Glue for dowels that join hull peices

[Andrew Chapman]

Hi all,

  Here is a question that I've been mulling over.  What sort of glue or approach is best when gluing sections of hull together in the bottle, when the hulls are aligned by dowels in one piece that fit into holes in the other.  I ask this, because I had two problems.  The first was when I used dilute white glue, but this expanded the hole or post or both, so that the fit was very tight, and I was very lucky to get the two hull pieces together.  The second problem was when I used 5-min epoxy, which I thought would not absorb into the wood, but then I think a touch of it got out of the holes, and between the two hull pieces, leaving a small permanent gap between my hull peices.

  I like a ship in the bottle, because the optical distortion of the glass is pretty forgiving for the odd imperfections, but what sort of glue do people usually use?

  Best wishes,

Andy 

[Onni]

I use white glue as well but haven’t really had any problems with it except that the hulls have to be joined together pretty quickly. I have never used epoxy to join them, that sounds a bit scary! To avoid expansion of the holes or dowels (cocktail sticks?) you could try using metal dowels cut from metal coat hangers. They are a slightly larger diameter than cocktail sticks but not greatly so. I’ve used them a couple of times and they work okay. 
onni

 

[John Fox III]

Greetings Andrew,

One thing to consider when gluing the pegs into holes is that air is trapped below the peg. One thing I do is score or cut a groove in the peg, so that as it's pushed into the hole air can escape through the groove. I've used both types of glues, and have had similar problems in the past when attaching upper to lower hull parts. The grooves help, but are not the perfect solution. Although much more difficult to do, one could place small blocks on the lower hull, just inside the edge of the hollowed out area on the underside of the upper hull, assuming one hollows out the area to run rigging lines through. Those blocks could align the upper hull as it's lowered so small pegs could be used to alleviate the air being trapped. I have never tried this, but just might if/when I build another bottle or light bulb model.

Anchor's A Weigh!

John Fox III

[JesseLee]

I have had the issue with white glue swelling the wood making things fit too tight compared to when it was dry. I have used metal wire instead of wood pegs or I would sometimes taper the end of the peg making it easier to start in the hole with the rest of the peg very slightly scraped a little narrower to allow for the swelling. This probably does the same thing as the grove John was talking about.

Jesse

[exwafoo]

Hi All,

Interesting conversation. I have found that tapering the peg and using an air escape hole (usually has a thread glued to the end of the peg to assist in getting the peg to locate in the hole passing through it)  helps considerably. The other thing I do is reduce the length of the peg just before putting in the bottle, its fine when building it when constant assembly/dissassembly may be required, but once in and glued up I don't think the full peg length is required. Once the hull pieces are in and located together, I place a small drop of thin CA glue on the hull joint in several places. It wicks in and is enough to give a good join. 

Best

Alan

[exwafoo]

Hi All,

Further to the above discussion on adhesives, I have been experimenting with an adhesive called Paraloid B72. I first saw this used on a Youtube Video of conservators at the British Museum doing some work on artefacts. A bit of research provided the following:

• Paraloid B72 is a glass-clear, non-yellowing, soluble plastic.
• It is a conservation grade adhesive and lacquer.
• The joint can be undone by the use of a drop of Acetone.

Supplied as beads, it is dissolved in Acetone to produce the required consistency:-

• In 50ml Acetone;
• 5gm makes 10% lacquer
• 10gm makes 20% lacquer
• 25gm makes 50% adhesive

In use, I got a couple of laboratory flasks with ground glass stoppers to mix in. I use pure Acetone from the Pharmacist, not nail varnish remover that has other ‘stuff’ in it.

I have two mixes, the 10% and 50% and use the 10% for fixing knots, stiffening thread, etc. The 50% mix I use for gluing up other stuff. It does not set straight away, so you get a bit of work time.

So far, I’ve been quite pleased with it. Like most glues, the pieces have to be set aside to dry. There have been a couple of failures, probably my fault somehow. The flasks need topping up with acetone now and again due to evaporation, so I marked the full mix level with indelible marker, only to find Acetone dissolved it if I spilt any on it, so a slight scratch with a sharpening stone does the job now. The big advantage I’ve found, is that unlike CA glue, it does not stick to me.

Time will tell if I keep on using it.

Best

Alan

[IgorSky]

I use bamboo pins.

[IgorSky]

Good idea, Alan! Please keep us informed about your experiments.