Making sheaves for blocks and bitt pins

[Kevin Kenny]

 

[Dr PR]

I do not have a lathe (on my wish list, but first I need a shop to put it in) so I have come up with a very simple way to make sheaves down to 0.078 inch (2 mm) diameter using ordinary brass washers. In this link I made sheaves for a 1:48 scale model:

 

https://modelshipworld.com/topic/19611-albatros-by-dr-pr-mantua-scale-148-revenue-cutter-kitbash-about-1815/?do=findComment&comment=616985

 

For a list of brass washer sizes see this link:

 

https://www.mcmaster.com/standard-washers/material~brass/

Edited October 1, 2021 by Dr PR

[Jaager]

This is another armchair experiment (denken experimenten) :

In light of the suggestion that the Dremel carbide cutoff disks be strengthened by a coat of low viscosity epoxy,

could sheaves be made from paper or cardboard soaked with epoxy?

A cork borer! could be used to cut the disk.  ! (a metal tube - usually brass -with one end pared to a knife edge)

Three layers of paper - the middle having a smaller diameter - makes the groove-   It could be made in any color.

[Kevin Kenny]

Phil thats a very useful site. Ill keep it for future projects.

[Bob Cleek]

10 hours ago, Jaager said:

This is another armchair experiment (denken experimenten) :

In light of the suggestion that the Dremel carbide cutoff disks be strengthened by a coat of low viscosity epoxy,

could sheaves be made from paper or cardboard soaked with epoxy?

A cork borer! could be used to cut the disk.  ! (a metal tube - usually brass -with one end pared to a knife edge)

Three layers of paper - the middle having a smaller diameter - makes the groove-   It could be made in any color.

Certainly, that could work easily. No need for epoxy, however. Thin shellac should do the trick easily. It will saturate the paper easily. There should be no need to glue the disks together. Just push a pin into the center of the stack of disks and soak them in shellac. This is how they used to make insulated electronic components in the days before plastics.

[Roger Pellett]

As I have posted before, I have been using shellac saturated paper to simulate steel plating on the model that I am currently building.  I was inspired to try this idea by Wefalk’s use of paper and paper derived materials for his beautiful small scale models.  I have been surprised at how tough paper becomes when impregnated.  In my case, I have enjoyed the convenience of shellac in one of the much maligned rattle cans as a quick pass with the spray can provides a sufficient coating.  The result cuts cleanly with a paper cutter and scissors. A brass tubing hole saw or punch should work equally well.

 

Roger

Edited October 2, 2021 by Roger Pellett

[Bob Cleek]

6 hours ago, Roger Pellett said:

In my case, I have enjoyed the convenience of shellac in one of the much maligned rattle cans as a quick pass with the spray can provides a sufficient coating.  

Allow me to further malign the rattle can! Shellac can be purchased in quart and, I believe, pint cans. It's thinned with denatured alcohol. It can be stored for a long time, stirred up and used easily. Apply it with a brush.  Brushes clean easily when swirled in a small container of alcohol. When the "rinse" alcohol gets too dirty for further brush cleaning, I use it for thinning shellac or, with some shellac added, as my "thinned shellac" stock. Far less expensive than rattle cans and it can be surgically applied to rigging, etc. with a brush without the overspray problem.

[Jaager]

7 hours ago, Roger Pellett said:

one of the much maligned rattle cans

I often use a cotton pad -  lots of spent Tee shirts and worn out sheets are around.  That is how French Polish was done

My aversion to spray anything is that aerosolized anything can be inhaled.  Bad luck if it is something that is potentially deadly - even 30 years on.

The best protection is to nit get it airborne to begin with.   Molecules that are naturally a gas at RT  can be a problem, but easy in can be easy out.

Something that would never be a gas at RT would condense and require external action to remove it.

An example of the damage being disproportionate to the insult  was a JAMA or NEJM Q&A:  You are on a crowded bus with someone with an active TB infection.

How many TB bacilli do you have to inhale to become infected?  The answer is = one.

 

[Tim Holt]

On 10/1/2021 at 3:36 AM, Kevin Kenny said:

Phil thats a very useful site. Ill keep it for future projects.

McMaster-Carr has EVERYTHING. 
 

My daughter uses it for work (theater) and has spent enough that they sent her the paper catalog , which she passed on to me.  It’s like the Sears Christmas catalog when you were a kid but a million times better. 

Edited October 3, 2021 by Tim Holt

[bridgman]

My perpetual question about shellac use is are people using dewaxed shellac or off the shelf, or rattle can shellac?

Past readings, from a woodworker view point, is that dewaxed shellac can be a  universal   undercoating for any type of 

finish, water or oil. Would be interested in comments experience.

Bridgman Bob

[Bob Cleek]

21 minutes ago, bridgman said:

My perpetual question about shellac use is are people using dewaxed shellac or off the shelf, or rattle can shellac?

Past readings, from a woodworker view point, is that dewaxed shellac can be a  universal   undercoating for any type of 

finish, water or oil. Would be interested in comments experience.

Bridgman Bob

Dewaxed shellac is indeed a universal undercoating for any overcoating I've ever encountered. It's one of the least permeable moisture barrier coatings around and non-toxic. (Shellac is what they coat jelly beans with to make them shiny.) It's easily sanded, rubbed, and polished, as well. "White" (clear) shellac is invisible. One of the biggest advantages of shellac for those using water-based coatings is that it does not raise the wood grain like anything containing water is prone to doing. There's nothing not to like about the stuff... and it's relatively cheap. $20 a quart, $13 a half pint.

 

[bridgman]

 Bob

Thanks for the clarification,note that your can is identified as "clear" which identifies it as wax free.

Seems that in my area stores only carry amber which is not wax free. Bummer.

Bridgman Bob

[Bob Cleek]

36 minutes ago, bridgman said:

Thanks for the clarification,note that your can is identified as "clear" which identifies it as wax free.

Seems that in my area stores only carry amber which is not wax free.

The amber colored shellac is called "orange" shellac. It's the same thing, just unbleached. (You can get orange dewaxed shellac, also. For ship modeling purposes, in fact, for most purposes, it doesn't matter if shellac is "waxed" or "dewaxed." Clear shellac has much less wax in it than darker colored shellac. The only issue with the natural wax in shellac is that it can sometimes cause problems with oil-based over-coatings such as gloss varathanes.) The "orange" shellac builds up to a very deep dark brown and is useful for classic furniture finishing. The "white" (clear) shellac is colorless. I buy Zinsser pre-mixed in the can. You can buy dry shellac flakes and mix them in your own denatured alcohol, but that's an extra step. If you want thicker shellac, just pour a little into an open container and let the alcohol evaporate until it's the consistency you want. Thick ("gooey") shellac is a good adhesive for some purposes. 

 

Shellac replaces a lot of adhesives in ship modeling. It's particularly useful in "gluing" rigging knots. (Nothing's more frustrating that tying off a line and cutting the tail, only to have the line come loose from a belaying pin, or whatever.) A drop of shellac on the knot will set it forever, but if you need to untie it sometime later, just a drop of alcohol will melt the shellac and easy untying or repositioning. Let the shellac dry before cutting off the end. It's similarly useful for preventing thread ends from fraying and, by applying shellac to a length of line, it can be formed to a catenary while drying and will stay that way when fully dried. Shellac is perfect for fixing hanks of line and gun tackle coils so they appear to hang naturally and don't move. It's also good for "hardening" soft woods like basswood. Lay on a generous coat of thinned shellac and let it soak into the wood. When dry, you can sand the surface easily without raising "fuzz." I'd put shellac right up there with sliced bread as one of the world's great inventions.

[Jaager]

Lee Valley has dry shellac flakes.   It is packaged in two weights   1/4 lb  for  $8.50  and 1 lb for $27.00      Three colors  light amber - which super blonde or clear ( or about as clear as shellac gets

Amber  which is regular (I think)   and dark amber which I thick is ruby.

I have light and dark.    The solubility of shellac in EtOH is inversely proportional to the wax content.  That is, the darker it is the more soluble it is.

I make up a 10% solution =  10 grams in 100 ml of EtOH.   that is close to 1 lb cut and for light is close to saturation.

Dry flakes do not store for 10 years.  The new went into solution quickly,   Some old Tiger Super Blonde flakes that I have had for about 10 years only partially dissolved.  Take home lesson:  if the flakes do not quickly dissolve, buy a new batch.  Buying the larger and lower cost per weight quantities is false economy.

For our uses the 1/4 lb is enough for the small surface area that we produce.

 

All of the negative factors for shellac as a final finish relate to full size furniture.  We are not going to set a wet glass with condensation on a model.  We are not going to abrade it in daily use.

 

My HMS Centurion is framed using Hard  Maple.  The Maple is a bit lighter than I wish. -  It is my intent to prime it with 5% super blonde  and then use as many coats of Dark as it need to get it looking like the NMM models done using Boxwood.

A rag with EtOH is a quick reverse gear if I go too far.

Edited October 4, 2021 by Jaager

[Bob Cleek]

15 hours ago, Jaager said:

All of the negative factors for shellac as a final finish relate to full size furniture.  We are not going to set a wet glass with condensation on a model.  We are not going to abrade it in daily use.

What Jaager said. If you are going to put your glass of scotch on the rocks on your model, use a coaster!  

[Snug Harbor Johnny]

  I'm a big shellac fan, and Zinsser's is a convenience with a couple CAVEATS.  Look at the date on the can!  Pre-mixed shellac is good for 1 - 2 years, so if the date is OVER 2 years - look for another can.  The issue is having it dry completely.  If you dissolve your own shellac flakes, do not use "Everclear" or 'clear grain alcohol' sold in liquor stores because it is only 190 'proof' - meaning 5% water.  I had trouble trying to use such a product and it 'clouded' the shellac.

 

  You need either 'Baker analyzed' pure chemists' ethanol (very expensive and not widely available), but you can use 'denatured' alcohol (methanol) sold in pure form in hardware stores.  The flakes dissolve nearly as well as with ethanol, but because of the fumes - good ventilation is necessary is using a LOT of product (like for furniture 'French' polishing, or covering any large area).  BTW, methanol is used in Zinsser's.  Applying a little here and there (like for securing rigging) is generally not a problem.  But inhaling too much methanol can be toxic.

 

  If you dissolve your own amber flakes, after a good bit of swirling until most of the flakes are dissolved, let the mixture sit undisturbed in a stoppered Erlenmeyer flask for at least a week.  I got some flasks from Edmunds's Scientific Company some years ago - but 'science stores' may have some.  The second choice is something tall - like a graduated cylinder, or even a tall glass flower vase.  The top portion will be lighter in color and this can be taken off with a pipette, ling dropper (or even a glass turkey baster).  This lighter color shellac is the best to use either on the wood or to fix knots, etc.  If using Zinsser's, don't shake the can, handle it gently and let it sit for a couple of weeks after purchase to 'settle out'.  Then draw off the top 'clearer' portion to use.

 

  Fair sailing ...  Johnny

[Jaager]

25 minutes ago, Snug Harbor Johnny said:

'clear grain alcohol' sold in liquor stores because it is only 190 'proof' - meaning 5% water.

Johnny,

There is a reason that 95% ethanol (EtOH) is the strongest that can be easily had.

Ethanol forms a non-covalent but very strong bond with water that saturates at 5% water.  It takes serious energy to remove the last 5% - one method was boiling in benzene.  The ethanol then has to be in a sealed container - like a glass ampule.  With any exposure to air - the water vapor in air is "pulled" into the ethanol until it becomes a 95% solution again.  It essence, it is impractical to try for anything above 95%.

Denatured means that a chemical is added that makes you vomit if you drink it.   The federal tax on alcohol is close to $30.00 per gal of 95%.  This what "Thunder Road" was all about.  Denature it and there is no tax.

I have a gallon tin of 99% isopropanol (IsoOH)  -  My idea there was 1- no water  and 2- longer open times.  I am not sure that the difference is enough to matter though.  I wonder if something else was going on with the Everclear? 

 

Methanol -  if exposed to the same metabolic pathway as ethanol in the body produces formaldehyde and formic acid.  A small amount probably only damages the liver - where it is formed - a larger amount that allows some to get back into the blood stream - brain and optic nerve react poorly to exposure.