Dumas US Army 74' Tug

This is my next project! If you read my log for building the Dumas Chris Craft 24 ft Sedan you may be surprised I bought another Dumas kit  Well, I did think more than twice about it, but it is a model of a type of ship I wanted to build, and the length is manageable. However, it will have a few challenges  There is some balsa in this kit, but not as much as in the other. It also seems a little harder. There is also a sheet of laser cut ply and three of die cut expanded polystyrene. The hull is vac formed plastic, but what plastic I don't know - ABS possibly. According to the comprehensive instructions normal epoxy style glues and fillers wont stick to it.



As well as a full instruction book, there are 72 illustrations.

First job is to remove the excess plastic from the hull. In fact not all is removed at this stage. A flange is left to assist in joining the two halves. In the photo the front half has been trimmed.



After clamping the two halves together, glue is run into the joint on the inside. the flange will be removed later, so you are only gluing as small area. To strengthen the joint, glass fibre tape is stuck over the joint using thin CA. It seems  to work



This is where I hit the first problem. The two halves did not meet up correctly along the whole hull. Around the stern one half was shorter than the other. I could find no way of making them align correctly, so I joined them leaving the problem to be sorted with filler after the hull was in one piece. I tried to photograph the problem, but there is too much white

I do have to resolve this on the outside before I can proceed to drill the hole for the prop shaft. I am not using the one in the kit  This consisted of a steel shaft, threaded and drilled at one end and a plain piece of brass tube the exact dimension of the shaft - no bearings. The prop was fixed by inserting a pin in the hole then tightening the prop onto it with a nut.  I have replaced it with a slimline M2 from Caldercraft.

I have added a sliver of plastic card and some filler to re-shape the area for the prop shaft. After more bodging tomorrow I should be able to drill the hole.

Barrie

hi barrie,
this looks very interesting   well and fix once no going back    i  hope it all works out better in the end, and should look great.

david

Thanks David. I think that bit will turn out OK - its underwater anyway so wont be seen

Barrie

I'm still bodging the stern, but have done enough to install the propshaft and rudder tube.



As you can see these have been sealed with P40. I am hoping this will stick firmly to the glass strip.

I have also stuck on the deck supports - using super glue.



I dry fitted the deck and you can see the problem



I don't understand why the deck supports don't go to the end - they were specifically to be only 16'5 inches.  So I decided to extend them



and now the deck is stuck down



Next job is to finish bodging the stern and remove the remainder of the flange.

Barrie

I have a liking for the Dumas Dauntless but this and your Sedan build has put made me ponder leaving it.

Dumas have some interesting models, BUT they use some strange materials. I have no problems with the hull, and the deck seems to be OK, but liteply would have been just as good. The quality of the strip wood for the bearers was not good - cutting the slots left lots of stringy bits. Not an issue where they are fixed, but would be a problem if they were visible on the finished model.

Barrie

I'm watching this one because I'm slowly building up to buying a hull and plan set so this fits in well with my learning so in the nicest way - get on with it!

I think you will find that I usually build pretty quickly - in fact much too quickly, despite only spending about a couple of hours a day.

Barrie

I take it the hulls vac formed? How thick is it (roughly)?

According to the booklet 0.040 inches. I haven't checked it.

Barrie

Proper measurements! that's accurate enough thank you.

Swab - checked a bit of offcut this morning - 0.8mm. I know what you mean bout proper measurements. I still think in Imperial, but find it much easier measuring in mm rather than fractions of an inch.

This morning I removed the tab round the remainder of the hull, and replaced it with a strip of the expanded polystyrene stuck with super glue - I've never used so much superglue on a model.



You can see from this shot that the misalignment at the stern carried through to the bulwarks.



That is being filled. Finally this session I stuck some rubber moulding to the stem.



When I've finished filling and sanding the stern, the same rubber goes all the way round, and two more strips partway along.

Barrie

A very fiddly morning Getting the rubber mouldings on was a challenge, mainly because they had been rolled up causing kinks and twists which were difficult to remove. I actually tried using a hair dryer to warm it up and make it easier. Its not perfect, but it is to be painted the same colour as the hull, so may not look too bad. Just an example where a little thought about packing the item would have simplified the use.

Next up were the coamings. This is how they tell you to fit them



No doubt a very accurate way of fitting them, but pretty wasteful as the support strips have to be removed once the coamings are glued I managed without using them
Next the fantail. The supports were fitted to the deck, then the fantail itself was made using 1/8th wide styrene strips o the polystyrene base. It just needs trimming.



Tomorrow its trim the fantail, then fit the capping strips and cut the freeing ports, which are covered with flaps, which make the cutting out rather pointless

Barrie

A bit of a disaster this morning  I started to trim the ends of the fantail strips and they kept flying off.  Then I realised I had tried to stick them on with liquid polystyrene, and the base is polythene
Two solutions presented themselves - re-stick with superglue, or cut a new base from plasticard. Wishing to avoid more superglue on my fingers I opted for the latter This has now been completed and sanded to fit.

Next job was the cappings. I wasn't happy about gluing these to the edge of the hull which is less than 1 mm thick. I find these cappings can take a lot of punishment when handling the model. I glued some 1.5mm square styrene down most of the hull to give a more substantial gluing surface, then stuck the cappings to that. These were laser cut from thin ply and I think the laser had not been correctly adjusted as the was a lot of ash on all the edges. The final piece of capping is ready to be trimmed and fixed down.

Barrie

The last piece of capping was trimmed and fixed, and a piece of plasticard added to the front of the fantail. The piece supplied was not deep enough, so I cut a piece from stock.

Next up - cutting the freeing ports. Having cut them, they were then covered      



The instructions suggest now is a good time to paint the hull, but I think I will leave it for now. I want to experiment with painting the rubber strips. The instructions state that Testors enamels will work, so I want to try Humbrol enamels.

Onto building the superstructure - from Balsa

Barrie

The framework for the superstructure is balsa  It is then clad in 1mm expanded polystyrene. This means more superglue  I've never used so much superglue to build a model.



This base unit is now trimmed and finished. Next up is the roof - more polystyrene with some balsa bits.



After taking this photo (its not fixed down) I discovered that my attempt to work in inches and fractions had failed  I had mis-calculated the centre line.  So all the balsa has to come off.  I'm not sure if I can re-use the actual roof, if not I will cut one from plasticard. The balsa bits can be re-made from scrap. I do intend to give the balsa frames a coat of resin to try and stiffen them. I may even clad with plasticard the bits of them that hold the structure in place round the coamings.

I had to go to Aldi this morning and picked up a spray can of matt grey paint. I will do some tests to see if it will cover the black rubber. If its not the correct colour it will do as an undercoat.

Barrie

I managed to salvage the roof. After removing the balsa I scraped it down and its now re-usable. The areas that had the parts in the wrong place will not show once the model is finished. After the remedial work it was on to the next challenge - fitting some plastic strip to the edge of the roof  Obviously the only glue is CA, so the challenge was to stick the strip but not the fingers



The forward steps were built up from balsa, ply and plastic strip. They don't fit very well, and will need attention once the glue has dried.



Next job is to fit and detail the many doors to the sides of the superstructure.

Barrie

Nine doors fitted and detailed this morning, and the stairs adjusted and glued in place. The doors were quite fiddly, and without engaging brain before starting, I managed to fit several on the wrong side of the doors, so had to remove and re-do.

Next in the build manual is to make the railings. I expect I will follow the sequence, but may skip that for later.

Barrie

Yesterday I made and fitted the grab rails for the cabin. I also cut all the brass for the handrails. The instructions include a detailed plan for these together with instructions for building them. I followed these and apart from being a bit wasteful of the brass, they worked very well.



The first photo shows some of the railings before soldering. Here are the finished items after trimming excess brass.



I then gave the hull and cabin a spray of grey acrylic primer which I managed to buy from my local petrol station



The hull seems to have come out OK, the cabin not so good. Its difficult when your nose is dripping and your wearing a full face mask

I have to decide if I am going to leave the upper parts this colour or if it needs painting a lighter grey.

Barrie

Today I set about making what is termed the skylight. Basically a small box that sits on the roof with portholes. Actually this consists of 20 parts



I don't suppose I should complain - it all adds to the construction time, which is a good thing. In fact the material for the basic wooden box was missing from the kit - 1/2" x 1/8" strip so I made it from 3mm liteply. It is clad in 1mm expanded polystyrene and the trim is plasticard.

After all that, it doesn't sit correctly on the roof which is curved



It will be adjusted

I also gave the cabin another coat of primer, and the hull was touched up in a couple of places. Now on to painting the hull.

Barrie

I actually gave the superstructure a coat of paint this morning. It will need one or several more
Then onto the wheelhouse and captain's cabin structure. Once again a mixed material construction using balsa, wood strip and expanded polyethene - at least that is what the instructions say. The wrap around should be in the polyethene, but I couldn't get it to curve without creasing, so I used 1mm plasticard instead.

I haven't finished trimming the cap which is vac moulded, or some of the cladding.

Barrie

Great progress looking good, modelers are great innovators

Dumas have some very interesting models, good instructions and diagrams, but their choice of materials is rubbish

Barrie

Hi barriew,

I am new here and really enjoying this thread, interesting kit and nice work. I too am building two US ST tugs of ww2, I am just waiting for admin approval to see if I can post the link to my builds on this forum as my builds are on a US forum, be easier if I can then I will carry on my build progress here if anyone is interested.

The wheelhouse and captain's cabin now completed except for railings etc. It and the skylight have had a coat of primer as I realised that just painting them would give a different colour. The main cabin has had another coat of paint, and the upper side of the hull also. I haven't marked the waterline yet - I mainly wanted to see how well it covered and if there was any filling required.

I think that is the major building work completed - just lots of fittings to make.

Barrie

Over the last couple of days the cabin, wheelhouse and skylight have some more coats of paint. I think they are now OK and ready for decals to be applied.
This morning I bent the railings and dry fitted them to the cabin roof. I then removed them and gave them a coat of paint ready for fixing. I also painted the roof of the cabin and the deck in their final colours. I also made the rudder which consists of a slotted brass rod and a 1mm expanded polyethene blade. These were supposed to be glued together, but I drilled two holes and using small brass pins riveted it together.



Barrie

This morning I fitted the railings. A bit tricky, especially trying to match up the rear ones to the sides. I still have to fit the handrails to the front steps - the first attempt was a failure.
I've also fitted the supplied windows, portholes and door trims. I can't say I'm impressed with these. They are printed on adhesive vinyl. I'll have to see what they look like after a coat of satin varnish.

Barrie

I decided that I didn't like the decals for the windows etc so this morning I removed them. The portholes came off OK, but the windows brought with them the paint

I have re-painted and will be making new windows and portholes from matt black vinyl. Not decided about the doors yet, but will probably remove them also.

Had to devote time this morning to making a new ramp for Grandson's finger skate boards - it taken all my liteply stock

Barrie

The new portholes and windows have been fitted and the cabins covered with Satincote.



I've also fitted the railings on top of the wheelhouse and Captain's cabin - to be painted.

I have a problem with the paint on the rubber mouldings on the hull. The instructions say that Testors enamel works on it, and before I painted the hull I carried out a test with Humbrol enamel, straight on the rubber, and on top of primer on the rubber. Everything was OK. Now some of it has remained sticky and a different colour to the actual hull. You can just see this on Monday's post.
This morning I attacked it with white spirit, and the sticky bits cleaned off quite easily, leaving those bits which had dried unaffected.

I have now given a small part another coat of enamel to see if that dries. If not I guess I will have to re-prime.

Barrie

Coming together nicely Barrie.

In amongst building Grandson's ramp, I have been making some fiddly fittings so not much to show. I'm still having problems with the paint on the rubber mouldings. I have tried several things including wiping down with be-natured alcohol (French Meths ) but it still discolours in places. Today I sprayed some of the primer into a dish and used it to paint the affected areas. Tomorrow I'll try painting again.

Barrie

The scale model community use a floor polish called Kleer which gives a gloss coat for decals to be added then matt varnishing, I wonder if that might seal the rubber?
Also this looks a nice build up.

Its a possibility. If the primer hasn't done the job my plan is to either use some acrylic paint, or maybe a varnish of some sort.

Barrie

I think I may have fixed the paint issue. I wont know for sure until tomorrow, but its looking good
I've added some of the items that I have been working on - the forward mast with lights, and the navigation lights. I had a problem with the searchlight. One arm was too short, and also they are moulded in a very hard metal - not like UK white metal castings - very difficult to get rid of flash, and every item has some flash
I decide to make my own arms from a sliver of brass and fix it to the supplied base after cutting off the faulty arms.
I am now working on the funnel and lifeboat - both very flimsy vacuum mouldings. I also looked in the fittings for the two lifebelts and couldn't find any, then realised that the two rusty steel washers were they
If the grey paint is really OK tomorrow, then I can get on with marking the waterline, masking and painting the lower hull.

Barrie

I think the paint is now OK. Still slightly tacky, but I hope a coat of varnish will deal with that In any case I have marked the waterline and masked it off. I then ran a coat of the light grey round the tape edge to seal it as it crosses one of the bumps. It will be ready for painting tomorrow.

More work on the funnel and lifeboat. These are almost ready for fixing on the skylight. The supports for the lifeboat have been made and fitted and the davits made ready for fixing.

The underside of the hull was given two coats of acrylic matt black. The funnel top was stuck on and the funnel fixed to the skylight. The lifeboat has had its cover attached. The handrails on the steps at the front of the cabin have been made, fixed and painted. The wheelhouse/cabin has been glued to the main cabin.



Unfortunately after these photos were taken and after the paint had dried. I removed the masking tape and with it quite a lot of grey paint

I really don't know where to go now. The hull was very carefully de-greased before spraying the primer. I think I can sand off the flat areas, but not the rubbing strips, but what do I use to re-paint? If I re-mask on the black will that come off as well?

Barrie

Hi Barrie,

Looking good, don't know if you know that you can buy a low tack masking tape, that should work I would imagine.

Hi Frank - yes it was supposed to be low tack.  I use 6mm low tack flexible tape to mark the line then add ordinary decorators tape to increase the area covered, but it was the low tack that brought off the paint!

I have ordered some Revell light grey acrylic - Humbrol don't do light grey acrylic.

On another topic do you know how these ships were named? The decals supplied for the names are U. S. ARMY ST - 74 for the bows and stern. I would have thought just ST - 74 was more likely.

Barrie

I have removed the paint from below the rubbing strip, and cleaned off the tacky paint from the strips. I think the problem was that the primer did not bond well with the hull. I was able to scrape most of it off quite easily. I will repaint with acrylics without primer. Just waiting for the grey paint to be delivered. I will then do some tests to ensure that Revell and Humbrol acrylics will mix without problems.

Barrie

Hi Barrie, I am sure you will sort it out easily enough, just a pain! I have attached a wartime picture of an ST although this is the design I am building i'm sure your model of ST would be the same showing on the bow the markings, I am not sure they were marked on the stern but possibly. Some were marked on the funnel too. So for an example ST488 was marked just 488 on the funnel. Hope this helps.

Thanks Frank - that looks very similar to the model of 74. I had found some photos of other ST types with a different style of naming.

Hopefully the new acrylics will cover without problems. It will be the end of the week before materials and modelling time coincide I think.

Barrie

Another nice pic

Managed to find an hour today, so made some more fittings. Primarily the bollards, but also painted the skirt on the lifeboat. This is now ready for lacing. The bollards will need another coat of paint at least. The laser burns are difficult to sand away and show through the light coloured paint. Just one more bollard to make then some more masts.

Barrie

My new paint finally arrived this morning. I have applied one coat - of course its a slightly different shade of grey.
There is no way I can repaint the superstructure so I just hope it wont be too obvious. I also painted a bit of scrap plastic so I can test its compatibility with Humbrol black acrylic. It has gone on the Humbrol grey enamel with no reactions yet.
The other thing to test is that the masking tape wont lift it from the hull. To this end I have painted part of the hull which will be black so I don't spoil the grey part if it does lift.

Barrie

I gave the hull another coat of light grey. Not happy with the colour difference so took a chance on mixing Humbrol and Revell acrylics to get closer to the Humbrol enamel. I think I succeeded - I will know more tomorrow when its dried fully.
If that is Ok, I can re-mark the waterline and get some black on the bottom.
The kit includes a black and white US flag      So I printed a paper one in colour, sprayed with some lacquer and fitted it to the main mast. The mast has been fitted to the cabin. I also laced the lifeboat cover and that is ready for fitting along with the davits, but I need the hull finished to do that.

Barrie

Today I masked up the waterline and painted the underside matt black. I took care to get on a good coat as I wanted to remove the masking tape as soon as possible to avoid it lifting paint. I managed to achieve this with only a minor bit of paint coming away and a few places where the tape leaked. Tomorrow I will mix up a little more light grey to do some patching.
The lifeboat is now in place - just waiting for the davits to be fitted once I can put the cabin on the hull again.

Barrie

Finished Just the davits to string - and the motor etc to install. I also need to make a better stand - the one in the kit isn't very good.

Barrie

Looks very nice Barrie, you should be pleased with that. 

OK, my penultimate post on this model. The motor etc are installed - not very neatly - and its ready for the water. I still have to string the davits and make the stand. I started that this morning but had to stop as its Fluathon Day at our surgery  I will post one final photo when the stand is complete.

Barrie

can you show us some photos of it when you sail it I'd love to see it run.