Flower-Class Corvette by king derelict - FINISHED - Bensworx Virtual Kit - 1/48 - a log for the less gifted

[Haze Gray]

3 hours ago, king derelict said:

I foresee several days of sanding and fairing of the hull to get it tidy. I'm reluctant to use any form of rotary tool sander because of the low melting point of the plastic.

I am going to need some putty for some of the less than perfect joins. I only have the Vallejo plastic putty which my work but I would be grateful if anyone has any better suggestions for filling the thin gaps between a few of the hull sections and a few print gaps.

Thanks

Alan

Considering how the weld lines stand proud and separate the surface of the hull into multiple sections sanding the plastic directly would be somewhat torturous (and rotary tool would remove weld lines in the blink of an eye no matter how careful you are).  A very thin layer of 75% gesso/ 25%water mix could help fill in the lines somewhat and then follow up with multiple layers of primer and then sanding could be a good way to go - but I recommend you print one additional of the hull sections to test whichever method you want to pursue since you will learn a lot about what works and what doesn't. 

Edited September 10, 2021 by Haze Gray

[CDW]

Just now, Haze Gray said:

but I recommend you print one additional of the hull sections to test whichever method you want to pursue since you will learn a lot about what works and what doesn't. 

 

Good idea

 

[king derelict]

1 hour ago, yvesvidal said:

 

I have used the same Vallejo Acrylic putty with success on my Corvette. Just make sure it dries completely before doing anything to it.

 

Yves

Thanks Yves, I will give that a try

Alan

[king derelict]

3 hours ago, lmagna said:

I have not done it myself yet on the 3D USS Olympia I received from Haze Gray, but he has told me that after some sanding with an orbital sander, he likes to apply a thin coat of Gesso, as a filler rather than relying on sanding alone.

https://www.amazon.com/Liquitex-BASICS-Gesso-Surface-Medium/dp/B000KNDMLG/ref=asc_df_B000KNDMLG/?tag=hyprod-20&linkCode=df0&hvadid=167148482147&hvpos=&hvnetw=g&hvrand=3973154835594336567&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9060507&hvtargid=pla-162268632052&psc=1

 

I have seen some of his other completed hulls and if a couple of them are any indication it appears to do the job.

 

Nice to see you making some relatively painless progress at last.

 

Thank you Lou. Its quite a thrill to see the hull assembled. The gesso is a great idea. I even have some in hand from the Penelope diorama.

Alan

[king derelict]

58 minutes ago, Haze Gray said:

Considering how the weld lines stand proud and separate the surface of the hull into multiple sections sanding the plastic directly would be somewhat torturous (and rotary tool would remove weld lines in the blink of an eye no matter how careful you are).  A very thin layer of 75% gesso/ 25%water mix could help fill in the lines somewhat and then follow up with multiple layers of primer and then sanding could be a good way to go - but I recommend you print one additional of the hull sections to test whichever method you want to pursue since you will learn a lot about what works and what doesn't. 

The gesso is a great idea. Thank you very much for the suggestion. sanding looked like it would be messy and tedious. Its bad enough cleaning up the brim lines.

Alan

[king derelict]

32 minutes ago, CDW said:

 

Good idea

 

I knew there was going to be a reason I shouldn't have thrown those early failed prints away. 😄

A test piece is definitely a good idea

Alan

[Old Collingwood]

1 hour ago, yvesvidal said:

 

I have used the same Vallejo Acrylic putty with success on my Corvette. Just make sure it dries completely before doing anything to it.

 

Yves

I have been using the same to fill any gaps in my Waterllo dio.

 

OC.

[Haze Gray]

King, I want to add that you need to resist any urge to lay on the Gesso in a thick layer - especially if you don't cut it by 20-25% water.  first time I used Gesso I laid three thick layers down and thought "this is amazing - I can make all those lines disappear"...but, once dry,  it took me a really, really long time just to get to the point the left over brush marks were not so visible. Gesso can be quite a durable coating, especially if it's not fully cured and if you lay it on thick it's going it could take a long time to cure. 

 

 As mentioned before,  test out what you want to do on a separate piece and see how it goes. 

Edited September 10, 2021 by Haze Gray

[reklein]

A good filler for harder surfaces is micro balloons mixed with epoxy. You mentioned using epoxy as an adhesive . So it must be compatible with the material you are printing with. Be sure to mix the microballoons fairly thick. The thicker you mix it the easier it is to sand.

 I've had bad luck with Gesso as it is sooo hard to sand. You should be able to get microballons at a good hobby shop which deals in R/C or online

[king derelict]

35 minutes ago, reklein said:

A good filler for harder surfaces is micro balloons mixed with epoxy. You mentioned using epoxy as an adhesive . So it must be compatible with the material you are printing with. Be sure to mix the microballoons fairly thick. The thicker you mix it the easier it is to sand.

 I've had bad luck with Gesso as it is sooo hard to sand. You should be able to get microballons at a good hobby shop which deals in R/C or online

Thanks Bill

I just ordered some micro balloons on your suggestion. I'll experiment to find the best solution.

Thanks again

Alan

[king derelict]

2 hours ago, Old Collingwood said:

I have been using the same to fill any gaps in my Waterllo dio.

 

OC.

Thanks OC. I've liked the Vallejo putty in other applications. Looks like I have a full armoury now.

Alan

[king derelict]

50 minutes ago, Haze Gray said:

King, I want to add that you need to resist any urge to lay on the Gesso in a thick layer - especially if you don't cut it by 20-25% water.  first time I used Gesso I laid three thick layers down and thought "this is amazing - I can make all those lines disappear"...but, once dry,  it took me a really, really long time just to get to the point the left over brush marks were not so visible. Gesso can be quite a durable coating, especially if it's not fully cured and if you lay it on thick it's going it could take a long time to cure. 

 

 As mentioned before,  test out what you want to do on a separate piece and see how it goes. 

Thank you for that. I bought some gesso for my Penelope diorama and slapped it on rather liberally and regretted it. Luckily it was being covered in resin but it took a long time to dry. I think experimentation is key here. Thank you for your input; its very helpful

Alan

[king derelict]

I joined the last sections of the hull this morning and set it aside to let the epoxy cure to full strength before starting to clean up the joints. 

Thank you for all the suggestions for filler and surfacing techniques.

Have a great weekend

Alan

[Old Collingwood]

36 minutes ago, king derelict said:

I joined the last sections of the hull this morning and set it aside to let the epoxy cure to full strength before starting to clean up the joints. 

Thank you for all the suggestions for filler and surfacing techniques.

Have a great weekend

Alan

As  cat says    - "are you talking about me"

 

Looking really good mate.

 

OC.

[king derelict]

4 minutes ago, Old Collingwood said:

As  cat says    - "are you talking about me"

 

Looking really good mate.

 

OC.

Thanks OC. She is the timid one of the pair. She is probably worrying about being launched out onto the lake in the hull for sea trials - and the alligator

Alan

[CDW]

I wonder how well Gesso would work for spraying on with an automotive paint gun, a small one like you use for door jambs or touchups? For a model as large as the Corvette, it could possibly come out a whole lot smoother spraying on vs: brushing it on. I think you could apply lighter coats as well and of course, no troublesome brush marks. 

[lmagna]

1 hour ago, CDW said:

spraying on with an automotive paint gun,

Something like this:

https://www.harborfreight.com/20-oz-hvlp-gravity-feed-air-spray-gun-62300.html

 

Should get the job done if you thinned the Gesso up and made sure you got it good and clean each time.  

[CDW]

Just now, lmagna said:

Something like this:

https://www.harborfreight.com/20-oz-hvlp-gravity-feed-air-spray-gun-62300.html

 

Should get the job done if you thinned the Gesso up and made sure you got it good and clean each time.  

 

Something more like this one:

Touch Up Spray Gun 1.6 mm Siphon Feed Performance Tool M578DB Paint | eBay

 

The one you pictured is a HVLP gun (high volume low pressure). Those type spray guns take a very significant compressor to operate. I used to have a 120 gallon 5HP compressor, and mine could not run the HVLP guns when they first came out. Not enough air volume. 

I was surprised when I looked, because it seems they no longer carry a touchup gun that's not HVLP. There used to be a little siphon feed one they carried that cost about $10, but I guess I'm showing my age. It's long gone. 

[Haze Gray]

1 hour ago, CDW said:

I wonder how well Gesso would work for spraying on with an automotive paint gun, a small one like you use for door jambs or touchups? For a model as large as the Corvette, it could possibly come out a whole lot smoother spraying on vs: brushing it on. I think you could apply lighter coats as well and of course, no troublesome brush marks. 

I've heard about gesso in a spray can but it's cut with significantly more water is my understanding - so many more coats required but maybe that's not an issue. 

[lmagna]

1 hour ago, CDW said:

There used to be a little siphon feed one they carried that cost about $10,

Today's $30 IS yesterdays $10!😞

[lmagna]

1 hour ago, Haze Gray said:

I've heard about gesso in a spray can

https://www.hobbylobby.com/Art-Supplies/Painting-Supplies/Palettes-Tools/Krylon-Gesso-Spray/p/3344?gclid=CjwKCAjwhOyJBhA4EiwAEcJdcfaMr1OUGkCjYI8MgoElZM-ZUGFmGJrWnoFsI0ZOGTPPXyCSX1H9GhoCaF0QAvD_BwE

 

Problem is that it is almost as expensive as the spray gun if you use much of it.😞 

[yvesvidal]

I use Gesso a lot, doing some art paintings on the side. No need to spray it, it is self leveling and very easy to apply with a brush.

You can get it at Jerry Artrama or Dick Blick for a small amount of dollars. It comes in white or black. I use the Liquitex but any brand should work fine.

 

However, I still would go with a good automotive primer with filling capabilities. It sticks better than Gesso, which is designed for canvas, first of all.

 

Yves

[Haze Gray]

I've also had some good experiences with automotive primer - not sure if I would give up Gesso for it on hulls but I use primer almost exclusively on small parts (with some light sanding prior to spraying) and there it works well for me - 

[king derelict]

Thanks for the very helpful input from everyone regarding priming the hull. I already have gesso (Liquitex) from a previous project and I will get some automotive primer and run some tests on bits of print samples. I have put two layers of thinned gesso on one piece. The first layer was actually too thin and almost ran off the piece. The second layer is closer to the 25% water mix and is drying nicely without brush marks.

Thanks for all the useful comments

Alan

[king derelict]

In amongst the Saturday errands I started cleaning up the joints in the hull. As stated earlier the PLA plastic is not nice to work with. I found the best tool so far to trim the remains of the brim and fair the two sides of the joint is a set of MicroMark plastic chisels. They are nice and sharp (so far) and shave the PLA off quite well. It still requires a lot of effort but it is possible to get a neat result.

I'm working this in short sessions as I'm finding it easy to get a bit frustrated and careless. I started adding the Vallejo filler to the gaps as I work along the hull. The chisels, scraper and the edge of a scalpel blade are being used  As you can see this hull is challenging my work space and may need to be moved to the work bench in the garage

The first two deck pieces have been printed and the third one is in progress

I added the corner brims to stop the decks attempting to warp or curl upwards. This is available as a plug in to Cura downloaded from the Marketplace option in the program.

 

It adds the circles seen at each corner and stops the corners lifting. It reduces material use and time as well as after print clean up when you don't need a full print.

This explains it all

Some of the options are different in my version of Cura but it is essentially the same and seems to work well.

I may try to work a 1/700 ship as light relief between sessions on the corvette. I'm not sure how that will work out. I may just print parts for a few weeks and build when Florida cools down a bit and the garage becomes a reasonable environment again.

I had initially thought of building this as the fictional Compass Rose (from the book The Cruel Sea of course) but she was an early corvette and this looks like a later version. Plenty of time for decisions. Now I need to order more filament.

Thanks for looking and helping.

Alan

 

[Haze Gray]

Alan, what temperature do you set the bed to when printing?  If your getting lifting during the print you can up the bed temp to around 60c  ….. currently I set my bed at 50c but I keep the bed on after the print is done.  

[king derelict]

On 9/11/2021 at 9:56 PM, Haze Gray said:

Alan, what temperature do you set the bed to when printing?  If your getting lifting during the print you can up the bed temp to around 60c  ….. currently I set my bed at 50c but I keep the bed on after the print is done.  

I'm preheating to 65C and printing at 63C. maybe that's a little too warm but I got to those values while suffering from bed adhesion problems. Maybe I am running it too hot.

Thanks for the suggestion.

Alan

[king derelict]

Oh wot a smashin' Sunday!

I was working on tidying up one of the worst joints in the hull at the mid section and was getting a bit medieval with the chisel forgetting that the hull wasn't really supported properly along its length. There was a very nasty cracking sound and a clatter and >>>>>>>>>>>>>>

Picking up the pieces it showed that the joints had failed at the epoxy glue. All the PLA parts were fine except for the dodgy ledges for the deck in section 7 which had now detached extensively. I completely separated the partly debonded elements of the aft half and started cleaning up the pieces. The epoxy had done a reasonable job of gluing the sections; I should not have got so carried away.

While I am cleaning the old epoxy off I am also using the plastic chisels to work on the joint edges (which is actually easier section by section) and dry fitting frequently to check the progress. I think it will be possible to get a closer fit second time round and then only have minimal clean up once assembled. This should prevent further brutalising of the assembled hull and we can return to some progress,

Two more deck sections have been printed in amongst the days activities.

Thanks for stopping by

Alan

[Haze Gray]

Alan,  I've been there done that myself!   bit surprised the epoxy gave way but the mating surface area for the hull joins on the corvette aren't super big - One question I have looking at the sections on the work table - when you join them are you somehow clamping the sections to the internal shape?  3d printed parts in a U shape will tend to have more tension on the outside and want to splay open a bit so I assume that's probably something that you have a method to deal with. 

[Haze Gray]

55 minutes ago, king derelict said:

I'm preheating to 65C and printing at 63C. maybe that's a little too warm but I got to those values while suffering from bed adhesion problems. Maybe I am running it too hot.

Thanks for the suggestion.

Alan

Usually going hotter would reduce the stress - so you're probably fine there unless you're seeing problems with the first layers spreading out like an 'elephants foot'.