're talking about with the alternating lattice idea?

Here's an image that shows the type of supports I've been using.  I color code them to keep track of the order... red, green, blue, red, green, blue, etc.  I highlighted one (yellow) so you can see the general shape - the supports reach out to the sides as well as the roof with cross beams to add lateral stability.  You can see the points that reach out to the sides are at different elevations which breaks up the forces that cause those ripples.  Not seen here, but I also anchor the bottom rim of the shell to a base so the shape is pretty much locked in everywhere.  When it's time to remove them I just push them over with a finger (they are not connected to each other - that's the key) and pull them out after the final cure.

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-Mike

[timwatson]

Here's an image that shows the type of supports I've been using.  I color code them to keep track of the order... red, green, blue, red, green, blue, etc.  I highlighted one (yellow) so you can see the general shape - the supports reach out to the sides as well as the roof with cross beams to add lateral stability.  You can see the points that reach out to the sides are at different elevations which breaks up the forces that cause those ripples.  Not seen here, but I also anchor the bottom rim of the shell to a base so the shape is pretty much locked in everywhere.  When it's time to remove them I just push them over with a finger (they are not connected to each other - that's the key) and pull them out after the final cure.

(Attachment Link)

-Mike

Thanks Mike for the visual, that’s a pretty simple and elegant approach. If my current try fails I might try that.

Here is an iteration on the ice tray support. I added roof rafters to the ice tray dividers so the roof is supported. They’re angled and offset to hopefully chill out the suction when the roof prints. I’ll check it in the morning.

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[timwatson]

I had been working on this lil project some recently before I “squirreled” myself. The most important recent thing I stumbled into was that I came up with a unique and effective support shape. It breaks cleanly with no dimpling and works best when the model is all cured. 2 things, up til now, we’ve not been able to do so well.

The shape makes for good bed adhesion and then tapers up - using the natural thing resin is good at. So it’s both support and raft.
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Breaking cleanly off
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I hope this helps in making your own simple supports. It’s changed th way I support models now.
Also important to note make sure you gap them 1-3mm apart so the resin doesn’t become trapped.

[Erock482]

Looks about like the direction I've been moving! what is the thickness at the point it contacts the model?