Bending timber and fibreglass sealing

[dragoncity]

1) Bending Timber : I've tried the amonia method with terrible results !! -- it did not work at all, can only assume
the type of timber being used did not react as it should -- I tried cedar, and balsa in 6x6 square sections about
300mm long, both broke when bending attempted. Decided to build "bread & butter" and carve the curve shapes.

I would suggest that you find out about steam bending methods which is most used in full sized timber boat building,
in a recent WOODEN BOATS MAG they had photos of a boat being build where the cross hull RIBS were being
bend _edge_
on after being steamed. ( ie: bending along the narrow (strongest) edge of the timber) . so the wood must have been
quite soft to achieve that pliability. However you must have quite strong holding methods to keep the timber in place
as its being fixed in place. (They used a special form with wedges & pegs - but I'm talking fullsized here :-)

2) Fibre Glass Resin finish : I have used the WEST Epoxy System ( USA product) as instructed and simply painted
over the
finished hull ( both inside and out) . WEST is a very thin epoxy so paints on very easily, unlike Glass Resin which
is somewhat thicker & goes off quicker.

If you want a really _strong_ finish on the outside of your hull, you should also use 'finishing tissue", which is a_very_
fine fibre glass "cloth" but like paper tissue. It a real bugger to handle however and takes a lot of care to use
sucessfully. The end results are excellent.

It is also possible to use "Timber Preserative and Reactive Dilutent Agent" which allows the resin to penetrate
into the timber and really water proof the hull.

3) glue - I use a terrific glue ( PurBond - made in Australia) which not only is waterproof but also expands to
fill gaps -- my favourite glue !!!

Good Luck

Brett S Hallett

[tbgray]

Tks Brett for the comeback I was beginning to think no one was around The
reason I was thinking of fiberglass resin was to not only seal inside @ out
but too add more strength @ I was going too add a pigment for my outside
color I don't think strenght is going to be too important because it is
really strong at this point already I am building plank @ frame I added some
extra support to the inside frames @ under the cross ribs At this point I
have it assembled @ shaped Have a few planks on the
deck to give it extra support while I plank the hull Have
just started that step Use Probond glue sounds the same
but dries slow Also using a Weldwood product Dries
fast, high strength(3800 lbs pr sq in) but doesn't fill @
is only water resistant Info re bending very helpfull Got me thinking I
might have to pause @ build a steamer @
do some experimenting Tks again 4 the comeback
Bob Hope BC

[Joe E Brown]

Bob,
For coating the hull Epoxy resin is a better choice than Polyester
resin for fiberglassing. I have been told that without using a
fiberglass mat that the resin has a high risk of cracking,
especially on models larger than 24 inches.

To apply 16 oz mat, or the super thin tissue type, I put a spray
adhesive on the hull, apply the mat, and then epoxy. For an easy
perfect finish use a piece of plastic, like a credit card, to scrape
off the excess epoxy on the first coat to remove bubbles and
creasing.

Have a good day,
Towboat Joe

[Derek Warner]

With the planking Decoy I tried pre [set] steam bending via simple boiling
water from the jug,
immersing the planks [cedar 1/8" wide x 3/8" high] in continually boiling
water steam on the
stove top, to microwaving a glass container with water & planks, but none of
the above
resulted in sufficient steam [heat] penetrating the timber, or by the time I
got to bend the planks
some were near cold

So to take a leaf from what Brett was saying is to ensure sufficient steam
[heat] is applied and
bend one plank at a time and it works

The most successful steam [heat] generator I found was to take the old
ceramic body electric
kitchen jug, drill a 1/2" diameter hole [carefully] thought the plastic lid,
fill with water & immerse
one plank at a time - carefully remove it after 5 minutes on the boil [cause
it's bloody hot] and
bend the individual planks around nominal radius or diameter formers

Much to the displeasure of my good wife, I found the preformed radii on
sections of our new
kitchen marble like bench tops were just perfect and naturally in close
proximity of the boiling
jug - Derek

[tbgray]

Morning PD's
Looking for something to fill in a few minutes? Interested in steam bending? Her's one for you "googles/ steam bending"
More than 64,000 sites came up Have a good day Bob

[Brian Peck]

My steam bending setup consists of a thriftshop kettle with a "T" connector
of 3 inch. galvanized pipe replacing the lid and a 3 foot length of pipe
attached to one end of the "T". The other outlet of the "T" is blocked off
and I just shove a rag in the open end of the 3 foot section of pipe. The
pipe needs something to elevate the strips of wood, I don't have anything
permanent yet.

To use just fill the kettle and set it on the stove and add your stock to be
bent.

I have successfully bent 24" X 1.5" X 3/16" stock with this setup. I was not
constructed with model making in mind but I will certainly use it for that
if I ever try a planked model.

Brian

[Mike Mayhew]

This topic is quite simple but many do not leave the timber in long enough. My own system is cheap, very safe and simple.
1.A household DIY wall paper stripper capable of 90 minutes steaming.
2. 55 inches of 3" plastic drain pipe. Ex gutter downpipe.
3. one fixed wooden bung, one removeable bung with a felt seal.
A small hole is drilled into the pipe 9" from the base and the wall paper stripper pipe where it meets the stripper pad removed and inserted into the hole. This must be a good fit. lay the pipe at 30 degrees from horizantal. base end down, fix the lower bung at the base and screw through the pipe.. place your timber in the pipe , put in bung at the top and switch on after filling stripper with clean water to the full level. remember steam is HOT and you can not always see it! For 12mm square I use two fillings ie/ 180 minutes at least no need to drill for nails as the timber is so soft. Use old welding type gloves!!!!!

Hope this helps. Waverley Mike. ps. Laser cut paddle wheels are a great success..£120 a set(pair)

[tbgray]

Hi Bert
Needed a break so thought I would check things out 380
dowels later I have the hull 25% planked Tempory burn out
Looking good though Looking forward to your reply re window's & door's Have an idea that will work to make my
own but want'd some input For those of you that are interested re bending with amonia It work's Soaked a piece
of 5/64x5/16 birch & twisted it 2 full turn's with no problems
or breakage It was like rubber Have I got your attention ??
BUT I soaked it in pure household amonia for at least 2 day's &it discoloured the wood Hint for anyone doing doweling After you have the dowel's sized &your ready to go
take about 6 to 8 & throw them in the microwave 4 about 1-1 1/2 min's power high depending on wood Had my break
gotta go make some more dowel's Have a good day Bob

[dragoncity]

Interesting, I tried the same technique , BUT even after a WEEK the timber would not bend !!
-- birch must really like amonia :-) Birch is not a common timber here ( Australia) but speciality
timber merchants might stock it.

Timber selection appears to be a vital part of this method,
dont know where you'd find information regarding what effect amonia has on a given timber type.

The amonia method is easier than steaming with less infrastructure required to use it.

On steaming, Mike M, uses a wallpaper stipper to source hi steam , I guess that one of those
'mini' household steame cleaning devices might work even quicker as they offer the steam under pressure,
should reduce the time requied.

Unless I misunderstood , Mikes unit took 6 hours ( 2 x 180 mins ?? ) to do the job, _much_ to slow for me !!!

Cheers,
Brett

[tbgray]

Hi Brett Re bending with ammonia I for one will be building a steamer
because it will be a lot faster & healthier than ammonia Those fumes can be
hard on the system even for short periods Steam will be much faster
(minutes versus days) & cheaper in the long run Approximately $20 Can. to
make Water is free where I live & a little bit of propane for the barby &
you can cook the steak's while you steam your wood Birch is much like a weed
here(BC Can) It is nice to work with wet or dry and if you screw up it burns
really good (excellent firewood) Birch & alder are often used for turning
spindles for furniture & falsely called maple The piece that I bent was
small & was soaked for at least two day's
That's a lot of Miller breaks It did twist well & once dry held it's shape
when released but it really discolored Have a good day Bob (buzzardcan)