dkuzminov

9 hours ago, vaddoc said:

For porcelain, best to get epoxy putty. It comes in two pieces of soft material (actually not too soft) that you mix well and then use to glue the pieces. I repaired a porcelain plate, the repair was invisible and rock solid.

Google Milliput

If I understood correctly which putty you mean, it is not thin and has color. Intuitively I expected that transparent liquid epoxy would be the best. I'm very surprised that your repair is invisible, so could you please provide more info?

The value of the cup is mostly by the fact that it was a gift. Regular "bone china". I just wish to feel that I've done the most I could do repairing it by myself.

I'm using general purpose 5 min Loctite, mostly because that was the cheapest option in Walmart (less than $3 for 0.85 oz). So far so good, but 5 minutes is too fast. Anyway, except of this fast curing, the experience is almost the same as with the epoxy I used 25 years ago in the ship modelling club I attended in my childhood.

I plan to get some 30 minutes epoxy, for now I'm regarding Great Planes Pro Epoxy 30-Minute Formula. Does anybody have the experience and recommendations?

For the pure curiosity: what is considered to be "natural" epoxy: the slow curing one or fast curing? Are there disadvantages in any of them (e.g. PSI)?

Another recommendation I'm asking: I plan to fix a porcelain cup. What are the features to pay special attention to: transparency, flexibility, strength? Could you recommend any special brand/model, especially for US market?

2 minutes ago, wefalck said:

Looking at your bulkheads, it appears that the real problems is, that they have not been faired. I can see the discolouring from the laser-cutting across their whole width. Of course, the planks will make kinks and buckle then, when bent across the sharp edge of the bulkhead.

No, that is not the case, I've shaped the bulkheads pretty well. The one that has this discolouring is the central bulkhead where the planks are perpendicular.

10 hours ago, wefalck said:

Sounds a bit strange. Perhaps you want to post a couple of pictures ?

Ok, here are the pictures.

The first picture shows the tips of the planks glued with PVA to the bulkhead. The thickness of the plywood is 6mm. This seam is almost invisible.

The next picture shows a bad seam where the planks bend significantly. You may see that two planks (the middle row) have torsion, and don't form the surface, partially because of the elasticity of PVA.

That is the reason why I'm streightening the inner surface with epoxy (you may see epoxy glittering from the inner surface of planking):

17 minutes ago, Jaager said:

You have already planked a POB hull?

The moulds are few in number and widely spaced?

This is a two layer planked hull and you are shaping the first layer?  The planking wood is thin and flexes under force?

 

As Wefalck writes,  the usual practice is to use filling material between the moulds, shaped to hull lines before any planking is applied.  Done correctly, only one layer of planking is then required.

It has been my impression that on a two layer hull, the first layer is relatively stiff and the display layer id often a thin decorative species veneer.  (To my eye, often a species with out of scale grain and open pores, but never mind that.)  Did you plank the first layer using the veneer?

 

Now, to your present situation:  epoxy sounds like a messy and much less than ideal solution.  I would obtain a supply of wood veneer that is thin enough to bend inside the 90 degree arc amidship. 

Use a sharp knife to cut popsicle stick wide or narrower strips and PVA glue a layer or two inside in a vertical orientation.  No compatibility problems.

So far I've done 5 rows of planks and plan to straighten them incrementally because it would be difficult to access the inner surface later.

This is a single-layer model with 2mm-thick sapelli planks and 8cm-wide moulds. Planks flex under force if not streighten with epoxy, but are much stiffer if a thin layer of epoxy is applied.

There is one more reason why I've started using epoxy to streighten the hull. The tips of planks are fixed on a 6mm plywood, thus each tip covers just a 3mm of plywood. That is enough to fix the plank, but if there is a little torsion, PVA is not enough to fix the tip perfectly. Adding epoxy to the corner solves the issue.

12 minutes ago, vaddoc said:

How  and where are you planning to apply the epoxy?

If you plan to fillet the joint of bulhead and plank from inside of the hull, best to thicken the epoxy with talk powder (or anything else, i ve used ground coffee in the past) to consistency of peannut butter and apply. It should work fine. Epoxy is a bit messy though. Uncured epoxy from hands cleans with vinegar but best to wear gloves

I'm applying epoxy to the inner surface of planks fastening them into a robust shell. Planks would bend while sanding otherwise.

What does thickening give in this case to compare with raw epoxy?

The advice about ground coffee is very surprising. Is there any benefit of ground coffee to compare with sawdust?

I'm gluing planks using a PVA-like glue (the manufactorer says it is "advanced proprietary polymer"). This is an easy solution for fixing planks to the bulkhead without nails. However I'm not satisfied with the stiffness of planks, so I plan to streighten the hull with epoxy. The question I have is how does epoxy adhere to PVA seams. What are the caveats, should I clean the planks from PVA where possible, or that is not needed?

Have anybody tried Deluxe Materials Sand'n'Seal to fill the dents on planking? https://images-na.ssl-images-amazon.com/images/I/51zoe26CkJL._AC_SL1000_.jpg

1 hour ago, vaddoc said:

Not really, it just shows when it is dry to sand. I ve succesfully mixed Elmers with acrylic paint. I suspect the purple, essentially colourless filler, can be mixed with wood dust for a near perfect colour match but this I have not tried this yet.

I had a similar idea of mixing white filler with acrylic paint, but I'm afraid that this paste would be extremely marky.

1 hour ago, vaddoc said:

After trying lots of fillers, I also now use Elmers colour changing filler. Dries quickly, sands nicely. Lovely staff.

Is that important that it is colour changing? Is it better than other Elmer's fillers coloured with oak/mahogany/etc.?

3 hours ago, Duanelaker said:

I have the Elmer’s that is purple and dries white, seems pretty strong.  There is also a wood filler by bondo and the product that has the muscle man on it is real strong (it is a powder you mix with water)...can’t think of the name 

This must be the Durham's Rock Hard Water Putty: it was recommented in another topic. The description looks good, but it mostly used for furniture and other large wooden items: I'm a little worried if it is as good for fine tuning of a ship model.

15 hours ago, Chuck said:

Elmers has a series of wood filler that comes in a tube.  They have a wide range of color choices and its water based.  I found that if you buy all the colors it is easy to mix them like paints and get pretty close.  In addition...if you have some weathering powders, you can add small amounts to color it further if needed.

The Elmer's wood filler that I've seen doesn't seem strong enough. I wish to correct the shape slightly, so i plan to put several layers of the filler and sand appropriately. The color is a lower priority issue.

Which wood filler do you use after planking? Most of wood fillers are white (or very light), so what do you do for the darker wood, like mahogany?

Please share the experience. I planned to use HobbyLite, but this item is ending soon. What are the other options?

I've got the same question. I'm going to plank Cutty Sark from Artesania Latina which is not double-planked. The instruction recommends to use nails but I have a feeling that this would spoil the whole view. I wish to collect the experiences from those who have finished nailing the planking (especially from those who finished Artesania Latina Sutty Sark) : would you use nails if you would have to repeat the assembly one more time?

I've already got the answer from NenadM here, but I guess this topic is a more appropriate place to ask this question.

I have a question regarding planking and using the nails. From my point of view the nails (being useful while the process of planking) spoil the final result. I haven't started planking yet, so my question is to those who finished the process: would you use nails if you would have to repeat the assembly one more time? Are there any problems with that (like sanding the body of the ship with nails in it)?

I'm planning to paint a wooden ship model with acrylic paint, but the variety of different paint types makes me embarrassed. So I'm asking for an advice which one to choose.

First, I'm planning to use a brush: is it a good idea? I have no workshop for airbrush, but I probably could use a spray.

Next, I need matte finish. One of the options is a chalk acrylic paint: but is it a good choice for a wooden model?

By default I plan to use a FolkArt chalk paint, please comment my choice.

Thank you