Boat Vent Material

[Bryan Murphy]

Hey everybody.  I'm designing a replacement part for a friend's boat.  This goes on top of the boat, outside, exposed to the elements.  I don't think heat is going to be too much of an issue, mostly water and UV exposure but I still want to take that into consideration.

If you were to print this, what material would you use?  I'm printing a PETG+GF prototype that looks really good, but I'm not sure I'd trust PETG long term in such a harsh environment.

Given the part's design, dimensional stability is another concern.  I've struggled with ASA, but maybe ASA+GF will work.  Or how about PCTG+GF?  I've yet to even try printing any Nylon and I think my buddy is going to settle on wanting white.

Thanks,
Bryan

[3D Printing Tips and Tricks]

ASA is specifically formulated for exposure to the elements. It would be my first choice for this use case. The glass fibers won’t add to the durability.

[Kurt The 3D Printer GUY!!]

If weather elements are of concern - what about painting the part to help protect it??? Just a thought...

-K

[Scott Bussinger]

Curling is going to be a tricky with ASA because of the long continuous run along the length, but I do think it would be the best material.

I'd second the suggestion to paint the part. I make a lot of kayak scuppers using ASA, and spray them with a clear thick glaze to smooth/fill/seal the layer lines and then several coats of clear UV protection spray. Yellowing hasn't been a problem.

I made some brackets for the side of the house out of white TPU and they yellowed pretty badly in the sun over the first summer. The more UV protection you use the better!

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From: 3d-printing-...@googlegroups.com <3d-printing-...@googlegroups.com> on behalf of Kurt The 3D Printer GUY!! <vr...@optonline.net>
Sent: Monday, April 27, 2026 4:01:18 AM
To: 3D Printing Tips and Tricks <3d-printing-...@googlegroups.com>
Subject: Re: Boat Vent Material

 

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[Kurt]

I concur with Scott - as I know ASA is a bit harder to print and has shrinking problems like ABS - and Straight Long Edges - like in your part - is the Bain for ABS. So - an easier material to print - along with coatings to protect from weather Elements & UV - that may be your best bet. 

Also - Bryan - you showed a pic but did not give an idea of dimensions - like just outer dimensions...

-K

[Bryan Murphy]

My printer isn't big enough to print the whole thing in one print.  I'm going to at least split it in two and make some kind of connector for the middle, that will help a little bit with the warping.

The design is very early, just trying to get the dimensions right.  It's about 430mm in length and lacks deflectors to direct the flow of air in the right direction.  I'm thinking of also breaking it into smaller sections that click or screw together. That would help with the warping, although it'll be a bit more complicated to model.

I like the coating idea.  Adding a clear coat is easy enough and will provide a little extra protection.

To view this discussion visit https://groups.google.com/d/msgid/3d-printing-tips--tricks/66a9d2aa-476d-45f7-bc8c-1338d9e3a749n%40googlegroups.com.

[Bryan Murphy]

Also, you can buy the part on Amazon for $25 but I'm doing it for the experience and fun.  If it fails, we've got a backup plan.

[Kurt]

A Backup plan is Always good!!!

Seems your reasons for doing the project is kinda Similar to my air ventilation/filtration design project for my Elegoo. For me though - I want to do something Better than other folks have done (including producing parts that DO NOT NEED Supports! Or - at the VERY Least - I may design Built in kinda supports - and specifically ones that do NOT need to be Removed...

-K

[3D Printing Tips and Tricks]

Use lots of helper disks.

[Scott Bussinger]

Multiple segments will help a lot with curling! Minimizing outer shells on the bottom layer, helper disks along the sides, and putting some cuts across on the bottom can make a big difference as well.

Depending on where this is going on the boat, do you have to worry about blocking water ingress? Rain, water splashing up the sides, angry seagulls?

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From: 3d-printing-...@googlegroups.com about <3d-printing-...@googlegroups.com> on behalf of Bryan Murphy <bmurp...@gmail.com>
Sent: Monday, April 27, 2026 7:21:34 AM
To: Kurt <kurt.the...@gmail.com>
Cc: 3D Printing Tips and Tricks <3d-printing-...@googlegroups.com>

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[Bryan Murphy]

The original design doesn't really do anything to block water ingress.  I actually think an improved modular design would work better but I'm trying to stick as close to the original as possible for the first iteration.  I figure there must be a reason it was designed this way.  If we have that part as a fallback I can experiment with more creative designs.

I've decided I'm going to cut the thing in half and print the first working prototype as two separate parts with a small flat connector in the middle and then glue (or screw) them together.  That should be enough to prove out the idea while still providing a functional replacement in the short term.  That should also help minimize any warping (fingers crossed).

[Bryan Murphy]

Lol, I forgot a keyword: "print vertically"

[Scott Bussinger]

If you print them vertically (which is a good idea), consider printing both sides at the same time, back-to-back a very short distance apart. Then put little bridges between the two parts so they serve as supports for each other. 

The bridges would be on the back, so not leaving visible defects and would be easily removed.  But they would help keep the tall structures from wobbling as it prints.

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From: Bryan Murphy <bmurp...@gmail.com>
Sent: Tuesday, April 28, 2026 7:35:03 AM
To: Scott Bussinger <sco...@bussinger.org>
Cc: Kurt <kurt.the...@gmail.com>; 3D Printing Tips and Tricks <3d-printing-...@googlegroups.com>

[Bryan Murphy]

Ooh that's a neat idea.  I changed the flat parts on the end to be contoured at 45º already to eliminate the need for supports in most places.