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

[Old Collingwood]

Sorry to see that Alan  - I am sure    you will fix it   - couldn't  you strenthen the joins  on the inside with some plastic strips over lapping both sections on the joins?

 

OC.

[king derelict]

12 hours ago, Old Collingwood said:

Sorry to see that Alan  - I am sure    you will fix it   - couldn't  you strenthen the joins  on the inside with some plastic strips over lapping both sections on the joins?

 

OC.

Thanks OC

I think its going to work out okay and it is giving me an opportunity to improve the gaps at the joints. The hull connectors provide an overlapping strip across each joint in the hull sections. To be fair I was being quite rough with the hull and I expected to find I had broken something serious. In "normal" usage I think the epoxy will be fine. 

Thanks

Alan

[king derelict]

14 hours ago, Haze Gray said:

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. 

Looking at the sections where the epoxy failed I didn't do a good job of running a continuous seam of glue around the connector. I'm being a bit more careful during the reassembly. I've also upgraded to a stronger epoxy. I actually got it because it has a longer working time. The fifteen minute epoxy I was using was setting up in under ten minutes maybe because the house is warm.

I extensively clamp the first hull section to the connector on the first side of each section. The second side is harder and I can only get a couple of the clamps into place. So far that has seemed to be enough to maintain the shape

Thanks for the helpful input. This is a whole new way of working for me

Alan

[lmagna]

Has anyone looking in on this build tried JB Weld, https://www.amazon.com/J-B-Weld-8265S-Cold-Weld-Reinforced/dp/B0006O1ICE/ref=asc_df_B0006O1ICE/?tag=hyprod-20&linkCode=df0&hvadid=198093606370&hvpos=&hvnetw=g&hvrand=16722993280447711505&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9060507&hvtargid=pla-320192516391&psc=1

 

As a possibly stronger epoxy?

[king derelict]

19 minutes ago, lmagna said:

Has anyone looking in on this build tried JB Weld, https://www.amazon.com/J-B-Weld-8265S-Cold-Weld-Reinforced/dp/B0006O1ICE/ref=asc_df_B0006O1ICE/?tag=hyprod-20&linkCode=df0&hvadid=198093606370&hvpos=&hvnetw=g&hvrand=16722993280447711505&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9060507&hvtargid=pla-320192516391&psc=1

 

As a possibly stronger epoxy?

Thanks for the information Lou

That looks like a good candidate. I just changed to the BSI slow cure

30 Minute Epoxy | Slow-Cure (bsi-inc.com)

Alan

[lmagna]

1 hour ago, king derelict said:

I just changed to the BSI slow cure

30 Minute Epoxy | Slow-Cure (bsi-inc.com)

Looking forward to your opinion. Most times the slower the cure time the better the bond. I think it is because the epoxy has a longer time to flow into the bonding area and also sets to a little more flexible bond. Could be wrong though. It's been known to happen.

[yvesvidal]

10 minutes ago, lmagna said:

Most times the slower the cure time the better the bond. I think it is because the epoxy has a longer time to flow into the bonding area and also sets to a little more flexible bond. 

 

Most definitely: the slower the curing, the harder it gets and the more it bonds. Always try to go with the 24 hours curing time.....

 

Yves

[CDW]

Epoxy will work best if first there is a little "tooth" sanded or filed into the areas to be bonded. Two smooth surfaces will not bond together as well.

Second, for decades I have used Sig epoxy to great success. I have tried other brands, but never found them to be as reliable or consistent as Sig. My purpose has been RC aircraft related as well as a few scale model water craft. 

SIG EPOXY GLUE - Sig Manufacturing (sigmfg.com) 

[king derelict]

4 hours ago, lmagna said:

Looking forward to your opinion. Most times the slower the cure time the better the bond. I think it is because the epoxy has a longer time to flow into the bonding area and also sets to a little more flexible bond. Could be wrong though. It's been known to happen.

Thanks Lou

I think that's a valid point. The slow cure I am now using is much thinner too and its easier to press the parts together and get a tighter join and also spread the glue over the whole surface. The thirty minute working time is optimistic - more like ten minutes. So far its working well

Alan

 

[king derelict]

4 hours ago, yvesvidal said:

 

Most definitely: the slower the curing, the harder it gets and the more it bonds. Always try to go with the 24 hours curing time.....

 

Yves

Thanks Yves; its a definite improvement and tidier to apply too

Alan

[king derelict]

4 hours ago, CDW said:

Epoxy will work best if first there is a little "tooth" sanded or filed into the areas to be bonded. Two smooth surfaces will not bond together as well.

Second, for decades I have used Sig epoxy to great success. I have tried other brands, but never found them to be as reliable or consistent as Sig. My purpose has been RC aircraft related as well as a few scale model water craft. 

SIG EPOXY GLUE - Sig Manufacturing (sigmfg.com) 

Thanks Craig

I roughed up the mating surfaces as I was cleaning out the old epoxy so it should be better this time round.

Alan

[king derelict]

The recovery continues. The stern sections are back together and although still not perfect the gaps at the joints are much improved. A little putty should result in a reasonable finish.

I switch to BSI slow cure epoxy and I am letting it cure as long as possible before moving on to the next section. I should be able to mate the two hull halves tomorrow morning and then leave for twenty four hours before puttying and fairing the joints.

In the meantime I am continuing with printing the deck pieces. The bed still shifts a little as time goes by. I got several deck pieces completed but it tripped up over this piece, Section E, and I had to run the levelling print and adjust a couple of the corners a touch. The second attempt is shown. The BENWORX logo caused problems with adhesion to the bed in the first print. The deck piece was too big to add corner brims and unfortunately the top right corner is lifting. I'm hoping a bit of hot water will flatten it out post printing.

I am not sure of the purpose of several of the deck pieces and its not obvious looking at the instructions. One of the pieces, the deck dagger plate doesn't look like the piece in the instructions so maybe its changed in the course of development.

I ran a trial of priming methods on some scrap pieces. Three thin coats of gesso, Rustoleum automotive primer and Mr Surfacer. The Rustoleum primer looks like the best result so I plan to go with that unless anyone has an insight that would make it a bad idea. I had a quick look on the web and couldn't find anything to suggest that it would react with the PLA and result in damage.

Thanks for looking in and thank you all for the support

Alan

 

 

 

[lmagna]

Nice to see it coming back together Alan. Now you need to test it like this guy did on his 3D tug build:

He does two tests in the video. One @2:38 and the other @5:39

 

He also has some fun with it in part 2:

https://www.youtube.com/watch?v=50CKuTlSi80

 

[king derelict]

19 hours ago, lmagna said:

Nice to see it coming back together Alan. Now you need to test it like this guy did on his 3D tug build:

He does two tests in the video. One @2:38 and the other @5:39

 

He also has some fun with it in part 2:

https://www.youtube.com/watch?v=50CKuTlSi80

 

Thanks Lou

Wow that guy has quite a launch technique. I don't think we will be trying his structural test - unless it is done by the smaller sister of my cats.

I think the MEK or Acetone route may give a stronger join but the fumes scare me a bit.

Alan

[king derelict]

The beast is back together again!

I made the last two joins today and it is now sitting to cure fully before adding a little putty and tidying up the hull before priming. Sorry for the ad-hoc photos but this thing is a challenge to place somewhere to photograph so the backgrounds may be more interesting than the model at some points. I added some of the deck pieces to check out how they are progressing.

 

As I hoped the joins are better this time so much less putty and fettling will be needed this time. Then a first coat of primer and we shall see what we have.

 

I'm still printing deck pieces. I got over confident after reading several articles about preventing warped parts but I am having mixed success. Several articles blamed having too hot a build plate after the initial layer so I have reduced the build plate temperature to 60C from my previous standard of 65C. I have also slowed down the print speed. Adhesion to the build plate is still good but the warping is still present. I got a couple of nice prints but the stern most deck piece is horrible even after a dip in hot water and manually flattening it. I think the distortion is too great. I have the next piece printing (section J) with an initial bed temperature of 60C and then reducing to 55C  and it is starting to warp at the corners too.

The on-line community has mixed views on the cures for warping so I may be going in the wrong direction with this. I think I will go back to adding the corner brims for the next piece. I'm finding the lack of consistency to be the frustrating part of this project. especially as repeating a bad part might take hours. It was meant to be a learning experience but sometimes I would prefer to not have to learn it all the hard way.

Thanks for looking in

Alan

 

[yvesvidal]

Alan, at least, you are making some great progress. That hull looks great.

 

Depending what you want to do, pay very close attention to the way all the decks are fitting. You can see that the Deck #4 (Galley/Funnel) is being too long and protruding out of the hull. It depends which ship you want to depict of course. I reduced the length of mine by a few millimetres so it would not be too obvious. All this preliminary work will pay off later on.

 

Yes, after some primer on the hull, you will have a better picture of what needs to be corrected. I used two cans of primer, with putty in between.

 

For the warping, make sure you stay at 60 degrees for the bed. No more no less.

 

Yves

Edited September 15, 2021 by yvesvidal

[king derelict]

22 hours ago, yvesvidal said:

Alan, at least, you are making some great progress. That hull looks great.

 

Depending what you want to do, pay very close attention to the way all the decks are fitting. You can see that the Deck #4 (Galley/Funnel) is being too long and protruding out of the hull. It depends which ship you want to depict of course. I reduced the length of mine by a few millimetres so it would not be too obvious. All this preliminary work will pay off later on.

 

Yes, after some primer on the hull, you will have a better picture of what needs to be corrected. I used two cans of primer, with putty in between.

 

For the warping, make sure you stay at 60 degrees for the bed. No more no less.

 

Yves

Thank you Yves

You set a high standard to follow but I'm doing my best. The forecastle decks will move forward a bit; there are some loose strands of filament on the bow section where the print was trying to print the fore deck in mid air and it took a few passes to establish a fused piece. I think it might just about work out.

I am still getting warping with a bed temperature of 60C. Very frustrating but the mouse ears at the corners are helping a lot.

Thanks again for all the help

Alan

[king derelict]

I returned to the completed hull after letting the epoxy cure for 24 hours. This time there was very little need for any serious viciousness and more a case of adding putty to the remaining gaps.

With the over spread of the putty it looks worse than it is. Most of this will scrape or sand off

Most of the joins really only needed a touch of putty

The printer has been working away too. I re-sliced the aft deck files to add the corner brims and reprinted the section I deck. Compared to the previous days version (at left) it is a much nicer print.

Its still not an infallible solution. For some reason on the current work in progress (deck H) it failed to print the corner brim at the bottom right corner even though it is present in the gcode file preview and you can see the skirt has made an allowance for it.

I also don't understand why the printer occasionally missed sections of the layer as seen in this photo. Its all a black art still!

I am using the book Flower Class Corvettes as a reference to select a suitable candidate for the model. 

The extended forecastle means it will be a later corvette although earlier ships were refitted. The mast aft of the bridge also is a feature of a later vessel but the lack of aft Oerlikons means its not a really late one. I would like some wooden decks which tend to disappear in the late builds so I'm looking somewhere in mid war period I think. I need to print a lot more parts to see what I have and what can be changed (is it possible to move the mast forward of the bridge?) before making a decision). Plenty of time really. Next objective is to finish the deck parts and sort out wood planks for the deck sections that need it and some plastic strips for shims and levelling then an order to those nice people at Sprue Brothers.

Thanks for looking in

Alan

 

 

 

[Haze Gray]

Hi Alan, what kind of filament are you using? Also, does the print cooling fan turn on when you're laying down the first layer or does it wait until you have .2 - .3 mm laid down?

 

It looks like maybe the the bed might not be fully level as the corner brims on the left side are incomplete but the one on the right side is. 

 

[mtaylor]

Alan,

My curiosity is up.  How are you leveling this machine?  Are you using a bubble level?  A measurement from the bench to the deck?  Is the bench level?   It strikes me as curious that the others aren't having this problem.  I would think a bubble level would be used to get it level so there's no variation anywhere else.  Then again, I might have missed this part of your set up.

[king derelict]

2 hours ago, Haze Gray said:

Hi Alan, what kind of filament are you using? Also, does the print cooling fan turn on when you're laying down the first layer or does it wait until you have .2 - .3 mm laid down?

 

It looks like maybe the the bed might not be fully level as the corner brims on the left side are incomplete but the one on the right side is. 

 

Hi; I'm using Overture PLA filament and the cooling fan is on for the first layer. Do you think I should change that in Cura? 

The corner brims are a plug in to Cura and are a little strange. They are supposed to print as a solid single layer disc. However i find that depending on the size of the corner brim there is often a section that is just a grid of filament. Maybe its something to do with my version of Cura versus what the plug in was written for.

The corner brim on the left is intended to be smaller than the one adjacent to it because I was running out of room on the plate. 

I will recheck the bed level; it has been holding up in recent days but may be out a little again.

Many Thanks for your help; I feel a bit out of my depth with the details of printing.

Alan

 

[king derelict]

1 hour ago, mtaylor said:

Alan,

My curiosity is up.  How are you leveling this machine?  Are you using a bubble level?  A measurement from the bench to the deck?  Is the bench level?   It strikes me as curious that the others aren't having this problem.  I would think a bubble level would be used to get it level so there's no variation anywhere else.  Then again, I might have missed this part of your set up.

Hi Mark

I think I am guilty of using poor terminology. Its really bed alignment rather than absolute level. It is about calibrating to get the print head to move completely parallel to the bed and the correct distance above the plate at all points. So when it lays down the first layer the distance between between the nozzle and the bed surface is close enough to press the filament down enough to stick to the plate but not too close where it will bulldoze the filament around the plate or skip parts of the layer. 

There are adjusting screws at each corner of the plate to move it up and down and in general a piece of paper is used as a feeler gauge to check the level between nozzle and plate at each corner looking for light drag as evidence of contact between nozzle and bed. Its a bit like using a micrometer. You are looking for enough drag to indicate good contact but not a hard clamp. 

I have been using a levelling print routine which prints a three layer ring around the edges of the bed and a square at each corner. The appearance of the print tells you where to adjust to improve the result. I like it because I can watch the first layer print and determine where a change is needed. I suspect I may be making the experienced printers wince with this but I find it seems to work better for me than the paper feeler gauge. It is possible though that it is only getting me close and I need to get better so developing skill with the feeler method may be the better long term solution.

It seems that print speed, nozzle temperature, bed temperature and nozzle alignment (levelling) are the basic knobs you can turn to affect the final print - and that seems an overwhelming series of options when you are new to the technology. Of course as with every important topic the internet is full of opposing theories with something new to try. At the moment the corner brims seem to work well. I did pick up some stick glue and hair spray but haven't tried them yet.

Thanks for the interest and help. Excuse my poor skills at written explanation; I do much better when i can wave my hands around

Alan

[mtaylor]

Thanks for the explanation.  I hope you can sort it out.  

[CDW]

4 hours ago, king derelict said:

Excuse my poor skills at written explanation; I do much better when i can wave my hands around

Alan

My Cuban cousin does that a lot.  😄

Of course, the other thing to make sure of, and you probably already have done this: Check to make sure that there is no excess friction, wobble, anything mechanical that could be a potential source of unwanted movement. When we're dealing with tolerances of fractions of a mm, just the slightest thing can cause it to be outside of tolerance.

Edited September 17, 2021 by CDW

[Canute]

I know a few Italians who operate the same way. Can't talk while sitting on hands.

 

Quite interesting following the discussion on keeping the print area level. Learning a lot. Thanks.

[lmagna]

54 minutes ago, Canute said:

Can't talk while sitting on hands.

Does that mean that we can't type while sitting on our hands either?

[Canute]

Unless your computer can read your mind, sure. Me, I am waving my hands over my keyboard, in the tried and true "hunt and peck" method of typing. 😁 Being only half Italian, this works for me.

[lmagna]

In my case it is more hunt than peck.

[king derelict]

20 hours ago, CDW said:

My Cuban cousin does that a lot.  😄

Of course, the other thing to make sure of, and you probably already have done this: Check to make sure that there is no excess friction, wobble, anything mechanical that could be a potential source of unwanted movement. When we're dealing with tolerances of fractions of a mm, just the slightest thing can cause it to be outside of tolerance.

Thanks Craig

These printers really are sensitive to the print head height. An eighth of a turn on the adjusting screws makes a huge difference in print behaviour. I don't know how much a turn of the screw changes the height but its in thousandths of an inch I suspect. I checked the rollers and guides for excess play and the belt tension and it seems good. That is the worry - that there is some as yet undiscovered variable in the machine that has me chasing my tail - or waving my arms about 😄

[king derelict]

11 hours ago, Canute said:

I know a few Italians who operate the same way. Can't talk while sitting on hands.

 

Quite interesting following the discussion on keeping the print area level. Learning a lot. Thanks.

Thanks mark

I'm trying to document my learning experience and solutions as I find them but I'm trying not to get too bogged down in it and become repetative.

Alan