Dunbrody by Mahuna - FINISHED - 1:48 - Cross-Section - Irish Famine Ship

[captainbob]

Frank, I'm glad you let us read your 'diary'.

 

Bob

[Mahuna]

HOLD TIMBERS - QUESTION

 

I've been working on the hold timbers, and need some help/advice before I proceed further.  

 

Dunbrody has a deck clamp with a shelf above it.  Naturally, these need to be aligned with the accommodation deck, so that the top of the shelf is at the height of the bottom of a deck beam.

 

Below the deck clamp is a small air space, then 4 strakes of bilge ceiling.  Under the ceiling is a striger configuration - 3 'second stringers', the stringer itself, then another 3 'second stringers'.  Finally, there are 11 floor ceiling strakes and then a limber strake.

 

I've illustrated this configuration in the following photo.

 

 

I've been assuming that the stringer arrangement, being structural timbers, should be parallel to the deck clamp/shelf arrangement.  This would mean that the bilge ceiling would be parallel as well, and that only the floor ceiling strakes would taper toward the bow and stern.  

 

I've installed the deck clamp/shelf and the main stringer on each side of the model, and before I go further I would greatly appreciate hearing if my assumption is correct, or if I should taper all of the hold timbers under the deck clamp/shelf.

 

Thanks for following, and thanks for your input.

[markjay]

Looking good Frank, the discussion at the club meeting proved worth while.

[Mahuna]

On re-reading chapter 12 of the Crothers book (Stiffening the Hull; Hold Ceiling) I found the following and I think it's the answer to my question:

 

"The stringer, in general, ran parallel with the lower deck, though at the extremities of the vessel this was not true due to the diminishing size of the knees ..."

 

Since the model is of the midship area, I think my assumption of the stringer being parallel to the clamp is correct.  This would imply that the upper 'second stringers' and the bilge ceiling strakes would also be parallel.  I would also proceed with keeping the lower 'second stringers' parallel for uniformity, and would only taper the floor ceiling strakes where necessary.

 

Still looking forward to any comments/corrections.

[Mahuna]

Looking good Frank, the discussion at the club meeting proved worth while.

 

Thanks Mark.  I think each meeting (besides being an enjoyable social gathering) provides at least one of us with an answered question, a new technique, or an idea on tools.

[Mahuna]

Part 20 – The Hold Timbers

 

I used the drilling fixture discussed in Part 19 to drill holes through the lower deck clamp previously installed.  Not all of the holes lined up perfectly – more of an operator problem than a problem with the fixture. 

 

                        

 

                        

 

I used copper wire as the bolts, feeding it through from the outside, then applying CA glue to the end on the outside and pulling it through until the glue was inside the timber.

 

                        

 

I wasn’t happy with glue stains, but the external planks will cover the bolts. 

 

                        

 

Dunbrody has a deck shelf sitting on the deck clamp.  The shelf is slightly larger than the clamp.  These shelves were installed next, and were also bolted to the frames using functional bolts.  The hull is now fairly strong after these bolts have been installed.

 

                        

 

I then tried installing the stringers.  These timbers needed to bend both laterally and on their edges due to the shape of the sectional model at its extreme ends.  I boiled the timbers and then clamped them in place. 

 

                        

 

After gluing the stringers in place, I wasn’t very happy with the results.  The shape of the stringers needed to be absolutely perfect for the adjacent timbers to lie properly, and I could see that there would be subsequent problems if I left them in place.

 

This prompted my question about the Hold Timbers in post #212.  After finding the answer in the Crothers book I de-installed the stringers using hot water and alcohol.  They came off relatively easily – thankfully I hadn’t used any bolts to secure them.

 

I then decided to work down from the deck clamp, installing the bilge ceiling strakes as the first install.  Between the uppermost bilge strake and the clamp there is a small air space to allow air circulation in the hull.  This space is 3 inches, which is 1/16 at the model scale.  I used 1/16 square strips as a spacer, lightly gluing them in place.

 

                        

 

                        

 

Once the first strake of bilge ceiling was installed this spacer could be removed.

 

I knew the measurement for the stringer placement from the plans, but I was concerned that any errors in milling the various timbers might affect the placement.  So I stacked the appropriate timbers as they would be installed and created tick strips from the actual configuration.  I used these strips to verify the stringer locations – they will be at the correct height.

 

                        

 

                        

 

The model will have a viewing port on the starboard side of the hold, so the bilge ceiling strakes will be only partially installed on that side.  I decided to focus on the full timbers on the port side first.

 

The bilge ceiling strakes (as in all of the planking for the Dunbrody model) are made of Castello.  I drilled bolt holes in the bilge ceiling strakes and installed and blackened the fastening bolts before the strakes were installed. 

 

The installation of the strakes was fairly simple, using the planking clamps discussed earlier.

 

                         

 

                        

 

                        

 

I made some mistakes in not clamping the bilge ceiling strakes properly, and I’m not totally satisfied with the way they lay.  I may decide to remove the strakes and re-install them. I'll sleep on it and decide tomorrow.

 

Thanks everyone for following!

 

[GuntherMT]

Looking good, and nice progress Frank.

 

Are you doing anything like marking one edge of the planks with pencil to highlight the edges/caulking, or do you prefer it to be clean?

[Mahuna]

Looking good, and nice progress Frank.

 

Are you doing anything like marking one edge of the planks with pencil to highlight the edges/caulking, or do you prefer it to be clean?

Hi Brian. No, I'm not doing anything with the edges. I haven't been real happy with using tinted glue, so on the planking I'll let the different hues of the wood (if any) set the planks off. Although I may change my mind as things progress.

[Sailor1234567890]

My wife is descended from County Cavan stock as well. We visited Ireland earlier this year and saw the famin monument in Dublin. The figures walking down the street next to the river. Very moving and very similar to the style of foundry work in Dave's image above. We took several pictures of them but I don't have any here I can put up. Nice work on the model Frank.

[albert]

Very nice work.

[EdT]

Great work, Frank.  As you probably know, I used epoxy rather than CA to fix the functional copper bolts, partly because of the glue stains on the wood that you experienced.  The CA penetrates the wood so is hard to remove, even if you wash it off right away with acetone.  This method, of course, involves a lot of solvent use.  Epoxy, even though it is time consuming to mix batches as you work, seems to come off the wood a lot easier.  I would use files.  Files seem to do a better job on both glue types than sandpaper.  Sandpaper rides over hard areas, so I save it for the final wood finish.

 

The neat regular spacing of your bolting is really nice.

 

Ed

[Mahuna]

Thanks Ed.  I glued the keelson bolts with epoxy and washed most of the excess epoxy off with isopropyl alcohol.  This seemed to work, but smoothing the bolts with a riffler caused epoxy to load up in the file, and i haven't been able to completely clean the file.  How did you avoid this?

[Mahuna]

My wife is descended from County Cavan stock as well. We visited Ireland earlier this year and saw the famin monument in Dublin. The figures walking down the street next to the river. Very moving and very similar to the style of foundry work in Dave's image above. We took several pictures of them but I don't have any here I can put up. Nice work on the model Frank.

 

Thanks Sailor.  I'll have to google the monument you mention, it sounds interesting.

[EdT]

Good question, Frank.   I cannot remember this being too much of a problem.  Is the epoxy fully hardened when you file it.   If so and the file still loads up with resin, all I can suggest is frequent use of the file card.  I don't use any solvent on the epoxy, but just let the blobs harden, clip them and the protruding wire off with cutters, then file off the remainder.  Any solvent used to dissolve off glue will cause it to penetrate into the wood.  Perhaps the alcohol is inhibiting the hardening of the epoxy?

 

Ed

[Mahuna]

Good question, Frank.   I cannot remember this being too much of a problem.  Is the epoxy fully hardened when you file it.   If so and the file still loads up with resin, all I can suggest is frequent use of the file card.  I don't use any solvent on the epoxy, but just let the blobs harden, clip them and the protruding wire off with cutters, then file off the remainder.  Any solvent used to dissolve off glue will cause it to penetrate into the wood.  Perhaps the alcohol is inhibiting the hardening of the epoxy?

 

Ed

 

 

Thanks Ed.  I thought I was being smart in removing the epoxy with alcohol, but I think you're right about it inhibiting the hardening.  I also think I was too impatient and didn't let the epoxy harden completely before removing it.  I hope I remember these lessons for next time.

[Mahuna]

Just a quick update on the Hold Timbers:

 

After a lot of thought I decided to remove the Bilge Ceiling planks.  Since they're on the port side they will be very visible through the viewing port.  Add to that I'm considering lighting the inside of the model with LED's, and this will accentuate the error I made.

 

One of my (many) objectives in working on this model is to improve my modeling skills.  If that means doing something over to get it right then so be it.  Once I start thinking "well, that's good enough" it probably isn't.

 

          

 

I think I'll be able to save the planks.  The water and alcohol have raised the grain, but that should be ok with a little fine sanding.  After that I'll need to blacken the bolts again, but that's not a big deal.  If I can't salvage the planks I'll make new ones - that will certainly reinforce the lesson learned.

[AON]

If ever you find yourself feeling a bit beat up with the errors and do overs just consider the wealth of knowledge you are passing on.

Thank you for the lessons!

[HIPEXEC]

Errors really put your brain to work in order to correct them.

[David Lester]

Hi Frank,

You're doing really beautiful work and I'm enjoying watching your progress. I am still just getting comfortable with POB kits so I am greatly impressed with the complexity of a scratch build POF model.

David

[Mahuna]

If ever you find yourself feeling a bit beat up with the errors and do overs just consider the wealth of knowledge you are passing on.

Thank you for the lessons!

Thanks Alan.  With my rate of error, I think you'll be getting even more wealthy (knowledge-wise).

 

 

Errors really put your brain to work in order to correct them.

 

Hi Rich - I'd rather my brain worked harder trying to avoid the errors, instead of working to correct them.

 

 

Hi Frank,

You're doing really beautiful work and I'm enjoying watching your progress. I am still just getting comfortable with POB kits so I am greatly impressed with the complexity of a scratch build POF model.

David

 

Thanks David.  I complain about the errors (mostly in jest) but I'm really enjoying the challenges in this build.  It's also a good learning experience - both in modeling techniques and in ship construction.  Glad you're enjoying it along with me.

Edited May 28, 2016 by Mahuna

[mtaylor]

Frank,

 

You're doing great.  It's a steep learning curve at best and I can fully attest to that.  

[druxey]

We all make mistakes and makeovers, no matter how experienced. 

 

As for raised grain, you don't need water to de-bond white or yellow glue. Use 95% or 99% isopropanol. The lack of water content in it will prevent this.

[Mahuna]

Thanks Druxey - next time I'll try using just the 99% isoproponal.  I thought hot water was part of the debonding process.

 

Although I have had experience with alcohol raising grain on soft woods when bird carving. Bird carvers use tupelo (very much like basswood), and when we think the bird has been thoroughly sanded and smooth we spray alcohol on it (saturating it) and let it sit for a while.  When the alcohol evaporates the grain has been raised and the piece needs to be sanded again - this time to a very smooth finish thanks to the alcohol.  This probably happens more with soft woods - I'll try it on the castello and madrone I'm using to see what happens.

[Mahuna]

Frank,

 

You're doing great.  It's a steep learning curve at best and I can fully attest to that.  

 

Thanks Mark.  Learning is fun!

[druxey]

I can't speak for softwoods, but I've had no issues with isopropanol on Castello or other hardwoods. Heat will speed up the debonding process for sure, but alcohol alone does the trick. All you need is a little patience while it works through the joint.

[Mahuna]

Part 21 – The Hold Timbers cont’d

 

The reason I removed the Bilge Ceiling planks is that there were some spaces between some of the planks.  When I clamped the planks to the frames I only used the planking clamps, assuming that these clamps would keep enough upward pressure on the planks so that they would lie securely against the plank laid previously.  This proved to be incorrect – there were fairly obvious spaces between the planks.  There was also a strake that wasn’t properly secured and lay proud of the other strakes.

 

On the second installation I spent considerably more time getting the clamping set up – I tested the setup for each strake before applying glue.  I also used my small machinist screw clamps to keep the new plank pressed against the previously installed plank, in addition to using the planking clamps which provided pressure against the frames.

 

                          

 

On the first two strakes I clamped against the deck shelf with the screw clamps. 

 

                       

 

On subsequent planks the machinist clamps are too small to reach from the shelf to the bottom of the lower two strakes, so I clamped them to the top of the first bilge ceiling strake, since these clamps are small enough for the nose of the clamp to fit into the air strake above it.

 

                    

 

                      

 

After the 4 strakes of bilge ceiling were installed I moved on to the “second stringers”.  Again the machinist screw clamps were too small to reach any area that could be used for clamping, so I needed another clamping approach.

 

I have some Bessey 2” Clippix needle nose spring clamps that will reach from the Stringer to the shelf, but I thought the tension wasn’t strong enough to properly pull the clamps together.  I wrapped a strong rubber band around the clamp jaws and this improved the tension enough to do the job.

 

                        

 

                        

 

Each of the stringers needs to be soaked and bent prior to installation, so this work is in progress.  While waiting for the stringers to dry I am also planking the starboard side.  I’m leaving the gap for the viewing port, and will address this in the next post.

 

                        

 

Thanks everyone!

 

 

[Omega1234]

Hi Frank

 

That's a hell of a lot of clamps, which no doubt will do the trick.

 

I'm really enjoying seeing what you're up to...and, to think that this is only the second ship you've built. Damn marvellous workmanship, I say!

 

Onwards to the next post on the viewing port!

 

Cheers

 

Patrick

Edited May 29, 2016 by Omega1234

[Mahuna]

Hi Frank

 

That's a hell of a lot of clamps, which no doubt will do the trick.

 

I'm really enjoying seeing what you're up to...and, to think that this is the second ship you've built. Damn marvellous workmanship, I say!

 

Onwards to the next post on the viewing port!

 

Cheers

 

Patrick

 

Thanks Patrick!  Can't have too many clamps.  Glad you're enjoying it - as I enjoy your work.  

Edited May 29, 2016 by Mahuna

[albert]

Great work Frank, very nice.

[EdT]

Looking great, Frank.  I can relate to your comments on intentional grain-raising as part of the finishing process.  I think this is good practice on all woods where a water-based finish - water stains, dyes, acrylic paints, inks, etc. - are used - or even in general for uniformity if glue has been washed off with water.  I do this routinely on model wood and did it for years on furniture work before final sanding - all hardwoods.  I used clean water.  I have not tried alcohol.  If the grain is not raised before finishing, the water in the finish will do it, often requiring more sanding.

 

Those planking clamps really come in handy on that internal bilge planking.  Keep in mind that over-tightening these in these positions can distort the frames outwards.  I did not find that to be a problem, but I believe it could be, depending on the molded breadth of the frames and the amount of stress - probably not a problem with the toothpicks(?) you are using, but with the nails I used, you can put a lot of stress on the frames.  Worth a check.

 

Ed